Prof. Remo Ruffini Festschrift. A conference in celebration of Prof. Remo Ruffini 80° birthday

ICRANet Seat at Villa Ratti Nice (France) and online 1, Avenue Ratti, 06000 - Nice
Gregory Vereshchagin (ICRANet), Jorge Armando Rueda Hernandez (ICRANet), Narek Sahakyan (ICRANet-Armenia)

Prof. Remo Ruffini Festschrift. A conference in celebration of Prof. Remo Ruffini 80° birthday

Remo Ruffini

Director of ICRANet and President of ICRA, coauthor of more than 650 scientific publications and 13 books, Remo Ruffini received his doctorate at Sapienza (1967). He taught in Hamburg, Princeton University and the Institute for Advanced Study, in Japan, in China (at USTC), in Australia and CBPF (Brazil). Some of his major results: boson stars, “Introducing the Black Hole” with J.A. Wheeler, the limiting critical mass of NS. He identified the first BH in our Galaxy (Cignus X-1) using UHURU satellite data with Riccardo Giacconi and received the Cressy Morrison Award (1973). Returning to Sapienza (1978), he promoted Rome-Stanford collaboration on gravitational wave detectors. With European, US and Chinese institutions he established ICRA and later ICRANet in Italy, Armenia, France and Brazil (2005). He developed the understanding of GRBs, confirmed by the largest telescopes on Earth and from space: from their discovery (1973) to their cosmological origin (1997) to the determination of seven different GRBs families and their conceptual understanding (2018).
He has given evidence for 7 episodes characterizing the most general GRB and identified, in the Christodoulou - Ruffini - Hawking Mass formula, the energy source of the most energetic GRBs, the BDHN I, based on the Wald - Papapetrou solution (2022). He is currently also active with his collaborators in identifying the nature of our galactic core in terms of Dark matter.


Chairs of the Scientific Organizing Committee (SOC): Pascal Chardonnet, Liang Li, Rahim Moradi, Jorge A. Rueda, Narek Sahakyan, Gregory Vereshchagin,Yu Wang, Shesheng Xue.


Scientific Organizing Committee (SOC): Yerlan Aimuratov, Lorenzo Amati, Stefano Ansoldi, Carlos Raul Arguelles, David Arnett, Xinhe Bao, Jim Bardeen, Eduar Antonio Becerra Vergara, Laura Becerra Bayona, Zurab Berezhiani, Carlo Luciano Bianco, Jiri Bicack, Donato Bini, Paul Boynton, Yifu Cai, Daniela Calzetti, Stefano Campion, Pascal Chardonnet (co-chair), Pisin Chen, Yen-Chen Chen, Christian Cherubini, Demetrios Christodolou, Atish Dabholkar, Zigao Dai, Thibault Damour, Paolo De Bernardis, Massimo Della Valle, Nathalie Deruelle, Hansjoerg Dittus, Behzad Eslampanah, Sareh Eslamzadeh Askestani, Christian Estrosi, Francis Everitt, Simonetta Filippi, Christopher Fryer, Marco Fuchs, Mauro Giavalisco, Paolo Giommi, Gabriele Gionti, Daniele Gregoris, Vincenzo Guidi, Francesco Haardt, Mimoza Hafizi, Wenbiao Han, Luca Izzo, Robert Jantzen, Luke Shim Jong-Hyeok, Mile Karlica, Roy Patrick Kerr, Margaret Kerr, Sang Pyo Kim, Serguei Komissarov, Michael Kramer, Claus Laemmerzahl, Giovanni Lamanna, Di Li, Liang Li (co-chair), Manuel Malheiro, Silvia Masi, Grant Mathews, Marco Merafina, John Mester, Felix Mirabel, Razmik Mirzoyan, Rahim Moradi (co-chair), Romain Murenzi, Ehud Nakar, Hans Ohanian, Roberto Peron, Vahe Petrosian, Francesco Piacentini, Tsvi Piran, Peter Predehl, Brian Punsly, Sang Pyo Kim, Asghar Qadir, Hernando Quevedo, Johann Rafelski, Fatemeh Rastegar Nia, José Fernando Rodriguez Ruiz, Piero Rosati, Jorge Armando Rueda Hernandez (co-chair), Narek Sahakyan (co-chair), Humitaka Sato, Stefano Scopel, Soroush Shakeri, Costantino Sigismondi, Yousef Sobouti, Luigi Stella, Rashid Sunyaev, Marco Tavani, Gerard 't Hooft, Aldo Treves, Gregory Vereshchagin (co-chair), Nicola Vittorio, Anzhong Wang, Yu Wang (co-chair), Janie Wardle, Bob Williams, David Wilthshire, Hyung Won Lee, Shesheng Xue (co-chair), Yefei Yuan, Alexander Zakharov, Cesar Zen Vasconcellos, Bing Zhang, Yunlong Zheng.


Invited speakers (TBC)


Registration fee: 50 Euros

Coronavirus Covid-19 safety regulations:
In the building, the regulations on minimum distance, hygiene and the wearing of a medical mask (FFP2 or OP) are mandatory.



