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ICRANet Newsletter



ICRANet Newsletter
September - October 2019



SUMMARY
1. ICRANet press release “On the role of a cavity in the hypernova ejecta of GRB 190114C”
2. New cooperation protocol between the United Center for Gravitational Wave Physics and ICRANet, October 12, 2019
3. New collaboration agreement between the UoS/SAASST and ICRANet, October 15, 2019
4. New collaboration agreement between the University of L’Aquila and ICRANet, October 21, 2019
5. Prof. Ruffini met Nobel Laureate Prof. Gérard Mourou, Elba Island, Italy, September 16, 2019
6. 21st RAGtime meeting, Opava, Czech Republic, September 18-19, 2019
7. 105° SIF national Congress, L’Aquila, Italy, September 23-27, 2019
8. First Hangzhou International meeting on gravitational waves and inauguration of the United Center for Gravitational Wave Physics, Hangzhou, China, October 11 - 13, 2019
9. Mission of Prof. Ruffini at Sharjah, United Arab Emirates, October 14-17, 2019
10. Prof. Ruffini met Prof. Vincenti and Prof. Quéré at ICRANet Seat Villa Ratti, Nice, September 23, 2019
11. Opening event of the project “Alternanza scuola-lavoro” with High School G. Galilei of Pescara at ICRANet center, October 4, 2019
12. Prof. Costantino Sigismondi (ICRANet research scientist) guided ESA scientists to visit the meridian line of S. Maria degli Angeli, Rome, September 11 – 13, 2019
13. Prof. Ruffini awarded the prize Delfino d’oro 2019, Pescara, October 10, 2019
14. Seminar of Prof. Sang Pyo Kim at ICRANet
15. Scientific visits to ICRANet
16. Upcoming meetings: the Fourth Zeldovich meeting, Minsk, Belarus, April 20-24, 2020
17. Recent publications



1. ICRANet press release “On the role of a cavity in the hypernova ejecta of GRB 190114C”

Since 2018, a new style of research has been introduced in Gamma-Ray-Bursts (GRBs) studies: it does not describe the prompt radiation phase observed by the Neil Gehrels Swift Observatory and the NASA Fermi Gamma-ray Space Telescope by a time-integrated spectral analysis, typically applied to long GRBs and obtaining a Band spectrum with various fitting parameters, this procedure, as recognized by David Band, does not permit a taxonomy of GRBs [1]. The approach followed by the ICRANet group, developing the Binary driven Hypernova (BdHN) model of long GRBs, focuses only on luminous GRBs with a large signal to noise ratio which allow to proceed to a time-resolved analysis. In doing so three main events in the prompt radiation phase have been identified [2]: 1) the supernova rise, 2) the moment of formation of a black hole coinciding with the onset of the GeV radiation and 3) the emission of a cavity, created by the explosion of electron-positron plasma in the expanding supernova ejecta, see Fig. 1. In addition to these results, the greatest novelty in this field has been so far the discovery of self-similarity and power laws in the data, following the black hole formation from 1.9 second to 3.9 seconds, see the accompanying article [2], leading to evidence of quantized versus continuous emission in the GeV radiation, see the accompanying article [3].
The new study, co-authored by R. Ruffini, J. D. Melon Fuksman, G. V. Vereshchagin [4], has been accepted for publication by the Astrophysical Journal on August 19, 2019. It presents the evidence of the formation of a cavity in the source of gamma-ray burst GRB 190114C. It is proposed that this GRB originates in a binary system composed of a massive carbon-oxygen core, described within the binary-driven hypernova I (BdHN I) scenario. In this scenario, the carbon-oxygen core undergoes a supernova explosion with the creation of a new neutron star, hypercritical accretion occurs onto the companion binary neutron star until it exceeds the critical mass for gravitational collapse.

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Fig. 1. The light curve of GRB190114c in the rest frame of the source contains the precursor up to 1.9 s (Episode 1), then ultrarelativistic prompt emission (UPE) up to 3.9 s (Episode 2), then the residual emission following the UPE from 3.9 s up to 11 s. The emission from the cavity (Episode 3) occurs at 11 s and continues up to 20 s

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Fig. 2. Spatial distributions of matter density (top), Lorentz factor (middle) and comoving temperature (bottom) at t = 11 s, showing the mildly relativistic reflection wave propagating backward in the cavity, as well as the ultrarelativistic electron-positron plasma wave propagating outside the cavity. The shock wave is visible inside the ejecta.


