The Experts below are selected from a list of 56109 Experts worldwide ranked by ideXlab platform
Peter Mészáros - One of the best experts on this subject based on the ideXlab platform.
-
The Theory of Gamma-Ray Bursts
Space Sci.Rev., 2017Co-Authors: Zi-gao Dai, F. Daigne, Peter MészárosAbstract:This chapter gives a brief review on the theory of Gamma-Ray Bursts (GRBs), including the models of multi-messengers (e.g., prompt multiwavelength electromagnetic emissions, high-energy neutrinos, ultra-high-energy cosmic Rays, and gravitational waves) and central engines (in particular, mergers of binary neutron stars for short GRBs). For detailed reviews, please see (Piran in Phys. Rep. 314:575, 1999, Rev. Mod. Phys. 76:1143, 2004, Mészáros in Annu. Rev. Astron. Astrophys. 40:137, 2002, Rep. Prog. Phys. 69:2259, 2006, Zhang and Mészáros in Int. J. Mod. Phys. A 19:2385, 2004, Zhang in Chin. J. Astron. Astrophys. 7:1, 2007, Nakar in Phys. Rep. 442:166, 2007, Kumar and Zhang in Phys. Rep. 561:1, 2015).
-
Gamma Ray Bursts
Astroparticle Physics, 2013Co-Authors: Peter MészárosAbstract:Gamma-Ray Bursts have been detected at photon energies up to tens of GeV. We review some recent developments in the X-Ray to GeV photon phenomenology in the light of Swift and Fermi observations, and some of the theoretical models developed to explain them, with a view towards implications for C.T.A.Comment: Updated references and some minor changes; review of GRBs, prepared for Astropart.Phys. special issue on C.T.A. science, S. Sarkar, Ed; cite as article in press as: P. M\'esz\'aros, Gamma Ray Bursts, Astropart. Phys. (2012), http://dx.doi.org/10.1016/j.astropartphys.2012.03.00
-
Gamma Ray Bursts
Science, 2012Co-Authors: N. Gehrels, Peter MészárosAbstract:Gamma-Ray Bursts (GRBs) are bright flashes of Gamma Rays coming from the cosmos. They occur roughly once per day, typically last for tens of seconds, and are the most luminous events in the universe. More than three decades after their discovery, and after pioneering advances from space and ground experiments, they still remain mysterious. The launch of the Swift and Fermi satellites in 2004 and 2008 brought in a trove of qualitatively new data. In this Review, we survey the interplay between these recent observations and the theoretical models of the prompt GRB emission and the subsequent afterglow.
-
Redshifts of the Long Gamma-Ray Bursts
arXiv: Astrophysics, 2007Co-Authors: Zsolt Bagoly, Attila Mészáros, Peter Mészáros, István Csabai, István T. Horváth, Lajos G. Balázs, R. VavrekAbstract:The low energy spectra of some Gamma-Ray Bursts' show excess components beside the power-law dependence. The consequences of such a feature allows to estimate the Gamma photometric redshift of the long Gamma-Ray Bursts in the BATSE Catalog. There is good correlation between the measured optical and the estimated Gamma photometric redshifts. The estimated redshift values for the long bright Gamma-Ray Bursts are up to z=4, while for the the faint long Bursts - which should be up to z=20 - the redshifts cannot be determined unambiguously with this method. The redshift distribution of all the Gamma-Ray Bursts with known optical redshift agrees quite well with the BATSE based Gamma photometric redshift distribution.
-
Optical afterglows of short Gamma-Ray Bursts and GRB 040924
The Astrophysical Journal, 2005Co-Authors: Yi-zhong Fan, Bing Zhang, Shiho Kobayashi, Peter MészárosAbstract:Short-duration Gamma-Ray Bursts (GRBs;
Tsvi Piran - One of the best experts on this subject based on the ideXlab platform.
-
neutrinos from Gamma Ray Bursts as a tool to explore quantum gravity induced lorentz violation
Nature Physics, 2007Co-Authors: Uri Jacob, Tsvi PiranAbstract:Neutrinos from Gamma-Ray Bursts as a tool to explore quantum-gravity-induced Lorentz violation
-
Gamma Ray Bursts as probes of quantum gravity
Lecture Notes in Physics, 2004Co-Authors: Tsvi PiranAbstract:Gamma Ray Bursts (GRBs) are short and intense pulses of $\Gamma$-Rays arriving from random directions in the sky. Several years ago Amelino-Camelia et al. pointed out that a comparison of time of arrival of photons at different energies from a GRB could be used to measure (or obtain a limit on) possible deviations from a constant speed of light at high photons energies. I review here our current understanding of GRBs and reconsider the possibility of performing these observations.
