| Newsletter French August/September 2018 |
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ICRANet Newsletter
Bulletin ICRANet
August - Septembre 2018
RÉSUMÉ
1. The event GRB 170817A-GW170817-AT 2017gfo as WD-WD merger 2. Prédiction et confirmation du GRB 180728A / SN 2018fip par les chercheurs d’ ICRANet 3. La Nuit des Chercheurs à l’ICRANet, Pescara, 28 Septembre 2018 4. Visite du Professeur Ruffini à la Tsinghua University (Pékin) et au TD Lee Institute (Shanghai), 8 -15 August 2018 5. Visite et séminaire du Professeur Ruffini au LAPP, Annecy, 3 - 4 Septembre 2018 6. Visite du Professeur Ruffini au Kazakhstan et 3 nouveaux Accords de Collaboration,6 - 8 Septembre 2018 7. Visites scientifiques au centre ICRANet 8. Édition spéciale de la revue “Science and Innovation” en Biélorussie 9. Publications récentes
1. The event GRB 170817A-GW170817-AT 2017gfo as WD-WD merger
The paper "GRB 170817A-GW170817-AT 2017gfo and the observations of NS-NS, NS-WD and WD-WD mergers" by J. A. Rueda, R. Ruffini, Y. Wang, Y. Aimuratova; U. Barres de Almeida, C. L. Bianco, Y. C. Chen, R. V. Lobato, C. Maia, D. Primorac, R. Moradia, and J. F. Rodriguez, is published in JCAP 10 (2018) 006 on October 3, 2018.
The LIGO-Virgo Collaboration has announced the detection of GW170817 and has associated it with the gamma-ray bursts (GRB) 170817A. These signals have been followed after 11 hours by the optical and infrared kilonova emission of AT 2017gfo. The origin of this complex phenomenon has been attributed to a neutron star-neutron star (NS-NS) binary merger. The kilonova in this case would be powered by the radioactive decay of r-process heavy material synthesized in the NS-NS merger. However, as we show in this work, the gamma- and X-rays emissions of GRB 170817A are in clear contrast with the ones of any short-duration GRB associated either with a NS-NS merger or with other merger types (see details below). In fact, in order to probe the GW-GRB-kilonova association we confront our current understanding of the gravitational waves and associated electromagnetic radiation with four observed GRBs originating in binaries with NS and white dwarf (WD) components: 1) GRB 090510 the prototype of the authentic short GRB (S-GRB) subclass produced by a NS-NS merger leading to a black hole (BH); 2) GRB 130603B the prototype of the short gamma-ray flash (S-GRF) subclass produced by a NS-NS merger leading to massive NS (MNS); 3) GRB 060614 the prototype of the GRF subclass produced by a NS-WD merger leading to a MNS; and 4) we propose GRB 170817A as the prototype of a new subclass of GRB by a WD-WD merger leading to massive WD, and an AT 2017gfo-like kilonova. None of them support the triptych GW-GRB-kilonova. 
There are a number of new astrophysical results: a. The NS-NS scenario cannot explain GRB170817A-GW170817 since this solution implies an X and gamma-ray prompt emission missing in GRB 170817A (see data up to 10 s data in the figure). b. Instead, X- and gamma-ray observations of GRB 170817A have led us to propose a new subclass of GRBs originating from WD-WD mergers leading to a massive WD. The occurrence rate of these mergers can explain the rate of GRB 170817A-like sources, they produce a gamma- and X-ray emission consistent with GRB 170817A and cannot be associated with GW170817. c. The kilonova AT 2017gfo can be powered by a different physical mechanism that the radioactive decay of r-processed heavy nuclei in the ejecta of NS-NS mergers: the cooling of the ejecta expelled in a WD-WD merger and heated up by fallback accretion onto the newly-formed massive WD. d. The WD-WD merger ejecta have a lighter nuclear composition with respect to the r-processed heavy nuclei present in the ejecta of a NS-NS merger. The identification of atomic species in kilonova spectra can therefore discriminate between the two scenarios. However, such an identification has not been possible in observed kilonovae since it needs accurate models of atomic spectra, nuclear reaction network, density profile, as well as radiative transport (opacity), not yet available in the literature. e. The outcome configuration of a GRB from WD-WD merger, namely a massive, highly magnetized, fast rotating WD, can become observable as a soft gamma repeater (SGR) or anomalous X-ray pulsar (AXP) as indicated in the WD-pulsar model introduced by Malheiro, Rueda and Ruffini in 2012. f. The association of GRB 170817A and GW170817, from an observational point of view is, in our opinion, not yet sufficiently established to formulate a well-motivated answer on the non-null chance coincidence probability of the events. It is thus auspicable that the LIGO collaboration releases the templates of GW170817 in the interferometers to reconstruct the precise chronology of the space-time sequence of events in the LIGO detectors and in the Fermi and Integral satellites, necessary to validate the GW170817-GRB 170817A association. JCAP website: http://iopscience.iop.org/article/10.1088/1475-7516/2018/10/006 arXiv: https://arxiv.org/abs/1802.10027
2. Prédiction et confirmation du GRB 180728A / SN 2018fip par les chercheurs d’ ICRANet
After having successfully predicted the SN 2013cq associated with GRB 130427A (Ruffini et al.2013), as an example for the BdHN case, on 28 July 2018, ICRANet researchers led by prof. Remo Ruffini had the opportunity to predict of the supernova (SN) appearance in an X-ray flash (XRF) case.