  • Aldo Treves
  • Alexander Zakharov
  • Aqsa Yasmin
  • Asghar Qadir
  • Bernard Raffaelli
  • Bing Zhang
  • Brian Punsly
  • Carlo Luciano Bianco
  • Carlos Argüelles
  • Cesar Augusto Zen Vasconcellos
  • Chris Fryer
  • Christian Cherubini
  • Claus Laemmerzahl
  • Costantino Sigismondi
  • Daniele Gregoris
  • Davood Rafiei Karkevandi
  • Demetrios Christodoulou
  • Donato Bini
  • Ehud Nakar
  • Elisabetta Natale
  • Fatemeh Rastegarnia
  • Felix Mirabel
  • Francesco Haardt
  • Gaetano Luciano
  • Giovanni Lamanna
  • Grant Mathews
  • Gregory Vereshchagin
  • Hansjoerg Dittus
  • Haridev S R
  • Harutyun Khachatryan
  • Hernando Quevedo
  • Hyung Won Lee
  • Istvan Horvath
  • Jeff Williams
  • Jiangong Gao
  • Jorge Armando Rueda Hernandez
  • José Fernando Rodríguez Ruiz
  • Kourosh Nozari
  • Laura Marcela Becerra Bayona
  • Liang Li
  • Lorenzo Amati
  • Luca Izzo
  • Luigi Stella
  • Luke Shim Jong - Hyeok
  • Manuel Malheiro
  • Marco Tavani
  • Massimo Della Valle
  • Michael Kramer
  • Mimoza Hafizi
  • Narek Sahakyan
  • Nathalie Deruelle
  • Pascal Chardonnet
  • Peter Predehl
  • Piero Rosati
  • Pisin Chen
  • Prakash Sarnobat
  • Qiang Wu
  • Rahim Moradi
  • Rahul Shah
  • Rashid Sunyaev
  • Remo Ruffini
  • Robert T Jantzen
  • Roy P Kerr
  • Saken Toktarbay
  • Sang Pyo Kim
  • Sara Saghafi
  • Sareh Eslamzadeh
  • She-Sheng Xue
  • Silvia Pietroni
  • Simonetta Filippi
  • Soroush Shakeri
  • Stefano Ansoldi
  • Stefano Scopel
  • Tao Zhu
  • Thibault DAMOUR
  • Tina Harriott
  • Tsvi Piran
  • Vladimir Karas
  • Wenbiao Han
  • Wenbin Lin
  • Xinhe Bao
  • Ye-Fei Yuan
  • Yerlan Aimuratov
  • Yi-Fu Cai
  • Yifang Wang
  • Yousef Sobouti
  • Yu Wang
  • Yunlong Zheng
  • Zhiqiang Shen
  • Zigao Dai
    • Contributions from Far East: Connections with China and Taiwan
      Convener: Yunlong Zheng
      • 1
        Congratulatory Letter upon the 80th Birthday of Professor Remo Ruffini

        see attached document

        Speaker: Xinhe Bao
      • 2
        Speaker: Yifu Cai
      • 3
        Pulsar timing and binary black holes

        The merging binary black holes (BBHs) have been detected by the ground gravitational-wave observatories, but it is very difficult to detect BBHs before their mergers. Since millisecond pulsars (MSPs) are remarkable precise ‘clocks’ in Universe, they could be used to detect the hidden BBHs, if they exist in systems of BBHs. Doing so, we construct a triple system which consists of a BBH and a third outer MSP. The theoretical studies have shown that the inner binary could cause additional time residuals (i.e. Romer delay) on the orbit of the outer MSP, which can be used to detect inner BBHs. Using N-body simulations, in this paper, we calculate such time residuals, and analyse the periodic signals of them by Fast Fourier Transform, which allow us to explore the effects of the parameters of the inner BBHs. Specifically, we assume that the triple system is coplanar and stable; the distance from the earth is ∼1 kpc; the mass of each black hole is 10 M⊙. We find that the amplitude of the time residual increases with the semimajor axis and eccentricity of the inner BBH. Moreover, we find that there are several prominent and characteristic periodic signals for different parameters of the inner BBHs. With the help of the analytic results, we find these frequencies are due to different orders of the eccentricities of both the inner and outer binaries. Thus, in principle, we can use these frequencies to determine the parameters of the inner BBHs.

        Speaker: Ye-Fei Yuan (University of Science and Technology of China)
      • 4
        Speaker: Zigao Dai
      • 5
        The motion of photons around black holes

        The motion of photons around black holes deter- mines the shape of shadow and match the ringdown proper- ties of a perturbed black hole. Observations of shadows and ringdown waveforms will reveal the nature of black holes. In this paper, we study the motion of photons in a general parametrized metric beyond the Kerr hypothesis. We inves- tigated the radius and frequency of the photon circular orbits on the equatorial plane and obtained fitted formula with var- ied parameters. The Lyapunov exponent which connects to the decay rate of the ringdown amplitude is also calculated. We also analyzed the shape of shadow with full parameters of the generally axisymmetric metric. Our results imply the potential constraint on black hole parameters by combining the Event Horizon Telescope and gravitational wave observations in the future.

        Speaker: Wenbiao Han
      • 6
        Connecting ringdown and shadow with photo motions

        To be added

        Speaker: Wenbiao Han
    • Morning session
      Convener: Gregory Vereshchagin (ICRANet)
      • 7
        Remo Ruffini: The Beginning 1967-1978

        I recall the beginning of Remo’s remarkable career through three meetings/schools we have attended together: Bologna University 1967, Brandeis Summer School 1968, and Les Houches Summer School 1972

        Speaker: Prof. Aldo Treves ( Università dell’Insubria)
      • 8
        Suggestion for a Possible Test of the RAR Model by the Cosmic Microwave Background

        Ruffini-Arguelles-Rueda (RAR) proposed that a self-gravitating gas of degenerate
        massive sterile neutrinos (or neutralinos) that forms a fully degenerate core, could not only explain the supermassive black holes that lie at the cores of galaxies (some of which date to very early times) but also provide the dark matter. Here we suggest that baryons would also fall into the gravitational wells of the degenerate cores at early times and leave an imprint on the cosmic microwave background (CMB). We provide a calculation of the capture of the baryons in the degenerate cores and suggest that the resultant imprint on the CMB could provide a test of the RAR model.

        Speaker: Asghar Qadir (None)
      • 9
        Long GRBs, Low Luminosity GRBs and Supernovae

        According to the Collapsar model, Long GRBs arise during a collapse of a massive star. The collapsing core produces a jet that penetrates the stellar envelope and the gamma-rays are generated once the jet is well outside the star. The jet propagation inside the stellar envelope is not simple. The interaction of the jet with the envelope dissipates the jet energy (as long as the jet is within the star) producing a hot cocoon. At times the jet is choked within the star and in this case, we may still observe directly its existence as the cocoon break out from the star produces a low luminosity GRB. I will provide observational evidence for that. Remarkably, as we show here, we may even identify the existence of a choked jet in cases when the low luminosity GRB is not detected. The cocoon leaves a unique signature of fast-moving matter that engulf the supernova. The observational imprint of such fast moving matter has been detected in several supernovae. If time permits, I will also discuss links of these ideas to the mechanisms that operate in short GRBs.

