Journal articles on the topic 'Gamma Ray Burst (GRB)'
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1
ZHANG, BING. "GAMMA-RAY BURST PROMPT EMISSION." International Journal of Modern Physics D 23, no. 02 (January 29, 2014): 1430002. http://dx.doi.org/10.1142/s021827181430002x.
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The origin of gamma-ray burst (GRB) prompt emission, bursts of γ-rays lasting from shorter than one second to thousands of seconds, remains not fully understood after more than 40 years of observations. The uncertainties lie in several open questions in the GRB physics, including jet composition, energy dissipation mechanism, particle acceleration mechanism and radiation mechanism. Recent broad-band observations of prompt emission with Fermi sharpen the debates in these areas, which stimulated intense theoretical investigations invoking very different ideas. I will review these debates, and argue that the current data suggest the following picture: A quasi-thermal spectral component originating from the photosphere of the relativistic ejecta has been detected in some GRBs. Even though in some cases (e.g. GRB 090902B) this component dominates the spectrum, in most GRBs, this component either forms a sub-dominant "shoulder" spectral component in the low energy spectral regime of the more dominant "Band" component, or is not detectable at all. The main "Band" spectral component likely originates from the optically thin region due to synchrotron radiation. The diverse magnetization in the GRB central engine is likely the origin of the observed diverse prompt emission properties among bursts.
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Burns, Eric, Dmitry Svinkin, Edward Fenimore, D. Alexander Kann, José Feliciano Agüí Fernández, Dmitry Frederiks, Rachel Hamburg, et al. "GRB 221009A: The BOAT." Astrophysical Journal Letters 946, no. 1 (March 1, 2023): L31. http://dx.doi.org/10.3847/2041-8213/acc39c.
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Abstract GRB 221009A has been referred to as the brightest of all time (BOAT). We investigate the veracity of this statement by comparing it with a half century of prompt gamma-ray burst observations. This burst is the brightest ever detected by the measures of peak flux and fluence. Unexpectedly, GRB 221009A has the highest isotropic-equivalent total energy ever identified, while the peak luminosity is at the ∼99th percentile of the known distribution. We explore how such a burst can be powered and discuss potential implications for ultralong and high-redshift gamma-ray bursts. By geometric extrapolation of the total fluence and peak flux distributions, GRB 221009A appears to be a once-in-10,000-year event. Thus, it is almost certainly not the BOAT over all of cosmic history; it may be the brightest gamma-ray burst since human civilization began.
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Ioka, Kunihito, Yudai Suwa, Hiroki Nagakura, Rafael S. de Souza, and Naoki Yoshida. "Population III Gamma-Ray Burst." Proceedings of the International Astronomical Union 7, S279 (April 2011): 301–4. http://dx.doi.org/10.1017/s1743921312013099.
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AbstractGamma-ray bursts (GRBs) are unique probes of the first generation (Pop III) stars. We show that a relativistic gamma-ray burst (GRB) jet can potentially pierce the envelope of a very massive Pop III star even if the Pop III star has a supergiant hydrogen envelope without mass loss, thanks to the long-lived powerful accretion of the envelope itself. While the Pop III GRB is estimated to be energetic (Eγ,iso ~ 1055 erg), the supergiant envelope hides the initial bright phase in the cocoon component, leading to a GRB with a long duration ~1000 (1 + z) s and an ordinary isotropic luminosity ~ 1052 erg s−1 (~ 10−9 erg cm−2 s−1 at redshift z ~ 20), although these quantities are found to be sensitive to the core and envelope mass. We also show that Pop III.2 GRBs (which are primordial but affected by radiation from other stars) occur >100 times more frequently than Pop III.1 GRBs, and thus should be suitable targets for future X-ray and radio missions. The radio transient surveys are already constraining the Pop III GRB rate and promising in the future.
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Wang, Yun, Lu-Yao Jiang, and Jia Ren. "GRB 201104A: A “Repetitive” Short Gamma-Ray Burst?" Astrophysical Journal 935, no. 2 (August 1, 2022): 179. http://dx.doi.org/10.3847/1538-4357/ac82ec.
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Abstract Gamma-ray bursts (GRBs) are divided into short gamma-ray bursts (SGRBs) and long gamma-ray bursts (LGRBs) based on the bimodal distribution of their durations. LGRBs and SGRBs are typically characterized by different statistical characteristics. Nevertheless, there are some samples that challenge such a framework, such as GRB 060614, a long-duration burst with short-burst characteristics. Furthermore, GRBs are generally considered to be an event with no periodic or repetitive behavior, since the progenitors usually undergo destructive events, such as massive explosions or binary compact star mergers. In this work, we investigated Fermi data for possible quasiperiodic oscillations and repetitive behaviors of GRBs using timing analysis methods and report a special event GRB 201104A, which is a long-duration burst with the characteristics of an SGRB, and it exhibits a “repetitive” behavior. We propose that such a situation may arise from lensed SGRBs and attempt to verify it by Bayesian inference. In addition, we extend the spectral analysis to Bayesian inference. In spite of the existence of at least two distinct time periods with a nearly identical spectrum, there is no strong evidence that they result from a lensing GRB. Taking the gravitational-lensing scenario out of consideration, a long burst would resemble a short burst in its repetitive behavior, which presents a challenge for the current classification scheme.
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Bisnovatyi-Kogan, G. S. "Physical Restrictions to Cosmological Gamma-Ray Burst Models." International Astronomical Union Colloquium 192 (2005): 491–96. http://dx.doi.org/10.1017/s0252921100009581.
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SummaryThe present common view about GRB origin is related to cosmology, and is based on statistical analysis, and on measurements of the redshifts in the GRB optical afterglows of long GRB. No correlation is found between redshifts, GRB spectrum, and total GRB fluence. Comparison of KONUS and BATSE data about statistics and hard X-ray lines is done, and some differences are noted. Hard gamma-ray afterglows, prompt optical spectra, hard X-ray lines, polarization measurements could be very important for farther insight into GRB origin. Possible connection of short GRB with soft gamma repeaters is discussed.
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Řípa, Jakub, and Arman Shafieloo. "Update on testing the isotropy of the properties of gamma-ray bursts." Monthly Notices of the Royal Astronomical Society 486, no. 3 (April 26, 2019): 3027–40. http://dx.doi.org/10.1093/mnras/stz921.
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Abstract Previously, we proposed a novel method to inspect the isotropy of the properties of gamma-ray bursts (GRBs), such as their duration, fluences and peak fluxes at various energy bands and different time-scales, complementary to existing studies of the spatial distribution of GRBs by other authors. The method was then applied to the Fermi Gamma-ray Burst Monitor (GBM) Burst Catalog containing 1591 GRBs. Except for one particular direction where we noticed some hints of violation from statistical isotropy, the rest of the data showed consistency with isotropy. In this work, we apply our method, with some minor modifications, to the updated Fermi GBM data sample containing 2266 GRBs, which is thus ∼40 per cent larger. We also test two other major GRB catalogues: the Burst And Transient Source Experiment (BATSE) Current GRB Catalog of the Compton Gamma Ray Observatory (CGRO), containing ∼2000 bursts, and the Swift Burst Alert Telescope (BAT) GRB Catalog, containing ∼1200 bursts. The new results using the updated data are consistent with our previous findings and we find no statistically significant anisotropic feature in the observed properties of these samples of all GRBs.