It is shown that the formation of a black hole captures 1057 baryons by enclosing them within its horizon, and thus a cavity of approximately 1011 cm is formed around it with initial density 10-7 g/cm3. A further depletion of baryons in the cavity originates from the expansion of the electron-positron-photon plasma formed at the moment of the collapse, reaching a density of 10-14 g/cm3 by the end of the interaction. It is demonstrated, using an analytical model complemented by a hydrodynamic numerical simulation, see Fig. 2, that part of the electron-positron-photon plasma is reflected off the walls of the cavity. The consequent outflow and its observed properties are shown to coincide with the featureless emission occurring in a time interval of duration, measured in the rest frame of the source, between 11 and 20 s of the GBM observation. Moreover, similar features of the GRB light curve were previously observed in GRB 090926A and GRB 130427A, all belonging to the BdHN I class. These results support the general framework presented in [2] and guarantees that a low baryon density is reached in the cavity, a necessary condition for the operation of the “inner engine” of the GRB, presented in the accompanying article [3].
The density of 10-14 g/cm3 here discovered points clearly to a completely different origin of the MeV and GeV emission hosted in the cavity: an electromagnetic machine, producing emission very close to the black hole horizon, and based on three components: 1) a Kerr black hole, 2) a uniform magnetic field following the Papapetrou theorem and 3) a low density plasma of 10-14 g/cm3 [4]. This contrasts with the traditional gravitational accretion of very high density matter onto a black hole. This result profoundly changes the traditional mechanism of emission of GRBs and can be extended to active galactic nuclei (AGNs) [5]. As a consequence, also the physics of GRBs afterglows has been modified avoiding the ultra relativistic blast wave emission and utilizing the synchrotron process occurring around the new neutron star expected in the BdHN model [6].


References:
1. D. Band, et al., “BATSE Observations of Gamma-Ray Burst Spectra. I. Spectral Diversity”, ApJ v.413, p.281 (1993).
2. Ruffini, R., Li, L., Moradi, R., Rueda, J. A., Wang, Y., Bianco, C., Melon Fuksman, J. D., Xue, S. S., Cherubini, C., Filippi, S., Karlica, M., & Sahakyan, N. (2019). “Self-similarity and power-laws in GRB 190114c”, arXiv:1904.04162.
3. Ruffini, R. & Moradi, R., e. a. (2019). “On the determination of the mass and spin of the black hole in the inner engine of GRB 190114c”, submitted.
4. R. Ruffini, J.D. Melon Fuksman, G.V. Vereshchagin, “On the role of a cavity in the hypernova ejecta of GRB 190114C”, ApJ, 2019, October 3, 2019; https://iopscience.iop.org/article/10.3847/1538-4357/ab3c51.
5. J. A. Rueda, R. Ruffini, “The blackholic quantum”, arXiv:1907.08066.
6. J. A. Rueda, R. Ruffini, M. Karlica, R. Moradi, Y. Wang, “Inferences from GRB 190114C: Magnetic Field and Afterglow of BdHN”, arXiv:1905.11339.



2. New cooperation protocol between the United Center for Gravitational Wave Physics and ICRANet, October 12, 2019

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On October 12, a cooperation protocol between ICRANet and the United Center for Gravitational Wave Physics (Hangzhou - China) was signed by Prof. Anzhong Wang (Director of UCGWP), by Prof. Bin Wang (Vice Director of UCGWP), by Prof. Jiliang Jing (Vice Director of UCGWP), by Prof. Remo Ruffini (Director of ICRANet) and by Prof. Jorge Rueda (ICRANet Faculty Professor). The main joint activities to be developed under the framework of this protocol include: the promotion of theoretical and observational activities within the field of Relativistic Astrophysics; the institutional exchange of faculty members, researchers, post-doctorate fellows and students; the promotion of technological developments; the development of Data Centers for Astrophysical data in all wavebands; the organization of training and teaching courses, seminars, conferences, workshops or short courses, and the development of inter-institutional research areas associated to local graduate programs; and joint publications. The agreement has been signed on the occasion of the Inauguration ceremony of the center and of the First Hangzhou International meeting on gravitational waves, both held in Zhejiang University (Hangzhou, China) from October 11 to 13, 2019. The cooperation protocol will be valid for 5 years.
For the text of the protocol, see: here.



