ICRANet Newsletter
April - May 2017
1. Two additional cases support the classification of short GRBs proposed in Ruffini et al. (2015)
A new paper "GRB 081024B and GRB 140402A: two additional short GRBs from binary neutron star mergers" by the group of scientists from ICRANet, including: Y. Aimuratov, R. Ruffini, M. Muccino, C.L. Bianco, A.V. Penacchioni, G.B. Pisani, D. Primorac, J.A. Rueda, Y. Wang has just been submitted for publication to Astrophysical Journal. The paper is available online at: http://lanl.arxiv.org/abs/1704.08179
This article continues the approach by the GRB group led by professor Ruffini on the way of understanding the physics of gamma-ray bursts [1, 2], with a special focus on short gamma-ray bursts [3, 4, 5]. According to the new classification of GRBs introduced in [1] the authentic short gamma-ray bursts (S-GRBs), with isotropic energy E iso>10 52 erg, are evidencing a BH formation in the binary neutron star merging process. The signature for the BH formation consists in the on-set of the high energy (0.1-100 GeV) emission, coeval to the prompt emission, in all S-GRBs.
The paper focuses on two additional examples of S-GRBs: GRB 081024B, with E iso =2.6x10 52 erg and E p,i=9.6 MeV, and GRB 140402A, with E iso =4.7x10 52 erg and E p,i=6.1 MeV. By performing the time-integrated and time-resolved spectral analyses on both these sources their cosmological redshifts are inferred: z=3.12 for the S-GRB 081024B and z=5.52 for the S-GRB 140402A, respectively. Their P-GRB spectral emission is also identified. For S-GRB 081024B it results as the convolution of BB spectra at different Doppler factors arising from a highly spinning BH. The P-GRB emission of S-GRB 140402A is consistent with a single BB, expected to occur for a moderately spinning BH [4].
It is shown that two additional S-GRBs, 081024B and 140402A, share the common behavior of GeV emission of the already identified members of such a subclass, namely 090227B [3], 090510 [4] and 140619B [5].
Figure 1. The rest-frame 0.1-100 GeV isotropic luminosities of the S-GRBs: 081024B (orange empty diamonds), 090510 (gray filled circles), 140402A (red filled squares), and 140619B (green empty squares). All the light curves are shown from the burst trigger times on, while in the case of the S-GRB 090510 it starts after the precursor emission, i.e., from the P-GRB emission on (see [4] for details). The dashed black line marks the common behavior of all the S-GRB light curves.
Most noteworthy, the existence of a common power-law behavior in the rest-frame 0.1-100 GeV luminosities (see Figure 1), following the BH formation, points to a commonality in the mass and spin of the newly-formed BH in all these S-GRBs. This result is explainable with the expected mass of the merging NSs, each one of M= 1.3-1.5 solar masses [6], and the expected range of the non-rotating NS critical mass M NS_crit=2.2-2.7 solar masses [5].
In all the identified S-GRBs, within the Fermi-LAT FoV, GeV photons are always observed [4, 1]. This implies that no intrinsic beaming is necessary for the S-GRB GeV emission.
References:
1. Ruffini, R., Rueda, J.A., Muccino, M., Aimuratov, Y. et al. 2016, ApJ, 832, 136.
2. Becerra, L., Bianco, C.L., Fryer, C.L., Rueda, J.A., Ruffini, R. 2016, ApJ, 833, 107.
3. Muccino, M., Ruffini, R., Bianco, C.L., Izzo, L., Penacchioni, A. 2013, ApJ, 763, 125.
4. Ruffini, R., Muccino, M., Aimuratov, Y., Bianco, C.L., et al. 2016, ApJ, 831, 178
5. Ruffini, R., Muccino, M., Kovacevic, M., Oliveira, F.G. et al. 2015, ApJ, 808, 190.
6. Ozel, F., Freire, P. 2016, ARA&A, 54, 401.
2. Fifteenth Marcel Grossmann meeting (MG15) announcement
The Fifteenth Marcel Grossmann Meeting on General Relativity and Relativistic Astrophysics (MG15) will be held on the campus of the University of Rome “La Sapienza” in Rome, Italy in the year 2018. The important dates are:
Sunday July 1 - Onsite registration
Monday July 2 – Conference opening
Saturday July 7 – Conference closing.