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King, Andrew. "Gamma-ray burst models." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 365, no. 1854 (February 9, 2007): 1277–80. http://dx.doi.org/10.1098/rsta.2006.1978.
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I consider various possibilities for making gamma-ray bursts, particularly from close binaries. In addition to the much-studied neutron star+neutron star and black hole+neutron star cases usually considered good candidates for short-duration bursts, there are also other possibilities. In particular, neutron star+massive white dwarf has several desirable features. These systems are likely to produce long-duration gamma-ray bursts (GRBs), in some cases definitely without an accompanying supernova, as observed recently. This class of burst would have a strong correlation with star formation and occur close to the host galaxy. However, rare members of the class need not be near star-forming regions and could have any type of host galaxy. Thus, a long-duration burst far from any star-forming region would also be a signature of this class. Estimates based on the existence of a known progenitor suggest that this type of GRB may be quite common, in agreement with the fact that the absence of a supernova can only be established in nearby bursts.
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Huang, Y. F., T. Lu, Z. G. Dai, and K. S. Cheng. "Beaming Effects in Gamma-Ray Burst Afterglows." Symposium - International Astronomical Union 214 (2003): 321–22. http://dx.doi.org/10.1017/s0074180900194653.
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Based on a refined dynamical model, afterglows from jetted γ-ray burst (GRB) remnants are investigated numerically. Measuring of GRB beaming by using orphan afterglow surveys is addressed. The possible existence of a kind of cylindrical jets is also discussed.
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Ivy Wang, Xiangyu, Bin-Bin Zhang, and Wei-Hua Lei. "GRB 200826A: A Precursor of a Long Gamma-Ray Burst with Missing Main Emission." Astrophysical Journal Letters 931, no. 1 (May 1, 2022): L2. http://dx.doi.org/10.3847/2041-8213/ac6c7e.
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Abstract The recently discovered peculiar gamma-ray burst GRB 200826A poses a dilemma for the collapsar model. Although all other characteristics of the burst are consistent with it being a Type II (i.e., collapse of a massive star) event, the observed duration of the event is only approximately 1 s, which is at odds with the predicted allowable timescale range for a collapsar event. To resolve this dilemma, this Letter proposes that the original burst could be an intrinsically long GRB comprising a precursor and a main emission phase. However, the main emission phase is missed due to either precession of the jet or the obstruction by a companion star, leaving only the precursor observed as a short-duration GRB 200826A. Interestingly, we found that the temporal and spectral properties of GRB 200826A broadly resembled those of the bright precursor observed in GRB 160625B. Furthermore, assuming the prototype burst of GRB 200826A is similar to that of GRB 160625B, we found that the observer may indeed miss its main emission because of geometric effects caused either by jet precession or companion-obstruction models. Our approach provides a natural explanation for the GRB 200826A–like bursts and agrees with the rarity of those events.
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Murase, Kohta, Mainak Mukhopadhyay, Ali Kheirandish, Shigeo S. Kimura, and Ke Fang. "Neutrinos from the Brightest Gamma-Ray Burst?" Astrophysical Journal Letters 941, no. 1 (December 1, 2022): L10. http://dx.doi.org/10.3847/2041-8213/aca3ae.
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Abstract We discuss implications that can be obtained by searches for neutrinos from the brightest gamma-ray burst (GRB), GRB 221009A. We derive constraints on GRB model parameters such as the cosmic-ray loading factor and dissipation radius, taking into account both neutrino spectra and effective areas. The results are strong enough to constrain proton acceleration near the photosphere, and we find that the single burst limits are comparable to those from stacking analysis. Quasi-thermal neutrinos from subphotospheres and ultra-high-energy neutrinos from external shocks are not yet constrained. We show that GeV–TeV neutrinos originating from neutron collisions are detectable, and urge dedicated analysis on these neutrinos with DeepCore and IceCube as well as ORCA and KM3NeT.
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Ciolfi, Riccardo. "Short gamma-ray burst central engines." International Journal of Modern Physics D 27, no. 13 (October 2018): 1842004. http://dx.doi.org/10.1142/s021827181842004x.
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Growing evidence connects the progenitor systems of the short-hard subclass of gamma-ray bursts (GRBs) to the merger of compact object binaries composed of two neutron stars (NSs) or of an NS and a black hole (BH). The recent observation of the binary NS (BNS) merger event GW170817 associated with GRB 170817A brought a great deal of additional information and provided further support to the above connection, even though the identification of this burst as a canonical short GRB (SGRB) remains uncertain. Decades of observational constraints and theoretical models consolidated the idea of a jet origin for the GRB prompt emission, which can also explain the multiwavelength afterglow radiation observed in most of the events. However, the mechanisms through which a BNS or NS–BH merger remnant would power a collimated outflow are much less constrained. Understanding the properties of the remnant systems and whether they can provide the right conditions for jet production has been a main driver of the great effort devoted to study BNS and NS–BH mergers, and still represents a real challenge from both the physical and the computational points of view. One fundamental open question concerns the nature of the central engine itself. While the leading candidate system is a BH surrounded by a massive accretion disk, the recent observation of plateau-shaped X-ray afterglows in some SGRBs would suggest a longer-lived engine, i.e. a metastable (or even stable) massive NS, which would also exclude NS–BH progenitors. Here we elaborate on this key aspect, considering three different scenarios to explain the SGRB phenomenology based on different hypotheses on the nature of the merger remnant. Then, we discuss the basic properties of GRB 170817A and how this event would fit within the different frameworks of the above scenarios, under the assumption that it was or was not a canonical SGRB.
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Huang, Yi-Yun, Hai-Ming Zhang, Kai Yan, Ruo-Yu Liu, and Xiang-Yu Wang. "Detection of GeV Emission from an Ultralong Gamma-Ray Burst with the Fermi Large Area Telescope." Astrophysical Journal Letters 940, no. 2 (November 28, 2022): L36. http://dx.doi.org/10.3847/2041-8213/aca147.
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Abstract GRB 220627A, detected by Fermi Gamma-ray Burst Monitor (GBM), shows two episodes of gamma-ray emission, which are separated by a ∼700 s long quiescent phase. Due to similar temporal shapes and spectra in the two episodes, GRB 220627A is speculated to be a gravitationally lensed gamma-ray burst (GRB). We analyze Fermi Large Area Telescope (LAT) data and find that about 49 gamma-ray photons above 100 MeV come from the GRB during the first episode, while there are no photons above 100 MeV in the second episode. Based on the broadband spectral study of the two episodes, the gravitationally lensing scenario can be ruled out at a high confidence level and we thus conclude that GRB 220627A is an intrinsically ultralong GRB with the prompt burst emission lasting longer than 1000 s. It is then the first case that GeV emission is detected from an ultralong GRB. We find that a short spike seen in the LAT light curve is also present in GBM detectors that see the burst, suggesting a common internal region of emission across the entire Fermi energy range. The detection of a 15.7 GeV photon during the early prompt phase places a lower limit of Γ ≥ 300 on the bulk Lorentz factor of the GRB ejecta. The constraint on the bulk Lorentz factor could shed light on the origin of ultralong GRBs.
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GEHRELS, N., and J. K. CANNIZZO. "GAMMA-RAY BURSTS — OBSERVATIONS." International Journal of Modern Physics D 19, no. 06 (June 2010): 977–84. http://dx.doi.org/10.1142/s021827181001710x.