3. New collaboration agreement between the UoS/SAASST and ICRANet, October 15, 2019

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On October 15, a cooperation agreement between ICRANet and the University of Sharjah (United Arab Emirates) was signed by H.E. Prof. Hamid Al-Naimiy (Chancellor of the UoS), by Prof. Gaffar Attaelmanan (Chairman of the Physics Department of the UoS), by Prof. Remo Ruffini (Director of ICRANet) and by Prof. Jorge Rueda (ICRANet Faculty Professor). The main joint activities to be developed under the framework of this agreement include: the promotion of theoretical and observational activities within the field of Relativistic Astrophysics; the institutional exchange of faculty members, researchers, post-doctorate fellows and students; the promotion of technological developments; the development of Data Centers for Astrophysical data in all wavebands; the organization of training and teaching courses, seminars, conferences, workshops or short courses, and the development of inter-institutional research areas associated to local graduate programs; and joint publications. The agreement has been signed on the occasion of the visit Prof. Ruffini payed in Sharjah October 14 to 17, 2019 and will be valid for 5 years.
For the text of the agreement, see: here.



4. New collaboration agreement between the University of L’Aquila and ICRANet, October 21, 2019

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On October 21, a cooperation agreement between ICRANet and the University of L’Aquila (Italy) was signed by Prof. Edoardo Alesse (Rector of the University of L’Aquila) and by Prof. Remo Ruffini (Director of ICRANet). The main joint activities to be developed under the framework of this agreement include: the promotion of theoretical and observational activities within the field of Relativistic Astrophysics; the institutional exchange of faculty members, researchers, post-doctorate fellows and students; the promotion of technological developments; the development of Data Centers for Astrophysical data in all wavebands; the organization of training and teaching courses, seminars, conferences, workshops or short courses, and the development of inter-institutional research areas associated to local graduate programs; and joint publications. The agreement will be valid for 5 years. For the text of the agreement: here.



5. Prof. Ruffini met Nobel Laureate, Prof. Gérard Mourou, Elba Island, Italy, September 16, 2019


On September 16, Prof. Ruffini met Prof. Gérard Mourou (Nobel Prize in Physics in 2018) at Hotel Hermitage in Elba Island (Italy), on the occasion of the EAAC 2019 conference. Prof. Gregory Vereshchagin (ICRANet Faculty Professor) and Prof. Sang Pyo Kim (Inje University – South Korea) were also present at the meeting. During that meeting, the 4 scientists had a fruitful and stimulating discussion, and Prof. Ruffini presented to Prof. Mourou the most recent scientific results on which ICRANet is working on.

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Fig. 3: Prof. Mourou discussing with Prof. Ruffini and Prof. Sang Pyo Kim.
 
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Fig. 4: from left to right: Prof. Gregory Vereshchagin, Prof. Remo Ruffini, Prof. Gérard Mourou and Prof. Sang Pyo Kim, during the meeting at Hotel Hermitage in Elba Island (Italy) on September 16, 2019.



6. 21st RAGtime meeting, Opava, Czech Republic, September 18-19, 2019


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Fig. 5: Prof. Remo Ruffini presenting his talk at the 21st RAGtime meeting in Opava, September 18, 2019.

From 18 to 19 September, Professor Ruffini, Director of ICRANet, visited Silesian University in Opava (Czech Republic). Together with Prof. Jorge Rueda (ICRANet faculty) and Dr Liang Li (ICRANet) they have been invited to deliver talks on the occasion of the 21st RAGtime meeting. Prof. Ruffini presented a talk entitled “On the BdHNI GRB 190114C and its energetic”, Prof. Rueda’s talk was entitled “The physical ingredients of a binary-driven hypernova (BdHN) and their role in the explanation of a long gamma-ray bursts” and Dr Liang Li delivered a talk entitled “Self-Similarities and Power-laws in the Time-and 190114C”. On that occasion, Prof. Ruffini released an interview that has been broadcasted on the Czech television.
During his visit, Prof. Remo Ruffini had the opportunity to meet personally Prof. Zdeneck Stuchlik (Head of the Research Center for Theoretical Physics and Astrophysics, Silesian University), who officially presented him the collaboration agreement between the Silesian University in Opava and ICRANet, signed on August 19, 2019.

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Fig. 6: Prof. Jorge Rueda presenting his talk at the 21st RAGtime meeting in Opava, September 19, 2019.
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Fig. 7: Dr Liang Li presenting his talk at the 21st RAGtime meeting in Opava, September 19, 2019.

