ICRANet Newsletter
Special Issue
July/October
July/October
1st Scientific ICRANet Meeting in Yerevan
"Black Holes: the largest energy sources in the Universe".
Main scientific results
"Black Holes: the largest energy sources in the Universe".
Main scientific results
After the opening ceremony Prof. Ruffini presented “Black Holes, Gamma-Ray Burst and Supernovae. The Leading Progress in Physics and Relativistic Astrophysics” talk which covers the history of discovery of GRBs as well as most recent results from observation/modeling of GRBs and also the recent progress of understanding GRB-supernovae connection.
In the strong field section of this Armenian meeting, worldwide experts Christoph H. Keitel (German), Karen Hatsagortsyan (Armenian) and Antonino Di Piazza (Italian) from Max Planck Institute (Heidelberg, Germany) presented their review talks on the studies of nuclear physics by using intense lasers, high-energy photons by the collision of laser beams and general review on the phenomena of strong electromagnetic fields.
Two review talks on high energy gamma-ray astrophysics were given by Razmick Mirzoyan (Germany-Armenia) and Alessandro De Angelis (Italy). Mirzoyan showed recent results of MAGIC observations of galactic sources (supernova remnant W51 and Crab nebulae), extragalactic sources (IC 310, Mrk 412 etc) and highlights of current status of Cherenkov telescope array. High energy gamma-ray astrophysics at relatively lower energies (around 10 GeV) with Cherenkov detectors have been presented by De Angelis.
ICRANet group (EMJD students, ICRANet Faculty members) presented results of their recent studies on GRBs and supernovae and GRB connections. The physics of neutron stars and recent progress have been discussed by Jorge Rueda, Riccardo Belvedere and Kuantay Boshkayev. In addition, Eckhard Strobel, Yuanbin Wu and Hendrik Ludwig, and others presented their research in the issue of strong electromagnetic fields and discussed with them any relevant phenomena and applications in physics and astrophysics.
Paolo Giommi and EMJD student Bruno Sversut presented a sample of high synchrotron peaked blazars which are interesting for TeV observations. They concluded, that most of them would be detected by upcoming Cherenkov telescope array, instead some of them at flaring state, even by the current generation Cherenkov telescopes. Prof Claus Laemmerzahl from Bremen University presented a talked about “Test particle motion in regular black hole space-times”.
In the strong field section of this Armenian meeting, worldwide experts Christoph H. Keitel (German), Karen Hatsagortsyan (Armenian) and Antonino Di Piazza (Italian) from Max Planck Institute (Heidelberg, Germany) presented their review talks on the studies of nuclear physics by using intense lasers, high-energy photons by the collision of laser beams and general review on the phenomena of strong electromagnetic fields.
Two review talks on high energy gamma-ray astrophysics were given by Razmick Mirzoyan (Germany-Armenia) and Alessandro De Angelis (Italy). Mirzoyan showed recent results of MAGIC observations of galactic sources (supernova remnant W51 and Crab nebulae), extragalactic sources (IC 310, Mrk 412 etc) and highlights of current status of Cherenkov telescope array. High energy gamma-ray astrophysics at relatively lower energies (around 10 GeV) with Cherenkov detectors have been presented by De Angelis.
ICRANet group (EMJD students, ICRANet Faculty members) presented results of their recent studies on GRBs and supernovae and GRB connections. The physics of neutron stars and recent progress have been discussed by Jorge Rueda, Riccardo Belvedere and Kuantay Boshkayev. In addition, Eckhard Strobel, Yuanbin Wu and Hendrik Ludwig, and others presented their research in the issue of strong electromagnetic fields and discussed with them any relevant phenomena and applications in physics and astrophysics.
Paolo Giommi and EMJD student Bruno Sversut presented a sample of high synchrotron peaked blazars which are interesting for TeV observations. They concluded, that most of them would be detected by upcoming Cherenkov telescope array, instead some of them at flaring state, even by the current generation Cherenkov telescopes. Prof Claus Laemmerzahl from Bremen University presented a talked about “Test particle motion in regular black hole space-times”.
