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Newsletter Italian Febbraio – Settembre 2024 Print E-mail


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February-September 2024


ICRANet Newsletter
Febbraio - Settembre 2024



SUMMARY
1. Comunicato stampa ICRA – ICRANet “Discovering Early Gamma-Ray Burst Emissions with Cosmological Time Dilation”, 9 maggio 2024
2.Il 6° meeting Galileo-Xu Guangqi (GX6), Aprile 19-24, Hengyang (Cina)
3. 17° meeting Marcel Grossmann (MG17), 7-12 luglio, Pescara (Italia)
4. La Notte Europea dei Ricercatori, 27 Settembre 2024
5. Prossimo evento: 3° Meeting Julio Garavito, 13-15 Novembre, Bucaramanga (Colombia)
6. Seminario del Prof. Ruffini "Il primo di sette Episodi di BdHNe", 17 Maggio 2024, Princeton University (USA).
7.Seminario del Prof. Gregory Vereshchagin e del Prof. Mikalai Prakapenia "Pair creation in hot electrosphere of compact astrophysical objects", 8 febbraio 2024, Pescara, Centro ICRANet (Italia)
8. Seminario del Prof. Ruffini a tema "The role of Black Holes in the Universe", 12 settembre 2024, Nizza (Francia)
9. ICRANet partecipa alla conferenza "Buchi neri e Cosmologia" (BHCos2024), 11-15 Marzo, Nassau (Bahamas)
10. ICRANet partecipa alla "Giornata del Planetario 2024", 17 marzo 2024, Ortona (Italia)
11. ICRANet partecipa alla 35° Mostra del Libro di Teheran (TIBF), 8-18 maggio, 2024
12. ICRANet partecipa alla "45° Assemblea Scientifica COSPAR", 13-21 luglio 2024, Busan (Corea del Sud)
13. ICRANet partecipa alla "XXIV Conferenza Astronomica Internazionale Gamow", 19-23 agosto 2024, Odesa (Ucraina)
14. Comunicato stampa di ICRANet "Anche in Italia è prevista un'aurora all'alba di sabato 11 maggio", 11 maggio 2024
15. Incontro tra il Prof. Ruffini e il Presidente della Regione Abruzzo, 16 settembre 2024
16. ICRANet partecipa al ricevimento all'Ambasciata cinese, 17 settembre 2024
17. ICRANet partecipa al ricevimento presso l'Ambasciata Armena, 25 settembre 2024
18. Il Prof. Ruffini tra il 2% degli autori più citati, secondo Elsevier
19. Pubblicazione dei dibattiti del 5° Meeting Zeldovich, 25 febbraio 2024
20. Pubblicazione di "Remo Ruffini Festschrift", 24 giugno 2024
21. Pubblicazione del libro "From “introducing the black hole” (1971) to the discoveries of an alive black hole in GRB 190114C (2021) a collection of documents prepared in occasion of the 17th Italo-Korean meetin", 6 settembre 2024
22. Tre conferenze sull'anno bisestile 2024 "“Julius Caesar's algorithm and Gregory XIII’s algorithm”, febbraio 2024
23. "Eclissi totale al massimo solare", osservazioni e conferenza, 6-8 aprile 2024
24. Giornate di Gerberto 2024: eruzioni solari a raggi X, emissioni di massa coronale e Aurore", 11-12 maggio 2024
25. Nuova "Convention de partenariat" tra ICRANet e la Città di Nizza, 22 aprile 2024
26. Rinnovo del protocollo di cooperation tra ICRANet e Università Nazione Kazaka al-Farabi (KAZNU), 2 maggio 2024
27. Nuovo protocollo di cooperazione tra ICRANet e l'università Gabriele d'Annunzio di Chieti-Pescara (Ud'A), 19 luglio 2024
28. Prof. Ruffini riceve il premio "Federico Valignani", 9 agosto 2024, Torrevecchia Teatina (Italia)
29. Appello congiunto a proposte "BRFFR - ICRANet 2025"
30. Visita di Liborio Stuppia, Rettore dell'Università Gabriele d'Annunzio di Chieti-Pescara (Ud'A) al centro ICRANet di Pescara, 25 marzo 2024
31. Visite scientifiche a ICRANet
32. Pubblicazioni recenti
 


1.ICRA – ICRANet comunicato stampa “Discovering Early Gamma-Ray Burst Emissions with Cosmological Time Dilation”, 9 maggio 2024
 

Gamma-ray bursts (GRBs), in a few seconds, release luminosities (in gamma-rays) comparable to the luminosity of all stars in the observable Universe, which makes them detectable to the dawn of galaxy and stellar formation. The repointing time of the XRT instrument onboard the Neil Gehrels Swift Observatory satellite has posed challenges in observing and studying GRB early X-ray emissions within ≈ 40 s after a GRB trigger by gamma-ray detectors. To address this issue, a team of scientists from ICRA and ICRANet adopted a novel approach that capitalizes on the cosmological time dilation in GRBs at the furthest boundaries of the observable Universe (with a cosmological redshift z ranging up to ∼ 9, i.e., only ∼ 500 million years after the big bang) and analyzed all the 368 GRBs with a measured distance in the Swift GRB catalog from the year 2005 until December 31st, 2023. This allowed to unveil the early X-ray emission in more than 220 GRBs and to validate the observation of the collapse of the carbon-oxygen (CO) core and the coeval newborn neutron star (νNS) formation triggering the GRB event in the binary-driven hypernova (BdHN) scenario. For three prototypical BdHNe I, it is shown the νNS spin-up due to supernova ejecta fallback and its subsequent slowing down due to the X-optical-radio synchrotron afterglow emission: a brief gravitational wave signal may separate the two stages due to a fast-spinning νNS triaxial-to-axisymmetric transition. By analyzing the long GRB redshift distribution for the different BdHN types, it is inferred that BdHNe II and BdHNe III may originate the NS binary progenitors of short GRBs. The paper has been published by The Astrophysical Journal on May 9th, 2024.

Important astronomical breakthroughs are often marked by the possibility of studying events occurring in the nearby Universe. On the contrary, in this work, it is presented how the observation of GRBs at a very high cosmological distance, by exploiting the cosmological time dilatation factor (1 + z) as a novel observational tool, can allow to enter the terra incognita of the very early GRB X-ray emission. This emission is currently inaccessible to the Swift/XRT detector in nearby events, which paradoxically would be more suitable to be studied: the significant instrumental delay of repointing the Swift/XRT detector following the GRB trigger, always bigger than ∼ 40 s expressed in the observer’s rest frame, prevents their early X-ray emission observations. However, due to the cosmological time dilation, a time interval ∆t measured on Earth corresponds to a time interval ∆t/(1 + z) in the cosmological source rest-frame, where z is its cosmological redshift. In other words, a phenomenon appearing to our instruments on the Earth to last 50 s may last 10 s if the source is at z = 4, like if we were observing the phenomenon in slow motion. Therefore, the time needed by Swift/XRT to start its observations after the GRB trigger may correspond to a much shorter actual time for sources with a large redshift z, exactly by a factor (1 + z). If, e.g., Swift/XRT starts to observe a GRB 60 s after the trigger in the observer frame, it is observing the X-ray signals emitted 60/(1 + z) s after the trigger in the cosmological rest-frame of the source. This corresponds to the possibility of observing 10 s after the trigger for a GRB with z = 5: the higher the GRB redshift, the shorter the time Swift/XRT can observe the source after the GRB trigger. This is clearly shown in Fig. 1 where it is presented the observational XRT time delays for all the 368 GRBs analyzed in the observer frame (upper panel) and the cosmological rest frame of each source (lower panel) as a function of their cosmological redshifts z. The green dotted line marks the 43.88 s minimum time delay in both panels, and the red dashed line in the bottom panel corresponds to this minimum delay rescaled as a function of the redshift of the source: 43.88/(1 + z) s. More than 220 sources, which were observed by Swift/XRT with a delay greater than 43.88 s, would not have been deemed interesting from the early X-ray emission point of view. However, thanks to their large cosmological redshift, when looking at their cosmological rest frames, it is clear that they have been observed less than 40 s after the trigger.

This new methodology allows the analysis of the very early transient X-ray regimes in GRB afterglows, which pose a stringent test for all GRB theoretical models. Within the context of the binary-driven hypernova (BdHN) model, it is applied to three BdHNe I at high redshift: GRB 090423 at z = 8.233, GRB 090429B at z ≈ 9.4, and GRB 220101A at z = 4.61. The cosmological time dilation enables observing the very early X-ray afterglow emission in these three GRBs (see, e.g., Fig. 2 and Fig. 3). It is thus validated the observation of the collapse of the carbon-oxygen (CO) core and the coeval newborn neutron star (νNS) formation triggering the GRB event in the BdHN scenario. It is also evidenced by the νNS spin-up due to supernova ejecta fallback and its subsequent slowing down due to the X-optical-radio synchrotron afterglow emission. A brief gravitational wave signal may separate the two stages due to a fast-spinning νNS triaxial-to-axisymmetric transition.

Equally important is the byproduct of analyzing the redshift distribution of all the 368 GRBs of the sample within the BdHN model. The similarity between the redshift distribution of BdHNe II and BdHNe III and that of short GRBs supports the hypothesis that the BdHNe II and BdHNe III remnants, after evolving into binary NS systems, could later become progenitors of short GRBs. This unique prediction of the BdHN scenario deserves further attention from an observational and a theoretical point of view.
Indeed, new missions with wide field-of-view soft X-ray instruments designed to simultaneously observe the GRB X-ray and gamma-ray emissions from the moment of the GRB trigger without any time delay, such as the THESEUS and HERMES missions, present a great opportunity.

For more information:
Contact: Prof. Remo Ruffini, Director, ICRANet | Phone: (+39) 085 2305 4201 | mobile: (+39) 339 475 2566 | E-mail: ruffini@icra.it
 
Reference article:
Probing electromagnetic-gravitational wave emission coincidence in a type I binary-driven hypernova family of long GRBs at very-high redshift"C.L. Bianco, M.T. Mirtorabi, R. Moradi, F. Rastegarnia, J.A. Rueda, R. Ruffini, Y. Wang, M. Della Valle, L. Li, S.R. Zhang; ApJ, 966 (2024) 219; DOI:https://doi.org/10.3847/1538-4357/ad2fa9
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FIG. 1. The Swift/XRT time delay in the observer’s frame (upper panel) and the cosmological rest-frame of the source (lower panel) as a function of their cosmological redshifts. The red points mark selected GRB sources. Details in Bianco et al., ApJ, 966 (2024) 219...
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FIG. 2. The Swift-XRT 0.3–10 keV luminosity of GRB 220101A in the cosmological rest-frame. The red line at 14.4 s corresponds to the first observation by XRT. It follows the end of the SN-rise and indicates the spin-up phase of the νNS by the fallback accretion of matter initially ejected by the SN. It is followed by the slowing down phase starting at 45 s, corresponding to the decaying part of the X-ray afterglow. The orange strip, which extends from 15.52 s to 45 s, indicates the data observable thanks to the cosmological effect at z = 4.61 duly considered in this article. One of the key questions to be addressed is the possibility that, at the end of the spin-up phase, a short time (≲ 1 s) process of gravitational wave emission occurs due to a transition to a triaxial configuration of the fast spinning νNS, with characteristic strain hc ∼ 10−23 at about kHz frequency. Details in Bianco et al., ApJ, 966 (2024) 219..
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FIG. 3. Time sequence of the Episodes identified in BdHNe I. The times are orders of magnitude estimates. Details in Bianco et al., ApJ, 966 (2024) 219..

Il comunicato stampa è stato ripubblicato anche da AAS.

2.Il 6° meeting Galileo-Xu Guangqi (gx6), Aprile 19-24, Hengyang (Cina)

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From April 19-24, 2024, ICRANet has organized the 6th Galileo-Xu Guangqi Meeting (GX6) in Hengyang, China. This meeting has been organized in conjunction with the 2024 Annual Meeting of the Division of Gravitation and Relativistic Astrophysics of the Chinese Physical Society, the most important gravity-related conference in China. These two meetings have been hosted jointly by the University of South China, the Hunan Normal University, the Lanzhou University, the Institute of Theoretical Physics at the Chinese Academy of Sciences (CAS), the Hunan University of Arts and Sciences, and the Purple Mountain Observatory of CAS.
Both these conferences provided a platform for researchers to communicate their new discoveries and latest progresses in the fields of gravitation and relativistic astrophysics. The contents will cover but are not limited to classical and quantum gravity theories, gravity experiments, black hole physics, gravitational waves, nuclear astrophysics, dark matter and dark energy, multi-messenger astronomy, and cosmology, and other cutting-edge scientific problems. Over 700 international scientists attended this 5 days meeting, coming in particular from Asia.
 
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fig. 4. The Swift/XRT time delay in the observer’s frame (upper panel) and the cosmological rest-frame of the source (lower panel) as a function of their cosmological redshifts. The red points mark selected GRB sources. Details in Bianco et al., ApJ, 966 (2024) 219...
 
Dal 19 al 24 aprile 2024, l'ICRANet ha organizzato il 6° meeting Galileo-Xu Guangqi (GX6) a Hengyang, in Cina. il meeting è stato organizzato in concomitanza con il 2024 Annual Meeting of the Division of Gravitation and Relativistic Astrophysics of the Chinese Physical Society, la più importante conferenza sulla relatività in Cina. entrambi i meeting sono stati organizzati nelle sedi dell'Università del Sud della Cina, l'Università normale di Hunan, l'Università Lanzhou, l'Istituto di Fisica teoretica presso l'Accademia Cinese delle scienze (CAS), l'UNiversità di Arte e Scienza di Hunan e l'Osservatorio della Montagna Purpurea presso il CAS.
Entrambe le conferenze hanno dato voce ai ricercatori, che hanno potuto condividere le recenti scoperte e gli ultimi progressi nel campo dell'Astrofisica Relativistica e Gravitazionale, con temi che hanno spaziato dalle teorie sulla gravità classica e quantica, esperimenti sulla gravità, fisica dei buchi neri, onde gravitazionali, astrofisica nucleare, materia oscura ed energia oscura, astronomia multimessaggera, cosmologia e altri innovativi quesiti fisici. Al meeting, durato 5 giorni, hanno partecipato più di 700 scienziati internazionali, provenienti soprattutto dall'Asia.
 
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fig. 5. foto di gruppo del meeting, con tutti i partecipanti eal centro il Prof. Remo Ruffini (Director of ICRANet)..
 
 
3.Il 17° meeting Marcel Grossmann (MG17), 7-12 luglio, Pescara (Italia)

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Dal 7 al 12 luglio 2024, a Pescara, presso l'Aurum e l'Università degli Studi G. D'Annunzio di Pescara (Ud'A), si è tenuto il 17° Meeting Marcel Grossmann (MG17) sugli Ultimi Sviluppi di Relatività Generale Teoretica e Sperimentale, Astrofisica e Teorie Del Campo Relativistico. Il meeting MG17 è stato organizzato dall'ICRA e dall'ICRANet, in collaborazione con il comune di Pescara e Ud'A. Al meeting hanno preso parte più di 700 scienziati, da oltre 45 paesi, che hanno presentato i più recenti e interessanti risultati sulla comprensione dell'Universo, possibili grazie alle equazioni di relatività generali di Albert Einstein. Molti scienziati provenienti da Paesi in via di sviluppo hanno potuto prendere parte alla conferenza grazie al supporto finanziario fornito dallo IUPAP. Il ricco programma della conferenza ha visto 41 presentazioni plenarie, 3 lezioni pubbliche e 64 sessioni parallele, per un totale di 631 contributi scientifici. il meeting ha avuto un successo oltre ogni aspettativa e ha confermato ancora una volta il suo ruolo fondamentale nel campo dell'Astrofisica Relativistica, oggetto di studio sin dal 1985 dall'ICRA presso l'Università La Sapienza di Roma e, negli ultimi anni, grazie alla collaborazione con l'ICRANet, a Pescara.
 