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We are in an exciting period of discovery for gamma-ray bursts. The Swift observatory is detecting 100 bursts per year, providing arcsecond localizations and sensitive observations of the prompt and afterglow emission. The Fermi observatory is observing 250 bursts per year with its medium-energy GRB instrument and about 10 bursts per year with its high-energy LAT instrument. In addition, rapid-response telescopes on the ground are providing new capabilities to study optical emission during the prompt phase and spectral signatures of the host galaxies. The combined data set is enabling great advances in our understanding of GRBs including afterglow physics, short burst origin, and high-energy emission.
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Watson, D., J. P. U. Fynbo, C. C. Thöne, and J. Sollerman. "No supernovae detected in two long-duration gamma-ray bursts." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 365, no. 1854 (February 12, 2007): 1269–75. http://dx.doi.org/10.1098/rsta.2006.1994.
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There is strong evidence that long-duration gamma-ray bursts (GRBs) are produced during the collapse of a massive star. In the standard version of the collapsar model, a broad-lined and luminous Type Ic core-collapse supernova (SN) accompanies the GRB. This association has been confirmed in observations of several nearby GRBs. Recent observations show that some long-duration GRBs are different. No SN emission accompanied the long-duration GRBs 060505 and 060614 down to limits fainter than any known Type Ic SN and hundreds of times fainter than the archetypal SN 1998bw that accompanied GRB 980425. Multi-band observations of the early afterglows, as well as spectroscopy of the host galaxies, exclude the possibility of significant dust obscuration. Furthermore, the bursts originated in star-forming galaxies, and in the case of GRB 060505, the burst was localized to a compact star-forming knot in a spiral arm of its host galaxy. We find that the properties of the host galaxies, the long duration of the bursts and, in the case of GRB 060505, the location of the burst within its host, all imply a massive stellar origin. The absence of an SN to such deep limits therefore suggests a new phenomenological type of massive stellar death.
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Chen, J. M., L. W. Jia, and E. W. Liang. "Statistical Properties of Gamma-Ray Burst Host Galaxies." Proceedings of the International Astronomical Union 8, S292 (August 2012): 190. http://dx.doi.org/10.1017/s1743921313001038.
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AbstractGRBs are the most luminous events in the Universe. They are detectable from local to high-z universe and may serve as probes for high-z galaxies (e.g., Savaglio et al. 2009; Kewley & Dopita 2002). We compile the observations for 61 GRB host galaxies from literature. Their redshifts range from 0.0085 to 6.295. We present the statistical properties of the GRB host galaxies, including the stellar mass (M*), star-forming rate (SFR), metallicity (Z), extinction (AV), and neutral hydrogen column density (NH). We explore possible correlations among the properties of gamma-ray burst host galaxies and their cosmic evolution with observations of 61 GRB host galaxies. Our results are shown in Figure 1. A clear Z-M* relation is found in our sample, which is Z ~ M0.4. The host galaxies of local GRBs with detection of accompanied supernovae also share the same relation with high-z GRB host galaxies. A trend that a more massive host galaxy tends to have a higher star-formation rate is found. The best linear fit gives a tentative relation, i.e, SFR ~ M0.75. No any correlation is found between AV and NH. A GRB host galaxy at a higher redshift also tends to have a higher SFR. Even in the same redshift, the SFR may vary over three orders of magnitude. The metallicity of the GRB host galaxies is statistically higher than that of the QSO DLAs. The full version of our results please refer to Chen et al. (2012).
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Agapitov, O. V., M. Balikhin, A. J. Hull, Y. Hobara, V. Angelopoulos, and F. S. Mozer. "First Detection of the Powerful Gamma-Ray Burst GRB 221009A by the THEMIS ESA and SST Particle Detectors on 2022 October 9." Astrophysical Journal Letters 948, no. 2 (May 1, 2023): L21. http://dx.doi.org/10.3847/2041-8213/accfa0.
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Abstract We present the first results study of the effects of the powerful gamma-ray burst GRB 221009A that occurred on 2022 October 9, and was serendipitously recorded by electron and proton detectors on board the four spacecraft of the NASA THEMIS mission. Long-duration gamma-ray bursts (GRBs) are powerful cosmic explosions, signaling the death of massive stars, and, among them, GRB 221009A is so far the brightest burst ever observed due to its enormous energy (E γ iso ≈ 1055 erg) and proximity (the redshift is z ≈ 0.1505). The THEMIS mission launched in 2008 was designed to study the plasma processes in the Earth’s magnetosphere and the solar wind. The particle flux measurements from the two inner magnetosphere THEMIS probes, THA and THE, and two outer probes (renamed ARTEMIS after 2010), THB and THC, orbiting the Moon captured the dynamics of GRB 221009A with a high time resolution of 4 (up to 8) measurements per second. This allowed us to resolve the fine structure of the GRB and determine the temporal scales of the two main bursts’ spiky structure, complementing the results from gamma-ray space telescopes and detectors.
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Salafia, Om Sharan, and Giancarlo Ghirlanda. "The Structure of Gamma Ray Burst Jets." Galaxies 10, no. 5 (August 30, 2022): 93. http://dx.doi.org/10.3390/galaxies10050093.
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Due to relativistic bulk motion, the structure and orientation of gamma-ray burst (GRB) jets have a fundamental role in determining how they appear. The recent discovery of the GW170817 binary neutron star merger and the associated GRB boosted the interest in the modeling and search for signatures of the presence of a (possibly quasi-universal) jet structure in long and short GRBs. In this review, following a pedagogical approach, we summarize the history of GRB jet structure research over the last two decades, from the inception of the idea of a universal jet structure to the current understanding of the complex processes that shape the structure, which involves the central engine that powers the jet and the interaction of the latter with the progenitor vestige. We put some emphasis on the observable imprints of jet structure on prompt and afterglow emission and on the luminosity function, favoring intuitive reasoning over technical explanations.
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Michałowski, Michał J., A. Karska, J. R. Rizzo, M. Baes, A. J. Castro-Tirado, J. Hjorth, L. K. Hunt, et al. "Molecular gas masses of gamma-ray burst host galaxies." Astronomy & Astrophysics 617 (September 2018): A143. http://dx.doi.org/10.1051/0004-6361/201833250.