Zeldovich-100 meeting proceedings
All contributions for the proceedings of Zeldovich-100 meeting held in Minsk in March 2014 have arrived at ICRANet: among them, 18 papers from the plenary session and 32 papers from the parallel sessions. The proceedings will be published by the end of 2014 in special issues of Astronomy Reports (papers from plenary session) and Nonlinear Phenomena in Complex Systems (papers from parallel session) journals. Both journals are indexed in Scopus, while Astronomy Reports is also indexed in Thomson Reuters. The editors of the special issues are Sergei Kilin (National Academy of Sciences of Belarus), Remo Ruffini (ICRANet) and Gregory Vereshchagin (ICRANet).
Publication of proceedings of the 13th Italian-Korean meeting on Relativistic Astrophysics
In this meeting, which takes place once every two years alternatively in Italy and Korea (see: here), in addition to many Korean professors, researchers and students, more than 10 participants from the ICRANet participated and presented their scientific works at this meeting. Their contributions have been recently published in the refereed and important “Journal of Korean Physical Society”. At this link is possible to read a preview: http://link.springer.com/journal/40042/65/6/page/1
Collaboration between ICRANet and the A. Einstein Institute of Potsdam
In July ICRANet started the new program “Exact solutions in the supersymmetric General Relativity” in collaboration with the group of Prof. Hermann Nicolai at the Albert Einstein Institute in Potsdam (Germany). This new direction is added now to the list of the thematics of the ICRANet sector “Exact Solutions of the Einstein and Einstein-Maxwell equations”.
The foremost target is construction of the exact supergravitational solitons.
The foremost target is construction of the exact supergravitational solitons.
Signed new agreements in Brazil, Italy and Mexico
The fervent diplomatic activity of prof. Ruffini continues in South America where, between July and August, were signed new important agreements with some major universities in Brazil and Mexico.
In particular the followings agreements have been signed: on July 1st, in Niterói (Brazil), with the UFF - Universidade Federal Fluminense; on July 9th in Mexico City with the UAM - Universidad Autónoma Metropolitana; on August 26th in Florianópolis (Brazil) with the UFSC - Universidade Federal de Santa Catarina; and on August 29, also in Brazil, with the UFPE - Universidade Federal de Pernambuco.
The first of August, in Rome, was signed the agreement with the CNR - National Research Center, directed by prof. Luigi Nicolais.
In particular the followings agreements have been signed: on July 1st, in Niterói (Brazil), with the UFF - Universidade Federal Fluminense; on July 9th in Mexico City with the UAM - Universidad Autónoma Metropolitana; on August 26th in Florianópolis (Brazil) with the UFSC - Universidade Federal de Santa Catarina; and on August 29, also in Brazil, with the UFPE - Universidade Federal de Pernambuco.
The first of August, in Rome, was signed the agreement with the CNR - National Research Center, directed by prof. Luigi Nicolais.
Agreement with the UAM |
Agreement with the UFSC |
Agreement with the UFPE |
Agreement with the CNR |
Great success for the "Researchers' Night" at ICRANet
For the second consecutive year, the Center ICRANet of Pescara has joined the national "Researchers' Night 2014" to promote, for the largest public, the research activity in Italy. On the morning of Friday, September 26, ICRANet scientists have presented the topics of their research to 150 students of the final two years of the high schools in Pescara. In addition, the headquarter remained open in the evening with a program of guided tours for the public, who has been able to see with their own eyes the places where scientists of ICRANet deepen our knowledge of the stars and the laws governing the Universe.
Finally, at the prestigious Aurum of Pescara, several scientists of our Center have animated a rich program of conferences and telescopic observations: Prof. Ruffini spoke of "Supernovae, Gamma Ray Burst and Blacks Holes" and dr. Costantino Sigismondi explored the theme "Supergiants Novae and Variables". In addition, until midnight dr. Luca Izzo and dr. Costantino Sigismondi conducted observations by telescope both of the sun and the stars.
Finally, at the prestigious Aurum of Pescara, several scientists of our Center have animated a rich program of conferences and telescopic observations: Prof. Ruffini spoke of "Supernovae, Gamma Ray Burst and Blacks Holes" and dr. Costantino Sigismondi explored the theme "Supergiants Novae and Variables". In addition, until midnight dr. Luca Izzo and dr. Costantino Sigismondi conducted observations by telescope both of the sun and the stars.