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Dal 1985, i Meeting Marcell Grossmann (sugli Ultimi Sviluppi di Relatività Generale Teoretica e Sperimentale, Astrofisica e Teorie Del Campo Relativistico) hanno l' obbiettivo di fornire l'opportunità di confrontarsi sugli ultimi sviluppi circa gravitazione, relatività generale e teorie del campo relativistico, ponendo l'accento sulle basi matematiche, predizioni fisiche e test sperimentali. Lo scopo di questi meeting è di sollecitare lo scambio tra scienziati, per approfondire la nostra conoscenza delle strutture spazio-tempo, e verificare lo stato degli esperimenti in corso, che mirano a testare la teoria gravitazionale einsteiniana, dalla Terra o dallo spazio. I meeting precedenti sono stati organizzati a Trieste (MG1: 1975, MG2: 1979), Shanghai ( (MG3: 1982), Roma (MG4: 1985, MG9: 2000, MG14: 2015, MG15: 2018), Perth (MG5: 1988), Kyoto (MG6: 1991), Stanford (MG7: 1994), Gerusalemme (MG8: 1997), Rio de Janeiro (MG10: 2003), Berlino (MG11: 2006), Parigi (MG12: 2009), Stoccolma (MG13: 2012), e online (MG16: 2021).

La cerimonia di apertura del meeting MG17 si è tenuta lunedì 8 luglio, alla presenza di Marco Marsilio, Presidente della Regione Abruzzo, e di Carlo Masci, sindaco di Pescara. Come ogni anno, i premi MG17 sono stati assegnati in una cerimonia ufficiale, tenutasi il 9 luglio. Quest'anno, i premi individuali sono stati assegnati a:
  • Prof. Di Li (Radiotelescopio FAST, Cina) "per i suoi rivoluzionari contributi alla definizione scientifica del radiotelescopio più sensibile le sue numerose innovazioni nel caratterizzare l'universo dinamico, che ha portato a misurazioni precise del campo magnetico interstellare e a sviluppi nel campo dei lampi radio veloci "

  • Prof. Christopher Lee Fryer (Los Alamos National Laboratory, USA) " per i suoi contributi all'innovativa e pioneristica simulazione teoretica e numerica, che hanno contribuito a migliorare la nostra conoscenza di supernove, lampi di raggi gamma, e l'evoluzione stellare
Il Premio all'Istituzione è andato al team CHIME/FRB, rappresentato dalla Prof.ssa Victoria Kaspi (McGill University, Canada) "per il rilevamento innovativo e l'analisi comprensiva di un grande gruppo di lampi radio veloci, contribuendo significativamente alle statistiche, incluse fonti ripetitive, potenziando la nostra comprensione della loro origine e applicazione nel tentativo di definire struttura e composizione dell'universo". La brochure dei Premi MG17 è consultabile al link: http://www.icra.it/mg/mg17/mg17_awards.pdf

Il vasto programma scientifico durato 5 giorni, con le presentazioni plenarie la mattina, tenutesi nella meravigliosa struttura dell' Aurum e le sessioni parallele pomeridiane, tenutesi sia all'Aurum che presso l'Università "D'Annunzio" di Pescara, ha portato ad un confrontosignificativo di nuovi risultati, discussioni accese su tematiche pìù calde incluse materia oscura ed energia oscura, tensioni cosmologiche, corpi compatti, transitori astrofisici, onde gravitazionali. Si è passati dai temi più tradizionali alle teorie alternative su gravità, gravità quantistica e gravitazione sperimentale. Le discussioni sono state alimentate dai rapporti sui risultati osservativi più recenti provenienti dai più grandi osservatori come ad esempio il "James Webb Space Telescope", strutture terrestri e sotterranei che operano in campi multimessenger come rilevatori di neutrini e onde gravitazionali. Particolare attenzione è stata dedicata al settore emergente dei metodi di intelligenza artificiale applicati all'analisi e l'interpretazione dei grandi dati raccolti dagli osservatori astrofisici operativi e in fase di progettazione.

Tutti gli abstract presentati alle sessioni parallele sono stati raccolti in un libro, disponibile sulla piattaforma Indico per MG17 al seguente link:https://indico.icranet.org/event/8/book-of-abstracts.pdf
Tre lezioni pubbliche sono state tenute nel sessioni serali da Prof. Wendy Freedman, Prof. Katherine Freese e Annapurni Subramanian.
 
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Group photo of the MG17 participants. Photo courtesy: Roberto Di Blasio..
 
I contributi elettronici del 17° Meeting Marcel Grossmann, tenutosi a Pescara dal 7 al 12 luglio 2024, verranno pubblicati da World Scientific. Gli editori saranno Remo Ruffini e Gregory Vereshchagin. Come consuetudine, i contributi delle plenarie saranno pubblicati su IJMPD. È iniziato il periodo per caricare i propri contributi. Si prega quindi di leggere le istruzioni per gli autori:https://indico.icranet.org/event/8/attachments/397/1170/instructions%20for%20authors.pdf Il limite è di 20 pagine, la scadenza è fissata al 31 ottobre 2024.

Sul canale Youtube di ICRANet sono disponibili le registrazioni delle varie sessioni (sessioni in plenaria e parallele, lezioni pubbliche e tavole rotonde). Qui il link al canale:https://youtube.com/playlist?list=PLr5RLbSWSonsaGpKxkAiy3C_yRkhwfrpv&si=tsHSI_QCH_ryqrOF Al meeting erano presenti diverse case editrici, in uno spazio dedicato alle mostre, tra cui Cambridge University Press, Universe, World Scientific e Cambridge Scientific Publishers.

Ogni sessione del meeting è stata trasmessa in tutto il mondo dai principali canali TV, siti e fonti stampa cinesi (https://www.icranet.org/documents/press_cinesi.pdf), italiani (https://www.icranet.org/documents/press_italiane.pdfe internazionali (https://www.icranet.org/documents/press_internazionali.pdf). Alcune notizie sono state viste da oltre 100 milioni di persone in Cina, confermando ancora una volta la rilevanza del meeting MG17 nel campo dell'Astrofisica Relativistica.

Sabato 6 luglio, prima dell'avvio del meeting MG17, il Comune di Pescara ha tenuto una conferenza stampa(https://www.ilpescara.it/attualita/meeting-marcel-grossman-7-12-luglio-presentazione-evento.html)
 
4.La Notte Europea dei Ricercatori, 27 Settembre 2024

Come ogni anno. in occasione della Notte Europea dei Ricercatori, ICRANet ha organizzato un evento per creare un dialogo tra cittadini e ricercatori. l'evento ha attratto molte persone, come di consueto, e ha offerto ai visitatori l'opportunità unica di prendere parte ad attività scientifiche, che miravano a mostrare il fascino della ricerca scientifica come carriera e per il suo importante impatto sulla società.
L'evento si è tenuto presso il centro ICRANet di Pescara e trasmesso online, alla presenza di due classi del liceo Galileo Galilei di Pescara, sotto la supervisione della Prof.ssa Tiziana Pompa (vincitrice del Premio Carlo Pace 2019).

Dopo le sue parole di benvenuto, il Prof. Ruffini, Direttore di ICRANet, ha presentato il suo discorso, dal titolo "I lampi di raggi gamma più estremi mai osservati, esplosi il 25 agosto: GRB 240825A". Il Prof. Ruffini ha mostrato il suo attuale lavoro su GRB 240825A, esploso il 25 agosto, posizionati esattamente al centro tra GRB lunghi e corti. Successivamente, il Prof. Yu Wang (Professore presso ICRANet e Presidente ICRA) ha presentato il suo discorso su "Intelligenza Artificiale nell'Astrofisica", mostrando l'importanza di usare e allenare l'Intelligenza Artificiale nell'Astrofisica, con la prospettiva di gestire enormi quantità di dati. Dopo di lui, il Prof. Costantino Sigismondi, Professore Associato ICRANet, ha illustrato il raggiungimento della massima luce solare nei mesi passati. In seguito alla parte teoretica, gli studenti sono stati accompagnati nel giardino della sede ICRANet per osservare il Sole con il telescopio ICRANet. In conclusione, il Prof. Ruffini ha ringraziato gli studenti per aver preso parte all'evento.
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Fig. 9 and 10: studenti del Liceo Galileo Galilei di Pescara osservano il Sole con il telescopio nel giardino ICRANet, 27 settembre 2024..
Tra gli ospiti anche Elisabetta Giannini, architetto presso l'Ordine degli Architetti di Pescara, e Laura Manfrini, dall'Accademia di Belle Arti de L'Aquila, a dimostrare l'importanza del legame tra scienza e arte.

Alle 20:30, il programma del meeting è andato avanti con una conferenza tenuta dal Prof. Remo Ruffini a tema "L'Universo dei Buchi Neri" nell'ambito dell'evento "Universo a Km0". La conferenza si è tenuta presso la Sala Incontri Valpolicella Benaco Banca a Valgatara (Italia).

Al link è disponibile la conferenza tenuta dal Prof. Ruffini:www.icranet.org/documents/talk_ruffini_valpolicella.mp4
5.Prossimo evento: 3° Meeting Julio Garavito, 13-15 Novembre, Bucaramanga (Colombia)
 
Siamo lieti di annunciare che l'ICRANet è organizzatore del 3° Meeting Julio Garavito, che si terrà dal 13 al 15 Novembre 2024 presso la Universidad Industrial de Santander (UIS), a Bucaramanga. L'evento scientifico, di cui l'UIS è co-organizzatore, sarà articolato in due conferenze dedicate alla memoria di Julio Garavito Armero, l'astronomo colombiano più famoso, alla cui memoria l'Unione Astronomica Internazionale ha dedicato il nome di uno dei crateri lunari. Al link tutte le informazioni sulle precedenti edizioni del meeting:https://www.icranet.org/index.php?option=com_content&task=view&id=1355

L'inaugurazione del 3° Meeting Julio Garavito si terrà martedì 12 Novembre 2024, a Bogotà, presso l'Università Pontificia Xaveriana. La cerimonia di apertura avrà luogo nell'Auditorium Carlos Corredor dell' l'Università Pontificia Xaveriana, seguita da interventi di 45 minuti. Al pranzo faranno seguito altri due interventi di 45 minuti, che saranno tenuti dagli organizzatori dell'evento.
 
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L'evento rispecchia l'impegno costante ai fini della cooperazione scientifica tra ICRANet e le università e i centri di ricerca colombiani. Molti i temi trattati, tutti legati a Astrofisica Relativistica, astronomia, planetologia, cosmologia e fisica solare. Temi chiave saranno stelle compatte (stelle di neutroni, stelle ibride, stelle di quark e nane bianche), buchi neri, nuclei di galassie attive e fenomeni ad alta energia, quali supernove, ipernove, lampi di raggi gamma e lampi radio veloci. Verranno trattami anche temi quali lenti gravitazionali, onde gravitazionali, fisica delle astroparticelle ad alta energia, materia oscura, cosmologia, modelli gravitazionali modificati e altri.
Di mattina verranno organizzate conferenze plenarie, mentre nel pomeriggio ampio spazio verrà riservato all'interazione tra studenti, professori e ricercatori, impegnati in sessioni poster e workshop. Le conferenze plenarie si terranno in forma ibrida, permettendo l'accesso tramite Zoom e sul canale Youtube di ICRANet. Sarà, inoltre, organizzata una lezione pubblica per rafforzare il nostro legame con la comunità.
 
6.Seminario del Prof. Ruffini "Il primo di sette Episodi di BdHNe", 17 Maggio 2024, Princeton University (USA).
 
Dal 16 al 18 Maggio 2024, il Prof. Remo Ruffini, Direttore di ICRANet, si è recato in visita negli Stati Uniti, dove venerdì 17 maggio 2024 alle ore 12 è stato invitato dal Prof. Lyman Page a tenere un seminario a tema "Il primo di sette Episodi di BdHNe" a Jadwin, nell'aula Joe Henry, presso la Princeton University. Questo Gravity Group Lunch Seminar della Princeton University si è tenuto nell'ambito del programma di collaborazione per l'astrofisica tra l'Istituto di Studi Avanzati e la Princeton University.
 
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Fig. 12: Lyman Page introduce Ruffini nell'aula Joe Henry presso la Princeton University, New Jersey, 17 maggio 2024..
 
Di seguito l'abstract:

The multimessenger GRBs data and the theoretical considerations of neutron stars (NS) and black holes (BH) have identified in a binary system composed of a 10 solar mass CO core and a companion NS the progenitors of GRBs and their associated supernovae (SN). The collapse of the CO core leads to a SN, resulting in a newly born NS (vNS). The accretion of SN ejecta onto the NS binary companion results in the formation of a BH over periods ranging from minutes to hours, while accretion onto the vNS leads to the synchrotron emission observed in the afterglow. Using GRB 190114C as a prototype, we demonstrate the consistency of the observed optical emission of the GRB afterglow with the magnitudes expected from the naked-eye observations of the 1054 SN . We address the first 630 days of the SN as reported in historical Chinese, Korean an possibly European records. Additionally, extrapolating GRB data originating from the vNS and the BH over 970 years offers the possibility of explaining the spectral distribution of the CRAB observed today. Some general conclusions are inferred. We also examine the Penrose Process, the largely unexplored physics of the irreducible mass, and the role of electrodynamical process versus the gravitational ones.

Il video del seminario:http://www.kaltura.com/tiny/e871e
7.Seminario del Prof. Gregory Vereshchagin e del Prof. Mikalai Prakapenia " Pair creation in hot electrosphere of compact astrophysical objects", 8 febbraio 2024, Pescara, Centro ICRANet (Italia).
 
On Thursday, February 8, 2024, Prof. Gregory Vereshchagin (ICRANet Faculty) and Prof. Mikalai Prakapenia (ICRANet Minsk) presented a seminar titled “Pair creation in hot electrosphere of compact astrophysical objects” with the following abstract:
The mechanism of pair creation in electrosphere of compact astrophysical objects such as quark stars or neutron stars is revisited, paying attention to evaporation of electrons and acceleration of electrons and positrons, previously not addressed in the literature. We perform a series of numerical simulations using the Vlasov-Maxwell equations. The rate of pair creation strongly depends on electric field strength in the electrosphere. Despite Pauli blocking is explicitly taken into account, we find no exponential suppression of the pair creation rate at low temperatures. The luminosity in pairs increases with temperature and it may reach up to L±∼1052 erg/s, much larger than previously assumed.

Giovedì 8 febbraio 2024, i Prof. Greogry Vereshchagin (ICRANet Faculty) e Mikalai Prakapenia (ICRANet Minsk) hanno presentato un seminario dal titolo "Pair creation in hot electrosphere of compact astrophysical objects” con il seguente abstract: The mechanism of pair creation in electrosphere of compact astrophysical objects such as quark stars or neutron stars is revisited, paying attention to evaporation of electrons and acceleration of electrons and positrons, previously not addressed in the literature. We perform a series of numerical simulations using the Vlasov-Maxwell equations. The rate of pair creation strongly depends on electric field strength in the electrosphere. Despite Pauli blocking is explicitly taken into account, we find no exponential suppression of the pair creation rate at low temperatures. The luminosity in pairs increases with temperature and it may reach up to L±∼1052 erg/s, much larger than previously assumed. Il seminario è basato sulla loro pubblicazione recente, dal titolo "Pair creation in hot electrosphere of compact astrophysical objects”, 2024
8.Seminario del Prof. Ruffini a tema "The role of Black Holes in the Universe", 12 settembre 2024, Nizza (Francia)
 
Dall'11 al 13 settembre 2024, il Prof. Remo Ruffini, Diretore di ICRANet, si è recato in visita presso la sede ICRANet di Nizza, a Villa Ratti. Nel corso della visita, giovedì 12 settembre 2024 alle ore 16, è stato invitato a tenere un seminario dal titolo " Black Holes in the Universe", presso il Museo di Belle Arti Jules Chéret di Nizza. Questo seminario si è tenuto nell'ambito dell'mostra " Berthe Morisot à Nice. Escales impressionnistes”, organizzata dal Museo in collaborazione con ICRANet. Di seguito un abstract: Les travaux développes à Princeton par John A. Wheeler et Remo Rufni en 1967 ont eu un éclat planétaire avec l'introducton conceptuelle du "Trou Noir" en astrophysique. Des intéressants anecdotes, qui se sont passés à la Vallée des Merveilles avec les Profs. Cécile Morette et Bryce DeWitt, seront mentionnés. Ensuite, la plus grande aventure scientifique jusqu'à aujourd’hui vient de se dérouler grâce à un numéro impressionnante d’observatoires dans l’espace ainsi que sur la surface terrestre, motivés par l’étude des Trous Noirs. Plusieurs Trous Noirs sont observés chaque jour dans tout l’Univers avec des masses de 10 à la 10 milliards de masses solaires. Parmi les plusieurs anecdotes, la préparation du Festschrift en l’honneur de Remo Ruffini à Villa Rat ainsi que les événements qui se sont déroules à Villa Rat par l’apposition des signatures par des éminents scientifiques et prix Nobel sur les murs de la Villa, seront présentés.
 