At 17:29:00 UT, on 28 July 2018, the Swift-BAT triggered and located GRB 180728A. The BAT light curve shows a small precursor followed ∼ 10 s later by a bright pulse of ∼ 20 s duration (Starling2018). Swift-XRT did not slew immediately due to the Earth limb constraint, it began observing the field 1730.8 s after the BAT trigger (Perri2018). The Fermi-GBM triggered and located GRB 180728A at 17:29:02.28 UT. The angle from the Fermi-LAT boresight at the GBM trigger time is 35 degrees. The GBM light curve consists of a precursor and a very bright peak with a duration (T90) of about 6.4 s (50-300 keV) (Veres2018). A red continuum is detected across the spectral range of VLT/X-shooter, the absorption features due to Mg II (3124, 3132), Mg I (3187), and Ca II (4395, 4434) at a consistent redshift of z = 0.117. Although Galactic extinction in this direction is significant, a cam- paign to study the anticipated associated supernova should still be practical with moderate-aperture telescopes at this redshift (Rossi2018). With the above first 3 days observations after the trigger of the GRB, the group has predicted that a supernova would appear in 14.7 ± 2.9 days (Ruffini2018), quoted here: GCN 23066: GRB 180728A: A long GRB of the X-ray flash (XRF) sub- class, expecting supernova appearance Link: https://gcn.gsfc.nasa.gov/gcn3/23066.gcn3 GRB 180728A has T90 = 6.4 s (Rossi2018), peak energy 142(-15, +20) keV, and isotropic energy Eiso = (2.33 ± 0.10) × 1051 erg (Frederiks2018). It presents the typical characteristic of a subclass of long GRBs called X-ray flashes (XRFs, seeRuffini et al.2016), originat- ing from a tight binary of a COcore undergoing a supernova explosion in presence of a companion neutron star (NS) that hypercritically accretes part of the supernova matter. The outcome is a new binary composed by a more massive NS (MNS) and a newly born NS (vNS). Using the averaged observed value of the optical peak time of supernova (Cano et al.2017) and considering the redshift z = 0.117 (Rossi2018), a bright optical signal will peak at 14.7 ± 2.9 days after the trigger (12 August 2018, uncertainty from August 9th to August 15th) at the location of RA=253.56472 and DEC=-54.04451, with an uncertainty 0.43 arcsec (LaPorte2018). The follow-up observations, especially the optical bands for the SN, as well as attention to binary NS pulsar behaviours in the X-ray afterglow emission, are recommended. On 18 July 2018, Izzo (2018) reported the discovery of the supernova appearance: GCN 23142: GRB 180728A: discovery of the associated supernova Link: https://gcn.gsfc.nasa.gov/gcn3/23142.gcn3 ... Up to now, we have observed at three epochs, specifically at 6.27, 9.32 and 12.28 days after the GRB trigger. The optical counterpart is visible in all epochs using the X-shooter acquisition camera in the g, r and z filters. We report a rebrightening of 0.5 ± 0.1 mag in the r band between 6.27 and 12.28 days. This is consistent with what is observed in many other low-redshift GRBs, which in those cases is indicative of an emerging type Ic SN ... For the last spectrum, we attempted the identification of a few features. In particular, we identify the broad dip at 7600 AA as due to the blend O I 8446 AA and Ca II 8492 AA, at the expansion velocity of 30,000 km s-1. At this velocity, we also identify the Si II 6355 doublet, as well as C II 6580. The width of the lines spans several thousand km s-1. Independent of the interpretation of the lines, the overall shape of the continuum, together with the presence of several absorption features a few thousands km s-1 wide, strongly indicate that this is a SN. The lack of identified H and He in the spectra suggests a classification of type Ic ... and the SN was confirmed in Selsing (2018). This SN associated with GRB 180728A is named SN 2018fip by the Transient Name Server. Therefore the prediction was confirmed.