Delegation of Danish students visiting the ICRANet center in Pescara
On October 23th, a delegation of 6 Danish students from Svendborg and guided by prof. Mads Fjeldvig Gammeltoft, guests of the students of prof. Alessandra Palma of the Liceo Scientifico "Leonardo da Vinci" in Pescara, visited our center of Pescara, where they witnessed, after the greetings of the Director, prof. Remo Ruffini, the lesson titled "Light and the exploration of the Universe" given by Dr. Gregory Vereshchagin, a member of the ICRANet faculty.
Presented the poster of the Fourteenth Marcel Grossman Meeting – Rome, Italy, July 12-18, 2015
The Fourteenth Marcel Grossmann Meeting will be held in Rome, Italy, at the University of Rome “Sapienza”, July 12-18, 2015. Since 1975, the Marcel Grossman Meetings have been organized in order to provide opportunities for discussing recent advances in gravitation, general relativity and relativistic field theories, emphasizing mathematical foundations, physical predictions and experimental tests. The objective of these meetings is to elicit exchange among scientists that may deepen our understanding of space-time structures as well as to review the status of ongoing experiments aimed at testing Einstein’s theory of gravitation either from the ground or from space. Previous meetings have been held in Trieste (1975 and 1979), Shanghai (1982), Rome (1985), Perth (1988), Kyoto (1991), Stanford (1994), Jerusalem (1997), Rome (2000), Rio (2003), Berlin (2006), Paris (2009) and Stockholm (2012). Interested scientists should address a member from any one of the organizing committees or the conference secretariat.
This edition of the Marcel Grossmann Meeting marks the 100th anniversary of the Einstein equations, the International Year of Light 2015, organized by UNESCO, and the Golden Jubilee of Relativistic Astrophysics; all of them will be celebrated by MG14 and other satellite meetings in Armenia, Brazil, China, France, Germany, India, Israel, Korea, Mexico and USA.
The meeting poster is ready and can be downloaded at: http://www.icra.it/mg/mg14/MG14_poster.pdf
The planning of the scientific program is in progress, with the renewal of selected past parallel sessions and the introduction of new ones.
Website: http://www.icra.it/MG/mg14/
email: mg14@icra.it
This edition of the Marcel Grossmann Meeting marks the 100th anniversary of the Einstein equations, the International Year of Light 2015, organized by UNESCO, and the Golden Jubilee of Relativistic Astrophysics; all of them will be celebrated by MG14 and other satellite meetings in Armenia, Brazil, China, France, Germany, India, Israel, Korea, Mexico and USA.
The meeting poster is ready and can be downloaded at: http://www.icra.it/mg/mg14/MG14_poster.pdf
The planning of the scientific program is in progress, with the renewal of selected past parallel sessions and the introduction of new ones.
Website: http://www.icra.it/MG/mg14/
email: mg14@icra.it
ICRANet Faculty and Student’s Scientific Research articles
GRB 130427A and SN 2013cq: A Multi-wavelength Analysis of An Induced Gravitational Collapse Event
R. Ruffini, Y. Wang, M. Kovacevic, C.L. Bianco, M. Enderli, M. Muccino, A.V. Penacchioni, G.B. Pisani, J.A. Rueda
Accepted by ApJ
In the particle physics, the interaction between particles generates new particles, named as S-matrix. For instance, a pair of quark and anti-quark produces W/Z boson and Higgs boson, the outcome of electron and positron interaction could be a pair of muon and anti-muon, the duration of such interaction is fleeting, the above two reactions only take 10−26 s and 10−23 s respectively.
In the marco-scale astrophysics, some phenomena are apparently similar to the micro-scale particle physics, a famous example is the similarity of electron and blackhole, both can be completely characterized by only mass, electric charge, and angular momentum. Here in our new accepted Astrophysical Journal paper, we introduce a new celestial matrix, C-matrix, an analogue to the S-matrix (Fig.1). C-matrix depicts a binary system composed of one neutron star and one massive star as the initial state, and the products after about 100s interaction are one new neutron star and one black hole. The story of this process can be outlined as: The massive star undergoes a supernova and eject its massive shell, the companion neutron star accretes the ejecta until reaching its critical mass and collapses into a black hole, simultaneously an over critical electrical field is generated around the black hole and electro-positron plasma are produced from it, this plasma flow expands ultra-relativisticly and collides with the inter-stellar medium, which gives origin to the gamma-ray burst (GRB), GRB is considered as an energetic explosion which emits huge abundant photons, mainly the gamma-rays.