For the text of the agreement: http://www.icranet.org/documents/agreementICRANet-SilesianUniversity.pdf
For the video of Prof. Ruffini’s conference and interview: http://www.icranet.org/index.php?option=com_content&task=view&id=1268



7. 105° SIF national Congress, L’Aquila, Italy, September 23-27, 2019

From September 23-27, the Italian Physical Society (Società Italiana di Fisica, SIF) held its 105th national congress in L’Aquila. Several ICRANet researchers were invited to participate and delivered talks on that occasion on Friday September 27, namely: Prof. Remo Ruffini (“Perspectives in physics and fundamental physics following the observations of a Kerr Black Hole in GRB 190114C”), Prof. Gregory Vereshchagin (“Cavity in the hypernova ejecta of GRB 190114C”), Prof. Jorge Rueda (“Induced gravitational collapse, binary-driven hypernovae, long gramma-ray bursts and their connection with short Gamma-ray bursts”), Prof. Shesheng Xue (“Emission from accelerated protons and electrons/positrons in the BdHN paradigm”) and Stefano Campion (“Neutrino production from proton-proton interactions in a BdHN event”).
The website of the conference: https://congresso.sif.it/



8. First Hangzhou International meeting on gravitational waves and inauguration of the United Center for Gravitational Wave Physics, Hangzhou, China, October 11 - 13, 2019

From October 11 to 13, Professor Ruffini, Director of ICRANet, visited Hangzhou (China) together with Prof. Shesheng Xue (ICRANet Faculty professor) where they have been invited to deliver a talk on the occasion of the inauguration of the United Center for Gravitational Wave Physics (UCGWP) and of the first Hangzhou International meeting on gravitational waves. Both the events took place in Zhejiang university (Hangzhou) and were attended by a large number of scientist from all over the world. On that occasion, Prof. Ruffini presented a congratulatory address and plenary lecture titled “Discovery of energy extraction by discrete “Black-Holic” quanta from a Kerr Black Hole in GRB 190114C”, while Prof. Xue gave a talk entitled “Cosmological constant, matter, inflation and cosmic coincidence”. During his visit, Prof. Remo Ruffini had the opportunity to sign the cooperation protocol between ICRANet and UCGWP, the new center located in Zhejiang University, on October 12.

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Fig. 8: Group photo of the first Hangzhou International meeting on gravitational waves.
 
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Fig. 9: Prof. Remo Ruffini at the inauguration of the United Center for Gravitational Wave Physics (UCGWP).
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Fig. 10: Prof. Anzhong Wang (Director of UCGWP) and Prof. Remo Ruffini (Director of ICRANet), signing the cooperation protocol between UCGWP and ICRANet.



9. Mission of Prof. Ruffini at Sharjah, United Arab Emirates, October 14-17, 2019

From October 14 to 17, Professor Ruffini, Director of ICRANet, visited Sharjah (United Arab Emirates). On that occasion, he had the opportunity to visit the University of Sharjah (UoS) and its laboratories, the Sharjah Academy for Astronomy, Space Sciences, and Technology (SAASST), as well as to meet the applied Physics & Astronomy faculty members and Prof. Hamid M. K. Ainaimiy (Chancellor of the UoS, President of the Arab Union for Astronomy and Space Sciences). During his visit, Prof. Ruffini was also invited to give two seminars: one to the general audience titled “Einstein, Fermi, Heisenberg and the Birth of Relativistic Astrophysics” and one to a professional audience, in presence of the Chancellor of UoS, titled “Discovery of energy extraction by discrete "Black-Holic" quanta from a Kerr Black Hole in GRB 190114C”. This fruitful visit gave also Prof. Ruffini the possibility to personally sign the collaboration agreement between the UoS/SAASST and ICRANet on October 15, 2019.

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Fig. 11: Prof. Remo Ruffini (Director of ICRANet) after the signature of the collaboration agreement between the UoS/SAASST and ICRANet on October 15, 2019.

For a press release of the event (in Arabic): http://www.sharjah.ac.ae/ar/Media/Pages/news-details.aspx?mcid=2792&clt=ar&fbclid=IwAR1P99Tgt8uP0uvn5ZCZa3jamS7xE25s25F53kA3w4wOinW5xuSZhg35Wgc#



10. Prof. Ruffini met Prof. Vincenti and Prof. Quéré at ICRANet Seat Villa Ratti, Nice, September 23, 2019

On September 23, Prof. Ruffini visited Nice (France) in order to meet Prof. Henri Vincenti and Prof Fabien Quéré from Centre CEA Paris-Saclay, at ICRANet Seat in Villa Ratti. During the meeting, the two scientists had the possibility to visit the Villa, and they had a fruitful discussion with Prof. Ruffini, who presented them the most recent scientific results achieved by ICRANet.



