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ICRANet Newsletter
October/November 2022
SUMMARY
1. ICRANet 4 GCN 2. Second announcement of the 5th Zeldovich meeting, June 12 - 17, 2023, Yerevan (Armenia) 3. Mission of Prof. Ruffini to the USA, November 6-11, 2022: lectures at the Cosmos Club, at the Institute for Advanced Studies (IAS) and at Princeton University 4. Prof. Ruffini among the top 2% of the most cited authors, according to Elsevier 5. Congratulations to Director of ICRANet-Armenia and ICRANet Faculty Professor Narek Sahakyan, awarded of the Doctor of Sciences (DSc) degree in physics, November 22, 2022 6. Partial solar eclipse and measurement of the solar diameter (October 25, 2022) and lunar eclipse at the antipodes (November 8, 2022), online and podcast events 7. Renewal of the cooperation agreement between ICRANet and the University Campus Bio-Medico of Rome (Italy), October 11, 2022 8. Seminars at ICRANet center in Pescara, November 25, 2022 9. Scientific visits to ICRANet 10. Recent publications
1. ICRANet 4 GCN
TITLE: GCN CIRCULAR
NUMBER: 32780 SUBJECT: GRB 221009A: A type I BdHN of exceptional energetics DATE: 22/10/17 11:16:22 GMT FROM: Remo Ruffini at ICRA ruffini@icra.it Y. Aimuratov, L. Becerra, C.L. Bianco, C. Cherubini, S. Filippi, M.Karlica, Liang Li, R. Moradi, F. Rastegar Nia, J.A. Rueda, R. Ruffini, N.Sahakyan, Y. Wang, S.S. Xue, on behalf of the ICRANet team, report: GRB221009A detected by Swift (Kennea et al. 2022 GCN32635), Fermi-GBM(Veres et al. 2022, GCN32636, Lesage et al. 2022, GCN32642), Fermi-LAT(Bissaldi et al. 2022, GCN32637), with redshift of z=0.151 and an isotropic equivalent energy of Eiso=2x1054 erg (de Ugarte Postigo et al. 2022,GCN32648 and GCN32642) is a typical Binary driven Hypernova of type I (BdHNI), originating from the collapse of a carbon-oxygen core (CO-core) in presence of a companion neutron star (NS) with common feature with three BdHN I: GRB130427A with "pile up" in the prompt phase (Ruffini et al. 2013,GCN14526); GRB190114C (Ruffini et al. 2019, GCN23715); and GRB180720B(Ruffini et al. 2018, GCN23019). As the above three sources, GRB221009Apresents: 1) the optical (Lipunov et al. 2022, GCN32634 and GCN32639;Perley. 2022 GCN32638; Broens. 2022, GCN32640; Hu et al. 2022, GCN32644;Mondy: Belkin et al. 2022, GCN32645; de Wet et al.2022, GCN32646; Xu et al.2022 GCN32647; Odeh 2022, GCN32649; Brivio et al. 2022, GCN32652; Izzo et al. 2022, GCN32765), radio (Bright et al. 2022, GCN32653 and Farah et al.2022, GCN32655) and X-ray (Kennea et al, 2022, GCN32635, and GCN32651)synchrotron afterglow emissions as well as the TeV emission (Yong Huang et al. 2022, GCN32677), which in BdHN I originate from accreting millisecond spinning newborn NS (Rueda et al. 2022, e-Print: 2204.00579 [astro-ph.HE]);2) the ultra-relativistic prompt emission (UPE) phase (Moradi et al. 2021,PRD 104, 063043 and Rastegarnia et al. 2022, EPJC 82, 778) and GeV emission(Rueda et al 2022 ApJ 929 56) originated from the black hole formed by hypercritical accretion of the supernova ejecta on the NS companion; and 3) the optical emission of the nickel decay of the supernova (SN), created bythe collapse of the CO-core. The first evidence of the supernova rise is reported by S. Belkin et al. 2022, (GCN32769). In this GRB the bolometric optical peak of SN is expected to be observed at 15.57+/-2.0 days after the Fermi-GBM trigger (October 24th 2022, uncertainty from October 22nd 2022 to October 26th 2022, with the bolometric optical luminosity of L=(9.45+/-2.8) x1042 erg/s; Aimuratov et al. in preparation). ******************************* TITLE: GCN CIRCULAR NUMBER: 32802 SUBJECT: GRB 221009A X-ray light-curve and the indication of TeV light-curve DATE: 22/10/19 15:28:45 GMT FROM: Remo Ruffini at ICRA ruffini@icra.it Y. Aimuratov, L. Becerra, C.L. Bianco, C. Cherubini, S. Filippi, M. Karlica, Liang Li, R. Moradi, F. Rastegar Nia, J.A. Rueda, R. Ruffini, N. Sahakyan, Y. Wang, S.S. Xue, on behalf of the ICRANet team, report: LHAASO observed more than 5000 very high energy (VHE) photons in GRB 221009A, with the highest energy reaching 18 TeV (GCN 32677). Previously, high energy TeV emissions were also observed in GRB 180720B (Abdalla et al. 2019), 190114C (MAGIC Collaboration 2019), 190829A (H.E.S.S. Collaboration 2021) and 201216C (Blanch et al. GCN 29075). A common feature of these bursts is that the TeV light-curve follows a power-law decay with a similar index as the X-ray light-curve, and the TeV luminosity is tens of percent of the X-ray luminosity (see attached figure 1 and the references of Abdalla et al. 2019, MAGIC Collaboration 2019 and H.E.S.S. Collaboration 2021, Ruffini et al. 2021, Rueda et al. 2022, Rastegarnia et al. 2022, Wang et al. 2022). Here we present the X-ray light-curve of GRB 221009A observed by Swift-XRT (GCN 32651), and the t0 is taken from the Fermi-GBM trigger time (GCN 32636), see attached figure 2, a power-law of index -1.58 is fitted. The shadow region shows 20%-60% of the X-ray luminosity, which is expected to be the 0.3-1 TeV luminosity (17% less luminous for 0.5-18 TeV assuming a power-law spectrum of photon index -2) of this new burst if it shares the same behavior as the previous ones. We encourage further observations, especially the VHE observations, because this burst probably is more luminous than the previous ones, and it will be precious to have a late time (after days) VHE luminosity which was never achieved before, as well as the optical observations for the supernova appearance (GCN 32670, GCN 32780).