On April 27, 2013, such aforementioned event occurred and triggered Fermi satellite, later various satellites and telescopes joined the observation. This event was named as GRB 130427A, it is one of the few GRBs which has hundreds of seconds simultaneous data in the optical, X-ray and GeV emission, especially precious is its GeV emission, due to the long duration, high intensity and containing the highest energy photon (95.3 GeV) ever observed in GRBs.
We proceeded to make a multi-wavelength analysis. The high energy GeV emission appears to be detectable at the end of the prompt radiation phase(∼ 20s), when the fluence of X-ray and γ-ray of the prompt exponentially decrease and becomes transparent for GeV photons.
After 200s, the Lorentz factors of X-ray and GeV are very different, and their physical origin are necessarily different. The high energy can originate from the interaction of some of the physical components (e.g., neutron star and black hole) newly created in the C-matrix.
![[fig1]](newsletters/luglio2014/fig1_small.jpg "fig1")
Figure 1: Three different matrices in fundamental physics. The first is the quark matrix leading to a Higgs boson. In the middle is the classical electron-positron pair matrix, generating an muon and anti-muon pair. The third matrix is the celestial one, which is considered in the present work. ∆t is the duration of intermediate state.
The interaction of the GRBs with the SN ejecta may well generate the X-ray emission and the associated thermal component. By analyzing the X-ray data from 195s to 461s, a crucial evidence was found, that adding a blackbody component could efficiently improve the fitting (Fig. 3), the obtained blackbody temperature is in the range of 0.3 KeV to 0.5 KeV, the radiation radius is deduced from about 7 × 1012 cm to 2.8 × 1013 cm, with the expansion speed at 0.8c, c is the speed of light. These above value is typical for the supernova ejecta accelerated by the collision with GRB outflow.
GCN 14526: The late X-ray observations of GRB 130427A by Swift-XRT clearly evidence a pattern typical of a family of GRBs associated to supernova (SN) following the Induce Gravitational Collapse (IGC) paradigm (Rueda & Ruffini 2012; Pisani et al. 2013). We assume that the luminosity of the possible SN associated to GRB 130427A would be the one of 1998bw, as found in the IGC sample described in Pisani et al. 2013. Assuming the intergalactic absorption in the I-band (which corresponds to the R-band rest-frame) and the intrinsic one, assuming a Milky Way type for the host galaxy, we obtain a magnitude expected for the peak of the SN of I = 22 - 23 occurring 13-15 days after the GRB trigger, namely between the 10th and the 12th of May 2013. Further optical and radio observations are encouraged.
After the first days observation, we found that the X-ray afterglow of GRB 130427A overlaps other GRBs induced by C-matrix (Fig.4), we concluded that this new GRB shared the same mechanism, which means a supernova is inevitable in the system though the optical signal is too weak too be observed, immediately we sent a letter to GCN on May 2, 2013, predicting that the optical R-band of a SN will reach its peak magnitude in about 10 days in the cosmological rest-frame on the basis of the IGC paradigm, and we encouraged observations.
![[fig2]](newsletters/luglio2014/fig2_small.jpg "fig2")
Figure 2: Flux of first 700 s. Blue points are the Fermi-LAT high energy emission from 100 MeV till 100 GeV, grey dotted line represents the Fermi-GBM, from 10 keV to 900 keV, green dashed line represents the photons detected by Swift BAT from 10 keV to 50 keV, and red solid line is the soft X-ray Swift-XRT detection, in the range of 0.3 KeV to 10 KeV. From this figure, clearly the Fermi-LAT emission reaches highest fluence at about 20 s while the gamma-ray detected by Fermi-GBM releases most of the energy within the first 10 s.
![[fig3]](newsletters/luglio2014/fig3_small.jpg "fig3")
Figure 3: Spectral fitting of three time intervals (196s - 246s, 246s - 326s, 326s - 461s) in Episode 3, data come from Swift-XRT (0.3 KeV - 10 KeV, without pile-up area). Black points are the deduced data, green dashed line presents the thermal component, blue long-dashed line is the power law component, and red line shows the combination of these two components. Clearly the flux of thermal component drops and the temperature decreases along the time.
