Microphysics and dynamics of the Gamma-Ray Burst 121024A
K. Varela, H. van Eerten, J. Greiner, P. Schady, J. Elliott, V. Sudilovsky, T. Krühler, A. J. van der Horst, J. Bolmer, F. Knust, C. Agurto, F. Azagra, A. Bello… 展开作者
K. Varela, H. van Eerten, J. Greiner, P. Schady, J. Elliott, V. Sudilovsky, T. Krühler, A. J. van der Horst, J. Bolmer, F. Knust, C. Agurto, F. Azagra, A. Belloche, F. Bertoldi, C. De Breuck, C. Delvaux, R. Filgas, J. Graham, A. Nicuesa Guelbenzu, D. A. Kann, S. Klose, K. M. Menten, A. Rau, A. Rossi, S. Schmidl, F. Schuller, T. Schweyer, M . Tanga, A. Weiss, P. Wiseman, F. Wyrowski
Aims. The aim of the study is to constrain the physics of gamma-ray bursts (GRBs) by analysing the multi-wavelength afterglow data set of GRB 121024A that covers the full range from radio to X-rays. Methods. Using multi-epoch broad-band observations of the GRB 121024A afterglow, we measured the three characteristic break frequencies of the synchrotron spectrum. We used six epochs of combined XRT and GROND data to constrain the temporal slopes, the dust extinction, the X-ray absorption, and the spectral slope with high accuracy. Two more epochs of combined data from XRT, GROND, APEX, CARMA, and EVLA were used to set constraints on the break frequencies and therefore on the micro-physical and dynamical parameters. Results. The XRT and GROND light curves show a simultaneous and achromatic break at around 49 ks. As a result, the crossing of the synchrotron cooling break is no suitable explanation for the break in the light curve. The multi wavelength data allow us to test two plausible scenarios explaining the break: a jet break, and the end of energy injection. The jet-break scenario requires a hard electron spectrum, a very low cooling break frequency, and a non-spreading jet. The energy injection avoids these problems, but requires $ε_e > 1 (k = 2)$, spherical outflow, and $ε_B < 10^{-9}$. Conclusions. In light of the extreme microphysical parameters required by the energy-injection model, we favour a jet-break scenario where $ν_m < ν_{sa}$ to explain the observations. This scenario gives physically meaningful microphysical parameters, and it also naturally explains the reported detection of linear and circular polarisation.
We consider a simple model for gamma-ray bursts induced by magnetic reconnection in turbulent media. The magnetic field in a jet is subject to kink instabilities, which distort the regular structure of the spiral magnetic field, drive turbulence, and trigger reconnection. The resulting reconnection takes place in a high Reynolds number medium, where turbulence is further enhanced and in turn accelerates the reconnection process. This boot-strap reconnection gives rise to bursts of reconnection events, through which the free energy of magnetic field is transformed into a gamma-ray burst. The ef…
The field of gamma-ray burst astronomy arguably went through three decades of growing pains before reaching maturity. What development lessons can be learned for the adolescent field of fast radio burst astronomy?
Recently, GRB 170817A was confirmed to be associated with GW 170817, which was produced by a neutron star - neutron star merger. It indicates that at least some short gamma-ray bursts come from binary neutron star mergers. Theoretically, it is widely accepted that short gamma-ray bursts can be produced by two distinctly different mechanisms, binary neutron star mergers and neutron star - black hole mergers. These two kinds of bursts should be different observationally due to their different trigger mechanisms. Motivated by this idea, we collect a universal data set constituted of 51 short gamm…
One of the most luminous explosions detected, gamma-ray bursts, especially the so-called long-duration bursts, most probably consist of an intrinsic core-collapse to a black hole inside a super massive star. We point out that this collapse alone will give a generic gravitational wave burst. It has been shown that the strength of this burst depends on the dimensionless spin parameter of the collapsing object. Under descent assumptions the gamma-ray burst's central engine powers the explosion electromagnetically due to the rotation of the newly formed black hole. We argue that the peak luminosit…
This Erratum modifies the original article entitled "Primordial black hole origin for thermal gamma ray bursts", which was published in Monthly Notices of the Royal Astronomical Society 506, 806 (2021).
The Pioneer Venus Orbiter (PVO) Gamma-ray burst experiment detected 318 gamma-ray bursts over about 14 years between 1978 and 1992 with near $4π$ coverage. This data set complements BATSE by determining the properties of the brightest gamma-ray bursts. PVO places a constrains on the slope of the bright end of the Log N-Log P distribution. The slope is -1.52$\pm 0.15$.
We demonstrate how pulse structures in Short gamma-ray bursts (SGRBs), coupled with observations of GRB/GW 170817A, constrain the geometries of dying HMXRB systems composed of merging neutron stars.