3. La Nuit des Chercheurs à l’ICRANet, Pescara, 28 Septembre 2018
La manifestation a eu lieu Vendredi 28 Septembre auprès du centre ICRANet de Pescara, en présence du Préfet de la ville, Madame Gerardina Basilicata, et de nombreux étudiants et citoyens. Après les souhaits de bienvenue du Professeur Remo Ruffini, Directeur d’ICRANet, plusieurs interventions se sont succédé par les chercheurs et les étudiants de Doctorat ICRANet (Dr Wang Yu, Yerlan Aimuratov et Dr Luca Izzo), qui ont illustré le GRB 180727A et la supernova du 15 Aout 2018, par le Prof. Costantino Sigismondi (ITIS Galileo Ferraris – Rome) sur le cinquantenaire de l’homme sur la lune, par le Professeur Ruffini e par la Faculté d’ ICRANet, qui ont engagé le débat avec les participants sur les perspectives récentes et futures de la science. 
Photo de group avec des participants à la “Nuit des Chercheurs à l’ICRANet” le 28 Septembre. A coté des conférences, il y a eu aussi des projections vidéo dans tout le centre, portant sur le “Caso Neutrino”, “l’Assoluto Relativo” et sur les conférences qui s’étaient tenues auprès de la Fondation Marco Besso à Rome, dans le cadre du projet financé par le Ministère italien pou l’Education, l’Université et la Recherche (MIUR) “Del Talento e della curiosità. Quando l’aquila e il passero volano insieme”. Par ailleurs, les participants ont aussi eu la possibilité de visiter les 2 expositions organisées par ICRANet, portant sur la naissance et les origines de l’Astrophysique Relativiste et sur ses représentants principaux, tels que Einstein, Heisenberg et Fermi, ainsi que sur la collaboration scientifique entre ICRANet et la Chine, centré sur la figure de Fang Li-Zhi, Premier Président du Comité de Direction de l’ICRANet. La manifestation a été conclue avec l’observation au télescope de Saturne et Mars, illustré et commenté par les étudiants du Lycée Galileo Galilei de Pescara. 
Les étudiants et les citoyens écoutent les interventions des Professeurs de l’ICRANet pendant la Nuit des Chercheurs du 28 Septembre. Le programme de la manifestation peut être consulté au lien : http://www.icranet.org/Notte_dei_ricercatori_2018/programma.pdf Pour informations complémentaire sur la manifestation: http://www.icranet.org/index.php?option=com_content&task=view&id=1210
4. Visite du Professeur Ruffini à la Tsinghua University (Pékin) et au TD Lee Institute (Shanghai), 8 -15 August 2018
Du 8 au 15 Aout 2018, le Professeur Remo Ruffini, Directeur d’ICRANet, s’est rendu en China à l’invitation du Professeur Shing-Tung Yau de tenir un séminaire auprès du Yau Mathematical Sciences Center à la Tsinghua University de Pékin le 9 Aout 2018. Le séminaire, intitulé “On the observation of supernovae in the late phases of Gamma-Ray Bursts” a présenté au public les résultats atteints par le Professeur Ruffini, les chercheurs ICRANet et les étudiants de Doctorat (Y. Aimuratov, L. Becerra, C.L. Bianco, Y.C. Chen, D.M. Fuksman, M. Karlica, G. Mathews, R. Moradi, D. Primorac, J.A. Rueda, N. Sahakyan, Y. Wang, S.-S. Xue).