![[fig4]](newsletters/luglio2014/fig4_small.jpg "fig4")
Figure 4: Overlapping of GRB 130427A and GRB 060729. Green cross is the light curve of GRB 060729. Red triangle and orange dots represent the light curve of GRB 130427A respectively before and after May 2, 2013. The vertical line marks the time of 2 × 104 s which is the lower limit for the domain of validity of the Pisani relation prior to GRB 130427A.
Indeed, starting from May 13, 2013, the telescopes GTC, Skynet and HST discovered the signals from the type Ic supernova SN 2013cq.
Accepted by ApJ
In the particle physics, the interaction between particles generates new particles, named as S-matrix. For instance, a pair of quark and anti-quark produces W/Z boson and Higgs boson, the outcome of electron and positron interaction could be a pair of muon and anti-muon, the duration of such interaction is fleeting, the above two reactions only take 10−26 s and 10−23 s respectively.
In the marco-scale astrophysics, some phenomena are apparently similar to the micro-scale particle physics, a famous example is the similarity of electron and blackhole, both can be completely characterized by only mass, electric charge, and angular momentum. Here in our new accepted Astrophysical Journal paper, we introduce a new celestial matrix, C-matrix, an analogue to the S-matrix (Fig.1). C-matrix depicts a binary system composed of one neutron star and one massive star as the initial state, and the products after about 100s interaction are one new neutron star and one black hole. The story of this process can be outlined as: The massive star undergoes a supernova and eject its massive shell, the companion neutron star accretes the ejecta until reaching its critical mass and collapses into a black hole, simultaneously an over critical electrical field is generated around the black hole and electro-positron plasma are produced from it, this plasma flow expands ultra-relativisticly and collides with the inter-stellar medium, which gives origin to the gamma-ray burst (GRB), GRB is considered as an energetic explosion which emits huge abundant photons, mainly the gamma-rays.
On April 27, 2013, such aforementioned event occurred and triggered Fermi satellite, later various satellites and telescopes joined the observation. This event was named as GRB 130427A, it is one of the few GRBs which has hundreds of seconds simultaneous data in the optical, X-ray and GeV emission, especially precious is its GeV emission, due to the long duration, high intensity and containing the highest energy photon (95.3 GeV) ever observed in GRBs.
We proceeded to make a multi-wavelength analysis. The high energy GeV emission appears to be detectable at the end of the prompt radiation phase(∼ 20s), when the fluence of X-ray and γ-ray of the prompt exponentially decrease and becomes transparent for GeV photons.
After 200s, the Lorentz factors of X-ray and GeV are very different, and their physical origin are necessarily different. The high energy can originate from the interaction of some of the physical components (e.g., neutron star and black hole) newly created in the C-matrix.
![[fig1]](newsletters/luglio2014/fig1.jpg "fig1")
Figure 1: Three different matrices in fundamental physics. The first is the quark matrix leading to a Higgs boson. In the middle is the classical electron-positron pair matrix, generating an muon and anti-muon pair. The third matrix is the celestial one, which is considered in the present work. ∆t is the duration of intermediate state.
The interaction of the GRBs with the SN ejecta may well generate the X-ray emission and the associated thermal component. By analyzing the X-ray data from 195s to 461s, a crucial evidence was found, that adding a blackbody component could efficiently improve the fitting (Fig. 3), the obtained blackbody temperature is in the range of 0.3 KeV to 0.5 KeV, the radiation radius is deduced from about 7 × 1012 cm to 2.8 × 1013 cm, with the expansion speed at 0.8c, c is the speed of light. These above value is typical for the supernova ejecta accelerated by the collision with GRB outflow.
GCN 14526: The late X-ray observations of GRB 130427A by Swift-XRT clearly evidence a pattern typical of a family of GRBs associated to supernova (SN) following the Induce Gravitational Collapse (IGC) paradigm (Rueda & Ruffini 2012; Pisani et al. 2013). We assume that the luminosity of the possible SN associated to GRB 130427A would be the one of 1998bw, as found in the IGC sample described in Pisani et al. 2013. Assuming the intergalactic absorption in the I-band (which corresponds to the R-band rest-frame) and the intrinsic one, assuming a Milky Way type for the host galaxy, we obtain a magnitude expected for the peak of the SN of I = 22 - 23 occurring 13-15 days after the GRB trigger, namely between the 10th and the 12th of May 2013. Further optical and radio observations are encouraged.