11. Opening event of the project “Alternanza scuola-lavoro” with High School G. Galilei of Pescara at ICRANet center, October 4, 2019

On October 4, ICRANet center in Pescara hosted the opening event of the project “Alternanza scuola-lavoro”. Students from the class 4°D of High School Galileo Galilei of Pescara had the possibility to visit ICRANet center and its library, welcomed by Prof. Remo Ruffini (Director of ICRANet), by Prof. Gregory Vereshchagin (ICRANet Faculty Professor) and by Prof. Costantino Sigismondi (ICRANet collaborator and professor at ITIS Galileo Ferraris in Rome). This event offered to the students a unique opportunity to take part in science activities aiming to showcase both the fascination of research as a career and its significant societal impact. After the opening remarks made by Prof. Ruffini, the most important scientific results on which ICRANet is working on, have been presented. Prof. Vereshchagin spoke about "How we discovered an echo from the formation of a Black Hole", then Prof. Costantino Sigismondi showed and commented to the students the video "Misura del diametro solare al meridiano e ad almucantarat zero". The last part of the event has been dedicated to the practical exercise of the students on the algorithm. Then Prof. Remo Ruffini presented the concluding remarks.

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Fig. 12: Prof. Gregory Vereshchagin (ICRANet Faculty Professor) presenting the lecture to the students entitled "How we discovered an echo from the formation of a Black Hole".
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Fig. 13: Prof. Costantino Sigismondi commenting the video "Misura del diametro solare al meridiano e ad almucantarat zero" to the students.
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Fig. 14: Prof. Ruffini’s opening remarks.

In the framework of the project “Alternanza scuola-lavoro” for the three year period 2019-2022, ICRANet will host students from the classes 4°B, 4°D and 4°F from High School Galileo Galilei of Pescara. These students, under the supervision of their tutor, Prof. Tiziana Pompa, will be accompanied and addressed by ICRANet Faculty Professors during that project. Its main aim is to involve students in the different phases of a scientific research process, concentrating on concrete case-studies.



12. Prof. Costantino Sigismondi (ICRANet research scientist) guided ESA scientists to visit the meridian line of Santa Maria degli Angeli, Rome, September 11 – 13, 2019

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Fig. 15: The meridian line in the church Santa Maria degli Angeli, Rome.

On the framework of the AIDA international workshop 2019 (https://www.cosmos.esa.int/web/aida-international-workshop), held from September 11 to 13 in the Terme di Diocleziano in Rome, Prof. Costantino Sigismondi (ICRANet research scientist) organized a side event alongside the meeting, guiding ESA scientists to visit the meridian line of Santa Maria degli Angeli church in Rome. The visit was focused on the 2018-19 Astrometric Campaign for the Clementine Gnomon, analyzing the new results for understanding the history and the potential of the instrument built by Francesco Bianchini in 1700-1702. The Meridian Line of Santa Maria degli Angeli was, in fact, built by him with the funding of cardinal Gianfrancesco Albani (who become Pope Clement XI during the building of the instrument). For this reason it was called "Clementine Gnomon" by Francesco Bianchini.



13. Prof. Ruffini awarded the prize Delfino d’oro 2019, Pescara, October 10, 2019

On October 10, Prof. Ruffini was awarded the prize Delfino d’oro 2019 by the Municipality of Pescara on the occasion of a solemn City Council in its seat. The ceremony has been opened by a welcome speech of the President of the city council, Dr Marcello Antonelli, and continued with the delivery of the prizes to several eminent personalities who have contributed, in their relevant field of study, to the cultural, scientific, economical and social development of the city of Pescara. Among them, there was Prof. Ruffini, who recalled all the steps which established the ICRANet center in Pescara as well as the fundamental role played in this process by Prof. Roy Kerr (Yevgeny Lifshitz Chair at ICRANet, Crafoord Prize in Astronomy 2016 and honorary citizen of Pescara since 2016). As the Mayor Carlo Masci reported in his speech, Prof. Ruffini brought “Pescara at the center of the Universe and the Universe in the center of Pescara”.