9. ICRANet partecipa alla conferenza "Buchi neri e Cosmologia" (BHCos2024), 11-15 Marzo, Nassau (Bahamas)
 
Il 15 marzo, i Prof. Ruffini (Direttore di ICRANet) e Prof. Jorge Rueda (ICRANet Faculty Professor e professore presso l'Università di Ferrara) sono stati invitati a tenere una lezione alla conferenza "Buchi Neri e Cosmologia" (BHCos 2024), tenutasi presso l'Università di Nassau alle Bahamas e online, dall'11 al 15 marzo 2024.
 
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La conferenza aveva come scopo quello di riunire esperti di fama mondiale e giovani ricercatori che studiano aspetti teoretici e osservazionali dei buchi neri. Durante la conferenza sono stati discussi temi quali Materia Oscura, Formazione della Struttura, Buchi Neri Primordiali, Astronomia della Onde Gravitazionali e Aspetti Quantici dei Buchi Neri. Il Prof. Rueda ha tenuto un discorso a tema " The black hole of binary-driven hypernovae powering gamma-ray bursts", mentre il tema del discorso del Prof. Ruffini era "On the Black Hole irreducible mass and the rotational energy extraction process". Qui l'abstract: The Nature of long and Short extragalactic Gamma Ray Bursts (GRBs) and of their associated Supernovae has been addressed within the Binary Driven Hypernovae model (BDHN). Seven new episodes of ultrarelativistic regimes, previously unknown in terrestrial or galactic observations, have been found. They are observed with the largest ever multi messenger effort. New theoretical directions are followed to identify the rotational energy extraction process in Black Holes: reexamining new fundamental issues related to the Penrose Process, the largely unexplored physics of the irreducible mass, and the role of electrodynamical process versus the gravitational ones.
 
10. ICRANet partecipa alla "Giornata del Planetario 2024", 17 marzo 2024, Ortona (Italia)
 
Domenica 17 marzo 2024, il Prof. Remo Ruffini, Direttore di ICRANet, e il Prof. Costantino Sigismondi, Professore associato di ICRANet, sono stati invitati a tenere una lezione in occasione della XXXIV Giornata del Planetario 2024, organizzata dall'Istituto Nautico IIS Acciaiuoli - Einaudi di Ortona (Abruzzo, Italia). Il Prof. Ruffini ha tenuto una lezione introduttiva sui recenti risultati dell'Astrofisica, e il Prof. Sigismondi ha tenuto una lezione a tema "Galileo, Jupiter's Satellites and the longitude problem".
 
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A seguito della conferenza, i Prof Ruffini e Prof. Sigismondi hanno visitato la scuola, il Planetario e la Nave-Scuola "San Tommaso", ancorata al porto di Ortona. Il Planetario di Ortona è dedicato al Prof. Antonio Malatesta, storico insegnante di Navigazione presso Istituto Nautico di Ortona. Installato nel 1964, il Planetario ha una cupola alta 6 metri, e può ospitare fino a 45 persone. Un unicum in Abruzzo, che attrae esperti, scienziati, studenti e appassionati di astronomia. Dal 1991, la Giornata del Planetario viene organizzata in Italia la domenica prima o dopo dell'equinozio di primavera. L'evento si tiene in contemporanea in tutti i principali Planetari italiani. Dal 1997, la Giornata del Planetario ha raggiunto la fama internazionale, come rappresentato dal logo comune adottato da tutti i Planetari partecipanti all'evento.
 
11.ICRANet partecipa alla 35° Mostra del Libro di Teheran (TIBF), 8-18 maggio, 2024
 
Dal 3 al 5 novembre 2021, ICRANet ha organizzato il meeting "ICRANet - Isfahan Astronomy Meeting. From the Ancient Persian Astronomy to Recent Developments in Theoretical and Experimental Physics, Astrophysics and General Relativity", il primo evento internazionale di ICRANet tenutosi in Iran, presso la Isfahan University of Technology (IUT) e online. Il discorso di apertura è stato tenuto da H.E. Mohammad ALi Zolfigol, allora Ministro della Scienza, della Ricerca e della Tecnologia della Repubblica Islamica dell'Iran. I risultati di questo meeting sono stati già pubblicati da Cambridge Scientific Publishers nel Eurasian Astronomical Society - Astronomical and Astrophysical Transactions, Volume 33, n° 3. La versione stampata dei dibattiti è stata recentemente pubblicata da Cambridge Scientific Publishers. Il volume "ICRANet-Isfahan Astronomy meeting: from ancient Persian astronomy to recent developments in theoretical and experimental Physics, Astrophysics and General Relativity", pubblicato da Cambridge Scientific Publishers, è stato presentato in una cerimonia ufficiale in occasione della 35° Fiera Internazionale del Libro (TIBF), che si terrà dall'8 al 18 maggio 2024, e acui il Prof. Remo Ruffini parteciperà con una presentazione online, insieme al Prof. Soroush Shakeri (Isfahan University of Technology) e a Janie Wardle (Presidente di Cambridge University Publisher).
 
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Fig. 15: panoramica della Fiera Internazionale del Libro di Teheran..
 
La Fiera Internazionale del Libro di Teheran si tiene ogni anno a maggio nella capitale iraniana. La prima edizione di questo evento culturale si tenne nel 1988, quando furono presentati 16mila libri. Questo evento culturale è diventato una pietra miliare nel suo genere in tutto il Medio Oriente e in Asia dopo ben 34 edizioni. Milioni i visitatori ogni anno, tra cui migliaia di studenti universitari, accademici e le loro famiglie. La fiera è uno degli eventi culturali più importanti in Iran.

Il sito della fiera: https://tibf.ir/en
12. ICRANet partecipa alla "45° Assemblea Scientifica COSPAR", 13-21 luglio 2024, Busan (Corea del Sud)
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Il 17 luglio 2024, il Prof. Ruffini (Direttore di ICRANet) è stato invitato a tenere una lezione in occasione della "45° Assemblea Scientifica COSPAR", tenutasi a Busan (Corea del Sud) dal 13 al 21 luglio 2024. Inaugurata nel 1958, l'Assemblea Scientifica COSPAR è passata da annuale a biennale dal 1980 e, negli ultimi quarant'anni, le assemblee tenutesi in anni pari sono state diventate di grande importanza accademica per gli scienziati studiosi di cosmologia e altri partecipanti esperti.

Per l'occasione il Prof. Ruffini ha tenuto un discorso dal titolo“On the Black Hole (BH) irreducible mass (Mirr) and the rotational energy extraction process”. Here below the abstract: The issue of the rotational energy extraction from BHs as the energy source of stellar mass BHs in Gamma-Ray Bursts (GRBs) and in BHs of 1010 stellar mass in AGNs is here analyzed in connection with the contribution of Rueda et al. and Bulanov et al. in this session. The fundamental BH formula by Christodoulou [1], Christodoulou and Ruffini [2], and S. Hawking [3] relates the BH mass-energy formula M to 3 parameters: 1) the angular momentum L, 2) the charge Q, and 3) the irreducible mass Mirr. The Mirr is related to the BH surface area S, monotonically increasing, by S = 16M2 irr. We first recall the BH properties as classic systems for mass larger than the Planck Mass. We review the three-particle ballistic process of Penrose extracting energy of an isolated Kerr BH in vacuum and recall as well the manyparticle generalizations. The constraints imposed on a pure gravitational extraction process are specifically evidenced. We then turn to the Kerr-Newman (KN) solutions and show how the energy source of GRBs, originating BHs, NSs, and SNs, as well as AGNs can be justified by relaxing the BH vacuum condition and the asymptotically flat solution by generalizing a Wald-Papapetrou solution in presence of plasma. We finally show how the irreducible mass is the classical alternative to the BH entropy.

The website of the meeting: https://cospar2024.org/
13. ICRANet ICRANet partecipa alla "XXIV Conferenza Astronomica Internazionale Gamow", 19-23 agosto 2024, Odesa (Ucraina)
 
Martedì 20 agosto 2024, il Prof. Ruffini (Diretore di ICRANet) è stato invitato a presentare una lezione plenaria durante i lavori della "XXIV Conferenza Astronomica Internazionale Gamow", tenutasi online da Odesa (Ucraina) dal 19 al 23 agosto 2024. La conferenza del 2024 celebra il 120° anniversario della nascita di George Gamow, uno dei grandi contributori alla rivoluzione fisica e astrofisica del 20° secolo. Quest'anno cade anche il 30° anniversario dalla prima Conferenza Gamow a Odesa, città dove lo scienziato nacque e svolse la sua carriera scientifica.
 
La conferenza ha concentrato l'attenzione sui trend contemporanei nello sviluppo della cosmologia e dell'astrofisica, soprattutto negli ambiti a cui Gamow contribuì attivamente.
Per l'occasione, il Prof. Ruffini ha tenuto un discorso dal titolo “The role of Fermi in the discussion of Gamow cosmology: an international implication”. Here below the abstract: We recall the work of Fermi in completing the cosmological nucleosynthesis and evidencing first the role of formation of the light element in cosmology, opening a new era in Relativistic Astrophysics of the Big Bang.

The website of the meeting: https://gamow.odessa.ua/
 
14. Comunicato stampa di ICRANet "Anche in Italia è prevista un'aurora all'alba di sabato 11 maggio", 11 maggio 2024
 
Le eruzioni solari sono fenomeni molto energetici e i due osservati il 10 maggio 2024 hanno raggiunto i 10^28 erg/s nella banda raggi (X4- class). L'esperto ICRANet di Fisica Solare, Costantino Sigismondi, ha prontamente organizzato un evento per osservare le due eruzioni di luce bianca, come per il Carrington Event nel 1859, dalle 6:30 alle 7:40 di venerdì 10 maggio, per poi presentare i risultati al liceo Galileo Galilei di Pescara lunedì 13 maggio. La NASA ha annunciato una forte tempesta geomagnetica nelle prime ore di sabato 11 maggio, che sarà possibile osservare nei cieli a Nord-Nord Est dalle ore 4 del mattina in tutta Europa, Italia compresa. Nei nostri cieli, a latitudini medie, sarà probabilmente visibile un'aurora rossastra, dovuta alla ionizzazione dell'atmosfera superiore, causata dai protoni provenienti dalle espulsioni di massa coronale che raggiungeranno il nostro Pianeta martedì 9 maggio. "Difficile distinguerla dall'inquinamento della luce" afferma Costantino Sigismondi, che l'ha avvistata nella tarda serata del 31 ottobre 2003 dal comune di Lanciano, "ma vale la pena svegliarsi per un evento astronomico unico!". Un evento ad alta energia così vicino alla Terra, più contenuto del potente GRB, ma capace di inviare raggi gamma in direzione del nostro paese, grazie alla riconnessione magnetica che rilascia una grande quantità di energia duranti i pochi minuti della durata dell'evento. ICRANet, per studiare il fenomeno, ha organizzato alcune osservazioni e alcune lezioni per gli studenti del Liceo Galileo Galilei di Pescara. L'evento, curato dall'astrofisico solare di ICRANet Costantino Sigismondi, coinvolge anche scuole superiori ERASMUS e studenti universitari:

Al link il comunicato stampa sul sito di ICRANet:https://icranet.org/communication/100524/press_release_Flare_en.pdf
15. Incontro tra il Prof. Ruffini e il Presidente della Regione Abruzzo, 16 settembre 2024
 
Il 16 settembre 2024, il Prof. Remo Ruffini, Direttore di ICRANet, si è recato in visita istituzionale a L'Aquila (Italia), presso il palazzo della Regione Abruzzo, per un incontro con il Dott. Marco Marsilio. All'incontro hanno preso parte anche il Dott. Roberto Santangelo (assessore regionale all'università e la ricerca), il Prof. Massimo della Valle (Presidente del Comitato Scientifico ICRANet, membro del consiglio d'amministrazione INAF) e il Prof. Yu Wang (Professore associato ICRANet e Presidente di ICRA).
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Fig. 17: da sinistra a destra: Prof. Yu Wang, Prof. Remo Ruffini, il Presidente della Regione Abruzzo Marco Marsilio, l'Assessore Roberto Santangelo e Prof. Massimo Della Valle durante la loro visita istituzionale del 16 settembre 2024..
 
L'incontro fa seguito al successo del 17° Incontro Marcel Grossmann, organizzato a luglio da ICRANet a Pescara, che ha visto la partecipazione di più di 700 scienziati da 52 paesi. Durante il corso dell'incontro istituzionale, è stato ribadito il ruolo centrale della Regione Abruzzo per gli scienziati e gli studiosi di Universo. Tutte le collaborazioni in corso includono anche i laboratori nazionali di fisica nucleare sotto il Gran Sasso, la ricerca nel Gran Sasso Science Institute (GSSI) e l'Osservatorio Astronomico Collurania di Teramo permettendo, dunque, studi ulteriori con il supporto e la collaborazione della Regione Abruzzo. Qui di seguito alcuni comunicati stampa sull'incontro istituzionale:
16. ICRANet partecipa al ricevimento all'Ambasciata cinese, 17 settembre 2024
 
Il 17 settembre 2024, il Prof. Remo Ruffini (Direttore di ICRANet) e il prof. Massimo della Valle (Presidente del Comitato Scientifico ICRANet, membro del consiglio d'amministrazione INAF) e il Prof. Yu Wang (Professore associato ICRANet e Presidente di ICRA) sono stati invitati al ricevimento in occasione del 75° anniversario dalla Fondazione della Repubblica Popolare Cinese, congiuntamente al 20° anniversario della Partnership Globale Strategica tra Italia e Cina. Il ricevimento, organizzato dall'ambasciatore cinese in Italia, Sua Eccellenza Jia Guide, si è svolto pr4esso l'Hotel Cavalieri Waldorf Astoria di Roma e ha visto la presenza di molte personalità di spicco della politica italiana.
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Fig. 18: da sinistra a destra: Prof. Massimo Della Valle e Prof. Remo Ruffini al ricevimento a Roma, 17 settembre 2024. Fig. 19: from the left to the right: da sinistra a destra: Prof. Massimo Della Valle e Prof. Yu Wang al ricevimento a Roma, 17 settembre 2024.
 
L'Ambasciatore Guide, da parte dell'Ambasciata Cinese in Italia, ci ha tenuto a esprimere la sua gratitudine a tutti i partecipanti, che hanno permesso lo sviluppo della Cina e hanno supportato le relazioni sino-italiane. Ha sottolineato come la Cina, in 75 anni di impegno e progresso, ha visto cambiamenti epocali, ha intrapreso con successo un cammino di sviluppo adatto alle condizioni del paese, raggiungendo i noti obiettivi di sviluppo e portando al mondo tante opportunità. L'alleanza globale strategica tra Cina e Italia, in 20 anni, ha dato i suoi frutti: la fiducia politica mutua è stata rinforzata e sono state promosse e sviluppate le cooperazioni multilaterali, benefiche per entrambi i paesi.
 