3. Professors Roy Kerr and Fulvio Melia at ICRANet and the ongoing scientific discussions
In May 2017 professor Roy Kerr, member of the Faculty of ICRANet, recipient of the Crafoord Prize 2016 and honorary citizen of Pescara is visiting ICRANet center in Pescara.
Professor Kerr during his stay in Pescara worked extensively with the ICRANet faculty to attempt to reach inferences for General Relativity from Advanced LIGO published results.
In the presence of prof. Kerr on 24 of May Professor Fulvio Melia from the University of Arizona has presented a seminar on zero active mass cosmology and illustrated how present day observations favor the cosmological model with constant rate of expansion with respect to the Lambda-CDM model.
For video please see:
https://youtu.be/mheIJOKMx10
4. Meeting at the Council of the Republic of Belarus for possible entrance of Belarus in ICRANet on 27 of April, 2017
The meeting between the Director of ICRANet, prof. Remo Ruffini and the Chairman of the Standing Committee of the Council of the Republic of the National Assembly of the Republic of Belarus for Foreign Affairs and National Security, prof. Sergey Rakhmanov, as well as the Vice Chairman of the Presidium of the National Academy of Sciences of Belarus, Academician Sergei Kilin was held on April 27, 2017 at the Council of the Republic of Belarus.
Prof. Ruffini has illustrated the opportunities for Belarus as a state to be member of ICRANet as international organization, as well as the scientific activities of ICRANet. He mentioned successful collaboration between ICRANet and National Academy of Sciences and Belarusian State University in organization of several international conferences in Minsk, active role of belarusian scientists in ICRANet, as well as opening of new ICRANet center in Minsk.
Prof. Rakhmanov has expressed strong interest and support from the Council of the Republic of the National Assembly of the Republic of Belarus for the initiative of the National Academy of Sciences for Belarus to become a member state of ICRANet.
5. New Cooperation Agreement signed between ICRANet and Belarusian Republican Foundation for Fundamental Research on 26 of April, 2017
The new Cooperation Agreement between ICRANet and Belarusian Republican Foundation for Fundamental Research (BRFFR) was signed on April 26, 2017 by the Director of ICRANet, prof. Remo Ruffini and Director of BRFFR, Academician Sergei Gaponenko.
BRFFR is the oldest scientific fund on the territory of the former USSR and it is the only institution providing financial support of fundamental research for Belarusian scientists on competitive basis.
This new agreement intends to provide funding for joint scientific activities between ICRANet and Belarus. Publication of joint calls for proposals is planned every two years.
The text of the Agreement can be found here:
here
6. The First ICRANet-Minsk workshop on high energy astrophysics and opening of ICRANet-Minsk Center, 26-28 of April, 2017
On April 26-28, 2017 the first ICRANet-Minsk workshop on high-energy astrophysics has been held at the National Academy of Sciences of Belarus in Minsk, Belarus. This workshop has been the first scientific event organized in the new ICRANet Center in Minsk and it provided an opportunity for young scientists working in relativistic astrophysics from European and Asian countries to exchange experience and to present results in their fields to the Belarusian scientists. The workshop was a parallel meeting to a larger symposium BelINP-2017 on nuclear physics at the National Academy of Sciences of Belarus. This event was organized within the 2017 Year of Science, declared by the Presidential decree.
At the conference opening, in presence of the Ambassador of Italy, Director of ICRANet, Professor Remo Ruffini and the Vice Chairman of the presidium of the National Academy of Sciences of Belarus, Academician Sergei Kilin, have signed the protocol of the opening of ICRANet-Minsk Center. The new center is located at the B.I. Stepanov Institute of Physics and has a high speed internet connection to other ICRANet centers.
The plenary session of the conference BelINP-2017 was opened with the public lecture, given by Professor Ruffini: “Black Holes, Gravitational Waves and Binary Driven Hypernovae”.
The ICRANet-Minsk workshop focused on the following topics: gamma-ray bursts, neutron stars, supernovae, topological defects in cosmology, dark energy, motion of extended bodies in General Relativity, propagation of high energy particles at cosmological distances. Such workshops are planned to be held on the regular basis, which will allow exchange of ideas among ICRANet scientists, as well as active participation of Belarusian researchers in scientific activities in relativistic astrophysics, coordinated by ICRANet.