费米伽马射线太空望远镜（英语：Fermi Gamma-ray Space Telescope）的大面积望远镜（英语：Large Area Telescope）是一个对转换望远镜，对超过40个能量十年的伽马射线敏感，介于20 MeV和300 GeV之间。LAT与伽马射线暴监测器（GBM）-任务上的另一种仪器-协同作用，在研究伽马射线暴（GRB）方面，在光谱覆盖范围、有效面积和仪器死时间方面具有前所未有的灵敏度。我们将回顾GRB的Fermi-LAT观测的主要结果，介绍GeV能区GRB的主要性质。
The recently discovered rapid transient GN-z11-flash has been suggested to be the prompt-emission ultraviolet flash associated with a gamma-ray burst serendipitously exploding in the ultra-high-$z$ galaxy GN-z11. We here place the flash into the context of the early ultraviolet emission of gamma-ray bursts, and find it is in agreement with the luminosity distribution of these events.
The binary neutron star merger responsible for the gravitational wave event, GW170817, strengthened the merger association with short-duration gamma-ray bursts (SGRBs) following the detection of the SGRB counterpart, GRB 170817A. Here we consider the constraints on a population of local gamma-ray bursts with moderately short duration ($T_{90}<4 \textrm{ s}$) and within $d < 200 \textrm{ Mpc}$, that may have originated from similar compact binary mergers. Using well localised gamma-ray bursts from $\sim14.5 \textrm{ years}$ of Swift/Burst Alert Telescope monitoring, we find no events with high …
Many different physical processes have been suggested to explain the prompt gamma-ray emission in gamma-ray bursts (GRBs). Although there are examples of both bursts with photospheric and synchrotron emission origins, these distinct spectral appearances have not been generalized to large samples of GRBs. Here, we search for signatures of the different emission mechanisms in the full Fermi Gamma-ray Space Telescope GBM catalogue. We use Gaussian Mixture Models to cluster bursts according to their parameters from the Band function ($α$, $β$, and $E_{pk}$) as well as their fluence and $T_{90}$. W…
The well-sampled afterglows of gamma ray bursts (GRBs) not associated with a supernova (SN) explosion, can be scaled down to a simple dimensionless universal formula, which describes well their temporal behavior. Such SN-less GRBs include short hard bursts (SHBs) and long SN-less GRBs. The universal temporal behavior of their afterglows is that expected from a pulsar wind nebula powered by the rotational energy loss of the newly born pulsar.
The canonball model, which unifies cosmic ray bursts (CRBs) and gamma ray bursts (GRBs), is used to predict the maximum isotropic equivalent gamma ray energy release in a GRB. The predicted maximum is based on the observed knee around 1 TeV in the energy spectrum of Galactic cosmic ray electrons, and on the Amati correlation in GRBs. Both were predicted by the cannonball model of CRBs and GRBs before their empirical discoveries. The predicted maximum agrees well with that concluded from up to date GRB observations.
This paper provides an overview of the current state of the stripping model for short gamma-ray bursts. After the historical joint detection of the gravitational wave event GW170817 and the accompanying gamma-ray burst GRB170817A, the relation between short gamma-ray bursts and neutron star mergers has been reliably confirmed. We show that many properties of GRB170817A, which turned out to be peculiar in comparison with other short gamma-ray bursts, are naturally explained in the context of the stripping model, specifically, the time (1.7 s) between the peak of the gravitational wave signal an…
Gamma-ray bursts are flashes of light from distant exploding stars. Cube satellites that monitor photons across different energy bands are used to detect these bursts. There is a need for computationally efficient algorithms, able to run using the limited computational resource onboard a cube satellite, that can detect when gamma-ray bursts occur. Current algorithms are based on monitoring photon counts across a grid of different sizes of time window. We propose a new algorithm, which extends the recently developed FOCuS algorithm for online change detection to Poisson data. Our algorithm is m…
We report on the 2015 June 25 sustained gamma-ray emission (SGRE) event associated with a halo coronal mass ejection and a type II radio burst in the decameter-hectometric (DH) wavelengths. The duration and ending frequency of the type II burst are linearly related to the SGRE duration as found in previous works involving intense gamma-ray events. This study confirms that the SGRE event is due to protons accelerated in the shock that produced the DH type II burst.
In search for the possible astrophysical sources behind origination of the diverse gamma-ray bursts, cluster analyses are performed to find homogeneous groups, which discover an intermediate group other than the conventional short and long bursts. However, very recently, few studies indicate a possibility of the existence of more than three (namely five) groups. Therefore, in this paper, fuzzy clustering is conducted on the gamma-ray bursts from the final 'Burst and Transient Source Experiment' catalog to cross-check the significance of these new groups. Meticulous study on individual bursts b…
Gamma-ray bursts are the most powerful explosions in the universe and are mainly placed at very large redshifts, up to $z\simeq 9$. In this short review, we first discuss gamma-ray burst classification and morphological properties. We then report the likely relations between gamma-ray bursts and other astronomical objects, such as black holes, supernovae, neutron stars, etc., discussing in detail gamma-ray burst progenitors. We classify long and short gamma-ray bursts, working out their timescales, and introduce the standard fireball model. Afterwards, we focus on direct applications of gamma-…