******************************* TITLE: GCN CIRCULAR NUMBER: 32808 SUBJECT: GRB 221009A: Peak luminosity of the supernova vs. synchrotron afterglow DATE: 22/10/20 14:57:47 GMT FROM: Remo Ruffini at ICRA ruffini@icra.it Y. Aimuratov, L. Becerra, C.L. Bianco, C. Cherubini, S. Filippi, M. Karlica, Liang Li, R. Moradi, F. Rastegar Nia, J.A. Rueda, R. Ruffini, N. Sahakyan, Y. Wang, S.S. Xue, on behalf of the ICRANet team, report: GRB 221009A appears to be a rare example (Jean-Luc Atteia et al. 2022, GCN 32793) of a particularly energetic and close GRB (de Ugarte Postigo et al. 2022, GCN 32648 and Lesage et al. 2022, GCN 32642 and N.P.M. Kuin et al. 2022, GCN 32656). Within the BdHN model, we have followed the X-ray, optical, and radio afterglows originating from synchrotron emission powered by fast spinning newborn neutron stars (vNS) with initial periods of fraction of a millisecond, accreting the supernova ejecta, created by the collapse of a carbon-oxygen core (Rueda et al. 2022, arXiv:2204.00579). Figures 1, 2 and 3 show the afterglows of three type I BdHNe, namely GRB 180720B (Ruffini et al. 2018, GCN 23019), GRB 190114C (Ruffini et al. 2019, GCN 23715), and GRB 211023A (Aimuratov et al. 2021, GCN 31056), and the prediction of their associated supernova. We have indicated the expected time of the occurrence of the supernova in GRB 221009A (Aimuratov et al. 2022, GCN 32780). The ongoing observations in optical, radio, and X-ray bands are strongly recommended for allowing the determination of the spin and magnetic field of the vNS. This will probe as well if the optical synchrotron emission, at ~ 106 s from the Fermi-GBM trigger, impedes the observations of the optical emission of the supernova originating from nickel decay (Aimuratov et al. in preparation, see also data from Ilfan Bikmaev et al. 2022, GCN 32752, and Jia. Ren et al. 2022, arXiv:2210.10673, reproduced in Fig. 4).