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Context. Long gamma-ray bursts (GRBs) can potentially be used as a tool to study star formation and recent gas accretion onto galaxies. However, the information about gas properties of GRB hosts is scarce. In particular, very few carbon monoxide (CO) line detections of individual GRB hosts have been reported. It has also been suggested that GRB hosts have lower molecular gas masses than expected from their star formation rates (SFRs). Aims. The objectives of this paper are to analyse molecular gas properties of the first substantial sample of GRB hosts and test whether they are deficient in molecular gas. Methods. We obtained CO(2-1) observations of seven GRB hosts with the APEX and IRAM 30 m telescopes. We analysed these data together with all other hosts with previous CO observations. From these observations we calculated the molecular gas masses of these galaxies and compared them with the expected values based on their SFRs and metallicities. Reults. We obtained detections for 3 GRB hosts (980425, 080207, and 111005A) and upper limits for the remaining 4 (031203, 060505, 060814, and 100316D). In our entire sample of 12 CO-observed GRB hosts, 3 are clearly deficient in molecular gas, even taking into account their metallicity (980425, 060814, and 080517). Four others are close to the best-fit line for other star-forming galaxies on the SFR-MH2 plot (051022, 060505, 080207, and 100316D). One host is clearly molecule rich (111005A). Finally, the data for 4 GRB hosts are not deep enough to judge whether they are molecule deficient (000418, 030329, 031203, and 090423). The median value of the molecular gas depletion time, MH2/SFR, of GRB hosts is ∼0.3 dex below that of other star-forming galaxies, but this result has low statistical significance. A Kolmogorov–Smirnov test performed on MH2/SFR shows an only ∼2σ difference between GRB hosts and other galaxies. This difference can partly be explained by metallicity effects, since the significance decreases to ∼1σ for MH2/SFR versus metallicity. Conclusions. We found that any molecular gas deficiency of GRB hosts has low statistical significance and that it can be attributed to their lower metallicities; and thus the sample of GRB hosts has molecular properties that are consistent with those of other galaxies, and they can be treated as representative star-forming galaxies. However, the molecular gas deficiency can be strong for GRB hosts if they exhibit higher excitations and/or a lower CO-to-H2 conversion factor than we assume, which would lead to lower molecular gas masses than we derive. Given the concentration of atomic gas recently found close to GRB and supernova sites, indicating recent gas inflow, our results about the weak molecular deficiency imply that such an inflow does not enhance the SFRs significantly, or that atomic gas converts efficiently into the molecular phase, which fuels star formation. Only if the analysis of a larger GRB host sample reveals molecular deficiency (especially close to the GRB position) would this support the hypothesis of star formation that is directly fuelled by atomic gas.
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Hjorth, Jens. "The supernova–gamma-ray burst–jet connection." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 371, no. 1992 (June 13, 2013): 20120275. http://dx.doi.org/10.1098/rsta.2012.0275.
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The observed association between supernovae and gamma-ray bursts represents a cornerstone in our understanding of the nature of gamma-ray bursts. The collapsar model provides a theoretical framework for this connection. A key element is the launch of a bipolar jet (seen as a gamma-ray burst). The resulting hot cocoon disrupts the star, whereas the 56 Ni produced gives rise to radioactive heating of the ejecta, seen as a supernova. In this discussion paper, I summarize the observational status of the supernova–gamma-ray burst connection in the context of the ‘engine’ picture of jet-driven supernovae and highlight SN 2012bz/GRB 120422A—with its luminous supernova but intermediate high-energy luminosity—as a possible transition object between low-luminosity and jet gamma-ray bursts. The jet channel for supernova explosions may provide new insights into supernova explosions in general.
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Song, Xin-Ying, Shao-Lin Xiong, Shuang-Nan Zhang, Cheng-Kui Li, Xiao-Bo Li, Yue Huang, Cristiano Guidorzi, et al. "The First Insight-HXMT Gamma-Ray Burst Catalog: The First Four Years." Astrophysical Journal Supplement Series 259, no. 2 (March 25, 2022): 46. http://dx.doi.org/10.3847/1538-4365/ac4d22.
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Abstract The Hard X-ray Modulation Telescope (Insight-HXMT) is China’s first X-ray astronomy satellite. It was launched on 2017 June 15. The anticoincidence CsI detectors of the High Energy X-ray telescope (HE) on board Insight-HXMT could serve as an all-sky gamma-ray monitor in about 0.2–3 MeV. In its first four years of operation, Insight-HXMT has detected 322 gamma-ray bursts (GRBs) by the offline search pipeline, including blind search and targeted search. For the GOLDEN sample of Insight-HXMT GRBs, joint analyses were performed with other GRB missions, including the Fermi Gamma-ray Burst Monitor (Fermi/GBM), the Swift Burst Alert Telescope (Swift/BAT), and the Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM). The analyses showed that Insight-HXMT can provide a better constraint on the GRB spectrum at a higher-energy band. The properties of Insight-HXMT GRBs are reported in detail, including their trigger time, duration, spectral parameters, peak fluxes of different timescales, and fluence. This catalog is an official product of the Insight-HXMT GRB team.
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Wang, Yun, Tian-Ci Zheng, and Zhi-Ping Jin. "GRB 220426A: A Thermal Radiation–Dominated Gamma-Ray Burst." Astrophysical Journal 940, no. 2 (November 30, 2022): 142. http://dx.doi.org/10.3847/1538-4357/aca017.
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Abstract The physical composition of the ejecta of gamma-ray bursts (GRBs) remains an open question. The radiation mechanism of the prompt gamma rays is also in debate. This problem can be solved for the bursts hosting distinct thermal radiation. However, the events with dominant thermal spectral components are still rare. In this work, we focus on GRB 220426A, a recent event detected by the Fermi Gamma-ray Burst Monitor. The time-resolved and time-integrated data analyses yield very hard low-energy spectral indices and rather soft high-energy spectral indices. This means that the spectra of GRB 220426A are narrowly distributed. And the Bayesian inference results are in favor of the multicolor blackbody model. The physical properties of the relativistic outflow are calculated. Assuming a redshift z = 1.4, the bulk Lorentz factors Γ of the shells are found to be between 274 − 18 + 24 and 827 − 71 + 100 , and the corresponding photosphere radii R ph are in the range of 1.83 − 0.50 + 0.52 × 10 11 and 2.97 − 0.15 + 0.14 × 10 12 cm. Similar to GRB 090902B, the time-resolved properties of GRB 220426A satisfy the observed Γ–L and E p –L correlations, where L is the luminosity of the prompt emission and E p is the spectral peak energy.
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BARBIELLINI, G., F. LONGO, N. OMODEI, D. GIULIETTI, A. CELOTTI, and M. TAVANI. "STOCHASTIC WAKEFIELD PLASMA ACCELERATION IN GAMMA-RAY BURSTS." International Journal of Modern Physics B 21, no. 03n04 (February 10, 2007): 627–32. http://dx.doi.org/10.1142/s0217979207042434.
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Gamma-Ray Burst (GRB) prompt emission can, for specific conditions, be so powerful and short-pulsed to strongly influence any surrounding plasma. In this paper, we briefly discuss the possibility that a very intense initial burst of radiation produced by GRBs satisfy the intensity and temporal conditions to cause stochastic wake-field particle acceleration in a surrounding plasma of moderate density. We consider a simple but realistic GRB model for which particle wake-field acceleration can first be excited by a very strong low-energy precursor, and then be effective in producing the observed prompt X-ray and gamma-ray GRB emission.
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MÉSZÁROS, PETER. "THE PROMPT AND HIGH ENERGY EMISSION OF GAMMA RAY BURSTS." International Journal of Modern Physics D 18, no. 10 (October 2009): 1551–55. http://dx.doi.org/10.1142/s0218271809015540.
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I discuss some recent results on the prompt emission of gamma-ray bursts, in particular the jet and radiation properties of the naked-eye burst GRB 080319b, based on Swift and related observations. I then discuss the recent observations by the Fermi satellite of GRB 080916C, the resulting constraints for the bulk Lorentz factor determinations, and the highest lower limit on the quantum gravity energy scale obtained so far.