17. ICRANet partecipa al ricevimento presso l'Ambasciata Armena, 25 settembre 2024
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Fig.20 : Prof. Ruffini incontra l'Ambasciatrice Tsovinar Hambardzumyan al ricevimento del 25 settembre, 2024..
 
Il 25 settembre 2024, il Prof. Remo Ruffini (Direttore di ICRANet) e il Prof. Yu Wang (Professore associato ICRANet e Presidente di ICRA) sono stati invitati a un evento a Roma in occasione della Giornata Nazionale Armena, il 33° anniversario di indipendenza della Repubblica di Armenia. Il ricevimento è stato organizzato dall'Ambasciata Armena a Roma anche in occasione della fine del mandato di Sua Eccellenza l'Ambasciatrice Tsovinar Hambardzumyan. Ospiti, tra i tanti, il vice-premier e Ministro dei Trasporti e delle Infrastrutture Matteo Salvini. Presenti anche il Sottosegretario dello Stato per gli Affari Esteri e la Cooperazione Internazionale Giorgio Silli, il Viceministro della Giustizia Francesco Paolo Sisto e il Sottosegretario dello Stato Andrea Delmastro Delle Vedova, il Primo Presidente della Corte di Cassazione Margherita Cassano, il Presidente della Corte d'Appello Giuseppe Meliado, il Procuratore Generale militare Maurizio Block, il presidente del Gruppo Amicizia Italia-Armenia, procuratori e senatori di tutte le forze politiche al Parlamento Italiano, presidenti di commissioni, rappresentanti del governo italiano e della Presidenza, Ambasciatori accreditati in Italia, diplomatici, personalità di spicco del settore accademico, culturale, giornalistico, sanitario ed educativo, consoli onorari della Repubblica di Armenia a Milano, Venezia e Bari, e personalità della comunità armena.
18. Il Prof. Ruffini tra il 2% degli autori più citati, secondo Elsevier
Un recente aggiornamento del database pubblico di Elsevier, dove figurano più di 100,000 scienziati di spicco, mostra che il Prof. Remo Ruffini (Direttore di ICRANet), il Prof. Behzad Eslam Panah (ICRANet-Mazandaran, Iran) and tanti altri scienziati ICRANet figurano in questa lista di eccellenza. Questo database degli scienziati più citati, creato da Elsevier, fornisce informazioni standard su citazioni, h-index, co-autori e citazioni in paper con diverse posizioni autoriali. Gli scienziati sono suddivisi in 22 ambiti scientifici e 174 sottoambiti, disponibili per tutti gli scienziati con almeno 5 pubblicazioni. I dati circa la carriera sono aggiornati alla fine del 2023 e i dati di un singolo anno si riferiscono alle citazioni ricevute nel 2023. La selezione è effettuata sui migliori 100,000 scienziati con c-score (con o senza autocitazioni) o con grado percentile del 2% o superiore nel sottoambito. Questa versione (1) è basata su un'istantanea del 1° agosto 2024 di Scopus, aggiornata alla fine dell'anno di citazione 2023. Questo lavoro utilizza dati Scopus. I calcoli sono stati effettuati usando tutti i profili di autori Scopus al 1° agosto 2024.
19. Pubblicazione dei dibattiti del 5° Meeting Zeldovich, 25 febbraio 2024
 
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Con grande piacere vi annunciamo che i dibattiti del 5° Meeting Zeldovich, tenutosi a Erevan (Armenia) dal 12 al 16 giugno 2024, sono stati pubblicati in un'edizione speciale di Astronomy Reports (Astronomy Reports, Volume 67, Issue 2 supplement) come documento accessibile:https://link.springer.com/journal/11444/volumes-and-issues/67-2/supplement
Questi dibattiti includono 200 paper, per un totale di 218 pagine di volume stampato su tutti gli argomenti discussi al meeting, quali astrofisica multimessaggera, universo primordiale, strutture su larga scala, radiazione cosmica di fondo, stelle di neutroni, buchi neri, lampi di raggi gamma, supernove, ipernove, onde gravitazionali, quantistica e gravità. Ricordiamo che questo evento celebra anche l'80° anniversario dell'Accademia Nazionale delle Scienze della Repubblica di Armenia, i cui membri hanno profondamente contribuito al campo dell'Astrofisica Relativistica. I redattori dei dibattiti sono Gregory Vereshchagin, Remo Ruffini e Narek Sahakyan.
20. Pubblicazione di "Remo Ruffini Festschrift", 24 giugno 2024
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Con grande piacere vi annunciamo che MDPI, Universe, nel giugno 2024, ha pubblicato un'edizione speciale dal titolo "Remo Ruffini Festschrift", disponibile anche documento open access:https://www.mdpi.com/journal/universe/special_issues/J0M337731D
A Nizza, dal 16 al 18 maggio 2022, si è tenuta una conferenza in onore dell'ottantesimo compleanno di Remo Ruffini, a cui hanno partecipato oltre 90 scienziati. Hanno tenuto un discorso Rashid Sunyaev, Peter Predehl, Demetrios Christodoulou, Thibault Damour, Nathalie Deruelle, Roy Kerr, Tsvi Piran, Claus Laemmerzahl, Asghar Qadir, Chen Pisin, e Marco Tavani. Invitato speciale Agnès Rampal, rappresentante del sindaco di Nizza. Durante l'incontro di Nizza a Rashid Sunyaev e Peter Predehl è stato consegnato il Premio Marcel Grossmann per la loro missione Spectr–Roentgen–Gamma (SRG). Questa edizione speciale contiene 10 paper scritti da importanti accademici, partecipanti all'incontro e collaboratori, dedicati al Prof. Ruffini in occasione del suo 80° compleanno.
I redattori di questa edizione speciale sono sono Remo Ruffini, Jorge Armando Rueda Hernández, Narek Sahakyan e Gregory Vereshchagin.

21. Pubblicazione dell'articolo "From “introducing the black hole” (1971) to the discoveries of an alive black hole in GRB 190114C (2021) a collection of documents prepared in occasion of the 17th Italo-Korean meetin", 6 settembre 2024
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Con piacere vi annunciamo la pubblicazione dell'articolo "From “introducing the black hole” (1971) to the discoveries of an alive black hole in GRB 190114C (2021) a collection of documents prepared in occasion of the 17th Italo-Korean meeting", da parte di AIP Publishing (Volume 2874, Issue 1), in data 6 settembre 2024.
Questo contributo del Prof. Ruffini (https://doi.org/10.1063/5.0216360)è parte delle discussioni del 17° meeting Italo - coreano (IK17), organizzato con la collaborazione di ICRANet, tenutosi dal 2 al 6 agosto 2021, online e preso la Kunsan National University della Repubblica di Corea: https://pubs.aip.org/aip/acp/issue/2874/1
Gli editori di queste discussioni sono Stefano Scopel, Remo Ruffini, Bum-Hoon Lee, Sangpyo Kim, Hyung Won Lee, Bogeun Gwak e Wonwon Lee.

22. Tre conferenze sull'anno bisestile 2024 "“Julius Caesar's algorithm and Gregory XIII’s algorithm”, febbraio 2024
Durante l'anno bisestile 2024, il prof. Costantino Sigismondi, Professore associato di ICRANet, ha organizzato tre conferenze: il 24 febbraio a Lanciano - Antoniano, il 26 e 27 febbraio presso il centro ICRANet e presso l liceo Galileo Galilei di Pescara, e il 29 febbraio a Roma, presso la Cattedrale di S. Maria degli Angeli e dei Martiri. L'obiettivo principale di questi meeting era capire meglio cosa nascondono le due riforme del calendario civile, valide in tutto il mondo, entrambe concepite a Roma: l'algoritmo di Giulio Cesare e l'algoritmo di Gregorio XIII.
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Fig.25 : Emblema pontificio di Greogrio XIII Boncompagni Bononiense (Cappella Gregoriana, Basilica di S. Pietro, pavimento)..
Nel 46 a.C., il Senato romano, su richiesta del Pontifex Maximus, modificò l'antico calendario di Numa Pompilio, introducendo il giorno bi-sesto delle Calende di Marzo, ogni quattro anni: cadeva il 24 febbraio. Nello stesso giorno, nel 1582, con il bollettino papale "Inter Gravissimas", il Pontefice Gregorio XIII corresse l'algoritmo giuliano eliminando tre anni bisestili ogni quattro. Entrambe le riforme eliminarono la differenza di giorni astronomici creatasi nei secoli. Dietro Giulio Cesare c'era l'Egitto della dinastia tolemaica e il calendario romano, che era prettamente lunare (le idi, le none e le calende); dietro Gregorio XIII c'era Pasqua, che si stava spostando dalla Primavera all'Estate bisognava calcolare anche la Luna Piena in modo chiaro, semplice e inequivocabile per i secoli futuri.
In the historical presentation on the occasion of these 3 conferences, prof. Sigismondi addressed also the logical-mathematical aspect of the two algorithms and of their observational verification, which for the Gregorian reform, implied for over a century and a half the activity of the Calendar Commission, lastly chaired by Francesco Bianchini (1662-1729), the author of the Clementine Sundial at S. Maria degli Angeli e dei Martiri (1702), in order to obtain the observations supporting the Gregorian algorithm.
Tomba di Gregorio XII, creata da Camillo Rusconi nel 1623: https://youtu.be/cLkvZHd9ngE
Algoritmi da Giulio Cesare a Gregorio XIII:https://youtu.be/Gz5hUhwqYvQ
Dagli appunti di Galileo:https://youtu.be/tUipCo4dRtg
Identificazione e studio di Corone di polline attorno al Sole:https://youtu.be/62rXZp6VZns

23. “Eclissi totale al massimo solare", osservazioni e conferenza, 6-8 aprile 2024
La stagione delle eclissi è al suo massimo con la Grande Eclissi Americana, che coinvolgerà milioni di persone in quest'esperienza ancestrale e scientifica. Nel suo Vangelo, San Luca (Lc 23:45) descrisse l'oscurità del Venerdì Santo, nel giorno della morte di Gesù sulla croce, come una grande eclissi, probabilmente da lui vista nel 29 d.C. ad Antiochia, sua città d'origine. Angelo Secchi osservò l'eclissi del 1860 vicino al massimo solare, e si coordinò con Warren de la Rue per fotografare quest'eclissi e misurare il parallasse della corona solare e le protuberanze, per verificare che non si trattasse di eclissi lunare. Dal 1999, studiamo le eclissi come metodo per misurare accuratamente il diametro solare, secondo una ricerca avviata nel XIX secolo dall'Osservatorio di Roma, in connessione con IAU Solar Eclipses Working Group, prima diretto da Jay Pasachoff (1943-2022), che partecipò alle precedenti edizioni di questo meeting. Questa eclissi ci dà l'occasione di raccogliere nuove informazioni e discutere delle vecchie, per scoprire i vari aspetti della variabilità solare e metterli in relazione al cambiamento climatico.
All'evento hanno partecipato esperto dell'ambito e il tema principale della discussione è stato il cambiamento climatico: le variazione osservabile del diametro solare e della corona solare al massimo solare. Al link il video della conferenza:https://youtu.be/TYYBcJTGczY
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Fig.26 : from M. Cimino, Le variazioni del diametro solare osservate all'Osservatorio di Roma, Accademia Nazionale dei Lincei, 1953. Fig. 27: Corona solare durante l'eclissi del 1860 a Desierto de las Palmas (Spagna), disegnata da Padre Angelo Secchi SJ.
Le onde dell'equinozio sizigiale sono quest'anno le più larghe (Newton, Principia, 1687) e,con l'eclissi in corso, abbiamo l'occasione di osservare i suoi effetti gravitazionali sul livello del mare, il cui segnale è solitamente disturbato dalle sesse metereologiche. Osservazioni oceanografiche fatte a Ortona (Istituto Nautico), Pescara e Ostia comparano l'evento astronomico.
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Fig.28 : Secche e maree (https://www.icra.it/solar/2008/ocean.pdf) Istituto Nautico di Ortona: XXXIV Giornata del planetario, maree dell'equinozio sizigiale: rilevazioni effettuate a Pescara nei tre giorni precedenti l'eclissi (https://www.youtube.com/playlist?list=PLJaer2KV4928x6gfx4N1jcbELVFi4hczd .
 
24. “Giornate di Gerberto 2024: eruzioni solari a raggi X, emissioni di massa coronale e Aurore", 11-12 maggio 2024
  • 9 Visita Erasmus allo Gnomone Clementino con macchie solari e spettroscopia LIBS (Roma, S. Maria degli Angeli)
  • 10 Osservazione di due eruzioni solari di classe X-4 (Roma, ITIS Galileo Ferraris)
  • 11 Osservazione dell'Aurora Boreale e dell'alba (ICRANet Pescara)
  • 12 Osservazione dell'Aurora Boreale e dell'alba (ICRANet Pescara)
  • 13 Raggi X classe X, eruzioni solari, CME e aurore, Liceo Galilei Pescara
  • 17 Attività solare nei millenni (Video conferenza attività solare nei millenni: https://youtu.be/V4hn-wWSJGE
Dopo una serie di CME ed eruzioni solari di raggi X, i modelli della NASA prevede un'aurora osservabile prima dell'alba di sabato 11 e domenica 12 maggio 2024. Il magnifico sistema AR3664 è stato osservato in tutto il mondo, anche sulla meridiana di S. Maria degli Angeli a Roma il 9 maggio, perché coinvolge più del 20% del diametro solare.
Qui i video di questo evento peculiare (per la prima volta in 25 annni) registrato durante una visita ERASMUS alla Basilica:
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Fig.29 : AR may 9 maggio 2024 (Osservatorio Astrofisico di Asiago). Fig. 30: The Sun in H-alpha and the AR 3664 on May 09 2024 (Asiago Astrophysical Observatory). Fig. 31: Immagine visibile scattata con telescopio 25 cm Newton Urania alle 8:44 a.m. a Roma (C. Sigismondi), ITIS Galileo Ferraris e immagine ingrandita di H-alpha scattata dall' Osservatorio Astrofisico di Asiago alle 8:5e (P. Ochner) il 10 maggio 2024.
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Fig.32 : Osservazioni del Sole, 10 maggio 2024 alle 09:30. Fig. 33: foto di Matteo Di Vito 5D Liceo Galilei, Pescara. Fig. 34:Pescara, ‘Aurora Point’, spiaggia pubblica Nave di Cascella, dove è stata osservata l'Aurora Boreale.