        Speaker: Tsvi Piran (The Hebrew University)
      • 10
        A roadmap in relativistic astrophysics in company of Remo Ruffini

        Since I arrived in Italy in 2006 as a graduate student, Remo Ruffini has been a constant guide for me in relativistic astrophysics. In this talk, I recall some of the most important scientific achievements we have been engaged in together. In essence, a new way of looking at relativistic stars, a new way of looking at the gamma-ray bursts and related transient high-energy phenomena, and a new way of looking at the dark matter in the Universe.

        Speaker: Jorge Armando Rueda Hernandez (ICRANet)
      • 10:50 AM
        Coffee break
      • 11
        Blazars in the multimessenger era

        ICRANet activities in Armenia will be presented. I will discuss the recent progress in multiwavelength and multimessenger observations of blazars and the current status of the theoretical models applied to model their emission.

        Speaker: Narek Sahakyan (ICRANet-Armenia)
      • 12
        GRB 180720B as a binary-driven hypernova of type I

        A time-resolved analysis of GRB 180720B confirms its binary-driven hypernovae (BdHN) I nature. The accretion of supernova (SN) ejecta onto the neutron star (NS) companion leads to its gravitational collapse forming a black hole (BH). The accretion onto the newborn NS ($\nu$NS) spins it up to a millisecond pulsar. By interpreting the data, we identify six episodes in addition to the X-ray, GeV, and sub-TeV afterglows. The BH formation is determined by the ultra-relativistic prompt emission (UPE) phase. After reviewing the nature of six different episodes in this GRB, we confirm a self-similar hierarchical structure of the UPE characterized by a cutoff power-law plus black body (CPL+BB) spectrum on decreasing time scales. This leads to identifying the multiple expanding $e^+~e^-$ pair electromagnetic plasma produced by the vacuum polarization quantum process in the inner engine, loaded with baryons, until the transparency point.

        Speaker: R. Moradi
      • 13
        Did gamma ray burst induce Cambrian explosion?

        One longstanding mystery in bio-evolution since Darwin’s time is the origin of the Cambrian explosion that happened around 540 million years ago (Mya), where an extremely rapid increase of species occurred. Here we suggest that a nearby GRB event 500 parsecs away, which should occur about once per 5 Gy, might have triggered the Cambrian explosion. Due to a relatively lower cross section and the conservation of photon number in Compton scattering, a substantial fraction of the GRB photons can reach the sea level and would induce DNA mutations in organisms protected by a shallow layer of water or soil, thus expediting the bio-diversification. This possibility of inducing genetic mutations is unique among all candidate sources for major incidents in the history of bio-evolution. A possible evidence for our theory would be the anomalous abundance of certain nuclear isotopes with long half-lives transmuted by the GRB photons in geological records from the Cambrian period. Our notion also imposes constraints on the evolution of exoplanet organisms and the migration of panspermia.

        Speaker: Prof. Chen Pisin (Leung Center for Cosmology and Particle Astrophysics, National Taiwan University)
    • Connection with Prof. Ruffini for greetings
      • 14
        Constraints on black hole charges in M87* and Sgr A* with the EHT observations

        Three years ago the Event Horizon Telescope collaboration presented the first image reconstruction around the shadow for the supermassive black hole in M87. It gives an opportunity to evaluate the shadow size. Recently, the Event Horizon Telescope collaboration constrained parameters (“charges”) of spherical symmetrical metrics of black holes from an estimated allowed interval for shadow radius from observations of M87. If we assume that a Reissner–Nordström black hole with a (tidal) charge exists in M87, therefore, based on results of the shadow size evaluation for M87 done by the Event Horizon Telescope collaboration we constrain a (tidal) charge. Similarly, we evaluate a (tidal) charge from shadow size estimates for Sgr A*.


        A.F. Zakharov, Universe 8, 141 (2022).

        Speaker: Prof. Alexander Zakharov (ITEP, Moscow)
      • 15
        Gravitational field of slightly deformed naked singularities

        We derive a particular approximate solution of Einstein equations, describing the gravitational field of a mass distribution that slightly deviates from spherical symmetry. The deviation is described by means of a quadrupole parameter that is responsible for the appearance of a curvature singularity, which is not covered by a horizon. We investigate the motion of test particles in the gravitational field of this naked singularity and show that the quadrupole parameter affects the properties of Schwarzschild trajectories. By investigating radial geodesics, we find that no effects of repulsive gravity are present. We interpreted this result as indicating that repulsive gravity is non-linear effect.

        Speaker: Saken Toktarbay (Al-Farabi Kazakh National University)
      • 16
        Short survey of matter in the Universe

        I survey our current research addressing evolution of matter in the Universe: Origin of matter is the quark-gluon phase of primordial Universe. Matter components evolve, at first we see hadronic universe, later we encounter lepton e+e-pair period followed by neutrino-photon free streaming towards recombination, dark matter and dark energy emergence. I show in detail the disappearance of antimatter at T=20.4keV demonstrating the big-bang nucelo-synthesis is occurring in a dense e+e- plasma. We explore the role of strong magnetic fields in early Universe and will propose how such field could alter our understanding of primordial processes.

        Over the past 10 years in my astro-particle work I benefited from academic contact with ICRANet and Remo Ruffini in particular.
        Happy 80th Remo: We wish you continued success in advancing our understanding of the relativistic astro-world.

        Speaker: Johann Rafelski (
      • 17
        Binary Neutron Star Mergers and the Quark-Matter Equation of State

        As neutron stars merge, very high nuclear densities are attained in the core. As the merged hyper neutron star collapses to form a black hole, it must inevitably pass through the transition from hadronic to a quark matter. Hence, the associated post-merger gravitational radiation could be used to probe properties of the quark-matter physics. In this talk, we analyze the evolution and gravitational wave emission from binary neutron star mergers using various parameterizations of the Quark-Hadron Crossover (QHC19) EOS. This EoS is motivated by the NJL nonperturbative description of quark matter including the quark pairing interaction and the formation of a color superconducting state. QCD. We show that the postmerger gravitational wave emission is very sensitive to properties of the high density-quark matter EOS and can be used to probe properties of matter in this non-perturbative phase of QCD.