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Rhodes, L., A. J. van der Horst, R. Fender, I. M. Monageng, G. E. Anderson, J. Antoniadis, M. F. Bietenholz, et al. "Radio afterglows of very high-energy gamma-ray bursts 190829A and 180720B." Monthly Notices of the Royal Astronomical Society 496, no. 3 (June 17, 2020): 3326–35. http://dx.doi.org/10.1093/mnras/staa1715.
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ABSTRACT We present high-cadence multifrequency radio observations of the long gamma-ray burst (GRB) 190829A, which was detected at photon energies above 100 GeV by the High Energy Stereoscopic System (H.E.S.S.). Observations with the Meer Karoo Array Telescope (MeerKAT, 1.3 GHz) and Arcminute Microkelvin Imager – Large Array (AMI-LA, 15.5 GHz) began one day post-burst and lasted nearly 200 d. We used complementary data from Swift X-Ray Telescope (XRT), which ran to 100 d post-burst. We detected a likely forward shock component with both MeerKAT and XRT up to over 100 d post-burst. Conversely, the AMI-LA light curve appears to be dominated by reverse shock emission until around 70 d post-burst when the afterglow flux drops below the level of the host galaxy. We also present previously unpublished observations of the other H.E.S.S.-detected GRB, GRB 180720B from AMI-LA, which shows likely forward shock emission that fades in less than 10 d. We present a comparison between the radio emission from the three GRBs with detected very high energy (VHE) gamma-ray emission and a sensitivity-limited radio afterglow sample. GRB 190829A has the lowest isotropic radio luminosity of any GRB in our sample, but the distribution of luminosities is otherwise consistent, as expected, with the VHE GRBs being drawn from the same parent distribution as the other radio-detected long GRBs.
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Piro, L. "Discovery of X-Ray Counterparts to Gamma Ray Bursts by BeppoSAX." Symposium - International Astronomical Union 188 (1998): 163–66. http://dx.doi.org/10.1017/s0074180900114676.
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The nature of Gamma-Ray Burst (GRB) has been the object of many investigations but their origin has remained a mistery primarily for the difficulties in finding a counterpart. This difficulty derived from the intrinsically poor positioning capability of available GRB detectors.
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Wang, Hao-Bing, and Mi-Xiang Lan. "Rotation of Polarization Angle in Gamma-Ray Burst Prompt Phase." Astrophysical Journal 946, no. 1 (March 1, 2023): 12. http://dx.doi.org/10.3847/1538-4357/acba0c.
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Abstract The rotations of the polarization angle (PA) with time (energy) can lead to the depolarization of the time-integrated (energy-integrated) polarization. However, we do not know how and when it will rotate. Here, we consider a magnetic reconnection model to investigate the polarizations, especially the PA rotations of gamma-ray burst (GRB) prompt emission. For a large-scale ordered aligned magnetic field configuration, we find that within T 50 PAs will rotate with time (energy) for slight off-axis observations. Our studies show that the rotations of the PAs are due to changes in the observed image of the emitting region before being averaged over the equal arrival time surface for the unresolved sources. We apply our model to the single-pulse bursts of GRB 170101A and GRB 170114A with time-resolved PA observations. We find it can interpret the violent PA variation of GRB 170101A, while the model could not predict the two 90° PA changes in GRB 170114A. A more detailed model should be considered.
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CLINE, DAVID B. "GAMMA RAY BURSTS AND PARTICLE PHYSICS." Modern Physics Letters A 10, no. 38 (December 14, 1995): 2897–913. http://dx.doi.org/10.1142/s0217732395003033.
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We provide a brief review of the current situation concerning gamma ray bursts, with emphasis on the role that particle physics may play in the interesting phenomena. The current understanding of GRB origins allows for a large range of physical processes from primordial black hole evaporation to neutron star and black hole collisions. There does not seem to be a simple standard luminosity function and the burst times range from ms to 1000 s of seconds five orders of magnitude. It is likely that some type of fireball model is needed to explain the GRBs. No counterparts of GRB have been detected. We indicate some ways in which progress can be made in either the study of the fine time structure (~μs) or the detection of very high energy photons (>100 GeV to >100 TeV). We also indicate how a small but unique class of the GRB could come from primordial black hole evaporation.
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Ackermann, M., M. Ajello, K. Asano, W. B. Atwood, M. Axelsson, L. Baldini, J. Ballet, et al. "Fermi-LAT Observations of the Gamma-Ray Burst GRB 130427A." Science 343, no. 6166 (November 21, 2013): 42–47. http://dx.doi.org/10.1126/science.1242353.
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The observations of the exceptionally bright gamma-ray burst (GRB) 130427A by the Large Area Telescope aboard the Fermi Gamma-ray Space Telescope provide constraints on the nature of these unique astrophysical sources. GRB 130427A had the largest fluence, highest-energy photon (95 GeV), longest γ-ray duration (20 hours), and one of the largest isotropic energy releases ever observed from a GRB. Temporal and spectral analyses of GRB 130427A challenge the widely accepted model that the nonthermal high-energy emission in the afterglow phase of GRBs is synchrotron emission radiated by electrons accelerated at an external shock.
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Jordana-Mitjans, N., C. G. Mundell, C. Guidorzi, R. J. Smith, E. Ramírez-Ruiz, B. D. Metzger, S. Kobayashi, et al. "A Short Gamma-Ray Burst from a Protomagnetar Remnant." Astrophysical Journal 939, no. 2 (November 1, 2022): 106. http://dx.doi.org/10.3847/1538-4357/ac972b.
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Abstract The contemporaneous detection of gravitational waves and gamma rays from GW170817/GRB 170817A, followed by kilonova emission a day after, confirmed compact binary neutron star mergers as progenitors of short-duration gamma-ray bursts (GRBs) and cosmic sources of heavy r-process nuclei. However, the nature (and life span) of the merger remnant and the energy reservoir powering these bright gamma-ray flashes remains debated, while the first minutes after the merger are unexplored at optical wavelengths. Here, we report the earliest discovery of bright thermal optical emission associated with short GRB 180618A with extended gamma-ray emission—with ultraviolet and optical multicolor observations starting as soon as 1.4 minutes post-burst. The spectrum is consistent with a fast-fading afterglow and emerging thermal optical emission 15 minutes post-burst, which fades abruptly and chromatically (flux density F ν ∝ t −α , α = 4.6 ± 0.3) just 35 minutes after the GRB. Our observations from gamma rays to optical wavelengths are consistent with a hot nebula expanding at relativistic speeds, powered by the plasma winds from a newborn, rapidly spinning and highly magnetized neutron star (i.e., a millisecond magnetar), whose rotational energy is released at a rate L th ∝ t −(2.22±0.14) to reheat the unbound merger-remnant material. These results suggest that such neutron stars can survive the collapse to a black hole on timescales much larger than a few hundred milliseconds after the merger and power the GRB itself through accretion. Bright thermal optical counterparts to binary merger gravitational wave sources may be common in future wide-field fast-cadence sky surveys.
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Urata, Yuji, Nobuyuki Kawai, Atsumasa Yoshida, Mitsuhiro Kohama, Tetsuya Kawabata, and Kazuya Ayani. "RIBOTS: An Automatic Telescope System for Gamma-Ray Burst Follow-Up Observations." International Astronomical Union Colloquium 183 (2001): 155–56. http://dx.doi.org/10.1017/s0252921100078775.