25. Nuova " Convention de partenariat" tra ICRANet e la Città di Nizza, 22 aprile 2024
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OIl 22 aprile 2024, ICRANet ha firmato un accordo di partenariato con la città di Nizza, per il Museo delle Belle Arti Jules Chèret.
Lo scopo dell'accordo è l'organizzazione congiunta tra il Museo delle Belle Arti Jules Chèret e ICRANet di attività, eventi di natura culturale destinati a un pubblico il più ampio possibile. Questo verrà svolto nel rispetto delle normative vigenti in materia di sicurezza: tour guidati e workshop speciali, conferenze, simposi, tavole rotonde e giornate di studio.
La convenzione è stata firmata dal Sindaco di Nizza, Christian Estrosi, e dal Prof. Ruffini, Direttore di ICRANet.
26. Rinnovo del protocollo di cooperation tra ICRANet e Università Nazione Kazaka al-Farabi (KAZNU), 2 maggio 2024
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l 2 maggio 2024 è stato rinnovato l'Accordo di Cooperazione tra ICRANet e l'Università Nazione Kazaka al-Farabi (KAZNU). Il rinnovo è stato firmato da Aitzhanova Zhamila (Membro del Consiglio del Vice-rettore per la Ricerca e l'Innovazione della KAZNU), Prof. Abishev Medeu (KAZNU), Prof. Remo Ruffini (Direttore di ICRANet) e Prof. Jorge Rueda (ICRANet Professore associato). L'accordo sarà valido per ulteriori 5 anni e le principali attività congiunte da sviluppare sono: ricerca congiunta su argomenti scientifici di interesse per entrambe le parti, organizzazione di eventi scientifici bilaterali ed eventi pratico-scientifici, scambio di esperienze tra impiegati della ricerca e dell'istruzione, pubblicazione di lavori scientifici congiunti su riviste internazionali e scambio di pubblicazioni, materiale didattico e lezioni.
Il testo dell'accordo:http://www.icranet.org/icranet-kazakhstan
27. Nuovo protocollo di cooperazione tra ICRANet e l'università Gabriele d'Annunzio di Chieti-Pescara (Ud'A), 19 luglio 2024
Il 19 luglio 2024, ICRANet ha firmato un nuovo protocollo di cooperazione con l'università Gabriele d'Annunzio di Chieti-Pescara (Ud'A) in Abruzzo (Italia). Il Protocollo di Cooperazione è stato firmato da Prof. Liborio Stuppia (Rettore di Ud'A), Prof. Piero di Carlo (Ud'A), Prof. Remo Ruffini (Direttore di ICRANet) e Prof. Jorge Rueda (Professore Associato ICRANet).
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L'accordo sarà valido per 5 anni e le principali attività congiunte da sviluppare sono: scambio istituzionale di studenti laureati in triennale e magistrale, ricercatori e docenti, sviluppo di attività di insegnamento e/o ricerca in relazione alle aree di interesse e specializzazione di entrambe le organizzazioni, organizzazione di simposi, seminari, conferenze e corsi brevi, promozione e supporto di eventi culturali e tecnico-scientifici e attività aperte al pubblico; sviluppo di opportunità di istruzione per docenti universitari e ricercatori, l'organizzazione di corsi e attività di formazione, nonché lo sviluppo di aree di ricerca interistituzionali associate ai programmi di laurea locali; la promozione di pubblicazioni congiunte; la realizzazione di iniziative per la società civile attraverso l'estensione dell’attività accademica; scambio di informazioni sulle attività didattiche e di ricerca delle due istituzioni firmatarie e portare avanti richieste per i programmi di sovvenzione internazionali per promuovere progetti di ricerca congiunti o implementare programmi di mobilità.
28.Prof. Ruffini riceve il premio "Federico Valignani", 9 agosto 2024, Torrevecchia Teatina (Italia)
Il 9 agosto 2024, Prof. Remo Ruffini, Direttore di ICRANet, è stato insignito del premio "Federico Valignani", in occasione della prima edizione di questo premio, assegnato durante la XXIV edizione del Festival Lettera d'Amore, promosso dal Comune di Torrevecchia Teatina (Italia), il Museo Lettera d'Amore e la Regione Abruzzo.
Il premio è stato assegnato al Prof. Ruffini dal Comitato Scientifico "per aver fatto della scienza un valore e, avendo raggiunto grandissimi risultati, per il merito di aver continuato il suo magistero valutando ed educando i migliori giovani studenti da tutto il mondo nel proprio ambito di ricerca".
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Fig.38 and Fig.39 : Prof. Ruffini riceve il premio “Federico Valignani”, in occasione della prima edizione di questo premio, assegnato durante la XXIV edizione del Festival Lettera d'Amore, promosso dal Comune di Torrevecchia Teatina (Italia), 9 agosto 2024. .

29. Appello congiunto a proposte "BRFFR - ICRANet 2025"
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Il 26 aprile 2024, la Fondazione Bielorussa per la Ricerca Fondamentale (BRFFR) e ICRANet hanno emesso un invito congiunto a presentare proposte per progetti di ricerca di base congiunta in Astrofisica Relativistica. Le aree di interesse dell'appello sono Astrofisica Relativistica, Cosmologia e Gravitazionalità.
Le iscrizioni congiunte di team di ricerca internazionali, ivi compresi scienziati bielorussi, dovranno essere presentate contemporaneamente usando i moduli approvati da entrambe le organizzazioni: team bielorussi si iscrivono presso la BRFFR, quelli internazionali presso ICRANet.
La durata del progetto è di massimo due anni e la scadenza per le iscrizioni è il 5 novembre 2024.
Per maggiori informazioni sull'annuncio e per scaricare il modulo di iscrizione, al link:https://www.icranet.org/index.php?option=com_content&task=view&id=1447

30. Visita di Liborio Stuppia, Rettore dell'Università Gabriele d'Annunzio di Chieti-Pescara (Ud'A) al centro ICRANet di Pescara, 25 marzo 2024
Il 25 marzo 2024, il Prof. Liborio Stuppia, Rettore dell'Università Gabriele d'Annunzio di Chieti-Pescara (Ud'A) si è recato in visita presso il centro ICRANet di Pescara, insieme al Prof. Angelo Cichelli, Direttore della Scuola Superiore Ud'A e al Prof. Piero di Carlo di Ud'A.
Durante la visita, hanno incontrato il Prof. Remo Ruffini, Direttore di ICRANet, che li ha accompagnati in un estensivo tour del centro, mostrando loro la biblioteca ICRANet e spiegando i più importanti risultati e le attuali ricerche del centro. Il Rettore ha incontrato anche i dipendenti ICRANet, i Professori e gli studenti, che hanno raccontato il loro importante lavoro e la loro esperienza qui a Pescara.
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Fig.41 and Fig.42 : Il Rettore Liborio Stuppia, Prof. Angelo Cichelli e Prof. Piero Di Carlo in visita al Centro ICRANet di Pescara, guidati dal Prof. Remo Ruffini, 25 marzo 2024. .

31. Scientific visits to ICRANet
  • Mikalai Prakapenia (ICRANet Minsk), 5-16 febbraio, 2024; 28 maggio –8 giugno, 2024
  • Rahim Moradi (Istituto di Fisica delle Alte Energie - Accademia Cinese delle Scienze IHEP CAS), 9-26 febbraio, 2024
  • Fatemeh Rastegarnia (Istituto di Fisica delle Alte Energie - Accademia Cinese delle Scienze IHEP CAS), 9-26 febbraio, 2024
  • Vincenzo Guidi (Univeristà di Ferrara), 12 marzo, 2024
  • Paolo Natoli (Univeristà di Ferrara), 12 marzo, 2024
  • Prof. Costantino Sigismondi (Professore ordinario ICRANet, ITIS Galileo Ferraris Roma), 5-7 aprile, 2024; 14-14 aprile, 2024; 24-29 aprile, 2024; 10-13 maggio, 2024; 15-16 giugno, 2024; 27-28 settembre, 2024;
  • Shurui Zhang (USTC, Università di Ferrara), 10-26 aprile, 2024; 3-11 settembre, 2024
  • Dr Stanislav Komarov (Belarusian State University, ICRANet center a Minsk - Bielorussia), 3-18 maggio, 2024
  • Nelson Alonso Velandia Heredia (Pontificia Universidad Javeriana), 23-25 giugno, 2024
  • Galileo Violini (Pontificia Universidad Javeriana), 23-25 giugno, 2024
  • Carlos Raul Arguelles (Universidad Nacional de La Plata, Argentina), giugno 30- luglio 14, 2024
  • Mohammad Seyed Taghi Mirtorabi (Alzahra University - Iran), luglio 6- agosto 13, 2024
  • Giorgio Torrieri (Universidade Estadual de Campinas), luglio 12-18, 2024
  • Mohammad Gadri (Università di Tripoli), luglio 29- agosto 5, 2024
  • Massimo Della Valle, 16-17 settembre, 2024
Durante le loro visite, gli scienziati hanno avuto l'opportunità di parlare della loro ricerca scientifica e di avere uno scambio fruttuoso con altri ricercatori ICRANet da diverse parti del mondo.

32. Pubblicazioni recenti
 
N. Sahakyan, D. Bégué, A. Casotto, H. Dereli-Bégué, P. Giommi, S. Gasparyan, V. Vardanyan, M. Khachatryan, and A. Pe'er, Modeling Blazar Broadband Emission with Convolutional Neural Networks. II. External Compton Model, published on The Astrophysical Journal, Volume 971, Issue 1, on August 6, 2024.
 
In the context of modeling spectral energy distributions (SEDs) for blazars, we extend the method that uses a convolutional neural network (CNN) to include external inverse Compton processes. The model assumes that relativistic electrons within the emitting region can interact with and up-scatter external photons originating from the accretion disk, the broad-line region, and the torus, to produce the observed high-energy emission. We trained the CNN on a numerical model that accounts for the injection of electrons, their self-consistent cooling, and pair creation-annihilation processes, considering both internal and all external photon fields. Despite the larger number of parameters compared to the synchrotron self-Compton model and the greater diversity in spectral shapes, the CNN enables an accurate computation of the SED for a specified set of parameters. The performance of the CNN is demonstrated by fitting the SED of two flat-spectrum radio quasars, namely 3C 454.3 and CTA 102, and obtaining their parameter posterior distributions. For the first source, the available data in the low-energy band allowed us to constrain the minimum Lorentz factor of the electrons, ϓmin, while for the second source, due to the lack of these data, ϓmin = 102 was set. We used the obtained parameters to investigate the energetics of the system. The model developed here, along with one from Bégué et al., enables self-consistent, in-depth modeling of blazar broadband emissions within a leptonic scenario.

D. Bégué, N. Sahakyan, H. Dereli-Bégué, P. Giommi, S. Gasparyan, M. Khachatryan, A. Casotto, and A. Pe'er, Modeling Blazar Broadband Emission with a Convolutional Neural Network. I. Synchrotron Self-Compton Model, published on The Astrophysical Journal, Volume 963, Issue 1 on February 29, 2024.
 
Modeling the multiwavelength spectral energy distributions (SEDs) of blazars provides key insights into the underlying physical processes responsible for the emission. While SED modeling with self-consistent models is computationally demanding, it is essential for a comprehensive understanding of these astrophysical objects. We introduce a novel, efficient method for modeling the SEDs of blazars by the mean of a convolutional neural network (CNN). In this paper, we trained the CNN on a leptonic model that incorporates synchrotron and inverse Compton emissions, as well as self-consistent electron cooling and pair creation–annihilation processes. The CNN is capable of reproducing the radiative signatures of blazars with high accuracy. This approach significantly reduces the computational time, thereby enabling real-time fitting to multiwavelength data sets. As a demonstration, we used the trained CNN with MultiNest to fit the broadband SEDs of Mrk 421 and 1ES 1959+650, successfully obtaining their parameter posterior distributions. This novel framework for fitting the SEDs of blazars will be further extended to incorporate more sophisticated models based on external Compton and hadronic scenarios, allowing for multimessenger constraints in the analysis. The models will be made publicly available via a web interface at the Markarian Multiwavelength Data Center to facilitate self-consistent modeling of multimessenger data from blazar observations.

N Sahakyan, G Harutyunyan, S Gasparyan, D Israyelyan, Broad-band study of gamma-ray blazars at redshifts z = 2.0-2.5, published in Monthly Notices of the Royal Astronomical Society, Volume 528, Issue 4 on January 31, 2024.
High redshift blazars are among the most powerful non-explosive sources in the Universe and play a crucial role in understanding the evolution of relativistic jets. To understand these bright objects, we performed a detailed investigation of the multiwavelength properties of 79 γ-ray blazars with redshifts ranging from z = 2.0 to 2.5, using data from Fermi LAT, Swift XRT/UVOT, and NuSTAR observations. In the γ-ray band, the spectral analysis revealed a wide range of flux and photon indices, from 5.32 × 10−10 to 3.40 × 10−7 photon cm−2 s−1 and from 1.66 to 3.15, respectively, highlighting the diverse nature of these sources. The detailed temporal analysis showed that flaring activities were observed in 31 sources. Sources such as 4C+71.07, PKS 1329-049, and 4C + 01.02, demonstrated significant increase in the γ-ray luminosity and flux variations, reaching peak luminosity exceeding 1050 erg s−1. The temporal analysis extended to X-ray and optical/ultraviolet (UV) bands, showed clear flux changes in some sources in different observations. The time-averaged properties of high redshift blazars were derived through modeling the spectral energy distributions with a one-zone leptonic scenario, assuming the emission region is within the broad-line region (BLR) and the X-ray and γ-ray emissions are due to inverse Compton scattering of synchrotron and BLR-reflected photons. This modeling allowed us to constrain the emitting particle distribution, estimate the magnetic field inside the jet, and evaluate the jet luminosity, which is discussed in comparison with the disc luminosity derived from fitting the excess in the UV band.

P. Giommi1,2,3, N. Sahakyan4,5, D. Israyelyan4, and M. Manvelyan4, The Remarkable Predictive Power of Infrared Data of Blazars, published in The Astrophysical Journal, Volume 963, Issue 1 on February 28, 2024.
Blazars are the brightest and most abundant persistent sources in the extragalactic γ-ray sky. Due to their significance, they are often observed across various energy bands, where the data of which can be used to explore potential correlations between emission at different energies, yielding valuable insights into the emission processes of their powerful jets. In this study we utilized IR data at 3.4 and 4.6 μm from the Near-Earth Object Wide-field Infrared Survey Explorer Reactivation Mission, spanning 8 yr of observations, X-ray data from the Neil Gehrels Swift Observatory collected throughout the satellite's lifetime, and 12 years of γ-ray measurements from the Fermi Large Area Telescope's all-sky survey. Our analysis reveals that the IR spectral slope reliably predicts the peak frequency and maximum intensity of the synchrotron component of blazar spectral energy distributions, provided it is uncontaminated by radiation unrelated to the jet. A notable correlation between the IR and γ-ray fluxes was observed, with the BL Lacertae subclass of blazars displaying a strong correlation coefficient of r = 0.80. IR band variability is more pronounced in flat spectrum radio quasars than in BL Lacertae objects, with mean fractional variability values of 0.65 and 0.35, respectively. We also observed that the synchrotron peak intensity of intermediate-high-energy-peaked objects can forecast their detectability at very high γ-ray energies. We used this predicting power to identify objects in current catalogs that could meet the detection threshold of the Cerenkov Telescope Array extragalactic survey, which should encompass approximately 180 blazars.

Dhurba Tripathi, Paolo Giommi, Adriano Di Giovanni, Rawdha R. Almansoori, Nouf Al Hamly, Francesco Arneodo, Andrea V. Macciò, Goffredo Puccetti, Ulisses Barres de Almeida, Carlos Brandt, Simonetta Di Pippo, Michele Doro, Davit Israyelyan, A. M. T. Pollock, and Narek Sahakyan, Firmamento: A Multimessenger Astronomy Tool for Citizen and Professional Scientists, published in The Astronomical Journal, Volume 167, Issue 3 on February 19, 2024.
 
Firmamento (https://firmamento.hosting.nyu.edu is a new-concept, web-based, and mobile-friendly data analysis tool dedicated to multifrequency/multimessenger emitters, as exemplified by blazars. Although initially intended to support a citizen researcher project at New York University–Abu Dhabi, Firmamento has evolved to be a valuable tool for professional researchers due to its broad accessibility to classical and contemporary multifrequency open data sets. From this perspective Firmamento facilitates the identification of new blazars and other multifrequency emitters in the localization uncertainty regions of sources detected by current and planned observatories such as Fermi-LAT, Swift, eROSITA, CTA, ASTRI Mini-Array, LHAASO, IceCube, KM3Net, SWGO, etc. The multiepoch and multiwavelength data that Firmamento retrieves from over 90 remote and local catalogs and databases can be used to characterize the spectral energy distribution and the variability properties of cosmic sources as well as to constrain physical models. Firmamento distinguishes itself from other online platforms due to its high specialization, the use of machine learning and other methodologies to characterize the data, and for its commitment to inclusivity. From this particular perspective, its objective is to assist both researchers and citizens interested in science, strengthening a trend that is bound to gain momentum in the coming years as data retrieval facilities improve in power and machine-learning/artificial-intelligence tools become more widely available.
 

MAGIC collaboration, Constraints on Lorentz invariance violation from the extraordinary Mrk 421 flare of 2014 using a novel analysis method, published in Journal of Cosmology and Astroparticle Physics, Volume 2024, Issue 07 on July 19, 2024.
 