        Speaker: Prof. Grant Mathews (University of Notre Dame/ICRANet)
    • Afternoon session
      Convener: Hansjoerg Dittus
      • 18
        The unity of time

        Within General Relativity there are several schemes to define a time scale. One geometry based time scale is given by the Marzke Wheeler clock or the standard clock defined by Perlick. Further time scales are given by the rotation of the Earth or pulsars around their own axis and by the rotation of objects around central gravitating bodies. And, finally, the most stable clocks today ar atomic clocks. We show that all these time scales coincide within the theory of General Relativity.

        Speaker: Claus Laemmerzahl (University of Bremen)
      • 19
        The eROSITA X-ray telescope on SRG

        3 years after its launch from the Russian Baikonur Cosmodrome, all systems and instruments are working properly on the Spektr-RG (SRG) observatory. With eROSITA, the German contribution, half of all 8 sky surveys have been completed so far. Millions of X-ray sources, mostly of extragalactic nature, have been discovered. This confirmes what we had hoped for before the launch and had already been able to verify before the sky survey began by a sample survey of a 140 square degree field: We will easily achieve our goals of discovering 100,000 galaxy clusters, 3 million AGN, and nearly 1 million galactic sources. Already, fundamental discoveries and investigations with unprecedented sensitivity have been made with eROSITA.

        Speaker: Peter Predehl (Max-Planck-Institut für extraterrestrische Physik)
      • 4:10 PM
        Coffe Break
      • 20
        Speaker: Rashid Sunyaev (Space Research Institute (IKI) of the Russian Academy of Sciences, Max Planck Institute for Astrophysics and Institute for Advanced Study, Princeton)
      • 21
        SPH simulations of the Induced Gravitational Collapse

        In the IGC paradigm, a carbon-oxygen star (COcore) collapses and explodes in a supernova (SN), the material ejected in the explosion is gravitational attracted by its companion, a neutron star (NS), taking place a hypercritical accretion process onto it. For compact systems, the accretion rate could be enough high to lead the NS to reach its critical mass, collapse in a black hole (BH) and emitted a gamma ray burst (GRB). With the aim to identify the separatrix of systems in which a BH is formed and characterize the observational signatures of each process, we have performed 3D-SPH numerical simulations of the SN expansion under the presence of the NS companion and explored a wide range of the initial parameter space.

        I will outline the consequences in the observation of long gamma-ray bursts (GRBs)

        Speaker: Laura Marcela Becerra
      • 22
        Finding my drumbeat: applying lessons learned from Remo Ruffini to understanding astrophysical transients

        Progress in our understanding of astrophysical transients has followed a series of fits and spurts, often moving forward in a random walk manner, sometimes moving forward, sometimes backward. In large part, this arises from the bandwagon nature of science, where contrary views are often stifled. In an era where deviations from the standard picture become increasingly difficult, Remo Ruffini has exemplified the importance of scientists each striving to march at the beat of a different drum which, in turn, drives innovation and new ideas. I will show how, following his example, Remo Ruffini helped me develop my research direction in both supernovae and gamma-ray bursts. I will review some of the new discoveries in astrophysical transients brought by his approach.

        Speaker: Chris Fryer (Los Alamos National Laboratory)
    • Contributions from Far East: Connections with Korea
      Convener: Hyung Won Lee
      • 23
        Speaker: Jong-Hyeok SHIM (President Sogang University)
      • 24
        Speaker: LEE Hyung Won
      • 25
        Remo Ruffini and Charged Black Holes

        Reissener-Nordstrom and Kerr-Newman black holes in the Einstein-Maxwell theory have electric and/or magnetic charges.ThiboutDamour and Remo Ruffini studied quantum electrodynamical (QED) effect in Kerr-Newman geometries that is the Sauter-Schwinger mechanism of pair creation from charged black holes [T. Damour and R. Ruffini, Phys. Rev. Lett. 35, 463 (1975)], and proposed the mechanism for extraction of huge energy such as gamma-ray bursts (GRBs) from rotating charged black holes. For details of Schwinger mechanism and astrophysical applications, see R. Ruffini, G. Vereshchagin and S-S Xue, Phys. Rept. 487, 1 (2010).

        Considering an enormous disparity between the electrostatic and gravitational forces in the standard model, it remains an open question how astrophysical objects accumulate net charges during direct formation processes [D N Page, Astrophys. J. 653, 1400 (2006)]. The mass difference between electrons and protons can yield a net accretion of charges 100 C per solar mass [M.Zajacek et al, NMRAS 480, 4408 (2018)].Magnetic fields around rotating black holes can boost charge accretion [R. Wald, Phys. Rev. D 10, 1680 (1974); G. W. Gibbons, A. H. Mujtaba and C. N. Pope, Class. Quant. Grav. 30, 125008 (2013)]. Dark QED with extremely weak interaction predicts black holes with maximal charges. Perspective of charged black holes in astrophysics will be discussed.

        Speaker: Sang Pyo Kim (Kunsan National University)
      • 26
        Speaker: Stefano Scopel (Sogang University)
    • Morning session
      Convener: Nathalie Deruelle
      • 27
        Binary Pulsars as Testbeds of Gravitational Theories

        We will describe the theoretical basis that allows one
        to use the timing of binary pulsars to test, with high precision, many
        aspects of relativistic gravity (including the strong-field regime and radiative aspects of gravity).
        All currently existing pulsar experimentals tests are in excellent agreement with
        the predictions of general relativity.

        Speaker: Thibault Damour
      • 28
        Speaker: Demetrios Christodoulou
      • 29
        Fifty Years Orbiting Remo's World Line?

        Remo likes 50 year anniversaries although is always not too concerned with the number of years being exactly 50, but this year 2022 is exactly the 50th anniversary of our meeting at Princeton in the spring of 1972, which completely changed the rest of my life and led to my adoption by Italy and a second life based in Rome filled with so many positive personal relationships.