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Fig. 16: Group photo of all the Delfino d’oro 2019 prize winners. during the official award ceremony held at the Municipality of Pescara on October 10, 2019.
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Fig. 17: Prof. Ruffini receiving the prize Delfino d’oro 2019, in presence of the Major of Pescara, Dr Carlo Masci (on the right) and of the President of the city council, Dr Marcello Antonelli.


Several press releases (in Italian) have been released on that event:
• Municipality of Pescara: http://www.comune.pescara.it/internet/index.php?codice=147&idnews=8136&navBackPage=148
• Il Centro: http://www.ilcentro.it/pescara/ciatt%C3%A8-d-oro-tra-i-premiati-marinelli-basel-e-ruffini-1.2304874
http://www.ilcentro.it/pescara/da-ruffini-a-don-palmerino-ecco-chi-ha-onorato-pescara-1.2306625
• Il Pescara: https://www.ilpescara.it/attualita/ciatte-delfino-oro-2019-nomi-premiati-pescara.html
• Rete 8: http://www.rete8.it/cronaca/123pescara-ciatte-doro-alla-memoria-del-direttore-di-rete8-pacilio/
A regional TV (TG Rete 8) has also took a video of the ceremony: https://www.youtube.com/watch?v=YjGfeuOAoXg




14. Seminar of Prof. Sang Pyo Kim at ICRANet

On Thursday, September 12, 2019, Prof. Sang Pyo Kim (Kunsan National University – Korea, Institute of Theoretical Physics - Chinese Academy of Sciences), gave a seminar entitled “Magnetars, Magnetized Black Holesand Laboratory Astrophysics” with the following abstract:
Neutron stars, in particular, magnetars (highly magnetized neutron stars) provide the most intense magnetic fields in the universe, which go by order of two or more beyond the critical field. The vacuum birefringence, a vacuum polarization effect, was predicted and has recently been observed by measuring optical spectrum from a neutron star. Damour and Ruffini studied the Schwinger mechanism in KN black holes and discussed a possibility of astrophysical source for GRBs. Blanford and Znajek proposed a central mechanism for gamma rays bursts (GRBs), in which magnetized rotating black holes power jets by mining the rotational energy through magnetic fields. Ruffini et al further proposed the dyadophere and dyadotorus model of charged black holes, and recently studied the effects of Wald’s type magnetic fields on GRBs in rotating black holes. In this talk, magnetized black holes are reviewed and possibility of black hole solutions with localized magnetic fields beyond Wald, Dokuchaev and Gibbons et al is discussed. Then QED physics in strong magnetic fields with/without electric fields are explained, and QED effects inneutron stars, magnetars and magnetized black holes are suggested. Finally, laboratory astrophysics is proposed using ultra-intense lasers, in which a strong gravity is emulated by Unruh effect of accelerating electrons or charges, and strong electromagnetic fields are provided by the lasers.

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Fig. 18 and 19: Professor Sang Pyo Kim giving his seminar at ICRANet center in Pescara, September 12, 2019.


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.




15. Scientific visits to ICRANet

  • Professor Sang Pyo Kim (Kunsan National University – Korea, Institute of Theoretical Physics - Chinese Academy of Sciences), September 3 – 17, 2019. Prof. Kim visited ICRANet center in Pescara and had the opportunity to discuss his research results with ICRANet scientists. He also gave a seminar titled “Magnetars, Magnetized Black Holesand Laboratory Astrophysics”.
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  • Mr. Mikalai Prakapenia (NASB, BSU – Belarus, IRAP PhD student), September 17 – 26, 2019. During his visit, Mr. Prakapenia had the opportunity to discuss his scientific research with ICRANet scientists, as well as to interact with his supervisor, prof. Gregory Vereshchagin.
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16. Upcoming meeting: the Fourth Zeldovich meeting, Minsk, Belarus

It is our pleasure to communicate that the Fourth Zeldovich meeting will be held in Minsk, Belarus, from April 20 to 24, 2020.

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From October 30, it is possible to submit an abstract through that form: https://uploader.icranet.org/zeld4/. The deadline for abstract submissions is April 1, 2020.