******************************* TITLE: GCN CIRCULAR NUMBER: 32828 SUBJECT: GRB 221009A: Determination of the black holes mass and spin DATE: 22/10/24 15:43:08 GMT FROM: Remo Ruffini at ICRA ruffini@icra.it Y. Aimuratov, L. Becerra, C.L. Bianco, C. Cherubini, S. Filippi, M. Karlica, Liang Li, R. Moradi, F. Rastegar Nia, J.A. Rueda, R. Ruffini, N. Sahakyan, Y. Wang, S.S. Xue, on behalf of the ICRANet team, report: In GRB 221009A, as in GRB 130427A (Ackermann et al. 2014, Science, 343, 42; and Ruffini et al. 2019, ApJ, 886, 82), the Fermi-GBM data in the prompt phase are piled up (Lesage et al. 2022, GCN 32642). In both cases there are missing the ultra-relativistic prompt emission (UPE) phases originating from quantum electro dynamical process around a Kerr BH (Ruffini et al. 2019, ApJ, 886, 82; and Rueda et al. 2022, ApJ, 929, 56), which were well observed in GRB 190114C (Moradi et al. 2021, Phys Rev D 104, 063043) and GRB 180720B (Rastegarnia et al. 2022, EPJC 82, 77). Under these conditions, for GRB 130427A the 0.1-100 GeV data of Fermi-LAT had allowed to determine only the lower limit on the BH mass, M>2.31 solar masses, and the upper limit of its spin parameter, α<0.4 (Ruffini et al. 2019, ApJ, 886, 82). For the BDHNI GRB 190114C (Ruffini et al. 2019, GCN 23715), the values of the BH mass and spin had been determined by taking into account the UPE contribution: M=4.53 solar masses, α=0.54 (Moradi et al. 2021, Phys Rev D 104, 063043). The analysis of GRB 130427A applied to GRB 221009A gives for the BH mass and spin parameters: M>2.36 solar masses and α<0.5. We identify the spike at 500s as the X-ray flare (see e.g. Ruffini et al. 2021 MNRAS 504, 5301-5326 for similar GRBs). We also identify the trigger in the 10 keV-10 MeV data of Fermi-GBM as the dawn of the supernova (SN-rise), associated with the gravitational collapse of the progenitor CO-core. The SN ejecta, accreting on the binary NS companion, give origin to the BH (BH rise, Rueda & Ruffini 2012, ApJ L, 758, L7) and accreting on the vNS they originate the afterglow (vNS rise, Ruffini et al. 2018, ApJ, 869.101; Becerra, et al. 2022, Phys Rev D 106, 083002). Additional data analysis from AGILE (GCN 32650), Fermi (GCN 32636, 32637, 32642, 32819), Swift (GCN 32635), LHAASO (GCN 32677), HXMT (Atel 15660) are needed to relate the SN-rise to the first appearance of the vNS (the vNS-rise) by the TeV radiation (GCN 32780, 32820, 32808), and also to relate the appearance of the BH (BH-rise) to the identification of the first GeV emission.
2. Second announcement of the 5th Zeldovich meeting, June 12 - 17, 2023, Yerevan (Armenia)
We are happy to inform you that the abstract submission for the 5th Zeldovich meeting is now open.
The list of invited speakers includes: • Gennady Bisnovatyi-Kogan, Space Research Institute (IKI), Russia • Massimo Della Valle, Capodimonte Astronomical Observatory and INAF, Italy (TBC) • Marat Gilfanov, Max-Planck Institute for Astrophysics, Germany and IKI, Russia (TBC) • Paolo Giommi, Italian Space Agency (ASI), Italy • Luca Izzo, Niels Bohr Institute, Denmark (TBC) • Michael Kramer, Max-Planck-Institut fuer Radioastronomie, Germany (TBC) • Jutta Kunz, University of Oldenburg, Germany (TBC) • Klaus Laemmerzahl, University Bremen, Germany • Di Li, National Astronomical Observatories of China, China • Ruoyu Liu, Nanjing University, China • Andrea Merloni, Max Planck Institute for extraterrestrial Physics, Germany (TBC) • Razmik Mirzoyan, Max-Planck-Institute for Physics, Germany • Tsvi Piran, The Hebrew University, Israel • Konstantin Postnov, Sternberg Astronomical Institute, Moscow State University, Russia • Rashid Sunyaev, Max-Planck Institute for Astrophysics, Germany and IKI, Russia (TBC) • Alexei Starobinsky, Landau Institute for Theoretical Physics, Russia • Lev Titarchuk, University di Ferrara, Italy and Astro Space Center, Lebedev Physical Institute, Russia • Nan Zhang, Institute of High Energy Physics, China At this 5th Zeldovich meeting, the new discoveries from the leading scientific missions in Relativistic Astrophysics will be reported: • Russian-German Spektr-RG telescope (SRG) • USA-European-Canadian James Webb Space Telescope (JWST) • USA-Italian Imaging X-ray Polarimetry Explorer (IXPE) • Chinese-European enhanced X-ray Timing and Polarimetry mission (eXTP) • Chinese Large High Altitude Air Shower Observatory (LHAASO) • Chinese Five-hundred-meter Aperture Spherical Telescope (FAST) • European Major Atmospheric Gamma Imaging Cherenkov Telescope (MAGIC) The early bird registration fee is 300 euro (100 euro for students). The late registration fee will be 400 euro (150 euro for students). It will cover conference kit, coffee breaks and publication of the conference papers. For the poster of the meeting: https://indico.icranet.org/event/6/attachments/382/560/poster.pdf For the website of the meeting: http://www.icranet.org/zeldovich5
3. Mission of Prof. Ruffini to the USA, November 6-11, 2022: lectures at the Cosmos Club, at the Institute for Advanced Studies (IAS) and at Princeton University
From November 6 to 11, 2022, Prof. Remo Ruffini, Director of ICRANet, visited the USA. During that visit, he has been invited to deliver a seminar at the prestigious Cosmos Club in Washington DC on Monday, November 7, 11:30 AM EST, titled "The Role of Supernovae in Triggering the Formation of a Black Hole in Gamma Ray Bursts". Here below the abstract:
Supernovae of constant luminosities, with a tight neutron star companion, trigger complex systems leading to the formation of fast rotating Kerr Black Holes. Their rotational energy feeds gamma ray bursts which are extremely luminous. This presentation identifies extensions of known physical laws, inquiring on the unique role of these cosmic events. We follow their implications for the life evolution of our universe. We also present recent understanding on the largest ever GRB221009A exploded on last October 19 and followed by the largest number of Observatories in all wavelengths from the ground and from space, from radio all the way to MeV, GeV and TeV radiation and UHCR.