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AbstractWe are constructing a fully automatic observation system named RIBOTS (RIken-Bisei Optical Transient Seeker). We aim to detect optical flashes and early afterglows of Gamma-ray bursts (GRB) with RIBOTS. We are constructing RIBOTS with a small telescope because a quick pointing to the burst is essential for our purpose. RIBOTS is linked to the GRB alert system provided by the HETE-2 satellite.
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Starling, Rhaana, Kim Page, and Martin Sparre. "The soft X-ray landscape of gamma-ray bursts: thermal components." Proceedings of the International Astronomical Union 7, S279 (April 2011): 175–82. http://dx.doi.org/10.1017/s1743921312012884.
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AbstractThe repository of GRB (gamma-ray burst) observations made by the Swift X-ray Telescope, now consisting of over 650 bursts, is a valuable and unique resource for the study of GRB X-ray emission. The observed soft X-ray spectrum typically arises from an underlying power law continuum, absorbed by gas along the line-of-sight. However, particularly at early times in a burst's evolution the continuum emission is not always understood and may comprise multiple components including thermal emission unexpected in the standard model. A thermal X-ray component has been discovered in two very unusual GRBs, perhaps suggesting an association only with this subset of events. However, evidence exists for thermal emission from more typical examples and here we present a new discovery of one such case and describe a systematic search for thermal components among all early GRB X-ray spectra.
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DELLA VALLE, Massimo. "Supernovae and gamma-ray burst connection." Astronomical and Astrophysical Transactions, Volume 33, Numéro 3 (December 15, 2022): 249–56. http://dx.doi.org/10.17184/eac.7527.
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I review the status of the Supernova/Gamma-Ray Burst connection. Two decades of observations have established that long-duration Gamma-ray Bursts are associated with very energetic SNe-Ib/c. These SN explosions are produced by the gravitational collapse of Wolf–Rayet progenitors, with masses on the main sequence, between 30–50 $M{\odot}$. Current measurements provide a GRB/SNe-Ibc ratio in the range $\sim$0.02–1.5$\%$, so GRBs are very rare events, even when compared with the SN frequency. There is a minority fraction of long-duration GRBs with no accompanying SN that are likely produced during the merging of neutron star or white dwarf neutron star merger.
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Abe, S., S. Asami, A. Gando, Y. Gando, T. Gima, A. Goto, T. Hachiya, et al. "A Search for Correlated Low-energy Electron Antineutrinos in KamLAND with Gamma-Ray Bursts." Astrophysical Journal 927, no. 1 (March 1, 2022): 69. http://dx.doi.org/10.3847/1538-4357/ac4e7e.
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Abstract We present the results of a time-coincident event search for low-energy electron antineutrinos in the KamLAND detector with gamma-ray bursts (GRBs) from the Gamma-ray Coordinates Network and Fermi Gamma-ray Burst Monitor. Using a variable coincidence time window of ±500 s plus the duration of each GRB, no statistically significant excess above the background is observed. We place the world’s most stringent 90% confidence level upper limit on the electron antineutrino fluence below 17.5 MeV. Assuming a Fermi–Dirac neutrino energy spectrum from the GRB source, we use the available redshift data to constrain the electron antineutrino luminosity and effective temperature.
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Chrimes, A. A., A. J. Levan, E. R. Stanway, J. D. Lyman, A. S. Fruchter, P. Jakobsson, P. O’Brien, et al. "Chandra and Hubble Space Telescope observations of dark gamma-ray bursts and their host galaxies." Monthly Notices of the Royal Astronomical Society 486, no. 3 (April 15, 2019): 3105–17. http://dx.doi.org/10.1093/mnras/stz1039.
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Abstract We present a study of 21 dark gamma-ray burst (GRB) host galaxies, predominantly using X-ray afterglows obtained with the Chandra X-Ray Observatory (CXO) to precisely locate the burst in deep Hubble Space Telescope (HST) imaging of the burst region. The host galaxies are well-detected in F160W in all but one case and in F606W imaging in 60 per cent of cases. We measure magnitudes and perform a morphological analysis of each galaxy. The asymmetry, concentration, and ellipticity of the dark burst hosts are compared against the host galaxies of optically bright GRBs. In agreement with other studies, we find that dark GRB hosts are redder and more luminous than the bulk of the GRB host population. The distribution of projected spatial offsets for dark GRBs from their host galaxy centroids is comparable to that of optically bright bursts. The dark GRB hosts are physically larger, more massive and redder, but are morphologically similar to the hosts of bright GRBs in terms of concentration and asymmetry. Our analysis constrains the fraction of high redshift (z > 5) GRBs in the sample to 14 per cent, implying an upper limit for the whole long-GRB population of ≤4.4 per cent. If dust is the primary cause of afterglow darkening amongst dark GRBs, the measured extinction may require a clumpy dust component in order to explain the observed offset and ellipticity distributions.
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Lan, Guang-Xuan, Jun-Jie Wei, Ye Li, Hou-Dun Zeng, and Xue-Feng Wu. "The Stellar-mass Function of Long Gamma-Ray Burst Host Galaxies." Astrophysical Journal 938, no. 2 (October 1, 2022): 129. http://dx.doi.org/10.3847/1538-4357/ac8fec.
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Abstract Long gamma-ray bursts (GRBs) have been discussed as a potential tool to probe the cosmic star formation rate (SFR) for a long time. Some studies found an enhancement in the GRB rate relative to the galaxy-inferred SFR at high redshifts, which indicates that GRBs may not be good tracers of star formation. However, in these studies, the GRB rate measured at any redshift is an average over all galaxies at that epoch. A deep understanding of the connection between GRB production and environment also needs to characterize the population of GRB host galaxies directly. Based on a complete sample of GRB hosts, we constrain the stellar-mass function (SMF) of GRB hosts, and examine redshift evolution in the GRB host population. Our results confirm that a strong redshift evolution in energy (with an evolution index of δ = 2.47 − 0.89 + 0.73 ) or in density ( δ = 1.82 − 0.59 + 0.22 ) is needed in order to account for the observations. The GRB host SMF can be well described by the Schechter function with a power-law index ξ ≈ −1.10 and a break mass M b,0 ≈ 4.9 × 1010 M ⊙, independent of the assumed evolutionary effects. This is the first formulation of the GRB host SMF. The observed discrepancy between the GRB rate and the galaxy-inferred SFR may also be explained by an evolving SMF.
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Levan, Andrew. "Constraining gamma-ray burst progenitors." Proceedings of the International Astronomical Union 7, S279 (April 2011): 95–101. http://dx.doi.org/10.1017/s1743921312012756.
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AbstractThe past decade has seen great progress towards the unmasking of the progenitors of gamma-ray bursts, starting with the unambiguous detection of a supernova in the light of the long-GRB 030329 almost ten years ago, and the discovery of the first afterglows to short-GRBs in 2005. Here I review progress towards unveiling the progenitors of both long and short-duration GRBs. Furthermore, I examine the diverse broader population of GRBs and high energy transients, and suggest that a full consideration of this parameter space leads to the conclusion that additional progenitor models are likely to be needed, if we are to understand the complete view of GRBs and the transient high-energy sky.
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Zhang, Hai-Ming, Yi-Yun Huang, Jian-He Zheng, Ruo-Yu Liu, and Xiang-Yu Wang. "Fermi-LAT Detection of a GeV Afterglow from a Compact Stellar Merger." Astrophysical Journal Letters 933, no. 1 (July 1, 2022): L22. http://dx.doi.org/10.3847/2041-8213/ac7b23.