After the first days observation, we found that the X-ray afterglow of GRB 130427A overlaps other GRBs induced by C-matrix (Fig.4), we concluded that this new GRB shared the same mechanism, which means a supernova is inevitable in the system though the optical signal is too weak too be observed, immediately we sent a letter to GCN on May 2, 2013, predicting that the optical R-band of a SN will reach its peak magnitude in about 10 days in the cosmological rest-frame on the basis of the IGC paradigm, and we encouraged observations.
![[fig2]](newsletters/luglio2014/fig2.jpg "fig2")
Figure 2: Flux of first 700 s. Blue points are the Fermi-LAT high energy emission from 100 MeV till 100 GeV, grey dotted line represents the Fermi-GBM, from 10 keV to 900 keV, green dashed line represents the photons detected by Swift BAT from 10 keV to 50 keV, and red solid line is the soft X-ray Swift-XRT detection, in the range of 0.3 KeV to 10 KeV. From this figure, clearly the Fermi-LAT emission reaches highest fluence at about 20 s while the gamma-ray detected by Fermi-GBM releases most of the energy within the first 10 s.
![[fig3]](newsletters/luglio2014/fig3.jpg "fig3")
Figure 3: Spectral fitting of three time intervals (196s - 246s, 246s - 326s, 326s - 461s) in Episode 3, data come from Swift-XRT (0.3 KeV - 10 KeV, without pile-up area). Black points are the deduced data, green dashed line presents the thermal component, blue long-dashed line is the power law component, and red line shows the combination of these two components. Clearly the flux of thermal component drops and the temperature decreases along the time.
![[fig4]](newsletters/luglio2014/fig4.jpg "fig4")
Figure 4: Overlapping of GRB 130427A and GRB 060729. Green cross is the light curve of GRB 060729. Red triangle and orange dots represent the light curve of GRB 130427A respectively before and after May 2, 2013. The vertical line marks the time of 2 × 104 s which is the lower limit for the domain of validity of the Pisani relation prior to GRB 130427A.
Letter in collaboration with Pror. Fryer, Los Alamos:
Hypercritical Accretion, Induced Gravitational Collapse, And Binary-Driven Hypernovae
Chris L. Fryer, Jorge A. Rueda, Remo Ruffini
ApJ Letters 793, 36 (2014)
The induced gravitational collapse (IGC) paradigm has been successfully applied to the explanation of the concomitance of gamma-ray bursts (GRBs) with supernovae (SNe) Ic. The progenitor is a tight binary system composed by a carbon-oxygen (CO) core and a neutron star (NS) companion. The explosion of the SN leads to hypercritical accretion onto the NS companion which reaches the critical mass, hence inducing its gravitational collapse to a black hole (BH) with consequent emission of the GRB. The first estimates of this process were based on a simplified model of the binary parameters and the Bondi-Hoyle-Lyttleton accretion rate. We present here the first full numerical simulations of the IGC phenomenon. We simulate the core-collapse and SN explosion of CO stars to obtain the density and ejection velocity of the SN ejecta. We follow the hydrodynamic evolution of the accreting material falling into the Bondi-Hoyle surface of the NS all the way up to its incorporation to the NS surface. The simulations go up to BH formation when the NS reaches the critical mass. For appropriate binary parameters the IGC occurs in short timescales (100-1000s) owing to the combined effective action of the photon trapping and the neutrino cooling near the NS surface. We also show that the IGC scenario leads to a natural explanation for why GRBs are associated only to SN Ic with totally absent or very little helium.