On the following day, November 8, Prof. Ruffini moved to Princeton, since he was invited to take part to the traditional Bahcall lunch at the Institute for Advanced Studies (IAS) a special joint lunch for both astrophysics and physics, members and faculty in Dilworth Room, Simons Hall. Following the lunch, Prof. Ruffini moved to Princeton University, where he was invited to present his seminar titled "The Role of Supernovae in Triggering the Formation of a Black Hole in Gamma Ray Bursts" at Jadwin Hall, in the new Gravity Initiative section. While at Princeton University, Prof. Ruffini also met, among others, Prof. Neta Bahcall, Prof. Lyman Page and Prof. Bruce Partridge and took this occasion to have fruitful scientific discussions with them. On the following days, Prof. Ruffini met Dr David Nirenberg, Director of IAS, in order to discuss with him about relevant scientific issues as well as about the recent scientific results obtained by ICRANet group. He also visited Princeton University Library and met Dr Abigail Johnson, from Princeton University Press, with whom he discussed about relevant editorial matters.
4. Prof. Ruffini among the top 2% of the most cited authors, according to Elsevier
Recent update of the publicly available database of over 100,000 top-scientists listed by Elsevier, show that Prof. Remo Ruffini (Director of ICRANet), Prof. Behzad Eslam Panah (ICRANet-Mazandaran, Iran) and several other ICRANet scientists are in this list.
Elsevier has created this publicly available database of top-cited scientists, which provides standardized information on citations, h-index, co-authorship adjusted hm-index and citations to papers in different authorship positions. Scientists are classified into 22 scientific fields and 174 sub-fields, which are also provided for all scientists with at least 5 papers. Career-long data are updated to the end of 2021 and single recent year data pertain to citations received during 2021. The selection is based on the top 100,000 scientists by c-score (with and without self-citations) or a percentile rank of 2% or above in the sub-field. This version of the list is based on the September 1, 2022 snapshot from Scopus, updated to end of citation year 2021. This work uses Scopus data provided by Elsevier through ICSR Lab (https://www.elsevier.com/icsr/icsrlab) and calculations were performed using all Scopus author profiles as of September 1, 2022.
5. Congratulations to Director of ICRANet-Armenia and ICRANet Faculty Professor Narek Sahakyan, awarded of the Doctor of Sciences (DSc) degree in physics, November 22, 2022
It is our pleasure to announce that on November 22, 2022, the Director of ICRANet-Armenia Narek Sahakyan has been awarded the Doctor of Sciences (D Sc) degree in physics, as announced by the Higher Attestation Commission (VAK) of Armenia (https://www.bok.am/en/node/14246). His dissertation "Study of multiwavelength and neutrino emission from blazars" has been successfully defended on the June 25, 2022. Professor Sahakyan has so become one of the few young Armenian researchers, awarded of this highest scientific degree in his country under the age of 40.
6. Partial solar eclipse and measurement of the solar diameter (October 25, 2022) and lunar eclipse at the antipodes (November 8, 2022), online and podcast events
Partial solar eclipse and measurement of the solar diameter (October 25, 2022)
On the occasion of the partial solar eclipse of October 25, 2022, Prof. Costantino Sigismondi, ICRANet collaborator, organized an online and podcast event, in a project carried on together with high school students from Pescara, Rome and Motta di Liveza (Italy), on the measurement of the solar diameter. This study is placed in a project of astrometry structured as follows: "Eclipses, equinoxes and sunsets: the methods to tame the horses of the Sun". The mythological wagon of Febo is channeled through a clear orbit, whose parameters are the object of study of the celestial mechanics. The astronomers after Galileo, with this sentence, alluded to the comprehension of the phenomenon of the atmospheric refraction which was measured exactly with the Sun between 20° and 70° from the Zenith by Giandomenico Cassini in 1655, after being measured by Tycho Brahe in 1572 with the Supernova in Cassiopeia observed by all over Europe. Prof. Sigismondi illustrated the following observational methods and analysis data with measurements of the position and the diameter of the Sun meridian and over the horizon: elements of astrometry (systems of celestial coordinates, Right Ascension and declination, eclectic longitude and latitude); the seasons form the astronomical point of view (the form of the Earth’ orbit: eccentricity and line of the apsides), the form and dimension of Earth from the data on the meridian at Rome S. Maria degli Angeli and dei Martiri in Motta di Livenza, timing of an astronomical observation using the video synchronized with UTC, timing of an astronomical observation from the webcam and the synchronization with the protocol NTP, the astronomical ephemerides NASA, IMCCE and the program Stellarium, the linear fit on the data from the autumnal equinox in 2022, the quadratic fit on the data from the summer solstice in 2022, the quadratic fit on the data from the partial eclipse of the Sun on October 25, 2022 and the online database of the observations held at the Clementine meridian as well as the worksheet for the reduction of the data. For the scientific rationale of the event: http://www.icranet.org/index.php?option=com_content&task=view&id=1461 For the videos analyzed during the event: http://www.icranet.org/index.php?option=com_content&task=view&id=1460#EclissiLuna For the YouTube playlist on the solar eclipse of October 25, 2022: https://www.youtube.com/playlist?list=PLJaer2KV492_Nu3nCaB3LhVxKXsAHhR7S The lunar eclipse at the antipodes (November 8, 2022)