The website of the meeting: http://www.icranet.org/imw
The website of the BelINP symposium: http://nasb.gov.by/npc/en/
Protocol of the opening of ICRANet-Minsk Center: http://www.icranet.org/documents/prtocollo_opening.pdf
The video of the public lecture of prof. Ruffini: https://www.youtube.com/watch?v=TCEzQp38YTc
Article in the newspaper of the Academy of Sciences “Navuka” (in Russian): http://gazeta-navuka.by/images/electronic-catalog/29.05.17.pdf
For local news reports (in Russian) see:
http://www.belta.by/regions/view/mezhdunarodnyj-tsentr-reljativistskoj-astrofiziki-icranet-otkrylsja-v-minske-244441-2017/
http://www.zviazda.by/ru/news/20170421/1492792731-mezhdunarodnyy-akademicheskiy-centr-icranet-otkroetsya-v-minske
http://www.ecopress.by/ru/news/19/detail/213926.html
7. Fifth Bego Rencontres - IRAP Ph.D. school, Nice-Rome, 15-19 May 2017
From 15 to 19 May the 5° Bego Rencontres “Gravitational waves in the strong field limit” was held in Nice (France) and Rome (Italy). The lectures in Nice were held in Villa Ratti, while those in Rome were held at the Department of Physics of University of Rome “La Sapienza”. There were around 40 participants, including prof. Roy Kerr and other distinguished scientists as well as graduate students, who are active in the fields of Physics and Relativistic Astrophysics, coming from: Argentina, Brazil, China, Colombia, Croatia, France, Germany, Italy and Russia.
Among the participants there were: Roy Patrick Kerr, Pascal Chardonnet, Vladimir Belinski, Narek Sahakyan, Felix Aharonian, Felix Mirabel, Paolo Giommi, Yu Wang, Paolo de Bernardis, Carlo Bianco, Christian Cherubini, Gregory Vereshchagin, Jose Rodriguez, She Sheng Xue, Camilo Delgado, Massimo Della Valle, Carlo Bianco, Giovanni Pisani, Carlos Arguelles, Marco Muccino, Andreas Krut, Donato Bini, Volcker Perlick, Tais Maiolino, Angeles Moliné, Jutta Kunz, Ana Penacchioni.
In this meeting an overview of black hole formation in binary systems has been given by prof. Felix Mirabel, based on his recent article “The Formation of Stellar Black Holes”, available online: http://www.sciencedirect.com/science/article/pii/S1387647316300501. A progress in understanding on gravitational wave emission in strong field limit and electrodynamics of gravitational accretion to the Kerr black hole in the Ruffini-Wilson framework have been discussed. Particularly important were lively discussions with prof. Mirabel who presented the latest observations of intermediate mass black holes of 10 Solar masses, e.g. Cygnus X-1.
The video of presentations can be seen here:
http://www.icranet.org/index.php?option=com_content&task=view&id=1121
The conference web page: http://www.icranet.org/5bego
8. Recent publications
Pugliese, D.; Quevedo, H.; Ruffini, R. “General classification of charged test particle circular orbits in Reissner-Nordström spacetime”, The European Physical Journal C 77 (2017) 206.
In this work charged particle circular motion in the gravitational field of a charged mass distribution described by the Reissner-Nordström spacetime is investigated. A set of independent parameters completely characterizing the different spatial regions in which circular motion is allowed, is introduced. A most complete classification of circular orbits for different sets of particle and source charge-to-mass ratios is given. This analysis shows in an alternative manner that the behavior of circular orbits can in principle be used to distinguish between black holes and naked singularities. This work plays an important role in the study of the coupled electromagnetic and gravitational interactions, and the investigation of the role of the charge in the gravitational collapse of compact objects.
Federico Cipolletta, Christian Cherubini, Simonetta Filippi, Jorge A. Rueda, Remo Ruffini, “On the last stable orbit around rapidly rotating neutron stars”, accepted by Physical Review D, also available at https://www.arxiv.org/abs/1612.02207.
