Newsletter English April/May 2017 |
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ICRANet Newsletter
April - May 2017
SUMMARY
1. Two additional cases support the classification of short GRBs proposed in Ruffini et al. (2015) 2. Fifteenth Marcel Grossmann meeting (MG15) announcement 3. Professors Roy Kerr and Fulvio Melia at ICRANet and the ongoing scientific discussions 4. Meeting at the Council of the Republic of Belarus for possible entrance of Belarus in ICRANet on 27 of April, 2017 5. New Cooperation Agreement signed between ICRANet and Belarusian Republican Foundation for Fundamental Research on 26 of April, 2017 6. The First ICRANet-Minsk workshop on high energy astrophysics and opening of ICRANet-Minsk Center, 26-28 of April, 2017 7. Fifth Bego Rencontres - IRAP Ph.D. school, Nice-Rome, 15-19 May 2017 8. Recent publications 9. The first project “School – Job” with High School “Galileo Galilei” is concluded 10. Danish students visited the ICRANet center in Pescara 11. New seminars for students of High School “Galileo Galilei” with Alessandra di Cecco 12. Chinese scientists, that work for the next mission on the moon, visited the ICRANet center in Pescara 13. Professor Kerr and Professor Ruffini dialoguing with students of High School “Galileo Galilei”
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 Eiso>1052 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 Eiso =2.6x1052 erg and Ep,i=9.6 MeV, and GRB 140402A, with Eiso =4.7x1052 erg and Ep,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]. 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 MNS_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
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 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.
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". 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.
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".
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 |