The lunar eclipse at the antipodes has been seen thanks to the calculations (November 8, 2022). In fact, in every eclipses’ season, every 6 draconitics months, the eclipses manifests them in pairs, sometimes also in three. All these statistics are legacies of the Celestial mechanics, and Prof. Costantino Sigismondi, ICRANet collaborator, has traced their main steps through 2 events. The first one has been held on November 5, 2022 at the Basilica of S. Maria degli Angeli (Rome). On the Clementine Line it has been simulated the meridian passages of the Moon of November 7 and 9, 2022 and computed the interpolation on November 8, imposing the condition of alignment among the centers of the Moon, the Earth as well as the Sun. It has been finally discovered that the Moon would be at almost 180° from the Sun on November 8, 2022 at h 12:00. The second one has been held on November 8, through the link to the website Timeanddate, where the images of the eclipse have been transmitted: https://www.timeanddate.com/eclipse/lunar/2022-november-8. Meanwhile, Prof. Sigismondi provided the scientific and historical comment in Italian. The lunar eclipses have been used to measure the longitude of the observational point, having a meridian. They represent the most accurate method for this purpose until the whole XVIII century. Also Cristoforo Colombo evaluated the longitude of Hispaniola with the lunar eclipse of February 29, 1504. Prof. Sigismondi then illustrated all the lunar eclipses that he had observed from January 9, 1982 in Lanciano, repeated after a cycle of Saros on January 21, 2000, while he was in Padua, as well as after a cycle of Metone on January 21, 2019 in Pescara and on August 7, 2017 from Snat’Angelo bridge in Rome. The last eclipse he observed has been on May 16, 2022 in Lanciano. For the website of the meeting, as well as the references on the works concerning the lunar eclipses: http://www.icranet.org/index.php?option=com_content&task=view&id=1460
7. Renewal of the cooperation agreement between ICRANet and the University Campus Bio-Medico of Rome (Italy), October 11, 2022
On October 11, 2022, the agreement between ICRANet and the Campus Bio-medico University of Rome has been renewed. This agreement will be valid for 2 years and the main joint activities to be developed under its framework include: the promotion of theoretical and observational activities within the field of Relativistic Astrophysics; the joint collaboration of faculty members, researchers, post-doctorate fellows and students; the organization of training and teaching courses, seminars, conferences, workshops or short courses, and the joint work on scientific publications. For the text of the agreement: http://www.icranet.org/bio-medico
8. Seminars at ICRANet center in Pescara, November 25, 2022
Seminar of Prof. Gennady Bisnovatyi-Kogan
On Friday, November 25, 2022, Prof. Gennady Bisnovatyi-Kogan (Space Research Institute of the Russian Academy of Sciences - SRI RAS) presented a seminar titled "About the Observational Check of the Mechanism of Gamma Radiation in Soft Gamma Repeaters (SGR)" with the following abstract: Soft gamma repeaters (SGR) are identified as single neutron stars (NS) inside the Galaxy, or nearby galaxies, with sporadic transient gamma radiation. A total number of discovered SGR, including relative Anomalous X-ray pulsars (AXP), is a few tens of objects. Many of them show periodic radiation, connected with NS rotation, with periods 2-12 s. The slow rotation is accompanied by small rate of loss of rotational energy, which is considerably smaller than the observed sporadic gamma ray luminosity, and is many orders less than the luminosity during giant bursts, observed in 4 SGR. Therefore the energy source is usually connected with annihilation of a very strong NS magnetic field. Another model is based on the release of nuclear energy stored in the NS non-equilibrium layer. We suggest here an observational test which could distinguish between these two models. The announcement of the seminar has also been published on ICRANet website: http://www.icranet.org/index.php?option=com_content&task=blogcategory&id=89&Itemid=781 For the video of the seminar: https://youtu.be/1lZLqJ_pogk
Seminar of Prof. Marco Merafina On Friday, November 25, 2022, Prof. Marco Merafina (University of Rome La Sapienza) presented a seminar titled "Multimass King models with Kroupa mass function" with the following abstract: Statistical analysis on Milky Way globular clusters distribution is developed in order to extract the best fit function and carry out the critical value of the onset of gravothermal catastrophe, connected with the maximum of the distribution function. Results show that gravothermal collapse for globular clusters onsets earlier than commonly believed and in accordance with theoretical results obtained by considering the presence of the effective potential which describes the effects of the tidal forces induced by the hosting galaxy. N-body simulations confirm the presence of the effective potential with the predicted form. Theoretical model is generalized to multimass one by using Kroupa mass function. A detailed description of the projected densities at different W0 indicates similar luminosity profiles in complete accordance with observations. We also consider the effects of the mass segregation on the distribution of stars and the consequences on the equipartition process. N-body simulations in connection with mass distribution and segregation as well the computational development applied to multimass model are also shown at the present state of the art. The announcement of the seminar has also been published on ICRANet website: http://www.icranet.org/index.php?option=com_content&task=blogcategory&id=89&Itemid=781 For the video of the seminar: https://youtu.be/gW4yGYbLdNA
9. Scientific visits to ICRANet
• Prof. Seyed Mohammad Taghi Mirtorabi (Alzahra University - Iran), October 1 - 18, 2022
• Prof. Massimo Della Valle (Osservatorio di Capodimonte - Italy), October 30 - November 1, 2022 • Prof. Gennady Bisnovatyi-Kogan (Space Research Institute of the Russian Academy of Sciences - SRI RAS), November 25 - 27, 2022 • Prof. Marco Merafina (University of Roma La Sapienza), November 25, 2022
During their visit, those scientists had an opportunity to discuss their scientific research and to have fruitful exchange of ideas with other researchers from ICRANet and from different parts of the world.