Pour la vidéo du séminaire, on vous prie de consulter le lien: https://www.youtube.com/watch?v=Q6xssDI7a84
Accompagné par le Dr Yu Wang, ancien étudiant de doctorat ICRANet, le Professeur Ruffini a aussi visité le Tsung-Dao Lee Institute de Shanghai, ou il a été invité à présenter une C. C. Lin lecture sur le même sujet présenté quelques jours avant à Pékin. Pendant cette visite, le Professeur Ruffini a aussi eu la possibilité de voir l’ MG14 Award décerné en 2015 à T. D. Lee “for his work on white dwarfs motivating Enrico Fermi’s return to astrophysics and guiding the basic understanding of neutron star matter and fields”.
Pour informations complémentaires sur le séminaire et la prédiction des 2 GCNs: http://www.icranet.org/documents/Abstract+2GCNs.pdf
5. Visite et séminaire du Professeur Ruffini au LAPP, Annecy, 3 - 4 Septembre 2018
Le 4 septembre 2018, le professeur Remo Ruffini, Directeur d’ICRANet, a visité le LAPP (Laboratoire d’Annecy de Physique des Particules) à Annecy, France, ou il a été invité à tenir un séminaire par le Directeur du centre, Giovanni Lamanna. Dans ce séminaire, intitulé “GRB180728A, our predicted Supernova denominated on 27 August SN2018fip and conceptual inferences” (https://indico.in2p3.fr/event/17864/), le Professeur Ruffini a illustré l’apparition d’une séquence d’événements à partir du 28 Juillet, quand le GRB190728A a été observé par les satellites SWIFT e Fermi. With his collaborators, they have identified this source as a member of the X-ray Flash (XRF) subclass of gamma-ray bursts (GRBs) in which a supernovae (SN) ejecta hypercritically accretes onto the neutron star (NS) companion leading to a more massive NS (MNS) and to a νNS-MNS binary. On the other hand, in the GCN23066 on 31 July 2018, they predicted the occurrence of a SN, indeed observed on 15 August (GCN23142). The significance of this result in discriminating the 8 different GRBs subclass has been analyzed.
6. Visite du Professeur Ruffini au Kazakhstan et 3 nouveaux Accords de Collaboration,6 - 8 Septembre 2018
Du 6 au 8 Septembre 2018, le Professeur Remo ruffini, directeur d’ICRANet, s’est rendu en visite officielle au Kazakhstan. Pendant la première journée, le Professeur Ruffini a visité la Nazarbayev University de Astana, ou il a tenu le séminaire “GRB180728A, our predicted Supernova denominated on 27 August SN2018fip and conceptual inferences” et rencontré son Vice-Président pour l’Innovation et la Recherche, M. Kanat Baigarin. Dans la même journée, il a aussi rencontré S.E. Pasquale D’Avino, Ambassadeur d’Italie à Astana: les deux ont eu une intéressante discussion portant sur les nombreuses opportunités de collaboration entre l’Italie et le Kazakhstan dans le domaine des sciences. Pendant sa visite, le professeur Ruffini a aussi signé un Accord de Coopération avec la L.N. Gumilyov Eurasian National University (ENU) de Astana avec son Recteur, le Prof. Yerlan Battashevich Sydykov. Les principales activités conjointes qui seront développées dans le cadre de cet accord comptent la promotion des activités de recherche et d'observation dans le champ der l’astrophysique relativiste; l’échange institutionnel des membres de la Faculté, des chercheurs, des post-doctorat fellows et des étudiants; la promotion des développement technologiques, ainsi que l’organisation de séminaires, conférences, workshops, cours de formations et de recherche et des publications conjointes. 