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Abstract It is usually thought that long-duration gamma-ray bursts (GRBs) are associated with massive star core collapse, whereas short-duration GRBs are associated with mergers of compact stellar binaries. The discovery of a kilonova associated with a nearby (350 Mpc) long-duration GRB—GRB 211211A, however, indicates that the progenitor of this long-duration GRB is a compact object merger. Here we report the Fermi-LAT detection of gamma-ray (>100 MeV) afterglow emission from GRB 211211A, which lasts ∼20,000 s after the burst, the longest event for conventional short-duration GRBs ever detected. We suggest that this gamma-ray emission results from afterglow synchrotron emission. The soft spectrum of GeV emission may arise from a limited maximum synchrotron energy of only a few hundreds of MeV at ∼20,000 s. The usually long duration of the GeV emission could be due to the proximity of this GRB and the long deceleration time of the GRB jet that is expanding in a low-density circumburst medium, consistent with the compact stellar merger scenario.
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Aloy, Miguel A. "The First Steps in the Life of a GRB." International Astronomical Union Colloquium 192 (2005): 483–89. http://dx.doi.org/10.1017/s025292110000957x.
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SummaryWe present some preliminary results of relativistic hydrodynamic simulations of post-neutron star merger disks as potential candidates for progenitors of short-lasting gamma-ray bursts. We discuss some of the generic conditions under which a gamma-ray burst can be initiated in this kind of progenitor and the main characteristics of the resulting outflow.
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BARSHAY, SAUL, and GEORG KREYERHOFF. "VERY HIGH-ENERGY NEUTRINOS FROM SLOWLY DECAYING, MASSIVE DARK MATTER AS A SOURCE OF EXPLOSIVE ENERGY FOR GAMMA-RAY BURSTS." Modern Physics Letters A 18, no. 07 (March 7, 2003): 477–89. http://dx.doi.org/10.1142/s0217732303009654.
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We consider a speculative model for gamma-ray bursts (GRB), which predicts that the total kinetic energy in the ejected matter is less than the total energy in the gamma rays. There is also secondary energy in X-rays, which are emitted contemporaneously with the gamma rays. The model suggests that bremsstrahlung and Compton up-scattering by very energetic electrons, are important processes for producing the observed burst radiation. The dynamics naturally allows for the possibility of a moderate degree of beaming of matter and radiation in some gamma-ray bursts. GRB are predicted to have an intrinsically wide distribution in total energies, in particular, on the low side. They are predicted to occur at large redshifts, z ~ 8, in local regions of dense matter.
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Cano, Zach, Shan-Qin Wang, Zi-Gao Dai, and Xue-Feng Wu. "The Observer’s Guide to the Gamma-Ray Burst Supernova Connection." Advances in Astronomy 2017 (2017): 1–41. http://dx.doi.org/10.1155/2017/8929054.
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We present a detailed report of the connection between long-duration gamma-ray bursts (GRBs) and their accompanying supernovae (SNe). The discussion presented here places emphasis on how observations, and the modelling of observations, have constrained what we know about GRB-SNe. We discuss their photometric and spectroscopic properties, their role as cosmological probes, including their measured luminosity–decline relationships, and how they can be used to measure the Hubble constant. We present a statistical summary of their bolometric properties and use this to determine the properties of the “average” GRB-SN. We discuss their geometry and consider the various physical processes that are thought to power the luminosity of GRB-SNe and whether differences exist between GRB-SNe and the SNe associated with ultra-long-duration GRBs. We discuss how observations of their environments further constrain the physical properties of their progenitor stars and give a brief overview of the current theoretical paradigms of their central engines. We then present an overview of the radioactively powered transients that have been photometrically associated with short-duration GRBs, and we conclude by discussing what additional research is needed to further our understanding of GRB-SNe, in particular the role of binary-formation channels and the connection of GRB-SNe with superluminous SNe.
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Beardmore, A. P., K. L. Page, P. T. O'Brien, J. P. Osborne, S. Kobayashi, B. Zhang, D. N. Burrows, et al. "The Swift gamma-ray burst GRB 050422." Monthly Notices of the Royal Astronomical Society 374, no. 4 (February 1, 2007): 1473–78. http://dx.doi.org/10.1111/j.1365-2966.2006.11249.x.
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Götz, D., S. Covino, A. Fernández-Soto, P. Laurent, and Ž. Bošnjak. "The polarized gamma-ray burst GRB 061122." Monthly Notices of the Royal Astronomical Society 431, no. 4 (April 9, 2013): 3550–56. http://dx.doi.org/10.1093/mnras/stt439.
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Dainotti, M. G., R. Del Vecchio, and M. Tarnopolski. "Gamma-Ray Burst Prompt Correlations." Advances in Astronomy 2018 (2018): 1–31. http://dx.doi.org/10.1155/2018/4969503.
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The mechanism responsible for the prompt emission of gamma-ray bursts (GRBs) is still a debated issue. The prompt phase-related GRB correlations can allow discriminating among the most plausible theoretical models explaining this emission. We present an overview of the observational two-parameter correlations, their physical interpretations, and their use as redshift estimators and possibly as cosmological tools. The nowadays challenge is to make GRBs, the farthest stellar-scaled objects observed (up to redshift z=9.4), standard candles through well established and robust correlations. However, GRBs spanning several orders of magnitude in their energetics are far from being standard candles. We describe the advances in the prompt correlation research in the past decades, with particular focus paid to the discoveries in the last 20 years.
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van Eerten, Hendrik. "Gamma-ray burst afterglow blast waves." International Journal of Modern Physics D 27, no. 13 (October 2018): 1842002. http://dx.doi.org/10.1142/s0218271818420026.
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The various stages of baryonic gamma-ray burst (GRB) afterglow blast waves are reviewed. These are responsible for the afterglow emission from which much of our understanding of gamma-ray bursts derives. Initially, the blast waves are confined to the dense medium surrounding the burster (stellar envelope or dense wind), giving rise to a jet-cocoon structure. A massive ejecta is released and potentially fed by ongoing energy release from the burster and a forward–reverse shock system is set up between ejecta and ambient density. Ultimately the blast wave spreads sideways and slows down, and the dominant afterglow emission shifts from X-rays down to radio. Over the past years significant progress has been made both observationally and theoretically/numerically in our understanding of these blast waves, unique in the universe due to their often incredibly high initial Lorentz factors of 100–1000. The recent discovery of a short gamma-ray burst counterpart to a gravitational wave detection (GW 170817) brings the promise of a completely new avenue to explore and constrain the dynamics of gamma-ray burst blast waves.
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Williams, Maia A., Jamie A. Kennea, S. Dichiara, Kohei Kobayashi, Wataru B. Iwakiri, Andrew P. Beardmore, P. A. Evans, et al. "GRB 221009A: Discovery of an Exceptionally Rare Nearby and Energetic Gamma-Ray Burst." Astrophysical Journal Letters 946, no. 1 (March 1, 2023): L24. http://dx.doi.org/10.3847/2041-8213/acbcd1.