-
Gamma-Ray Bursts
International Journal of Modern Physics A, 2002Co-Authors: Tsvi PiranAbstract:Gamma-Ray Bursts (GRBs) are the most relativistic objects discovered so far. I describe here two aspects of the relativistic nature of GRBs. Their likely association with the formation of black holes and their possible role as sources of gravitational radiation.
-
demotion looms for Gamma Ray Bursts
Science, 2002Co-Authors: Tsvi PiranAbstract:Gamma-Ray Bursts have long been the record holders for the most energetic explosions in the universe. Results reported at a workshop last November and discussed by Piran in his Perspective show, however, that the previous energy estimates were too high because the emission was believed to be isotropic. With respect to energetics, Gamma-Ray Bursts tie with supernovae. Gamma-Ray Bursts continue to hold the record as the brightest objects in the universe.
T. Astraatmadja - One of the best experts on this subject based on the ideXlab platform.
-
First search for neutrinos in correlation with Gamma-Ray Bursts with the ANTARES neutrino telescope
Journal of Cosmology and Astroparticle Physics, 2013Co-Authors: S. Adrian-martinez, Imen Al Samarai, A. Albert, M. Andre, M. Anghinolfi, G. Anton, S. Anvar, M. Ardid, A. Assis Jesus, T. AstraatmadjaAbstract:A search for neutrino-induced muons in correlation with a selection of 40 Gamma-Ray Bursts that occurred in 2007 has been performed with the ANTARES neutrino telescope. During that period, the detector consisted of 5 detection lines. The ANTARES neutrino telescope is sensitive to TeV--PeV neutrinos that are predicted from Gamma-Ray Bursts. No events were found in correlation with the prompt photon emission of the Gamma-Ray Bursts and upper limits have been placed on the flux and fluence of neutrinos for different models.
Gerald J. Fishman - One of the best experts on this subject based on the ideXlab platform.
-
Gamma-Ray Bursts
2013Co-Authors: Gerald J. FishmanAbstract:The present status of Gamma-Ray burst research is reviewed, with an emphasis on recent observations of their temporal, spectral, and global distribution properties. The observed sky distribution of weak Gamma-Ray Bursts constrains the allowable geometrical models to sources in either a giant spherical galactic halo or to sources at cosmological distances. Observations of time dilation consistent with the latter have been reported. Extensive searches for a counterpart to Gamma-Ray Bursts in other wavelength regions have thus far proved negative. In spite of the abundance of new observations of Gamma-Ray Bursts, their energy source and emission mechanism remain highly speculative. New, rapid counterpart search efforts and several new space-borne experiments may provide the needed observations to make progress in the field
-
Stellar flares and Gamma‐Ray Bursts
AIP Conference Proceedings, 2008Co-Authors: P Li, K. Hurley, Gerald J. Fishman, C KouveliotouAbstract:We have searched for Gamma‐Ray Bursts during stellar flares using Ulysses and BATSE/CGRO data. A total of five stellar flares were identified (two from AD Leo and three from AU Mic), but neither BATSE nor Ulysses observed any Gamma‐Ray Bursts which could be attributed to them. Using the BATSE trigger threshold, and the known distances to these flare stars, upper limits to the Gamma‐Ray luminosity were obtained. The conditions under which stellar flare Gamma‐Ray Bursts could be detected by BATSE as weak events were studied. In particular, we found that if weak events (10−7 ergs cm−2 s−1) are to be explained by flares as recently suggested, the stellar X‐Ray emission (≳25 keV) must be comparable to its optical emission, and the ratio of Lx/Lopt must be higher than that for solar flares by at least 4 orders of magnitude. The stellar flare logN‐logS and spatial distributions are studied and their implications for Gamma‐Ray Bursts are discussed.
-
Gamma-Ray Bursts: An Update
2001Co-Authors: Gerald J. Fishman, Ann F. WhitakerAbstract:Gamma-Ray Bursts are now known to originate from cosmological distances and represent the largest known explosions in the Universe. The observed characteristics of Bursts in the Gamma-Ray region, primarily from data obtained with the BATSE experiment on the Compton Observatory, will be described. These include the temporal and spectral characteristic of Bursts, and their intensity and sky distribution. A summary of recent discoveries and observations in other wavelength regions will also be presented, along with their implications for models of the burst emission mechanism. Various models for the energy source of Gamma-Ray Bursts will be described.