        Speaker: Robert Theodore Jantzen (Villanova University)
      • 30
        Speaker: Roy P Kerr (Canterbury University)
      • 31
        Speaker: Rashid Sunyaev (Space Research Institute (IKI) of the Russian Academy of Sciences, Max Planck Institute for Astrophysics and Institute for Advanced Study, Princeton)
      • 11:00 AM
        Coffee Break
      • 32
        Magnetized Kerr-Newman black hole: dynamics of charged particles in exact solutions

        Flow lines of plasma near a weakly magnetised Kerr-Newman black hole were studied in seminal papers by Ruffini, Damour, Hanni, and others in 1970s. Here, following Karas & Vokrouhlicky, we recall the motion of charged particles around magnetized black holes within the framework of the guiding centre approximation, construct surfaces of constant magnetic and electric fluxes, and show the shapes of the plasma horizon in one of generalized, exact magnetized Kerr-Newman (MKN) spacetime.

        Speaker: Vladimír Karas
      • 33
        Speaker: Pascal Chardonnet
      • 34
        Delivery of MG16 award ceremony
        Speaker: Demetrios Christodoulou
      • 35
        Delivery of MG16 award ceremony
        Speaker: Tsvi Piran (The Hebrew University)
      • 36
        Delivery of MG16 award ceremony
        Speaker: Peter Predehl (Max-Planck-Institut für extraterrestrische Physik)
      • 37
        Delivery of MG16 award ceremony
        Speaker: Prof. Rashid Sunyaev (Space Research Institute (IKI) of the Russian Academy of Sciences, Max Planck Institute for Astrophysics and Institute for Advanced Study, Princeton)
      • 38
        Greetings on behalf of the Mayor of Nice

        Greetings to Prof. Ruffini, in representation of the Mayor of Nice, H.E. Christian Estrosi by Agnès RAMPAL (Adjointe to the Mayor of Nice) and by Xavier LATOUR (Vice-président de la Métropole Nice Côte d’Azur)

        Speakers: Agnès Rampal, Xavier Latour
    • Connection with Prof. Ruffini for greetings
      Convener: Yu Wang
      • 39
        Speaker: Simonetta Filippi (Campus Bio-Medico University of Rome)
      • 40
        Shadow Behavior of Extra Dimensional Charged Black Hole In Einstein-Horndeski-Maxwell Theory

        Motivated by string theory and AdS/CFT correspondence, we investigate certain behavior of the shadow geometrical shapes of higher-dimensional charged black hole solution in Einstein-Horndeski-Maxwell theory. We apply the Hamilton-Jacobi method to analyze photon orbits around the black hole and use the formulation of geodesic equations by the Carter approach. The influence of extra dimensions and electric charge on the shadow size of the black hole is analytically calculated. We discover that the size of the shadow of black holes, which depends on their central mass and electric charge, is also determined by the extra dimensions. Interestingly, it turns out that for fixed values of electric charge in Einstein-Horndeski-Maxwell theory, the size of the shadow decreases in higher dimensions except for the cases with dimensions more than $8$. We observe that for more values of charge, the shadow radius for $d=4$ and $d=11$ approach each other. On the other hand, for fixed dimensions, increasing the electric charge results in decreasing the shadow radius of such charged black holes in Einstein-Horndeski-Maxwell theory. These outcomes may lead to the possibility of testing this Einstein-Horndeski-Maxwell charged black hole solution by using astrophysical observations.

        Speaker: Dr Sara Saghafi (University of Mazandarn)
    • Afternoon session
      Convener: Claus Laemmerzahl (University of Bremen)
      • 41
        Black holes in the Early Universe

        I.F. Mirabel & L.F. Rodriguez

        The existence of supermassive black holes (SMBHs) of ~10^9 solar masses in quasars at z ~7.5, when the Universe was ~700 Myr old, is an intriguing puzzle and their origin remains unconstraint. It have been proposed that those SMBHs result from rapidly growing BH seeds of stellar and/or intermediate masses BHs at redshifts z ~30. However, there is no consensus on whether such extreme rapid mass growth of BHs may be sustainable during the required 600 hundred million years. Direct detections in the mid-infrared of massive BHs in galaxies at z = 7 to 15 with the JWST, and indirect detections of radio loud BH signals in the redshifted 21cm line of HI at z~20 with radio arrays as SKA, may constrain the ultimate origin of the SMBHs observed up to z ~7.5. In this talk, I would discuss these issues along the lines of a review accepted for publication in New Astronomy Reviews, and posted in

        Speaker: Dr Felix Mirabel (IAFE-Argentina & CEA-France)
      • 42
        ESCAPE – Open Data and Open Science in Astrophysics

        The H2020 ESCAPE science cluster project ( has brought together the main research infrastructures (RIs) in Astronomy, Astroparticle Physics, Particle and Nuclear Physics to act in a coherent way towards the European Open Science Cloud and associated funding actions. These RIs are ESFRI projects and landmarks such as CTAO, ELT, EST, FAIR, HL-LHC, KM3NeT and SKAO as well as other pan-European research infrastructures such as CERN, ESO, JIV-ERIC and EGO. ESCAPE addresses the challenges shared by its partners and the relevant scientific communities for the implementation of open-science practices and the management of FAIR (Findable, Accessible, Interoperable and Reusable) digital research objects into the core operation of ESFRI projects and landmarks and other relevant world class RIs. These challenges are technical, operational, sociological and scientific, aiming at enhancing the diversity of research activities and scientific objectives. A potential future evolution of the scientific programme of ICRANET could consider a support to reinforce the synergies among phenomenological studies and analysis of astrophysical observational data in an “Open Science” European as well as global contexts. The reproducibility of scientific results as well as the rewarding of scientists committed in open research, deserve the evolution of practices on the assessment of research, increasing value to wide range of digital objects beyond publications and data, including software, workflows, and processes, such as open peer-reviews.