10. Recent publications
J. A. Rueda, Liang Li, R. Moradi, R. Ruffini, N. Sahakyan, and Y. Wang, On the X-Ray, Optical, and Radio Afterglows of the BdHN I GRB 180720B Generated by Synchrotron Emission, published on November 3, 2022 in ApJ, Volume 939, Number 2.
Gamma-ray bursts (GRBs) are systems of unprecedented complexity across all the electromagnetic spectrum, including the radio, optical, X-rays, gamma rays in the MeV and GeV regimes, as well as ultrahigh-energy cosmic rays, each manifested in seven specific physical processes with widely different characteristic evolution timescales ranging from 10−14 s to 107 s or longer. We here study the long GRB 180720B originating from a binary system composed of a massive carbon-oxygen (CO) star of about 10M⊙ and a companion neutron star (NS). The gravitational collapse of the CO star gives rise to a spinning newborn NS (νNS), with an initial period of P0 = 1 ms that powers the synchrotron radiation in the radio, optical, and X-ray wavelengths. We here investigate solely the GRB 180720B afterglows and present a detailed treatment of its origin based on the synchrotron radiation released by the interaction of the νNS and the SN ejecta. We show that in parallel to the X-ray afterglow, the spinning νNS also powers the optical and radio afterglows and allows to infer the νNS and ejecta parameters that fit the observational data. DOI: http://dx.doi.org/10.3847/1538-4357/ac94c9 J. A. Rueda, R. Ruffini, L. Li, R. Moradi, J. F. Rodriguez, and Y. Wang, Evidence for the transition of a Jacobi ellipsoid into a Maclaurin spheroid in gamma-ray bursts, published on October 7, 2022 in Phys. Rev. D 106, 083004. In the binary-driven hypernova (BdHN) scenario, long gamma-ray bursts (GRBs) originate in a cataclysmic event that occurs in a binary system composed of a carbon-oxygen (CO) star and a neutron star (NS) companion in close orbit. The collapse of the CO star generates at its center a newborn NS (νNS), and a supernova (SN) explosion. Matter from the ejecta is accreted both onto the νNS because of fallback and onto the NS companion, leading to the collapse of the latter into a black hole (BH). Each of the ingredients of the above system leads to observable emission episodes in a GRB. In particular, the νNS is expected to show up (hereafter νNS−rise) in the early GRB emission, nearly contemporary or superimposed to the ultrarelativistic prompt emission (UPE) phase, but with a different spectral signature. Following the νNS−rise, the νNS powers the afterglow emission by injecting energy into the expanding ejecta leading to synchrotron radiation. We here show that the νNS−rise and the subsequent afterglow emission in both systems, GRB 180720B and GRB 190114C, are powered by the release of rotational energy of a Maclaurin spheroid, starting from the bifurcation point to the Jacobi ellipsoid sequence. This implies that the νNS evolves from a triaxial Jacobi configuration, prior to the νNS−rise, into the axially symmetric Maclaurin configuration observed in the GRB. The triaxial νNS configuration is short-lived (less than a second) due to a copious emission of gravitational waves, before the GRB emission, and it could be in principle detected for sources located at distances closer than 100 Mpc. This appears to be a specific process of emission of gravitational waves in the BdHN I powering long GRBs. DOI: https://doi.org/10.1103/PhysRevD.106.083004 L. M. Becerra, R. Moradi, J. A. Rueda, R. Ruffini, and Y. Wang, First minutes of a binary-driven hypernova, published on October 3, 2022 in Phys. Rev. D 106, 083002. We simulate the first minutes of the evolution of a binary-driven hypernova event, with a special focus on the associated accretion processes of supernova ejecta onto the newborn neutron star (νNS) and the NS companion. We calculate the rotational evolution of the νNS and the NS under the torques exerted by the accreted matter and the magnetic field. We take into account general relativistic effects through effective models for the NSs binding energy and the specific angular momentum transferred by the accreted matter. We use realistic hypercritical accretion rates obtained from three-dimensional smoothed-particle-hydrodynamics numerical simulations of the binary-driven hypernova event for a variety of orbital periods. We show that the rotation power of the νNS has a unique double-peak structure while that of the NS has a single peak. These peaks are of comparable intensity and can occur very close in time or even simultaneously depending on the orbital period and the initial angular momentum of the stars. We outline the consequences of the above features in the early emission and their consequent observation in long gamma-ray bursts. DOI: https://doi.org/10.1103/PhysRevD.106.083002 Carvalho, G. A.; Anjos, R. C. dos; Coelho, J. G.; Lobato, R. V.; Malheiro, M.; Marinho, R. M.; Rodriguez, J. F.; Rueda, J. A.; Ruffini, R., Orbital Decay of Double White Dwarfs: Beyond Gravitational-wave Radiation Effects, published on November 23, 