-
History and Observation of Gamma-Ray Bursts
1999Co-Authors: Gerald J. FishmanAbstract:Gamma-Ray Bursts are now generally believed to originate from cosmological distances and represent the largest known explosions in the Universe. This talk will describe the temporal and spectral characteristic of Gamma-Ray Bursts, their intensity and sky distribution, and other observed characteristics in the Gamma-Ray region, primarily from data obtained with the Burst and Transient Source Experiment (BATSE) experiment on the Compton Observatory.
-
The Mystery of Gamma-Ray Bursts
1998Co-Authors: Gerald J. FishmanAbstract:Gamma-Ray Bursts remain one of the greatest mysteries in astrophysics. Observations of Gamma-Ray Bursts made by the BATSE experiment on the Compton Gamma-Ray Observatory will be described. Most workers in the field now believe that they originate from cosmological distances. This view has been reinforced by observations this year of several optical afterglow counterparts to Gamma-Ray Bursts. A summary of these recent discoveries will be presented, along with their implications for models of the burst emission mechanism and the energy source of the Bursts.
R. Vavrek - One of the best experts on this subject based on the ideXlab platform.
-
Redshifts of the Long Gamma-Ray Bursts
arXiv: Astrophysics, 2007Co-Authors: Zsolt Bagoly, Attila Mészáros, Peter Mészáros, István Csabai, István T. Horváth, Lajos G. Balázs, R. VavrekAbstract:The low energy spectra of some Gamma-Ray Bursts' show excess components beside the power-law dependence. The consequences of such a feature allows to estimate the Gamma photometric redshift of the long Gamma-Ray Bursts in the BATSE Catalog. There is good correlation between the measured optical and the estimated Gamma photometric redshifts. The estimated redshift values for the long bright Gamma-Ray Bursts are up to z=4, while for the the faint long Bursts - which should be up to z=20 - the redshifts cannot be determined unambiguously with this method. The redshift distribution of all the Gamma-Ray Bursts with known optical redshift agrees quite well with the BATSE based Gamma photometric redshift distribution.
-
Estimation of the Redshifts for Long Gamma‐Ray Bursts
AIP Conference Proceedings, 2003Co-Authors: Zsolt Bagoly, Attila Mészáros, Peter Mészáros, István Csabai, Lajos G. Balázs, István Horváth, R. VavrekAbstract:It is known that the soft tail of Gamma‐Ray Bursts’ spectra show excesses from the exact power‐law dependence. In this article we show that this departure can be detected in the peak flux ratios of different BATSE DISCSC energy channels. This effect allows us to estimate the redshifts of bright long Gamma‐Ray Bursts given in the BATSE Catalog. For the 8 Gamma‐Ray Bursts, which have both BATSE DISCSC data and measured optical spectroscopic redshifts, the correlation between the true and estimated redshifts is remarkable, and the average error is Δz ≈ 0.5. The method is similar to the photometric redshift estimation of galaxies in the optical range, hence we call it “Gamma photometric redshift estimation”. These redshifts for the remaining 857 long bright Gamma‐Ray Bursts are are up to z ≃ (4 – 7). For the the faint long Bursts — which should be up to z ≃ 20 — the redshifts hardly can be determined unambiguously from this method.
-
A Remarkable Angular Distribution of the Intermediate Subclass of Gamma-Ray Bursts
The Astrophysical Journal, 2000Co-Authors: Attila Mészáros, Zsolt Bagoly, Lajos G. Balázs, István Horváth, R. VavrekAbstract:We develop a method of testing the null hypothesis of intrinsic randomness in the angular distribution of Gamma-Ray Bursts collected in the Current BATSE Catalog. The method is a modified version of the well-known counts-in-cells test and fully eliminates the nonuniform sky-exposure function of the BATSE instrument. Applying this method to the case of all Gamma-Ray Bursts, we found no intrinsic nonrandomness. The test also did not find intrinsic nonrandomness for the short and long Gamma-Ray Bursts. However, using the method on the new, intermediate subclass of Gamma-Ray Bursts, the null hypothesis of intrinsic randomness for 181 intermediate Gamma-Ray Bursts is rejected on the 96.4% confidence level. Taking 92 dimmer Bursts from this subclass, we obtain a surprising result: this "dim" subclass of the intermediate subclass has an intrinsic nonrandomness on the 99.3% confidence level. On the other hand, the 89 "bright" Gamma-Ray Bursts show no intrinsic nonrandomness.