Le Professeur Remo Ruffini, accompagné par le Prof. Abishev Medeu, pendant la cérémonie de signature du Memorandum of cooperation in science and education avec le Center for Space Research & Technology (NCSR) à Almaty. Le jour suivant, le Professeur Ruffini s’est rendu à Almaty ou, dans la matinée, accompagné par le Professeur Abishev Medeu (Al-Farabi Kazakh National University), a eu un rendez-vous avec le Professor Chingis Omarov, président du National Center for Space Research & Technology (NCSR). Dans cette occasion, l’ICRANet a signé un Memorandum of cooperation in science and education avec le NCSR, représenté par le Professeur Omarov (Président du centre). Le memorandum sera valable pour 5 années à compter de la date de sa signature. Les principales formes de coopération prévues comptent l’échange d’expertise scientifique, des activités de recherche conjointes, la participation conjointe aux appels de recherche et l’échange de matériel et savoir scientifique. Après la cérémonie de signature, le Professeur Ruffini a visité le Fesenkov Astrophysical Institute (FAPHI), et a eu l’opportunité d’observer le météorite Sikhote-Alin, un météorite en fer tombé sur les montagnes du Sikhote-Alin, au sud-est de la Russie en 1947. Meme si on avait déjà des témoignages de la chute de grands météorites en fer, jamais auparavant on a eu une chute d’un météorite si grand. Dans cet institut, le Professeur Ruffini a aussi tenu son séminaire “GRB180728A, our predicted Supernova denominated on 27 August SN2018fip and conceptual inferences”.
Par ailleurs, le Professeur Ruffini a aussi renconté l’Académicien Tolegen Kozhamkulov, Président de la Kazakh Physical Society (KPS) et, dans cette occasion, il a signé un Accord de Coopération avec l’ICRANet, représenté par son Directeur. Les principales activités conjointes qui seront développées dans le cadre de cet accord comptent la promotion des activités de recherche et d'observation dans le champ der l’astrophysique relativiste; l’échange institutionnel des membres de la Faculté, des chercheurs, des post-doctorat fellows et des étudiants; la promotion des développement technologiques, ainsi que l’organisation de séminaires, conférences, workshops, cours de formations et de recherche et des publications conjointes. Le Samedi 8 Septembre, le Professeur Ruffini, accompagné par le Prof. Kozhamkulov, le Prof. Abishev et par l’étudiant de Doctorat Yerlan Aimuratov, a rencontré S. E. Yerlan Sagadiyev, Ministre de l’Education et de la Science du Kazakhstan auprès du Palais de l’Academy of Sciences de Almaty. Le principal sujet abordé a été la coopération entre le Kazakhstan et l’ICRANet.
Pour la vidéo du séminaire du Professeur Ruffini au Fesenkov Astrophysical Institute (FAPHI), Almaty, du 7 Septembre 2018: https://www.youtube.com/watch?v=f_w5-UZ1-sQ Pour les communiqués de presse: http://www.kaznu.kz/en/3/news/one/14314/ https://www.inform.kz/ru/kazahstanskie-astrofiziki-sovmestno-s-ital-yancami-budut-izuchat-chernye-dyry_a3390191 (en russe) Per les 3 accords: • http://www.icranet.org/documents/AgreementICRANet-ENU.pdf (Accord ICRANet - ENU) • http://www.icranet.org/index.php?option=com_content&task=view&id=1203 (Accord ICRANet - KPS) • http://www.icranet.org/documents/AgreementICRANet-JSC-NCRS.pdf (MoU ICRANet - JSC NCRS)
7. Visites scientifiques au centre ICRANet
8. Édition spéciale de la revue “Science and Innovation” en Biélorussie
* "Current state art in astrophysics and perspectives in Belarus" par Gregory Vereshchagin, ICRANet Faculty Professor; * "Cosmology and astrophysics today: dark energy and dark matter" par Ivan Siutsou and Yuri Vyblyi, chercheurs du centre ICRANet-Minsk; * "Gamma-ray bursts - the most bright and mysterious objects in the Universe" par Ivan Siutsou et Gregory Vereshchagin. Pour informations complémentaire (en russe): http://innosfera.by/content_2018_08
9. Publications récentes
Bini D., Geralico A., Gravitational self-force corrections to tidal invariants for spinning particles on circular orbits in a Schwarzschild spacetime, to appear on Phys. Rev. D (2018), arXiv:1806.03495