The preliminary list of invited speakers include:
• Abhay Ashtekar, Institute for Gravitation & the Cosmos, Penn State University, USA
• Rong-Gen Cai, Institute of Theoretical Physics, Chinese Academy of Sciences, China
• Jens Chluba, Jodrell Bank Centre for Astrophysics, University of Manchester, UK
• Alexander Dolgov, Novosibirsk State University and ITEP, Russia
• Jaan Einasto, Tartu Observatory, Estonia
• Stefan Gillessen, Max Planck Institute for Extraterrestrial Physics, Germany
• Claus Lämmerzahl, ZARM, Germany
• Vladimir Lipunov, Moscow State University, Russia
• Felix Mirabel, CEA Saclay, France
• Slava Mukhanov, Ludwig-Maximilians-Universität München, Germany
• Konstantin Postnov, Sternberg Astronomical Institute of the Moscow State University, Russia
• Piero Rosati, University of Ferrara, Italy
• Jorge Rueda, ICRANet, Italy
• Remo Ruffini, ICRANet, Italy
• Nikolay Shakura, Sternberg Astronomical Institute of the Moscow State University, Russia
• Alexey Starobinsky, Landau institute for theoretical physics, RAS, Russia

For more information concerning the meeting, please consult the official website at the following link: http://www.icranet.org/zeldovich4
For the registration form: http://dbserver.icra.it:8080/meetings/registration_zeld4.htm



17. Recent publications

R. Ruffini, R. Moradi, J. A. Rueda, L. Becerra, C. L. Bianco, C. Cherubini, S. Filippi, Y. C. Chen, M. Karlica, N. Sahakyan, Y. Wang, S. S. Xue, GeV emission and the Kerr black hole energy extraction in the BdHN I GRB 130427A, in press in The Astrophysical Journal.
We propose that the "inner engine" of a type I binary-driven hypernova (BdHN) is composed of a Kerr black hole (BH) in a non-stationary state, embedded in a uniform magnetic field B0 aligned with the BH rotation axis, and surrounded by an ionized plasma of extremely low density of 10−14g/cm−3. Using GRB 130427A as a prototype we show that this "inner engine" acts in a sequence of "elementary impulses". Electrons are accelerated to ultra-relativistic energy near the BH horizon and, propagating along the polar axis, θ=0, they can reach energies of ∼1018 eV, and partially contribute to ultra-high energy cosmic rays (UHECRs). When propagating with θ≠0 through the magnetic field B0, they give origin by synchrotron emission to GeV and TeV radiation. The mass of BH, M=2.31M, its spin, α=0.465, and the value of magnetic field B0=3.48×1010 G, are determined self-consistently in order to fulfill the energetic and the transparency requirement. The repetition time of each elementary impulse of energy E∼1037 erg, is ∼10−14 s at the beginning of the process, then slowly increasing with time evolution. In principle, this "inner engine" can operate in a GRB for thousands of years. By scaling the BH mass and the magnetic field the same "inner engine" can describe active galactic nuclei (AGN).
Link arXiv: https://arxiv.org/abs/1812.00354


Liang Li, Thermal Components in Gamma-Ray bursts. I. How Do They Affect Nonthermal Spectral Parameters?, The Astrophysical Journal Supplement Series Volume 245, Number 1, p. 7, 2019.
The spectral components of the prompt emission of gamma-ray bursts (GRBs) mainly consist of two possible origins: synchrotron (nonthermal) and photosphere (thermal). The typical spectral properties of GRBs can be modeled by a dominant nonthermal component (a Band-like function or cutoff power law), while some of them have an additional thermal component (a Planck-like function). In this paper, we investigate the effects of thermal components on the nonthermal spectral parameters. We focus on eight Fermi Gamma-ray Burst Monitor bursts of which the spectra deviate from a Band-only function, and the thermal components are significant. We sort them into thermal-subdominant Group I (e.g., GRB 110721A) and thermal-dominant Group II (e.g., GRB 090902B). Several interesting results are found assuming the spectral component is totally attributed to the nonthermal component: (i) the low-energy photon index α becomes harder; (ii) the peak energy E c is significantly smaller and lies between the peak temperature of blackbody component and the peak energy of the cutoff power law + blackbody (CPL+BB) model; (iii) total flux F is generally the same; (iv) the changes (Δα and ΔE c) are positively correlated with the ratio between the thermal flux and total flux; and (v) parameter relations (F–α, F–E c, and E c–α) also changed prominently. The GRBs in both groups show the same results. Our analysis indicates that the thermal component is important, and it significantly affects the spectral parameters and the consequential physical interpretations.
Link arXiv: https://iopscience.iop.org/article/10.3847/1538-4365/ab42de
 
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