        Speaker: Giovanni Lamanna
      • 43
        Exploring Gravity with Quantum Devices

        An increasing number of space activities for the precise measurement of gravitational fields by means of quantum sensors has been carried out during the last 20 years. Results proved the importance of those experiments and demonstrate the necessity of further technology developments in order to set up new approaches to spacetime geometry.
        Recent and planned space missions and their results will be reported discussed .

        Speaker: Hansjoerg Dittus (University of Bremen)
      • 44
        Dark matter at all scales: from the Galactic center to the entire halo

        Relaxation mechanisms of collisionless self-gravitating systems of fermions in cosmology, can lead to spherical equilibrium states which are stable, long-lived, and able to explain the dark matter (DM) halos in galaxies. We show that the most general fermionic DM profile out of such a mechanism, develops a degenerate compact core which is surrounded by an extended halo. When applied to the Milky Way, it is demonstrated that while the outer halo can explain the rotation curve of the Galaxy, the central DM-core explain the dynamics of all the best resolved S-cluster stars orbiting SgrA *, without the need of assuming a central black hole (BH). In particular it is shown how this dense DM-core alternative to the BH can pass the test of General Relativistic effects including the gravitational redshift and the periapsis precession of the S2 star. On halo scales, and independently of rotation curve tracers, it is further shown the ability of the fermionic DM profile to explain the kinematics of recently detected stellar streams by the GAIA mission. Finally, this fermionic DM model can provide a mechanism of supermassive BH formation from the core-collapse of the central core, leading to a paradigm shift in the understanding of galactic halos in terms of quantum fermionic particles.

        Speaker: Carlos Raúl Argüelles (Universidad Nacional de La Plata)
      • 4:50 PM
        Coffe Break
      • 45
        Carlo MASCI, Mayor of Pescara Ceremony Mersenne Prize 2022 from ICRANet Hq in Pescara, coordinated by Costantino SIGISMONDI
        Speaker: Costantino Sigismondi (ICRA Sapienza and ICRANET Pescara)
      • 46
        Direct Observational Constraints on the Structure and Composition of the Base of the Jet in M87

        It has become commonplace is astronomy to describe the transverse coarse structure of jets in loosely defined terms such as sheath" andspine" based on discussions of parsec scale properties. But, the applicability, dimension and prominence of these features on sub-lt-yr scales has previously been unconstrained by observation. The first direct evidence of jet structure near the source in M\,87 is extreme limb brightening (a double-rail morphology), 0.3 - 0.6 mas from the source, that is prominent in observations with high resolution and sensitivity. Intensity cross-cuts of these images provide three strong, interdependent constraints on the geometry responsible for the double-rail morphology: the rail to rail separation, the peak to nadir intensity ratio and the rail widths. Analyzing these constraints indicates that half or more of the jet volume resides in a thick-walled, tubular, mildly relativistic, protonic jet only $\sim 0.25$ lt-yr (or $\sim 300$ M, where M is the central black hole mass in geometrized units) from the source. By contrast, the Event Horizon Telescope Collaboration interprets their observations with the aid of general relativistic magnetohydrodynamic simulations that produce an invisible (by construction) electron-positron jet with a surrounding luminous, thin sheath. Yet, it is shown that synthetic images of simulated jets are center brightened 0.3 - 0.6 mas from the source. This serious disconnection with observation occurs in a region previously claimed in the literature to be well represented by the simulations. The limb brightening analysis motivates a discussion of possible simulation modifications to improve conformance with observations.

        Speaker: Brian Punsly (ICRANet)
    • Contributions from Far East: Connections with Asia
      Convener: Prof. Jiangong Gao
      • 47
        Greeting from Prof. Jiangong Gao

        This is Gao Jian gong from China.
        Dear Remo,
        Happy 80th birthday! I hope you have an amazing 80th birthday, filled with love from family, friends, and happy memories. Life has gone by so fast! Do you still remember 40 years ago, after the Marcel Grossman meeting in Shanghai, when you traveled to Urumqi, Xinjiang, in the central area of Asia and northwestern border of China? You left footprints in Turpan, the Heaven Pool (lakes on the tops of the Tianshan Mountain) and Tianshan glaciers. You have greatly contributed to the widespread of new knowledge and progress in modern astrophysics. You helped to build connections among universities, colleges in Xinjiang and the International Centre for Theoretical Physics and significantly promoted academic communications between scientists in this relatively closed region and the outside world. You sowed the seeds of science and friendship in this region. These seeds have sprouted and grown. Now, an astrophysics research group has been established in Xinjiang University (The former Xinjiang Institute of Technology has been merged into Xinjiang University), and courses on General Relativity and Relativistic Astrophysics are offered to graduate students. Your efforts for scientific and cultural exchanges between China and Italy will never be forgotten.
        Auguro un Buon Compleanno!
        Allow me to conclude by congratulating your birthday in Chinese: 祝你生日快乐,福如东海,寿比南山!(I wish you a happy birthday, good fortune as oceans and longevity as mountains)

        Speaker: Prof. Jiangong Gao
      • 48
        Three arguable concepts: point particle singularity, asymmetric action of EM on quantum wave functions, and the Left out restricted Lorentz gauge from U(1)*

        We address three concepts. i. The point particle assumption inherent to
        non-quantum physics is singular and entails divergent fields and integrals.
        ii. In quantum physics electromagnetism (EM) plays an asymmetric role.
        It acts on quantum wave fields (wave functions) but the wave fields do not
        react back. We suggest to promote the one sided action of EM on quantum
        waves into a mutual action-reaction partnership. By so doing, the quantum
        wave shares its analyticity with the EM field and removes the latter’s
        singularities and divergences. iii) The conventional U(1) symmetry leaves
        quantum dynamics invariant under a ’general’ Lorentz gauge and imposes
        the standard minimal coupling of the quantum wave to the EM 4-vector potential.
        One, however, has the option to ask for invariance under the ’restricted’
        Lorentz gauge. This in turn invites in a coupling to the derivatives of the
        vector potential in addition to the minimal coupling and, so to say, enlarges
        the U(1) symmetry. We examine the Dirac electron in this context and find
        that the electron exhibits distributed charge and current densities.
        The enlarged symmetry is expected to bring in its own constant of motion.
        Indeed it does. The anomalous g-factor of the so designed electron emerges,
        up to order (𝛼/𝜋)^2 as the new constant of motion in agreement with the
        QED theorized values.