The Lorentz Invariance Violation (LIV), a proposed consequence of certain quantum gravity (QG) scenarios, could instigate an energy-dependent group velocity for ultra-relativistic particles. This energy dependence, although suppressed by the massive QG energy scale E_QG, expected to be on the level of the Planck energy 1.22 × 1019 GeV, is potentially detectable in astrophysical observations. In this scenario, the cosmological distances traversed by photons act as an amplifier for this effect. By leveraging the observation of a remarkable flare from the blazar Mrk 421, recorded at energies above 100 GeV by the MAGIC telescopes on the night of April 25 to 26, 2014, we look for time delays scaling linearly and quadratically with the photon energies. Using for the first time in LIV studies a binned-likelihood approach we set constraints on the QG energy scale. For the linear scenario, we set 95% lower limits E_QG>2.7×1017 GeV for the subluminal case and E_QG> 3.6 ×1017 GeV for the superluminal case. For the quadratic scenario, the 95% lower limits for the subluminal and superluminal cases are E_QG>2.6 ×1010 GeV and E_QG>2.5×1010 GeV, respectively.
 

MAGIC collaboration, Constraints on axion-like particles with the Perseus Galaxy Cluster with MAGIC, published in Physics of the Dark Universe, Volume 44 on May 2024.
 
Axion-like particles (ALPs) are pseudo-Nambu–Goldstone bosons that emerge in various theories beyond the standard model. These particles can interact with high-energy photons in external magnetic fields, influencing the observed gamma-ray spectrum. This study analyzes 41.3 h of observational data from the Perseus Galaxy Cluster collected with the MAGIC telescopes. We focused on the spectra the radio galaxy in the center of the cluster: NGC 1275. By modeling the magnetic field surrounding this target, we searched for spectral indications of ALP presence. Despite finding no statistical evidence of ALP signatures, we were able to exclude ALP models in the sub-micro electronvolt range. Our analysis improved upon previous work by calculating the full likelihood and statistical coverage for all considered models across the parameter space. Consequently, we achieved the most stringent limits to date for ALP masses around 50 neV, with cross sections down to gαγ = 3x 1012 GeV−1.
 

MAGIC collaboration, Insights into the broadband emission of the TeV blazar Mrk 501 during the first X-ray polarization measurements, published in Astronomy & Astrophysics, Volume 685 on May 22, 2024.
 
Aims. We present the first multiwavelength study of Mrk 501 that contains simultaneous very-high-energy (VHE) γ-ray observations and X-ray polarization measurements from the Imaging X-ray Polarimetry Explorer (IXPE). Methods. We used radio-to-VHE data from a multiwavelength campaign carried out between March 1, 2022, and July 19, 2022 (MJD 59639 to MJD 59779). The observations were performed by MAGIC, Fermi-LAT, NuSTAR, Swift (XRT and UVOT), and several other instruments that cover the optical and radio bands to complement the IXPE pointings. We characterized the dynamics of the broadband emission around the X-ray polarization measurements through its multiband fractional variability and correlations, and compared changes observed in the polarization degree to changes seen in the broadband emission using a multi-zone leptonic scenario. Results. During the IXPE pointings, the VHE state is close to the average behavior, with a 0.2–1 TeV flux of 20%–50% of the emission of the Crab Nebula. Additionally, it shows low variability and a hint of correlation between VHE γ-rays and X-rays. Despite the average VHE activity, an extreme X-ray behavior is measured for the first two IXPE pointings, taken in March 2022 (MJD 59646 to 59648 and MJD 59665 to 59667), with a synchrotron peak frequency > 1 keV. For the third IXPE pointing, in July 2022 (MJD 59769 to 59772), the synchrotron peak shifts toward lower energies and the optical/X-ray polarization degrees drop. All three IXPE epochs show an atypically low Compton dominance in the γ-rays. The X-ray polarization is systematically higher than at lower energies, suggesting an energy stratification of the jet. While during the IXPE epochs the polarization angles in the X-ray, optical, and radio bands align well, we find a clear discrepancy in the optical and radio polarization angles in the middle of the campaign. Such results further support the hypothesis of an energy-stratified jet. We modeled broadband spectra taken simultaneous to the IXPE pointings, assuming a compact zone that dominates in the X-rays and the VHE band, and an extended zone stretching farther downstream in the jet that dominates the emission at lower energies. NuSTAR data allow us to precisely constrain the synchrotron peak and therefore the underlying electron distribution. The change between the different states observed in the three IXPE pointings can be explained by a change in the magnetization and/or the emission region size, which directly connects the shift in the synchrotron peak to lower energies with the drop in the polarization degree.
 

MAGIC collaboration, Performance and first measurements of the MAGIC stellar intensity interferometer, published in Monthly Notices of the Royal Astronomical Society, Volume 529, Issue 4 on March 11, 2024.
 
In recent years, a new generation of optical intensity interferometers has emerged, leveraging the existing infrastructure of Imaging Atmospheric Cherenkov Telescopes (IACTs). The MAGIC telescopes host the MAGIC-SII system (Stellar Intensity Interferometer), implemented to investigate the feasibility and potential of this technique on IACTs. After the first successful measurements in 2019, the system was upgraded and now features a real-time, dead-time-free, 4-channel, GPU-based correlator. These hardware modifications allow seamless transitions between MAGIC’s standard very-high-energy gamma-ray observations and optical interferometry measurements within seconds. We establish the feasibility and potential of employing IACTs as competitive optical Intensity Interferometers with minimal hardware adjustments. The measurement of a total of 22 stellar diameters are reported, 9 corresponding to reference stars with previous comparable measurements, and 13 with no prior measurements. A prospective implementation involving telescopes from the forthcoming Cherenkov Telescope Array Observatory’s Northern hemisphere array, such as the first prototype of its Large-Sized Telescopes, LST-1, is technically viable. This integration would significantly enhance the sensitivity of the current system and broaden the UV-plane coverage. This advancement would enable the system to achieve competitive sensitivity with the current generation of long-baseline optical interferometers over blue wavelengths.
 

MAGIC collaboration, The variability patterns of the TeV blazar PG 1553 + 113 from a decade of MAGIC and multiband observations, published in Monthly Notices of the Royal Astronomical Society, Volume 529, Issue 4 on March 4, 2024.
 
PG 1553 + 113 is one of the few blazars with a convincing quasi-periodic emission in the gamma-ray band. The source is also a very high energy (VHE; >100 GeV) gamma-ray emitter. To better understand its properties and identify the underlying physical processes driving its variability, the MAGIC Collaboration initiated a multiyear, multiwavelength monitoring campaign in 2015 involving the OVRO 40-m and Medicina radio telescopes, REM, KVA, and the MAGIC telescopes, Swift and Fermi satellites, and the WEBT network. The analysis presented in this paper uses data until 2017 and focuses on the characterization of the variability. The gamma-ray data show a (hint of a) periodic signal compatible with literature, but the X-ray and VHE gamma-ray data do not show statistical evidence for a periodic signal. In other bands, the data are compatible with the gamma-ray period, but with a relatively high p-value. The complex connection between the low- and high-energy emission and the non-monochromatic modulation and changes in flux suggests that a simple one-zone model is unable to explain all the variability. Instead, a model including a periodic component along with multiple emission zones is required.
 

MAGIC collaboration, First characterization of the emission behavior of Mrk 421 from radio to very high-energy gamma rays with simultaneous X-ray polarization measurements, published in Astronomy & Astrophysics, Volume 684 on April 11, 2024.
 
Aims. We have performed the first broadband study of Mrk 421 from radio to TeV gamma rays with simultaneous measurements of the X-ray polarization from IXPE. Methods. The data were collected as part of an extensive multiwavelength campaign carried out between May and June 2022 using MAGIC, Fermi-LAT, NuSTAR, XMM-Newton, Swift, and several optical and radio telescopes to complement IXPE data. Results. During the IXPE exposures, the measured 0.2–1 TeV flux was close to the quiescent state and ranged from 25% to 50% of the Crab Nebula without intra-night variability. Throughout the campaign, the very high-energy (VHE) and X-ray emission are positively correlated at a 4σ significance level. The IXPE measurements reveal an X-ray polarization degree that is a factor of 2–5 higher than in the optical/radio bands; that implies an energy-stratified jet in which the VHE photons are emitted co-spatially with the X-rays, in the vicinity of a shock front. The June 2022 observations exhibit a rotation of the X-ray polarization angle. Despite no simultaneous VHE coverage being available during a large fraction of the swing, the Swift-XRT monitoring reveals an X-ray flux increase with a clear spectral hardening. This suggests that flares in high synchrotron peaked blazars can be accompanied by a polarization angle rotation, as observed in some flat spectrum radio quasars. Finally, during the polarization angle rotation, NuSTAR data reveal two contiguous spectral hysteresis loops in opposite directions (clockwise and counterclockwise), implying important changes in the particle acceleration efficiency on approximately hour timescales.
 

MAGIC collaboration, Multi-year characterisation of the broad-band emission from the intermittent extreme BL Lac 1ES 2344+514, published in Astronomy & Astrophysics, Volume 682 on February 9, 2024.
 
Aims. The BL Lac 1ES 2344+514 is known for temporary extreme properties characterised by a shift of the synchrotron spectral energy distribution (SED) peak energy νsynch, p above 1 keV. While those extreme states have only been observed during high flux levels thus far, additional multi-year observing campaigns are required to achieve a coherent picture. Here, we report the longest investigation of the source from radio to very high energy (VHE) performed so far, focussing on a systematic characterisation of the intermittent extreme states. Methods. We organised a monitoring campaign covering a 3-year period from 2019 to 2021. More than ten instruments participated in the observations in order to cover the emission from radio to VHE. In particular, sensitive X-ray measurements by XMM-Newton, NuSTAR, and AstroSat took place simultaneously with multi-hour MAGIC observations, providing an unprecedented constraint of the two SED components for this blazar. Results. While our results confirm that 1ES 2344+514 typically exhibits νsynch, p > 1 keV during elevated flux periods, we also find periods where the extreme state coincides with low flux activity. A strong spectral variability thus happens in the quiescent state, and is likely caused by an increase in the electron acceleration efficiency without a change in the electron injection luminosity. On the other hand, we also report a strong X-ray flare (among the brightest for 1ES 2344+514) without a significant shift of νsynch, p. During this particular flare, the X-ray spectrum is among the softest of the campaign. It unveils complexity in the spectral evolution, where the common harder-when-brighter trend observed in BL Lacs is violated. By combining Swift-XRT and Swift-UVOT measurements during a low and hard X-ray state, we find an excess of the UV flux with respect to an extrapolation of the X-ray spectrum to lower energies. This UV excess implies that at least two regions significantly contribute to the infrared/optical/ultraviolet/X-ray emission. Using the simultaneous MAGIC, XMM-Newton, NuSTAR, and AstroSat observations, we argue that a region possibly associated with the 10 GHz radio core may explain such an excess. Finally, we investigate a VHE flare, showing an absence of simultaneous variability in the 0.3−2 keV band. Using time-dependent leptonic modelling, we show that this behaviour, in contradiction to single-zone scenarios, can instead be explained by a two-component model.
 

Pace, C. M., The Solution of the Einstein’s Equations in the Vacuum Region Surrounding a Spherically Symmetric Mass Distribution, published in Journal of Modern Physics, Volume 15 on August 2024.
 
In this article, we address the solution of the Einstein’s equations in the vacuum region surrounding a spherically symmetric mass distribution. There are two different types of mathematical solutions, depending on the value of a constant of integration. These two types of solutions are analysed from a physical point of view. The comparison with the linear theory limit is also considered. This leads to a new solution, different from the well known one. If one considers the observational data in the weak field limit this new solution is in agreement with the available data. While the traditional Schwarzschild solution is characterized by a horizon at r=2GM/c2, no horizon exists in this new solution.
 

Pace, C. M., The Correct Reissner-Nordstrøm, Kerr and Kerr-Newman Metrics, published in Journal of Modern Physics, Volume 15 on September 2024.
 
In a very recent article of mine I have corrected the traditional derivation of the Schwarzschild metric thus arriving to formulate a correct Schwarzschild metric different from the traditional Schwarzschild metric. In this article, starting from this correct Schwarzschild metric, I also propose corrections to the other traditional Reissner-Nordstrøm, Kerr and Kerr-Newman metrics on the basis of the fact that these metrics should be equal to the correct Schwarzschild metric in the borderline case in which they reduce to the case described by this metric. In this way, we see that, like the correct Schwarzschild metric, also the correct Reissner-Nordstrøm, Kerr and Kerr-Newman metrics do not present any event horizon (and therefore do not present any black hole) unlike the traditional Reissner-Nordstrøm, Kerr and Kerr-Newman metrics.
 
 
B Eslam Panah, B Hazarika, P Phukon, Thermodynamic Topology of Topological Black Hole in F(R)-ModMax Gravity’s Rainbow, published in Progress of Theoretical and Experimental Physics, Volume 2024, Issue 8, on August 2024.
 
In order to include the effect of high energy and topological parameters on black holes in F(R) gravity, we consider two corrections to this gravity: energy-dependent spacetime with different topological constants, and a nonlinear electrodynamics field. In other words, we combine F(R) gravity’s rainbow with ModMax nonlinear electrodynamics theory to see the effects of high energy and topological parameters on the physics of black holes. For this purpose, we first extract topological black hole solutions in F(R)-ModMax gravity’s rainbow. Then, by considering black holes as thermodynamic systems, we obtain thermodynamic quantities and check the first law of thermodynamics. The effect of the topological parameter on the Hawking temperature and the total mass of black holes is obvious. We also discuss the thermodynamic topology of topological black holes in F(R)-ModMax gravity’s rainbow using the off-shell free energy method. In this formalism, black holes are assumed to be equivalent to defects in their thermodynamic spaces. For our analysis, we consider two different types of thermodynamic ensembles. These are: fixed q ensemble and fixed ensemble. We take into account all the different types of curvature hypersurfaces that can be constructed in these black holes. The local and global topology of these black holes are studied by computing the topological charges at the defects in their thermodynamic spaces. Finally, in accordance with their topological charges, we classify the black holes into three topological classes with total winding numbers corresponding to -1,0, and 1. We observe that the topological classes of these black holes are dependent on the value of the rainbow function, the sign of the scalar curvature, and the choice of ensembles.
 

J. Sedaghat, B. Eslam Panah, R. Moradi, S. M. Zebarjad & G. H. Bordbar, Quark stars in massive gravity might be candidates for the mass gap objects, published in European Physical Journal C 84 (2024) 259 on February 2024.
 
We have investigated the structural properties of strange quark stars (SQSs) in a modified theory of gravity known as massive gravity. In order to obtain the equation of state (EOS) of strange quark matter, we have employed a modified version of the Nambu–Jona-Lasinio model (MNJL) which includes a combination of NJL Lagrangian and its Fierz transformation by using weighting factors (1-α) and α. Additionally, we have also calculated dimensionless tidal deformability Λ in massive gravity. To constrain the allowed values of the parameters appearing in massive gravity, we have imposed the condition Λ1.4M☉ ≤ 580. Notably, in the MNJL model, the value of α varies between zero and one. As α increases, the EOS becomes stiffer, and the value of Λ increases accordingly. We have demonstrated that by softening the EOS with increasing the bag constant, one can obtain objects in massive gravity that not only satisfy the constraint Λ1.4M☉ ≤ 580, but they also fall within the unknown mass gap region (2.5 M - 5 M). To establish that the obtained objects in this region are not black holes, we have calculated Schwarzschild radius, compactness, and ΛMTOV in massive gravity.
 

B. Eslam Panah, S. Zare & H. Hassanabadi, Accelerating AdS black holes in gravity’s rainbow, published in European Physical Journal C 84, 259 (2024) on March 2024.
 
Motivated by the effect of the energy of moving particles in C-metric, we first obtain exact accelerating black hole solutions in gravity’s rainbow. Then, we study the effects of gravity’s rainbow and C-metric parameters on the Ricci and Kretschmann scalars, and also the asymptotical behavior of this solution. Next, we indicate how different parameters of the obtained accelerating black holes in gravity’s rainbow affect thermodynamics quantities (such as the Hawking temperature, and entropy) and the local stability (by evaluating the heat capacity). In the following, we extract the geodesic equations to determine the effects of various parameters on photon trajectory in the vicinity of this black hole, as well as obtain the radius of the photon sphere and the corresponding critical impact parameter to gain insight into AdS black hole physics by adding the gravity’s rainbow to C-metric.
 