ApJ Letters 793, 36 (2014)
The induced gravitational collapse (IGC) paradigm has been successfully applied to the explanation of the concomitance of gamma-ray bursts (GRBs) with supernovae (SNe) Ic. The progenitor is a tight binary system composed by a carbon-oxygen (CO) core and a neutron star (NS) companion. The explosion of the SN leads to hypercritical accretion onto the NS companion which reaches the critical mass, hence inducing its gravitational collapse to a black hole (BH) with consequent emission of the GRB. The first estimates of this process were based on a simplified model of the binary parameters and the Bondi-Hoyle-Lyttleton accretion rate. We present here the first full numerical simulations of the IGC phenomenon. We simulate the core-collapse and SN explosion of CO stars to obtain the density and ejection velocity of the SN ejecta. We follow the hydrodynamic evolution of the accreting material falling into the Bondi-Hoyle surface of the NS all the way up to its incorporation to the NS surface. The simulations go up to BH formation when the NS reaches the critical mass. For appropriate binary parameters the IGC occurs in short timescales (100-1000s) owing to the combined effective action of the photon trapping and the neutrino cooling near the NS surface. We also show that the IGC scenario leads to a natural explanation for why GRBs are associated only to SN Ic with totally absent or very little helium.
Semiclassical pair production rate for time-dependent electrical fields with more than one component: WKB-approach and world-line instantons
Strobel, Eckhard; Xue, She-Sheng
Nuclear Physics B 886, 1153 (2014)
Description: The Schwinger-effect describes how pairs of electrons and positrons can be produced from the vacuum with the help of a very strong electric field. While this effect is believed to play a important rule in astrophysics, especially for gamma ray burst, it has never been observed directly in a laboratory. The reason for this is that currently one can not produces the field strengths which are necessary to produce a measurable number of pairs. This might change with the construction of new high energy laser systems, like the Extreme Light Infrastructure (ELI).
It has recently been shown that pair creation rate changes over several orders of magnitude depending on the form of the laser pulse. To design an experiment in which Schwinger pair creation can be measured directly it is substantial to understand this dependence. While a lot of computations can be performed numerical it is worthwhile to continue to study approximate analytical methods to strengthen this understanding.
In the paper we generalize two well-known analytical methods, namely the WKB and the world line instant on method, to fields which have more than one time-dependent component. The comparison of the two methods shows when to best use which of the methods. The generalizations enables us to find a analytic solution for the momentum spectrum of the produced pairs in a rotating electric field. As displayed in Figure no pairs are produced which have zero momentum. This is a big difference to the known cases of one-component fields, where most pairs are produced with zero momentum. Since the rotating electric field is a approximation for the field in the anti-node of a circularly polarized standing wave, which can be produced in laser experiments, the characteristic shape of this momentum spectrum might help to distinguish the pairs produced by the Schwinger process from those produced due to other strong field effects.
Nuclear Physics B 886, 1153 (2014)
Description: The Schwinger-effect describes how pairs of electrons and positrons can be produced from the vacuum with the help of a very strong electric field. While this effect is believed to play a important rule in astrophysics, especially for gamma ray burst, it has never been observed directly in a laboratory. The reason for this is that currently one can not produces the field strengths which are necessary to produce a measurable number of pairs. This might change with the construction of new high energy laser systems, like the Extreme Light Infrastructure (ELI).
It has recently been shown that pair creation rate changes over several orders of magnitude depending on the form of the laser pulse. To design an experiment in which Schwinger pair creation can be measured directly it is substantial to understand this dependence. While a lot of computations can be performed numerical it is worthwhile to continue to study approximate analytical methods to strengthen this understanding.
In the paper we generalize two well-known analytical methods, namely the WKB and the world line instant on method, to fields which have more than one time-dependent component. The comparison of the two methods shows when to best use which of the methods. The generalizations enables us to find a analytic solution for the momentum spectrum of the produced pairs in a rotating electric field. As displayed in Figure no pairs are produced which have zero momentum. This is a big difference to the known cases of one-component fields, where most pairs are produced with zero momentum. Since the rotating electric field is a approximation for the field in the anti-node of a circularly polarized standing wave, which can be produced in laser experiments, the characteristic shape of this momentum spectrum might help to distinguish the pairs produced by the Schwinger process from those produced due to other strong field effects.