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Abstract We report the discovery of the unusually bright long-duration gamma-ray burst (GRB), GRB 221009A, as observed by the Neil Gehrels Swift Observatory (Swift), Monitor of All-sky X-ray Image, and Neutron Star Interior Composition Explorer Mission. This energetic GRB was located relatively nearby (z = 0.151), allowing for sustained observations of the afterglow. The large X-ray luminosity and low Galactic latitude (b = 4.°3) make GRB 221009A a powerful probe of dust in the Milky Way. Using echo tomography, we map the line-of-sight dust distribution and find evidence for significant column densities at large distances (≳10 kpc). We present analysis of the light curves and spectra at X-ray and UV–optical wavelengths, and find that the X-ray afterglow of GRB 221009A is more than an order of magnitude brighter at T 0 + 4.5 ks than that from any previous GRB observed by Swift. In its rest frame, GRB 221009A is at the high end of the afterglow luminosity distribution, but not uniquely so. In a simulation of randomly generated bursts, only 1 in 104 long GRBs were as energetic as GRB 221009A; such a large E γ,iso implies a narrow jet structure, but the afterglow light curve is inconsistent with simple top-hat jet models. Using the sample of Swift GRBs with redshifts, we estimate that GRBs as energetic and nearby as GRB 221009A occur at a rate of ≲1 per 1000 yr—making this a truly remarkable opportunity unlikely to be repeated in our lifetime.
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Panaitescu, A. D., and W. T. Vestrand. "Properties of the Prompt Optical Counterpart Arising from the Cooling of Electrons in Gamma-Ray Bursts." Astrophysical Journal 938, no. 2 (October 1, 2022): 155. http://dx.doi.org/10.3847/1538-4357/ac9315.
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Abstract This work extends a contemporaneous effort to study the properties of the lower-energy counterpart synchrotron emission produced by the cooling of relativistic gamma-ray burst (GRB) electrons through radiation (synchrotron and self-Compton) emission and adiabatic losses. We derive the major characteristics (pulse duration, lag time after burst, and brightness relative to the burst) of the prompt optical counterpart (POC) occurring during or after the GRB. Depending on the magnetic field lifetime, duration of electron injection, and electron transit time Δt o from hard X-ray (GRB) to optical-emitting energies, a POC may appear during the GRB pulse (of duration δ t γ ) or after (delayed OC). The signature of counterparts arising from the cooling of GRB electrons is that POC pulses (Δt o < δ t γ ) last as long as the corresponding GRB pulse (δ t o ≃ δ t γ ), while delayed OC pulses (Δt o > δ t γ ) last as long as the transit time (δ t o ≃ Δt o ). If OC variability can be measured, then another signature for this OC mechanism is that the GRB variability is passed on to POCs but not to delayed OCs. Within the GRB electron cooling model for counterparts, POCs should be on average dimmer than delayed ones (consistent with the data), and harder GRB low-energy slopes β LE should be associated more often with the dimmer POCs. The latter sets an observational bias against detecting POCs from (the cooling of electrons in) GRBs with a hard slope β LE, making it more likely that the detected POCs of such bursts arise from another mechanism.
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HORVATH, J. E. "DETECTABILITY OF GRAVITATIONAL WAVE BURSTS FROM A CLASS OF NEUTRON STAR STARQUAKE GRB MODELS." International Journal of Modern Physics D 05, no. 01 (February 1996): 35–43. http://dx.doi.org/10.1142/s0218271896000047.
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A large class of gamma-ray burst (GRB) models (overwhelming until recently) involve-the release of energy in a neutron star quake. Even though the extreme isotropy of the GRB sky established by the BATSE experiment has now shifted the interest to cosmological models, the former starquake scenarios are still attractive and may naturally produce a gravitational wave burst which carries most of the released energy. We discuss the prospects for detection of these high-frequency bursts by the forthcoming interferometers and spheroidal antennas, emphasizing the most recent results on the distribution and nature of the GRB sources. We find that, even if the overall picture is correct, the positive detection of GRB-associated gravitational wave bursts is unlikely and therefore these events will not be a prime target for the detectors.
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Zhang, K., Z. B. Zhang, Y. F. Huang, L. M. Song, S. J. Zheng, X. J. Li, D. Li, and F. F. Su. "How are gamma-ray burst radio afterglows populated?" Monthly Notices of the Royal Astronomical Society 503, no. 3 (February 19, 2021): 3262–78. http://dx.doi.org/10.1093/mnras/stab465.
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ABSTRACT We systematically analyse two GRB samples with radio-loud and radio-quiet afterglows, respectively. It is interestingly found that the radio-selected GRB samples exhibit a clear dichotomy in terms of their distributions of intrinsic durations (Tint), isotropic energies in γ-rays (Eγ, iso), the circum-burst medium density (n), the spectral radio peak luminosity (Lν, p) and flux densities (Fhost) of host galaxies. On average, the values of Tint, Eγ, iso, n, Lν, p, and Fhost of radio-quiet GRBs are relatively smaller than those of radio-loud ones. However, the redshifts and host flux densities of both samples are similarly distributed. In addition, a positive power-law correlation of $L_{\nu ,p}\propto E_{\gamma ,\rm iso}^{0.41\pm 0.04}$ is found for the radio-loud sample, especially in accord with the supernova-associated GRBs, which is marginally consistent with that of the radio-quiet GRB sample. A negative correlation between Tint and z is confirmed to similarly hold for both radio-loud and radio-quiet GRBs. The dividing line between short and long GRBs in the rest frame is at Tint ≃1 s. Consequently, we propose that the radio-selected GRBs could be originated from distinct progenitors and central engines, together with environments.
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ZHANG, BING, and PETER MÉSZÁROS. "GAMMA-RAY BURSTS: PROGRESS, PROBLEMS & PROSPECTS." International Journal of Modern Physics A 19, no. 15 (June 20, 2004): 2385–472. http://dx.doi.org/10.1142/s0217751x0401746x.
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The cosmological gamma-ray burst (GRB) phenomenon is reviewed. The broad observational facts and empirical phenomenological relations of the GRB prompt emission and afterglow are outlined. A well-tested, successful fireball shock model is introduced in a pedagogical manner. Several important uncertainties in the current understanding of the phenomenon are reviewed, and prospects of how future experiments and extensive observational and theoretical efforts may address these problems are discussed.
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Shrestha, M., I. A. Steele, S. Kobayashi, R. J. Smith, H. Jermak, A. Piascik, and C. G. Mundell. "GRB 210619B: First Gamma-Ray Burst Detection by the Novel Polarimeter MOPTOP." Research Notes of the AAS 7, no. 6 (June 7, 2023): 118. http://dx.doi.org/10.3847/2515-5172/acdb64.
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Abstract GRB 210619B was a bright long gamma-ray burst (GRB) which was optically followed up by the novel polarimeter MOPTOP on the Liverpool Telescope. This was the first GRB detection by the instrument since it began science observations. MOPTOP started observing the GRB 1388 s after the Swift Burst Alert Telescope trigger. The R band light-curve decays following a broken power law with a break time of 2948 s after the trigger. The decay index values are α 1 = 0.84 ± 0.03 (pre-break) and α 2 = 0.54 ± 0.02 (post-break), indicating that the observation was most probably during the forward shock-dominated phase. We find a polarization upper limit of ∼7%. In the forward shock we expect the polarization to mostly come from dust in the local ambient medium which only produces low degrees of polarization. Hence our non-detection of polarization is as expected for this particular burst.