Behzad Eslam Panah, Analytic Electrically Charged Black Holes in F(R)-ModMax Theory, published in Progress of Theoretical and Experimental Physics, Volume 2024, Issue 2, February 2024.
 
Motivated by a new model of nonlinear electrodynamics known as Modified Maxwell (ModMax) theory, an exact analytical solution for black holes is obtained by coupling ModMax nonlinear electrodynamics and F(R) gravity. Then, the effects of the system’s parameters (F(R)-ModMax gravity parameters) on the event horizons are analyzed. The obtained black hole thermodynamic properties in the F(R)-ModMax theory are investigated by extracting their thermodynamic quantities such as Hawking temperature, electric charge, electric potential, entropy, and also total mass. The first law of thermodynamics for the system under study is evaluated. Next, by considering these black holes, the impacts of various parameters on both the local stability and global stability are investigated by examining the heat capacity and the Helmholtz free energy, respectively. Finally, the thermodynamic geometry of the black hole in F(R)-ModMax gravity is investigated by applying the Hendi–Panahiyan–Eslam Panah–Momennia thermodynamic metric (HPEM’s metric).
 

Kh Jafarzade, B Eslam Panah and M E Rodrigues, Thermodynamics and optical properties of phantom AdS black holes in massive gravity, published in Classical and Quantum Gravity, Volume 41, Number 6 on February 2024.
 
Motivated by high interest in Lorentz invariant massive gravity models known as dRGT massive gravity, we present an exact phantom black hole solution in this theory of gravity and discuss the thermodynamic structure of the black hole in the canonical ensemble. Calculating the conserved and thermodynamic quantities, we check the validity of the first law of thermodynamics and the Smarr relation in the extended phase space. In addition, we investigate both the local and global stability of these black holes and show how massive parameters affect the regions of stability. We extend our study to investigate the optical features of the black holes such as the shadow geometrical shape, energy emission rate, and deflection angle. Also, we discuss how these optical quantities are affected by massive coefficients. Finally, we consider a massive scalar perturbation minimally coupled to the background geometry of the black hole and examine the quasinormal modes by employing the WKB approximation.
 

A. Bagheri Tudeshki, G.H. Bordbar, B. Eslam Panah, Effect of rainbow function on the structural properties of dark energy star, published in Physics Letters B Volume 848 on January 2024.
 
Confirming the existence of compact objects with a mass greater than 2.5 M☉ by observational results such as GW190814 makes that is possible to provide theories to justify these observational results using modified gravity. This motivates us to use gravity's rainbow, which is the appropriate case for dense objects, to investigate the dark energy star structure as a suggested alternative case to the mass gap between neutron stars and black holes in the perspective of quantum gravity. Hence, in the present work, we derive the modified hydrostatic equilibrium equation for an anisotropic fluid, represented by the extended Chaplygin equation of state in gravity's rainbow. Then, for two isotropic and anisotropic cases, using the numerical solution, we obtain energy-dependent maximum mass and its corresponding radius, and the other properties of the dark energy star including the pressure, energy density, stability, etc. In the following, using the observational data, we compare the obtained results in two frameworks of general relativity and gravity's rainbow.
 

B. Eslam Panah, K. Jafarzade & Á. Rincón, Three-dimensional AdS black holes in massive-power-Maxwell theory, published in General Relativity and Gravitation, Volume 56, article number 46, on April 2024.
 
Recently, it was shown that the power-Maxwell (PM) theory could remove the singularity of the electric field (B. Eslam Panah, Europhys. Lett. 134, 20005 (2021). Motivated by a great interest in three-dimensional black holes and a surge of success in studying massive gravity from both the cosmological and astrophysical points of view, we investigate three-dimensional black hole solutions in de Rham, Gabadadze, and Tolley massive theory of gravity in the presence of PM electrodynamics. First, we extract exact three-dimensional solutions in this theory of gravity. Then we study the geometrical properties of these solutions. Calculating conserved and thermodynamic quantities, we check the validity of the first law of thermodynamics for these black holes. We also examine the stability of these black holes in the context of the canonical ensemble. We continue calculating this kind of black hole’s optical features, such as the photon orbit radius, the energy emission rate, and the deflection angle. Considering these optical quantities, finally, we analyze the effective role of the parameters of models on them.
 

Shakeri, Soroush; Karkevandi, Davood RafieI, Bosonic dark matter in light of the NICER precise mass-radius measurements, published in Physical Review D, Volume 109, Issue 4 on February 2024.
 
We explore the presence of self-interacting bosonic dark matter (DM) within neutron stars (NSs) in light of the latest multimessenger observations of the Neutron Star Interior Composition Explorer (NICER) and LIGO/Virgo detectors. The bosonic DM is distributed as a core inside the NS or as a halo around it leading to formation of a DM admixed NS. We focus on the variation of the visible and dark radius of the mixed object due to DM model parameters and fractions. It is shown that DM core formation reduces the visible radius and the total mass pushing them below observational limits while halo formation is in favor of the latest mass-radius observations. Moreover, we scan over the parameter space of the bosonic DM model considering two nuclear matter equation of states by applying the radius, maximum mass and tidal deformability constraints. Our investigation allows for the exclusion of a range of DM fractions, self-coupling constant and sub-GeV boson masses, which limits the amount of accumulated DM to relatively low values to be consistent with astrophysical bounds. In this paper, we introduce main features of the pulse profile corresponding to the DM admixed NS as a novel observable quantity. We find that the depth of minimum fluxes in the pulse profiles crucially depends on the amount of DM around NS and its compactness. The current/future astrophysics missions may test for the possibility of the existence of DM within NSs and break the degeneracies between different scenarios via multiple observations.
 

Sigismondi, Costantino; De Vincenzi, Paolo, Eclipses: A Brief History of Celestial Mechanics, Astrometry and Astrophysics, published in Universe, Volume 10, Issue 2 on February 2024.
 
Solar and lunar eclipses are indeed the first astronomical phenomena which have been recorded since very early antiquity. Their periodicities gave birth to the first luni-solar calendars based on the Methonic cycle since the sixth century before Christ. The Saros cycle of 18.03 years is due to the Chaldean astronomical observations. Their eclipses' observations reported by Ptolemy in the Almagest (Alexandria of Egypt, about 150 a.C.) enabled modern astronomers to recognize the irregular rotation rate of the Earth. The Earth's rotation is some hours in delay after the last three millenia if we use the present rotation to simulate the 721 b.C. total eclipse in Babylon. This is one of the most important issues in modern celestial mechanics, along with the Earth's axis nutation of 18 yr (discovered in 1737), precession of 25.7 Kyr (discovered by Ipparchus around 150 b.C.) and obliquity of 42 Kyr motions (discovered by Arabic astronomers and assessed from the Middle Ages to the modern era, IX to XVIII centuries). Newtonian and Einstenian gravitational theories explain fully these tiny motions, along with the Lense–Thirring gravitodynamic effect, which required great experimental accuracy. The most accurate lunar and solar theories, or their motion in analytical or numerical form, allow us to predict—along with the lunar limb profile recovered by a Japanese lunar orbiter—the appearance of total, annular solar eclipses or lunar occultations for a given place on Earth. The observation of these events, with precise timing, may permit us to verify the sphericity of the solar profile and its variability. The variation of the solar diameter on a global scale was claimed firstly by Angelo Secchi in the 1860s and more recently by Jack Eddy in 1978. In both cases, long and accurate observational campaigns started in Rome (1877–1937) and Greenwich Observatories, as well as at Yale University and the NASA and US Naval Observatory (1979–2011) with eclipses and balloon-borne heliometric observations. The IOTA/ES and US sections as well as the ICRA continued the eclipse campaigns. The global variations of the solar diameter over a decadal timescale, and at the millarcsecond level, may reflect some variation in solar energy output, which may explain some past climatic variations (such as the Allerød and Dryas periods in Pleistocene), involving the outer layers of the Sun. "An eclipse never comes alone"; in the eclipse season, lasting about one month, we can have also lunar eclipses. Including the penumbral lunar eclipses, the probability of occurrence is equi-distributed amongst lunar and solar eclipses, but while the lunar eclipses are visible for a whole hemisphere at once, the solar eclipses are not. The color of the umbral shadow on the Moon was known since antiquity, and Galileo (1632, Dialogo sopra i Massimi Sistemi del Mondo) shows clearly these phenomena from copper color to a totally dark, eclipsed full Moon. Three centuries later, André Danjon was able to correlate that umbral color with the 11-year cycle of solar activity. The forthcoming American total solar eclipse of 8 April 2024 will be probably the eclipse with the largest mediatic impact of the history; we wish that also the scientific impulse toward solar physics and astronomy will be relevant, and the measure of the solar diameter with Baily's beads is indeed one of the topics significantly related to the Sun–Earth connections.
 

Prakapenia, Mikalai; Vereshchagin, Gregory, Pair Creation in Hot Electrosphere of Compact Astrophysical Objects, published in The Astrophysical Journal, Volume 963, Issue 2 on March 2024.
 
The mechanism of pair creation in the electrosphere of compact astrophysical objects such as quark stars or neutron stars is revisited, paying attention to evaporation of electrons and acceleration of electrons and positrons, which were previously not addressed in the literature. We perform a series of numerical simulations using the Vlasov–Maxwell equations. The rate of pair creation strongly depends on electric field strength in the electrosphere. Although Pauli blocking is explicitly taken into account, we find no exponential suppression of the pair creation rate at low temperatures. The luminosity in pairs increases with temperature and it may reach up to L ± ∼ 1052 erg s‑1, much larger than previously assumed.
 

Rafiei Karkevandi, Davood; Shahrbaf, Mahboubeh; Shakeri, Soroush; Typel, Stefan, Exploring the Distribution and Impact of Bosonic Dark Matter in Neutron Stars, published in Particles, Volume 7, Issue 1 on March 2024.
 
The presence of dark matter (DM) within neutron stars (NSs) can be introduced by different accumulation scenarios in which DM and baryonic matter (BM) may interact only through the gravitational force. In this work, we consider asymmetric self-interacting bosonic DM, which can reside as a dense core inside the NS or form an extended halo around it. It is seen that depending on the boson mass (mχ), self-coupling constant (λ) and DM fraction (Fχ), the maximum mass, radius and tidal deformability of NSs with DM admixture will be altered significantly. The impact of DM causes some modifications in the observable features induced solely by the BM component. Here, we focus on the widely used nuclear matter equation of state (EoS) called DD2 for describing NS matter. We show that by involving DM in NSs, the corresponding observational parameters will be changed to be consistent with the latest multi-messenger observations of NSs. It is seen that for mχ≳200 MeV and λ≲2π, DM-admixed NSs with 4%≲Fχ≲20% are consistent with the maximum mass and tidal deformability constraints.

Millauro, C. ; Argüelles, C. R.; Vieyro, F. L.; Crespi, V.; Mestre, M. F., Accretion discs onto supermassive compact objects: A portal to dark matter physics in active galaxies, published in Astronomy & Astrophysics, Volume 685 on May 2024.
 
Context. The study of the physics of the accretion discs that develop around supermassive black hole (BH) candidates provides essential theoretical tools to test their nature. Aims: Here, we study the accretion flow and associated emission using generalised α-discs accreting onto horizonless dark compact objects in order to make comparisons with the traditional BH scenario. The BH alternative proposed here consists in a dense and highly degenerate core made of fermionic dark matter (DM) and surrounded by a more diluted DM halo. This dense core-diluted halo DM configuration is a solution of Einstein's equation of general relativity (GR) in spherical symmetry, which naturally arises once the quantum nature of the DM fermions is duly accounted for. Methods: The methodology followed in this work consists in first generalising the theory of α-discs to work in the presence of regular and horizonless compact objects, and then applying it to the case of core-halo DM profiles typical of active-like galaxies. Results: The fact that the compactness of the dense and transparent DM core scales with particle mass allows the following key findings of this work: (i) There is always a given core compacity - corresponding particle mass - that produces a luminosity spectrum that is almost indistinguishable from that of a Schwarzschild BH of the same mass as the DM core. (ii) The disc can enter deep inside the non-rotating DM core, allowing accretion-powered efficiencies of as high as 28%, which is comparable to that of a highly rotating Kerr BH. Conclusions: These results, together with the existence of a critical DM core mass of collapse into a supermassive BH, open new avenues of research for two seemingly unrelated topics: AGN phenomenology and dark matter physics.

Punsly, B., First image of a jet launching from a black hole accretion system: Kinematics, published in Astronomy & Astrophysics, Volume 685 on May 2024.
 
Jets are endemic to both Galactic solar mass and extragalactic supermassive black holes. A recent 86 GHz image of M 87 shows a jet emerging from the accretion ring around a black hole, providing the first direct observational constraint on the kinematics of the jet-launching region in any black hole jetted system. The very wide (∼280 μas), highly collimated, limb-brightened cylindrical jet base is not predicted in current numerical simulations. The emission was shown to be consistent with that of a thick-walled cylindrical source that apparently feeds the flow that produces the bright limbs of the outer jet at an axial distance downstream of 0.4 mas < z < 0.65 mas. The analysis here applies the conservation laws of energy, angular momentum, and magnetic flux to the combined system of the outer jet, the cylindrical jet, and the launch region. It also uses the brightness asymmetries of the jet and counterjet to constrain the Doppler factor. The only global solutions have a source that is located < 34 μas from the event horizon. This includes the Event Horizon Telescope annulus of emission and the regions interior to this annulus. The axial jet begins as a magnetically dominated flow that spreads laterally from the launch radius (< 34 μas). It becomes super-magnetosonic before it reaches the base of the cylindrical jet. The flow is ostensibly redirected and collimated by a cylindrical nozzle formed in a thick accretion disk. The flow emerges from the nozzle as a mildly relativistic (0.3c < v < 0.4c) jet with a significant protonic kinetic energy flux.
 

Bianco, C. L.; Mirtorabi, M. T.; Moradi, R.; Rastegarnia, F.; Rueda, J. A.; Ruffini, R.; Wang, Y.; Della Valle, M.; Li, Liang; Zhang, S. R., Probing Electromagnetic Gravitational-wave Emission Coincidence in a Type I Binary-driven Hypernova Family of Long Gamma-Ray Bursts at Very High Redshift, published in The Astrophysical Journal, Volume 966, Issue 2 on May 2024.
 
The repointing time of the X-Ray Telescope (XRT) instrument on the Neil Gehrels Swift Observatory satellite has posed challenges in observing and studying the early X-ray emissions within ≈40 s after a gamma-ray burst (GRB) trigger. To address this issue, we adopt a novel approach that capitalizes on the cosmological time dilation in GRBs with redshifts ranging from 3 to 9. Applying this strategy to Swift/XRT data, we investigate the earliest X-ray emissions of 368 GRBs from the Swift catalog, including short and long GRBs. We compare the observed time delay between the GRB trigger and the initial Swift/XRT observation, measured in the GRB observer frame, and the corresponding cosmological rest-frame time delay (RTD). This technique is here used in the analysis of GRB 090423 at z = 8.233 (RTD ∼8.2 s), GRB 090429B at z ≈ 9.4 (RTD ∼10.1 s), and GRB 220101A at z = 4.61 (RTD ∼14.4 s). The cosmological time dilation enables us to observe the very early X-ray afterglow emission in these three GRBs. We thus validate the observation of the collapse of the carbon–oxygen core and the coeval newborn neutron star (νNS) formation triggering the GRB event in the binary-driven hypernova (BdHN) scenario. We also evidence the νNS spin-up due to supernova ejecta fallback and its subsequent slowing down due to the X-ray/optical/radio synchrotron afterglow emission. A brief gravitational-wave signal may separate the two stages owing to a fast-spinning νNS triaxial-to-axisymmetric transition. We also analyze the long GRB redshift distribution for the different BdHN types and infer that BdHNe II and III may originate the NS binary progenitors of short GRBs.