Submitted Articles:
Induced Gravitational Collapse At Extreme Cosmological Distances: The Case Of Grb 090423
R. Ruffini, L. Izzo, M. Muccino, G.B. Pisani, J.A. Rueda, Y. Wang, C. Barbarino, C.L. Bianco, M. Enderli, M. Kovacevic
A&A 569, A39 (2014)
R. Ruffini, L. Izzo, M. Muccino, G.B. Pisani, J.A. Rueda, Y. Wang, C. Barbarino, C.L. Bianco, M. Enderli, M. Kovacevic
A&A 569, A39 (2014)
The Genuine Short Grb 090227b And The Disguised By Excess Grb 090510
M. Muccino, C.L. Bianco, L. Izzo, Y. Wang, M. Enderli, M. Kovacevic, G.B. Pisani, A.V. Penacchioni, R. Ruffini
Gravitation and Cosmology, 20, 197 (2014)
M. Muccino, C.L. Bianco, L. Izzo, Y. Wang, M. Enderli, M. Kovacevic, G.B. Pisani, A.V. Penacchioni, R. Ruffini
Gravitation and Cosmology, 20, 197 (2014)
On The Core-Halo Distribution Of Dark Matter In Galaxies
Remo Ruffini, Carlos Argüelles, Jorge A. Rueda
Submitted to Phys. Rev. Lett.
Remo Ruffini, Carlos Argüelles, Jorge A. Rueda
Submitted to Phys. Rev. Lett.
Just Published Articles:
Semiclassical Pair Production Rate For Time-Dependent Electrical Fields With More Than One Component: Wkb-Approach And World-Line Instantons
Strobel, Eckhard; Xue, She-Sheng
Nuclear Physics B 886, 1153 (2014)
Strobel, Eckhard; Xue, She-Sheng
Nuclear Physics B 886, 1153 (2014)
Transparency Parameters From Relativistically Expanding Outflows
Bégué, D.; Iyyani, S.
ApJ 792, 42 (2014)
Bégué, D.; Iyyani, S.
ApJ 792, 42 (2014)
Dynamical Instability Of White Dwarfs And Breaking Of Spherical Symmetry Under The Presence Of Extreme Magnetic Fields
J. G. Coelho, R. M. Marinho, M. Malheiro, R. Negreiros, D. L. Cáceres, J. A. Rueda, R. Ruffini
ApJ 794, 86 (2014)
J. G. Coelho, R. M. Marinho, M. Malheiro, R. Negreiros, D. L. Cáceres, J. A. Rueda, R. Ruffini
ApJ 794, 86 (2014)
Are The Most Super-Massive Dark Compact Objects Harbored At The Center Of Dark Matter Halos?
Carlos R. Argüelles, Remo Ruffini
Essay selected for Honorable mention 2014 by the Gravity Research Foundation
Carlos R. Argüelles, Remo Ruffini
Essay selected for Honorable mention 2014 by the Gravity Research Foundation
Strangeness Content Of Neutron Stars With Strong Sigma-Hyperon Repulsion
M. Razeira, A. Mesquita, C. A. Z. Vasconcellos, R. Ruffini, J. A. Rueda, R. O. Gomes
Astronomische Nachrichten 335, 739 (2014)
M. Razeira, A. Mesquita, C. A. Z. Vasconcellos, R. Ruffini, J. A. Rueda, R. O. Gomes
Astronomische Nachrichten 335, 739 (2014)
Effective Field Theory For Neutron Stars With Strong Sigma--Hyperon Repulsion
M. Razeira, A. Mesquita, C. A. Z. Vasconcellos, R. Ruffini, J. A. Rueda, R. O. Gomes
Astronomische Nachrichten 335, 733 (2014)
M. Razeira, A. Mesquita, C. A. Z. Vasconcellos, R. Ruffini, J. A. Rueda, R. O. Gomes
Astronomische Nachrichten 335, 733 (2014)
A search for Fermi bursts associated with supernovae and their frequency of occurrence
Kovacevic, M.; Izzo, L.; Wang, Y.; Muccino, M.; Della Valle, M.; Amati, L.; Barbarino, C.; Enderli, M.; Pisani, G. B.; Li, L.
Astronomy & Astrophysics, Volume 569, id.A108, 6 pp. (A&A Homepage)
Kovacevic, M.; Izzo, L.; Wang, Y.; Muccino, M.; Della Valle, M.; Amati, L.; Barbarino, C.; Enderli, M.; Pisani, G. B.; Li, L.
Astronomy & Astrophysics, Volume 569, id.A108, 6 pp. (A&A Homepage)