        Speaker: Yousef Sobouti
      • 49
        Some words on the roled played by prof. Ruffini in my scientific growth

        In my talk, I will briefly share some memories about the important role played by prof. Ruffini in some of the most important stages and scientific experiences of my career. I will speak about the time of when I was a master student in prof. Ruffini's group at La Sapienza first, and then as a PhD student in the Erasmus Mundus program. Finally, I will spend some words about the concept of irreducible mass of black holes formulated by Christodoulou-Ruffini and its relationship to my latest paper "Understanding Gravitational Entropy of Black Holes: A New Proposal via Curvature Invariants", PRD 105 (2022) 104017.

        Speaker: Daniele Gregoris (
      • 50
        Boson Stars and Dark Matter

        The concept of boson stars (BSs) was first introduced by Kaup and Ruffini-Bonazzola in the 1960s. Following this, a lot of attention has been directed to the possible role of BSs in astrophysics whether as a dark matter (DM) candidate or as the less exotic alternative to different types of black holes.
        Here, for the first time, we introduce a new class of compact objects as a mixture of self-interacting bosonic DM and normal baryonic matter named DM admixed neutron star (NS). It is  shown that depending on the model parameters a dense DM core inside NS or an extended dark halo around it can be formed. Moreover, the observational consequences of DM admixed NSs is discussed in light of the current and future multi-messenger observations.

        Speaker: Prof. Soroush Shakeri ( IUT and ICRANet-Isfahan)
      • 51
        Coordinates in general relativity: the time from perihelion to aphelion

        With a coordinate transformation, the Schwarzschild metric in the standard coordinate can become the one in the Kerr-Schild coordinate. In this work, we derive the second post-Newtonian solutions for the test particle’s motion in the Schwarzschild spacetime under these two coordinates, and show that the calculation results for the time from the perihelion to the aphelion are different. Since the time from the perihelion to the aphelion of the celestial body is an observable quantity in astronomy, this example demonstrates that the solutions achieved in the specific coordinates may not be the final answer to the investigated problem even they are formulated in terms of the physical quantities such as the orbital energy and angular momentum. They should be mapped into the observer's reference frame before being compared with the observations.

        Speaker: Prof. Wenbin Lin (University of South China)
    • Morning session
      Convener: Tsvi Piran (The Hebrew University)
      • 52
        The physics of fast radio bursts


        Speaker: Bing Zhang (University of Nevada, Las Vegas)
      • 53
        The Amati relation in Gamma-Ray Bursts: observations, implications and perspectives.

        The correlation between spectral peak energy, Ep,i , and isotropic-equivalent total radiated energy, Eiso, referred to as "Amati relation" in the scientific literature, is one of the most relevant and investigated properties of Gamma-Ray Bursts (GRBs) , with strong implications for prompt emission physics, identification and understanding of different sub-classes, using these phenomena for measuring cosmological parameters. I will review the observational status of the Amati relation, its main properties and consequences, the expected developments from near future (e.g., SVOM) and next generation (e.g., THESEUS) space missions deticated to GRBs.

        Speaker: Lorenzo Amati (INAF - OAS Bologna)
      • 54
        Latest developments in the binary-driven hypernova scenario of long gamma-ray bursts

        I will give an overview and show the latest developments about the physical ingredients and associated observables of the binary-driven hypernova (BdHN) scenario of long gamma-ray bursts (GRBs). In particular, I focus on the role of the newborn neutron star (newNS) formed in the core-collapse supernova (SN) of the carbon-oxygen (CO) star, the NS binary companion, and the black hole (BH) formed from the induced gravitational collapse of the latter, in the physical description of the precursors, the prompt emission, the high-energy (GeV) emission, and the afterglow in the X-rays, optical and radio wavelengths of long GRBs.

        Speaker: Jorge Armando Rueda Hernandez (ICRANet)
      • 10:50 AM
        Coffe Break
      • 55
        Observational constraints on the energy source of gamma-ray bursts and associated supernovae

        I will discuss various constraints, derived from radio, optical and gamma-ray observations, on the properties of the energy source in long gamma-ray bursts. First, I will present a study of the observational imprint of a jet driven explosion and compare it to available data to determine whether the jet can generate both the gamma-ray burst and the associated supernova. Second, I will show an analysis of the prompt gamma-ray emission that constrains the time scale over which the gamma-ray emission shuts off.

        Speaker: Ehud Nakar
      • 56
        Bayesian Time-resolved Spectral Properties in the BdHN GRBs

        The binary-driven hypernova (BdHN) model has been successfully applied to explain the observed properties of multi-band gamma-ray bursts (GRBs) for many years. Here we report the spectral properties of the prompt emission of 21 BdHN bursts and their multi-wavelength afterglow properties.

        Speaker: Liang Li (ICRANet, Piazza della Repubblica 10, I-65122 Pescara, Italy)
      • 57
        A Brief Review of Binary Driven Hypernova

        Binary driven hypernova (BdHN) models long gamma-ray bursts (GRBs) as occurring in the binary systems involving a carbon-oxygen core and a companion compact star. This model, first proposed in 2012, succeeds and improves upon the fireshell model and the induced gravitational collapse paradigm. After nearly a decade of development, the BdHN model has reached a nearly mature structure. In this talk, on behalf of the group, I will present a summary of the BdHN model and the physical processes at work in each of the episodes during its occurrence and lifetime, and to give examples by GRB 180728A and 190829A.

        Speaker: Yu Wang
      • 58
        Kinetic effects in nonequilibrium electron-positron plasmas

        In astrophysics optically thick electron-positron plasma is a source of emission from compact objects. Attempts to create relativistic plasma are made in large projects such as ELI and XCELS. Short time-scales of variability and non-thermal spectra of observed radiation in astrophysical sources, as well as small spatial dimensions in laboratory experiments imply absence of equilibrium. We review kinetic effects in relativistic plasmas in the process of thermalization.