2022 in ApJ, Vol. 940, n. 1. The traditional description of the orbital evolution of compact-object binaries, like double white dwarfs (DWDs), assumes that the system is driven only by gravitational-wave (GW) radiation. However, the high magnetic fields with intensities of up to gigagausses measured in WDs alert a potential role of the electromagnetic (EM) emission in the evolution of DWDs. We evaluate the orbital dynamics of DWDs under the effects of GW radiation, tidal synchronization, and EM emission by a unipolar inductor generated by the magnetic primary and the relative motion of the nonmagnetic secondary. We show that the EM emission can affect the orbital dynamics for magnetic fields larger than megagausses. We applied the model to two known DWDs, SDSS J0651+2844 and ZTF J1539+5027, for which the GW radiation alone does not fully account for the measured orbital decay rate. We obtain upper limits to the primary's magnetic field strength, over which the EM emission causes an orbital decay faster than observed. The contribution of tidal locking and the EM emission is comparable, and together they can contribute up to 20% to the measured orbital decay rate. We show that the gravitational waveform for a DWD modeled as purely driven by GWs and including tidal interactions and EM emission can have large relative dephasing detectable in the mHz regime of frequencies relevant for space-based detectors like LISA. Therefore, including physics besides GW radiation in the waveform templates is essential to calibrate the GW detectors using known sources, e.g., ZTF J1539+5027, and to infer binary parameters. DOI: 10.3847/1538-4357/ac9841 S-S. Xue, W boson mass tension caused by its right-handed gauge coupling at high energies?, published on October 16, 2022 in Nuclear Physics B, Volume 985. The CDF collaboration's recent high-precision measurement of the W mass is in 7.0σ disagreement with the Standard Model expectation. This tension will be relieved if the W boson has a non-trivial right-handed gauge coupling at high energies. At TeV scales, the SM gauge symmetric four-fermion interactions induce a right-handed gauge coupling, and SM fermions compose massive composite particles. We investigate the top-quark mass produced by spontaneous symmetry breaking and compute the W and Z boson propagators and decays. The right-handed coupling corrections to their masses and widths are consistent with experimental measurements. We discuss how SM gauge bosons and composite particles can restore parity-preserving gauge symmetries at TeV scales. DOI: https://doi.org/10.1016/j.nuclphysb.2022.115992 N. Sahakyan, D. Israyelyan, G. Harutyunyan, S. Gasparyan, V. Vardanyan, M. Khachatryan, Modelling the time variable spectral energy distribution of the blazar CTA 102 from 2008 to 2022, published on October 2, 2022 in Monthly Notices of the Royal Astronomical Society. We present long-term multiwavelength observations of blazar CTA 102 (z = 1.037). Detailed temporal and spectral analyses of γ-ray, X-ray, and UV/optical data observed by Fermi-LAT, Swift XRT, NuSTAR, and Swift-UVOT over a period of 14 yr, between 2008 August and 2022 March, were performed. We found strong variability of source emission in all the considered bands; especially in the γ-ray band it exhibited extreme outbursts when the flux crossed the level of 10−5 photon cm−2 s−1. Using the Bayesian Blocks algorithm, we split the adaptively binned γ-ray light curve into 347 intervals of quiescent and flaring episodes and for each period built corresponding multiwavelength spectral energy distributions (SEDs), using the available data. Among the considered SEDs, 117 high-quality (quasi) contemporaneous SEDs, which have sufficient multiwavelength data, were modelled using JETSET framework within a one-zone leptonic synchrotron and inverse-Compton emission scenario assuming the emitting region is within the broad-line region and considering internal and external seed photons for the inverse-Compton up scattering. As a result of modelling, the characteristics of the relativistic electron distribution in the jet as well as jet properties are retrieved and their variation in time is investigated. The applied model can adequately explain the assembled SEDs and the modelling shows that the data in the bright flaring periods can be reproduced for high Doppler boosting and magnetic field. The obtained results are discussed in the context of particle cooling in the emitting region. DOI: https://doi.org/10.1093/mnras/stac2875 B. Eslam Panah, Two-dimensional Lifshitz-like AdS black holes in F(R) gravity, published on November 2 in the Journal of Mathematical Physics 63, 112502 (2022). Two-dimensional (2D) Lifshitz-like black holes in special F(R) gravity cases are extracted. We indicate an essential singularity at r = 0, covered by an event horizon. Then, conserved and thermodynamic quantities, such as temperature, mass, entropy, and the heat capacity of 2D Lifshitz-like black holes in F(R) gravity, are evaluated. Our analysis shows that 