Bini D., Geralico A., Gravitational self-force corrections to tidal invariants for particles on eccentric orbits in a Schwarzschild spacetime, published on Phys. Rev. D, Vol. 98, Iss. 6 - 15 September 2018, arXiv:1806.06635 We study tidal effects induced by a particle moving along a slightly eccentric equatorial orbit in a Schwarzschild spacetime within the gravitational self-force framework. We compute the first-order (conservative) corrections in the mass ratio to the eigenvalues of the electric-type and magnetic-type tidal tensors up to the second order in eccentricity and through the 9.5 post-Newtonian order. Previous results on circular orbits are thus generalized and recovered in a proper limit. Link: https://journals.aps.org/prd/abstract/10.1103/PhysRevD.98.064026 Bini D., Geralico A., Gravitational self-force corrections to tidal invariants for particles on circular orbits in a Kerr spacetime, published on Phys. Rev. D, Vol. 98, Iss. 6 - 15 September 2018, arXiv:1806.08765 We generalize to the Kerr spacetime existing self-force results on tidal invariants for particles moving along circular orbits around a Schwarzschild black hole. We obtain linear-in-mass-ratio (conservative) corrections to the quadratic and cubic electric-type invariants and the quadratic magnetic-type invariant in series of the rotation parameter up to the fourth order and through the ninth and eighth post-Newtonian orders, respectively. We then analytically compute the associated eigenvalues of both electric and magnetic tidal tensors. Link: https://journals.aps.org/prd/abstract/10.1103/PhysRevD.98.064040 Rosquist K., Bini D., Mashhoon B., Twisted Gravitational Waves of Petrov type D, published on Phys. Rev. D 98, 064039 (2018), Iss. 6 - 15 September 2018, arXiv:1807.09214 Twisted gravitational waves (TGWs) are nonplanar unidirectional Ricci-flat solutions of general relativity. Thus far only TGWs of Petrov type II are implicitly known that depend on a solution of a partial differential equation and have wave fronts with negative Gaussian curvature. A special Petrov type D class of such solutions that depends on an arbitrary function is explicitly studied in this paper and its Killing vectors are worked out. Moreover, we concentrate on two solutions of this class, namely, the Harrison solution and a simpler solution we call the w-metric and determine their Penrose plane-wave limits. The corresponding transition from a nonplanar TGW to a plane gravitational wave is elucidated. Link: https://journals.aps.org/prd/abstract/10.1103/PhysRevD.98.064039 N. Sahakyan, Lepto-hadronic γ-ray and neutrino emission from the jet of TXS 0506+056, Accepted for publication in ApJ on 16 Aug 2018, arXiv:1808.05651 The observation of IceCube-170922A event from the direction of TXS 0506+056 when it was in its enhanced γ-ray emission state offers a unique opportunity to investigate the lepto-hadronic processes in blazar jets. Here, the observed broadband emission of TXS 0506+056 is explained by boosted synchrotron/synchrotron self Compton emission from the jet whereas the γ-ray data observed during the neutrino emission- by inelastic interactions of the jet-accelerated protons in a dense gaseous target. The proton energy distribution is ∼E-2.50p, calculated straightforwardly from the data obtained by Fermi-LAT and MAGIC and if such distribution continues up to Ec,p=10 PeV, the expected neutrino rate is as high as ∼0.46 events during the long active phase of the source or ∼0.15 if the activity lasts 60 days. In this interpretation, the energy content of the protons above > GeV in blazar jets can be estimated as well: the required proton injection luminosity is ≅2.0×1048ergs-1 exceeding 103 times that of electrons ≅1045ergs-1 which are in equipartition with the magnetic field. As the required parameters are physically realistic, this can be an acceptable model for explanation of the neutrino and γ-ray emission from TXS 0506+056. Link: https://arxiv.org/abs/1808.05651 Hagen Kleinert and She-Sheng Xue, Composite fermions and their pair states in a strongly-coupled Fermi liquid, published in Nuclear Physics B936 (2018) 352-363 Our goal is to understand the phenomena arising in optical lattice fermions at low temperature in an exter-nal magnetic field. Varying the field, the attraction between any two fermions can be made arbitrarily strong, where composite bosons form via so-called Feshbach resonances. By setting up strong-coupling equations for fermions, we find that in spatial dimension d>2 they couple to bosons which dress up fermions and lead to new massive composite fermions. At low enough temperature, we obtain the critical temperature at which composite bosons undergo the Bose-Einstein condensate (BEC), leading to BEC-dressing massive fermions. These form tightly bound pair states which are new bosonic quasi-particles producing a BEC-type condensate. A quantum critical point is found and the formation of condensates of complex quasi-particles is speculated over. Link: https://doi.org/10.1016/j.nuclphysb.2018.09.023 |
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