Gao, Li-Yang ; Xue, She-Sheng ; Zhang, Xin, Dark energy and matter interacting scenario to relieve H 0 and S8 tensions, published in Chinese Physics C, Volume 48, Issue 5 on May 2024.
 
We consider a new cosmological model (called ΛCDM), in which the vacuum energy interacts with matter and radiation, and test this model using the current cosmological observations. Using the CMB+BAO+SN (CBS) dataset to constrain the model, we find that H0 and S8 tensions are relieved to 2.87σ and 2.77σ, respectively. However, in this case, the ΛCDM model is not favored by the data, compared with ΛCDM. We find that when the H0 and S8 data are added to the data combination, the situation is significantly improved. In the CBS+ H0 case, the model relieves the H0 tension to 0.47σ, and the model is favored over ΛCDM. In the CBS+ H0 + S8 case, we obtain a synthetically best situation, in which the H0 and S8 tensions are relieved to 0.72σ and 2.11σ, respectively. In this case, the model is most favored by the data. Therefore, this cosmological model can greatly relieve the H0 tension and simultaneously effectively alleviate the S8 tension.

Xue, She-Sheng, Holographic massive plasma state in Friedman universe: cosmological fine-tuning and coincidence problems, published in Journal of Cosmology and Astroparticle Physics, Volume 2024, Issue 05 on May 2024.
 
Massive particle and antiparticle pair production and oscillation on the horizon form a holographic and massive pair plasma state in the Friedman Universe. Via this state, the Einstein cosmology term (dark energy) interacts with matter and radiation and is time-varying Λ̃ in the Universe's evolution. It is determined by a close set of ordinary differential equations for dark energy, matter, and radiation energy densities. The solutions are unique, provided the initial conditions given by observations. In inflation and reheating, dark energy density decreases from the inflation scale, converting to matter and radiation energy densities. In standard cosmology, matter and radiation energy densities convert to dark energy density, reaching the present Universe. By comparing with ΛCDM, quintessence and dark energy interacting models, we show that these results can be the possible solutions for cosmological fine-tuning and coincidence problems.

Mahmoudi, Somayyeh; Sadegh, Mahdi; Khodagholizadeh, Jafar; Motie, Iman; Xue, She-Sheng; Blanchard, Alain, Generation of the CMB cosmic birefringence through axion-like particles, sterile and active neutrinos, published in The European Physical Journal C, Volume 84, Issue 6 on June 2024.
 
The cosmic birefringence (CB) angle refers to the rotation of the linear polarization plane of Cosmic Microwave Background (CMB) radiations when parity-violating theories are considered. We analyzed the Quantum Boltzmann equation for an ensemble of CMB photons interacting with the right-handed sterile neutrino dark matter (DM) and axion-like particles (ALPs) DM in the presence of the scalar metric perturbation. We used the birefringence angle of CMB to study those probable candidates of DM. It is shown that the CB angle contribution of sterile neutrino is much less that two other sources considered here. Next, we combined the results of the cosmic neutrinos' contribution and the contribution of the ALPs to producing the CMB birefringence and discussed the uncertainty on the parameter space of axions caused by the share of CMB-cosmic neutrino interaction in generating this effect. Finally, we plotted the EB power spectrum of the CMB and showed that this spectrum behaves differently in the presence of cosmic neutrinos and ALPs interactions in small l. Hence, future observed data for CEBl, will help us to distinguish the CB angle value due to the various sources of its production.

Bini, Donato; Geralico, Andrea; Jantzen, Robert T.; Ruffini, Remo, On Fermi's Resolution of the "4/3 Problem" in the Classical Theory of the Electron, published in Foundations of Physics, Volume 54, on June 2024.
 
We discuss the solution proposed by Fermi to the so called "4/3 problem" in the classical theory of the electron, a problem which puzzled the physics community for many decades before and after his contribution. Unfortunately his early resolution of the problem in 1922–1923 published in three versions in Italian and German journals (after three preliminary articles on the topic) went largely unnoticed. Even more recent texts devoted to classical electron theory still do not present his argument or acknowledge the actual content of those articles. The calculations initiated by Fermi at the time are completed here by formulating and discussing the conservation of the total 4-momentum of the accelerated electron as seen from the instantaneous rest frame in which it is momentarily at rest.

Ruffini, Remo; Sigismondi, Costantino, Fitting the Crab Supernova with a Gamma-Ray Burst, published in Universe, Volume 10, Issue 7 on June 2024.
 
Here, we reconsider the historical data, assuming a gamma-ray burst (GRB) as its source. A Supernova correlated with the GRB explains well the fading time observed by the ancient Chinese astronomers in the daytime and the nighttime, while the GRB power law explains the present X-rays and GeV emission of the Crab. On the grounds of a recent understanding of the first episode of binary-driven hypernova GRB (BDHN GRB) in terms of the collapse of a ten solar masses core, we propose the possible identification of the real Supernova event at an earlier time than Chinese chronicles. This work allows a new understanding of the significance of historical astronomical observations, including a fireball due to gamma-ray air shower observation and a plague of acute radiation syndrome, documented with several thousands of victims in the Eurasian area (Egypt, Iraq, and Syria).

Zhang, Shu-Rui; Prakapenia, Mikalai, The transformation of the rotational energy of a Kerr black hole, published in Classical and Quantum Gravity, Volume 41, Issue 13 on July 2024.
 
This paper analyzes the feedback of the rotational energy extraction from a Kerr black hole (BH) by the 'ballistic method', i.e. the test particle decay in the BH ergosphere pioneered by Roger Penrose. The focus is on the negative energy counterrotating particles (which can be massive or massless) going in towards the horizon, and the feedback on the BH irreducible mass is assessed. Generally, the change in irreducible mass is a function of the conserved quantities of the particle. For an extreme Kerr BH and in the limit , all the reduced transformable energy goes into the irreducible mass (i.e. ), resulting in high irreversibility. The amount of extracted energy from the BH using test particles is much lower than the change of transformable energy. For non-extreme Kerr BHs, the effective potential of particle motion on the equatorial plane in Kerr spacetime is analyzed, and it is demonstrated that the Penrose process can only be undergone by BHs with a dimensionless spin if the decay point coincides with the turning point. Based on that, the lower limit of the change in irreducible mass is provided as a function of the dimensionless spin of the BH. The significance of the increase in the irreducible mass of the BH during the energy extraction process is generally and concisely illustrated by introducing the concept of transformable energy of the BH. The feedback from the Penrose process on the irreducible mass demonstrates the irreversibility of energy extraction and highlights that the total amount of energy that can be extracted from a BH is less than previously anticipated.

Gao, Hao-Xuan; Geng, Jin-Jun; Sun, Tian-Rui; Li, Liang; Huang, Yong-Feng; Wu, Xue-Feng, Probing Thermal Electrons in Gamma-Ray Burst Afterglows, published in The Astrophysical Journal, Volume 971, Issue 1 on August 2024.
 
Particle-in-cell simulations have unveiled that shock-accelerated electrons do not follow a pure power-law distribution, but have an additional low-energy "thermal" part, which owns a considerable portion of the total energy of the electrons. Investigating the effects of these thermal electrons on gamma-ray burst (GRB) afterglows may provide valuable insights into the particle acceleration mechanisms. We solve the continuity equation of electrons in energy space, from which multiwavelength afterglows are derived by incorporating processes including synchrotron radiation, synchrotron self-absorption, synchrotron self-Compton scattering, and γ–γ annihilation. First, there is an underlying positive correlation between the temporal and spectral indices due to the cooling of electrons. Moreover, thermal electrons result in simultaneous nonmonotonic variations of both the spectral and temporal indices at multiple wavelengths, which could be individually recorded by the 2.5 m Wide Field Survey Telescope and Vera Rubin Observatory Legacy Survey of Space and Time (LSST). The thermal electrons could also be diagnosed using afterglow spectra from synergistic observations in the optical (with LSST) and X-ray (with the Microchannel X-ray Telescope on board the Space Variable Objects Monitor) bands. Finally, we use Monte Carlo simulations to obtain the distribution of the peak flux ratio (RX) between the soft and hard X-rays, and of the time delay (Δt) between the peak times of the soft X-ray and optical light curves. The thermal electrons significantly raise the upper limits of both RX and Δt. Thus, the distribution of GRB afterglows with thermal electrons is more scattered in the RX‑Δt plane.

Ajmal, S.; Gaglione, J. T.; Gurrola, A.; Panella, O.; Presilla, M.; Romeo, F.; Sun, H.; Xue, S. -S., Searching for exclusive leptoquarks with the Nambu-Jona-Lasinio composite model at the LHC and HL-LHC, published in Journal of High Energy Physics, Volume 2024, Issue 8 on August 2024.
 
We present a detailed study concerning a new physics scenario involving four fermion operators of the Nambu-Jona-Lasinio type characterized by a strong-coupling ultraviolet fixed point where composite particles are formed as bound states of elementary fermions at the scale Λ=OTeV. After implementing the model in the Universal FeynRules Output format, we focus on the phenomenology of the scalar leptoquarks at the LHC and the High-Luminosity option. Leptoquark particles have undergone extensive scrutiny in the literature and experimental searches, primarily relying on pair production and, more recently, incorporating single, Drell-Yan t-channel, and lepton-induced processes. This study marks, for the first time, the examination of these production modes at varying jet multiplicities. Novel mechanisms emerge, enhancing the total production cross section. A global strategy is devised to capture all final state particles produced in association with leptoquarks or originating from their decay, which we termed "exclusive", in an analogy to the nomenclature used in nuclear reactions. The assessment of the significance in current and future LHC runs, focusing on the case of a leptoquark coupling to a muon–c quark pair, reveals greater sensitivity compared to ongoing searches. Given this heightened discovery potential, we advocate the incorporation of exclusive leptoquark searches in future investigations at the LHC.

Della Valle, Massimo; Shafter, Allen W.; Starrfield, Sumner, Jet-induced Enhancement of the Nova Rate in M87, published in Research Notes of the AAS, Volume 8, Issue 8, on August 2024.
 
We argue that the Bondi accretion mechanism has the potential to enhance classical nova production near the M87 jet. According to our estimates, the jet's influence can increase the nova rate in its vicinity by up to a factor of two over the background rate by triggering explosions on single white dwarfs. This result may offer a straightforward explanation for the recently observed excess of novae near the M87 jet.

Mestre, Martín Federico; Argüelles, Carlos Raul; Carpintero, Daniel Diego; Crespi, Valentina; Krut, Andreas, Modeling the track of the GD-1 stellar stream inside a host with a fermionic dark matter core-halo distribution, published in Astronomy & Astrophysics, Volume 68 on September 2024.
 
Context. Traditional studies of stellar streams typically involve phenomenological ΛCDM halos or ad hoc dark matter (DM) profiles with different degrees of triaxiality, which preclude us from gaining insights into the nature and mass of the DM particles. Recently, the maximum entropy principle of halo formation has been applied to provide a DM halo model that incorporates the fermionic (quantum) nature of the particles while leading to DM profiles that depend on the fermion mass. These profiles develop a more general "dense core – diluted halo" morphology that can explain the Galactic rotation curve, while the degenerate fermion core can mimic the central massive black hole (BH). Aims. We model the GD-1 stellar stream using a spherical core-halo DM distribution for the host that simultaneously explains the dynamics of the S-cluster stars through its degenerate fermion core without a central BH. Methods. We used two optimization algorithms in order to fit both the initial conditions of the stream orbit and the fermionic model. We modeled the baryonic potential with a bulge and two disks (thin and thick) with fixed parameters according to the recent literature. The stream observables were 5D phase-space data from the Gaia DR2 survey. Results. We were able to find good fits for both the GD-1 stream and the S-stars for a family of fermionic core-halo profiles parameterized by the fermion mass. The particle masses are constrained in the range 56 keV c‑2, with a corresponding DM core of ∼103 Schwarzschild radii, to 360 keV c‑2, which corresponds to the most compact core of 5 Schwarzschild radii prior to the gravitational collapse into a BH of about 4 × 106 M. Conclusions. This work provides evidence that the fermionic profile is a reliable model for the massive central object and for the DM of the Galaxy. Remarkably, this model predicts a total Milky Way mass of 2.3 × 1011 M, which agrees with recent mass estimates obtained from Gaia DR3 rotation curves (Gaia RC). In summary, with one single fermionic model for the DM distribution of the Milky Way, we obtain a good fit on three totally different distance scales of the Galaxy: ∼10‑6 kpc (central, S-stars), ∼14 kpc (middle, GD-1), and ∼30 kpc (boundary, Gaia RC mass estimate).

Li, Liang; Wang, Yu, GRB 190114C: Fireball Energy Budget and Radiative Efficiency Revisited, published in The Astrophysical Journal, Volume 972, Issue 2 on September 2024.
 
The jet composition of gamma-ray bursts (GRBs), as well as how efficiently the jet converts its energy to radiation, are long-standing problems in GRB physics. Here, we reported a comprehensive temporal and spectral analysis of the TeV-emitting bright GRB 190114C. Its high fluence (∼4.4 × 10‑4 erg cm‑2) allows us to conduct the time-resolved spectral analysis in great detail and study their variations down to a very short timescale (∼0.1 s) while preserving a high significance. Its prompt emission consists of three well-separated pulses. The first two main pulses (P1 and P2) exhibit independently strong thermal components, starting from the third pulse (P3) and extending to the entire afterglow, the spectra are all nonthermal, and the synchrotron plus Compton upscattering model well interprets the observation. By combining the thermal (P1 and P2) and the nonthermal (P3) observations based on two different scenarios (global and pulse properties) and following the method described in Zhang et al., we measure the fireball parameters and GRB radiative efficiency with little uncertainties for this GRB. A relevantly high GRB radiative efficiency is obtained based on both the global and pulse properties, suggesting that if GRBs are powered by fireballs, the efficiency can sometimes be high. More interestingly, though the observed parameters are individually different (e.g., the amount of mass loading M), the radiative efficiency obtained from P1 (ηγ = 36.0% ± 6.5%) and P2 (ηγ = 41.1% ± 1.9%) is roughly the same, which implies that the central engine of the same GRB has some common properties.

Moradi, R.; Rastegarnia, F.; Wang, Y.; Mirtorabi, M. T., FNet II: spectral classification of quasars, galaxies, stars, and broad absorption line (BAL) quasars, published in Monthly Notices of the Royal Astronomical Society, Volume 533, Issue 2 on September 2024.
 
In this work, we enhance the FNet, a 1D convolutional neural network (CNN) with a residual neural network (ResNet) architecture, to perform spectral classification of quasars, galaxies, stars, and broad absorption line (BAL)-quasars in the SDSS-IV catalogue from DR17 of eBOSS. Leveraging its convolutional layers and the ResNet structure with different kernel sizes, FNet autonomously identifies various patterns within the entire sample of spectra. Since FNet does not require the intermediate step of identifying specific lines, a simple modification enabled our current network to classify all SDSS spectra. This modification involves changing the final output layer from a single value (redshift) to multiple values (probabilities of all classes), and accordingly adjusting the loss function from mean squared error to cross-entropy. FNet achieves a completeness of 99.00 per cent ± 0.20 for galaxies, 98.50 per cent ± 0.30 for quasars, 99.00 per cent ± 0.18 for BAL-quasars, and 98.80 per cent ± 0.20 for stars. These results are comparable to those obtained using QuasarNET, a standard CNN employed in the SDSS routine, comprises convolutional layers without the ResNet structure with equal kernel sizes, and is utilized for redshift measurement and classification by identifying seven emission lines. QuasarNET, in order to overcome the problem of finding a C IV emission line with broad absorption which is slightly more challenging than that of detecting emission lines requires to add BAL C IV line to the list of lines that the network learns to identify. However, this procedure is not necessary in FNet as it learns the features through a self-learning procedure.

 
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