The binding energy and angular momentum of a test-particle at the last stable circular orbit (LSO) on the equatorial plane around a general relativistic, rotating neutron star (NS) is computed. Simple, analytic, but accurate formulas for these quantities that fit the numerical results and which can be used in several astrophysical applications are presented. The accuracy of these formulas for three different equations of state (EOS) is demonstrated based on nuclear relativistic mean-field theory models and it is argued that they should remain still valid for any NS EOS that satisfy current astrophysical constraints. These numerical results are compared and contrasted with the corresponding ones for the Kerr metric characterized by the same mass and angular momentum.
9. The first project of school – job with High School “Galileo Galilei” is concluded
On May 2017, the first project “School-Job” with the students of High School “Galeileo Galilei” of Pescara has been successfully concluded. Dr. Marco Muccino, member of the ICRANet Faculty, had given a lecture "Gamma-ray Bursts: the biggest explosions in the universe".
Within this lecture the following topics were illustrated:
Electromagnetic spectrum; Discovery of GRBs, nuclear tests and cold war; satellites performing astrophysical observations such as Vela, BATSE, Beppo-SaX, Swift and Fermi satellites; Luminosity distance; Formation of a black hole; Vacuum polarization; Compactness problem; GRB progenitors.
The link of the lecture: http://www.icranet.org/index.php?option=com_content&task=view&id=1066
10. Danish students visited the ICRANet center in Pescara
On the 5 of April 2017, at the ICRANet center of Pescara, there was a meeting with six young Danish students that came to Italy for a cultural exchange, organized by the High School “Da Vinci” of Pescara.
In this occasion, the students have met Professor Remo Ruffini, Director of ICRANet, Dr. Giovanni Pisani, member of ICRANet Faculty, and Gabriel Gomez, student IRAP PhD.
Dr. Giovanni Pisani has given a lecture “Big Bang and Gamma Ray Burts”, illustrating some subjects of the relativistic astrophysics.
During the discussion with Gabriel Gomez, IRAP PhD student from Colombia, the students asked questions about his motivation to choose ICRANet for doctorate studies, his motivations to come to Italy and the reasons that have led him to choose the relativistic astrophysics as subject of his studies.
11. New seminar for students of the High School “Galileo Galilei” with Alessandra di Cecco
On the 12 of May 30 students of High School “Galileo Galilei” visited ICRANet in Pescara for a lecture of Dr. Alessandra Di Cecco "the Space debris".
In this occasion the students deepened their knowledge on the following topics: Solar System, Satellites in orbits, Kepler laws and orbital perturbations, ESA space missions, the manned space flight and the International Spatial Station, the danger of the Space debris, European Programs of "Spatial Overseeing and Tracing (SST)", proliferation of the Space debris and measures of mitigation.
12. Chinese scientists of the next mission on the Moon, visited the ICRANet center in Pescara
After 40 years since the last mission of Soviet Union “Luna 24”, Chinese space mission “Chang'e 5” will come back on the Moon, with the goal to pick up and study samples of rocks. The mission is planned for November 2017.
On 2 of May 2017 20 Chinese scientists, a team, led by prof. Xie Gengxin, that work for the Chinese space mission “Chang'e 5”, visited the ICRANet headquarters in Pescara, together with Professor Paolo Giommi from ASI. They have met professors and researchers of ICRANet, and attended the presentation of Professor Ruffini, Director of ICRANet.
13. Professor Kerr and Professor Ruffini dialoguing with students of High School “Galileo Galilei”
On 24 of May, students of the High School “Galileo Galilei”, met at the ICRANet headquarters in Pescara, Professor Roy Patrick Kerr, recipient of the Crafoord Prize 2016 and honorary citizen of Pescara, and Professor Fulvio Melia, of Italian-origin expert in cosmology from the University of Arizona. The Mayor of Pescara, Marco Alessandrini, has also participated in this meeting together with Paolo Mastri, journalist of Italian newspaper "Il Messaggero”. Professor Kerr reminded to the students the importance of the scientific research as fundamental element in the everyday life. With a constantly evolving world and new experimental facilities made available, there is a constant increase of knowledge and fundamental discoveries in new research areas are made possible. A good example being the work on GRBs. Science is very possibly an endless field of activities moving to greater and greater discoveries. Professor Sigismondi Constantino completed the meeting.
The important message of profs. Kerr and Ruffini can be followed in the video, recorded also for posterity:
http://www.icranet.org/index.php?option=com_content&task=view&id=1118
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