2D Lifshitz-like black hole solutions can be physical solutions, provided that the cosmological constant is negative (Λ < 0). Indeed, there is a phase transition between stable and unstable cases by increasing the radius of AdS black holes. In other words, the 2D Lifshitz-like AdS black holes with large radii are physical and enjoy thermal stability. The obtained 2D Lifshitz-like AdS-black holes in F(R) gravity turn into the well-known 2D Schwarzschild AdS-black holes when the Lifshitz-like parameter is zero (s = 0). Moreover, correspondence between these black hole solutions and the 2D rotating black hole solutions is found by adjusting the Lifshitz-like parameter. DOI: https://doi.org/10.1063/5.0104272 A. Bagheri Tudeshki, G. H. Bordbar, and B. Eslam Panah, Dark Energy Star in Gravity's Rainbow, published on October 19 in Physics Letters B. 835, 137523 (2022). The concept of dark energy can be a candidate for preventing the gravitational collapse of compact objects to singularities. According to the usefulness of gravity's rainbow in UV completion of general relativity (by providing a new description of spacetime), it can be an excellent option to study the behavior of compact objects near phase transition regions. In this work, we obtain a modified Tolman-Openheimer-Volkof (TOV) equation for anisotropic dark energy as a fluid by solving the field equations in gravity's rainbow. Next, to compare the results with general relativity, we use a generalized Tolman-Matese-Whitman mass function to determine the physical quantities such as energy density, radial pressure, transverse pressure, gravity profile, and anisotropy factor of the dark energy star. We evaluate the junction condition and investigate the dynamical stability of dark energy star thin shell in gravity's rainbow. We also study the energy conditions for the interior region of this star. We show that the coefficients of gravity's rainbow can significantly affect this non-singular compact object and modify the model near the phase transition region. DOI: https://doi.org/10.1016/j.physletb.2022.137523 García, Cristhian; Santa, Camilo; Romano, Antonio Enea, Deep learning reconstruction of the large scale structure of the Universe from luminosity distance, published on October 19, 2022 in Monthly Notices of the Royal Astronomical Society. Supernovae Ia (SNe) can provide a unique window on the large-scale structure (LSS) of the Universe at redshifts where few other observations are available, by solving the inversion problem (IP) consisting in reconstructing the LSS from its effects on the observed luminosity distance. So far the IP was solved assuming some restrictions about space-time, such as spherical symmetry for example, while we obtain for the first time solutions of the IP problem for arbitrary space-time geometries using deep learning. The method is based on the use of convolutional neural networks (CNN) trained on simulated data. The training data set is obtained by first generating random density and velocity fields, and then computing their effects on the luminosity distance. The CNN, based on an appropriately modified version of U-Net to account for the tridimensionality of the data, is then trained to reconstruct the density and velocity fields from the luminosity distance. We find that the velocity field inversion is more accurate than the density field, because the effects of the velocity on the luminosity distance only depend on the source velocity, while in the case of the density it is an integrated effect along the line of sight, giving rise to more degeneracy in the solution of the IP. Improved versions of these neural networks, modified to accommodate the non-uniform distribution of the SNe, can be applied to observational data to reconstruct the LSS of the Universe at redshifts at which few other observations are available. DOI: https://doi.org/10.1093/mnras/stac2916 Cadavid, Alexander Gallego; Romano, Antonio Enea; Liddle, Andrew R., Reconstructing homospectral inflationary potentials, published on October 13, 2022 in Phys. Rev. D 106, 083512. Purely geometrical arguments show that there exist classes of homospectral inflationary cosmologies, i.e., different expansion histories producing the same spectrum of comoving curvature perturbations. We develop a general algorithm to reconstruct the potential of minimally coupled single scalar fields from an arbitrary expansion history. We apply it to homospectral expansion histories to obtain the corresponding potentials, providing numerical and analytical examples. The infinite class of homospectral potentials depends on two free parameters, the initial energy scale and the initial value of the field, showing that, in general, it is impossible to reconstruct a unique potential from the curvature spectrum unless the initial energy scale and the field value are fixed, for instance, through observation of primordial gravitational waves. DOI: https://doi.org/10.1103/PhysRevD.106.083512 |
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