        Speaker: Gregory Vereshchagin (ICRANet)
    • Connection with Prof. Ruffini for greetings
      Convener: Yu Wang
      • 59
        Supernova-GRB connection
        Speaker: Massimo Della Valle
      • 60
        Magnetohydrodynamics beyond the ideal limit

        While the ideal limit of magnetohydrodynamics is a convenient and effective framework to model astrophysical sources, there are, possibly, physical situations that do not fall within this approximation. We discuss, in a historical perspective, some (mostly existing) scattered ideas that extend this framework.

        Speakers: Stefano Ansoldi (University of Udine), Benjamin Hernandez
    • Afternoon session
      Convener: Mimoza Hafizi (University of Tirana)
      • 61
        Spontaneous Peccei-Quinn symmetry breaking renders sterile neutrino, axion and $\chi$boson to be candidates for dark matter particles

        We study the Peccei-Quinn (PQ) symmetry of the sterile right-handed neutrino sector and the gauge
        symmetries of the Standard Model. Due to four-fermion interactions, spontaneous breaking of these
        symmetries at the electroweak scale generates top-quark Dirac mass and sterile-neutrino Majorana
        mass. The top quark channels yield massive Higgs, $W^{\pm }$ and $Z^{0}$ bosons. The sterile
        neutrino channel yields the heaviest sterile neutrino Majorana mass, sterile Nambu-Goldstone
        axion (or majoron) and massive scalar $\chi $boson. Four-fermion operators effectively induce
        their tiny couplings to SM particles. We show that a sterile QCD axion is the PQ solution to the strong CP problem. The lightest and heaviest sterile neutrinos ($m_{N}^{e}\sim 10^{2}$ keV and $m_{N}^{\tau }\sim 10^{2}$ GeV), a sterile QCD axion ($m_{a}< 10^{-8}$ eV, $g_{a\gamma }< 10^{-13} {\mbox{GeV}}^{-1}$) and a Higgs-like $\chi $boson ($m_{\chi }\sim 10^{2}$ GeV) can be dark matter particle candidates, for the constraints of their tiny couplings and long lifetimes inferred from the $W$-boson decay width, Xenon1T and precision fine-structure-constant experiments. The axion and $\chi $boson couplings to SM particles are
        below the values reached by current laboratory experiments and astrophysical observations for directly or indirectly detecting dark matter particles.

        Speaker: Prof. She-Sheng Xue (ICRANet, Physics Department, Sapienza University of Rome)
      • 62
        Magnetohydrodynamical processes around a Kerr black hole in horizon penetrating coordinates

        Selected magnetohydrodynamical processes around a Kerr black hole are analytically investigated adopting horizon penetrating coordinates and focusing in particular on the associated electrodynamics and energetics.

        Speaker: Christian Cherubini (Department of Science and Technology for Humans and the Environment and ICRA, Campus Bio-Medico University of Rome, 00128 Rome, Italy and International Center for Relativistic Astrophysics Network-ICRANet, 65122 Pescara, Italy)
      • 63
        Hyperbolic encounters in a two-body system

        I will discuss the recent developments concerning the analytic determination of the scattering angle, including both the conservative and the radiative parts.

        Speaker: Dr Donato Bini (Istituto per le Applicazioni del Calcolo "M. Picone", CNR, Rome)
      • 64
        The Structure and Stability of Massive Hot White Dwarfs

        We investigate the structure and stability against radial oscillations, pycnonuclear reactions, and inverse beta-decay of hot white dwarfs. We find that the temperature produces important effects on the equilibrium and radial stability of white dwarfs. The stable equilibrium configuration results are compared with white dwarfs estimated from the Extreme Ultraviolet Explorer Survey and Sloan Digital Sky Survey. These massive stars are in the mass region where the general relativity effects are important. Regarding the radial stability of these stars as a function of the temperature, we obtain that the radial stability decreases with the increment of central temperature.

        Speaker: Manuel Malheiro (Instituto Tecnológico de Aeronáutica)
      • 65
        Speaker: Prof. Cesar Augusto Zen Vasconcellos (ICRANet/UFRGS)
      • 4:15 PM
        Coffe Break
      • 66
        Speaker: Jose Rodriguez
      • 67
        Redshift Estimates for Short Gamma-Ray Bursts from the Fermi-GBM Catalogue Using Ep,i-Eiso Correlation

        Currently operating and future planned missions need robust methods in determining the distances to GRBs. We purpose to provide a simple method for estimating distances to cosmological gamma-ray bursts. We construct $E_{\rm p, i}$-$E_{\rm iso}$ correlation for short gamma-ray bursts based on events with well established spectral peak energies. Applying minimal criteria, we sample SGRBs from the GBM catalogue and calculate spectral peak energy and isotropic energy using a range of distances between maximal and minimal observed redshifts. We iterate through a range of redshifts, and each event is examined for the condition to cross the main line of the $E_{\rm p, i}$-$E_{\rm iso}$ relation and additionally, its $\pm1\sigma$ and $\pm3\sigma$ uncertainty areas. Consequently, we take those intersections as the best redshift estimates for an individual burst. Redshifts estimated in such a way are then compared to those bursts with measured distances.

        Speaker: Dr Yerlan Aimuratov (Fesenkov Astrophysical Institute / al-Farabi Kazakh National University)
      • 68
        C3 matching conditions in relativistic astrophysics

        We propose an alternative method to solve the problem of matching two solutions of Einstein equations along a matching surface. It is based upon the use of the eigenvalues of the Riemann curvature tensor, which are required to coincide along the matching surface. In addition, the extrema of the eigenvalues are used to determine the minimum radius of the matching surface, a procedure that involves third-order derivatives of the metric tensor (C3 matching). In the case of spherically symmetric spacetimes, the C3 matching leads to physically meaningful results, whereas other matching procedures permit non-physical junctures.

        Speaker: Prof. Hernando Quevedo (National Autonomous University of Mexico)
      • 69
        Speaker: Marco Tavani
      • 70
        Speaker: Luca Izzo (University of Copenhagen)
      • 71
        Concluding remarks
        Speaker: Remo Ruffini (ICRANet, ICRA, INAF)