Observational follow-up of well localized short gamma-ray bursts (SGRBs) has left $20-30\%$ of the population without a coincident host galaxy association to deep optical and NIR limits ($\gtrsim 26$ mag). These SGRBs have been classified as observationally hostless due to their lack of strong host associations. It has been argued that these hostless SGRBs could be an indication of the large distances traversed by the binary neutron star system (due to natal kicks) between its formation and its merger (leading to a SGRB). The distances of GRBs from their host galaxies can be indirectly probed by the surrounding circumburst densities. We show that a lower limit on those densities can be obtained from early afterglow lightcurves. We find that $\lesssim16\%$ of short GRBs in our sample took place at densities $\lesssim10^{-4}$ cm$^{-3}$. These densities represent the expected range of values at distances greater than the host galaxy's virial radii. We find that out of the five SGRBs in our sample that have been found to be observationally hostless, none are consistent with having occurred beyond the virial radius of their birth galaxies. This implies one of two scenarios. Either these observationally hostless SGRBs occurred outside of the half-light radius of their host galaxy, but well within the galactic halo, or in host galaxies at moderate to high redshifts ($z\gtrsim 2$) that were missed by follow-up observations.
It has been widely recognized that gamma-ray burst (GRB) afterglows arise from interactions between GRB outflow and circumburst medium, while their evolution follows the behaviors of relativistic shock waves. Assuming the distribution of circumburst medium follows a general power-law form, that is, $n = A_{\ast} R^{-k}$, where $R$ denotes the distance from the burst, it is obvious that the value of density-distribution index $k$ can affect the behaviors of the afterglow. In this paper, we analyze the temporal and spectral behaviors of GRB radio afterglows with arbitrary $k$-values. In the radi…
Long gamma-ray bursts (GRBs) are considered to be originated from core collapse of massive stars. It is believed that the afterglow property is determined by the density of the material in the surrounding interstellar medium. Therefore, the circumburst density can be used to distinguish between an interstellar wind $n(R) \propto R^{\rm -k}$, and a constant density medium (ISM), $n(R) = const$. Previous studies with different afterglow samples, show that the circumburst medium of GRBs is neither simply supported by an interstellar wind, nor completely favored by an ISM. In this work, our new sa…
The reverse shock (RS) model is generally introduced to interpret the optical afterglows with the rapid rising and decaying, such as the early optical afterglow of GRB 990123 (which is also called optical flash). In this paper, we collected 11 gamma-ray bursts (GRBs) early optical afterglows, which have such signatures of dominant RS emission. Since the temporal slopes of the optical flashes are determined by both the medium density distribution index $k$ and the electron spectral index $p$, we apply the RS model of the thin shell case to the optical flashes and determine the ambient medium of…
We present deep Apache Point Observatory optical observations within seconds of the outburst of the periodic fast radio burst (FRB) 180916.J0158+65 obtained on 3 September 2020. FRB 180916.J0158+65 is located in a nearby spiral galaxy 150 Mpc away and has an "active phase" with a well-measured period of approximately 16.3 days. Targeting the FRB at the peak of its expected active phase and during a recent 30 minute observing window by the Canadian Hydrogen Intensity Mapping Experiment (CHIME), we did not detect any transient optical emission at m_i=24.7~mag (3-sigma) from 2.2 to 1938.1 seconds…
Constraints on the central engine of merger-driven long gamma-ray bursts
Università di Tor Vergata（托尔维加塔大学）；INAF–Istituto di Radioastronomia（意大利国家天体物理研究所射电天文研究所）；The Open University of Israel（以色列开放大学）；The University of Tokyo（东京大学）；The Pennsylvania State University（宾夕法尼亚州立大学）
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?
VLBI and Archival VLA and WSRT Observations of the GRB 030329 Radio Afterglow
我们介绍VLBI和档案卡尔G。Jansky甚大阵列（VLA）和Westerbork综合射电望远镜（WSRT）对2003年3月29日伽马射线暴（GRB 030329）的射电余辉的观测，在爆发后672至2032天之间进行。EVLA和WSRT的数据表明，在5 GHz的通量简单的幂律衰减，没有任何明显的迹象，从反喷流的再亮。我们报告了一个未解决的来源，在2032天的大小$1.18\pm0.13$ mas，我们使用结合膨胀率的爆发，认为存在一个统一的，ISM样环爆介质。我们发展了一种半解析的方法来模拟伽马射线暴的余辉，并将其应用到5 GHz的光变曲线进行爆发量热。自行受到$< 0.067$ mas yr $^{-1}$的限制，支持伽马射线暴的标准余辉模型。
Some afterglow light curves of gamma-ray bursts (GRBs) exhibit very complex temporal and spectral features, such as a sudden intensity jump about one hour after the prompt emission in the optical band. We assume that this feature is due to the late collision of two relativistic shells and investigate the corresponding high-energy neutrino emission within a multi-messenger framework, while contrasting our findings with the ones from the classic afterglow model. For a constant density circumburst medium, the total number of emitted neutrinos can increase by about an order of magnitude when an op…
Extra-galactic X-ray absorption and optical extinction are often found in gamma-ray burst (GRB) afterglows and they could be tracers of both circumburst and host galaxy environments. By performing spectral analyses for spectral energy distribution of 9 short GRB (SGRB) afterglows with known redshift, we investigated a ratio of the equivalent hydrogen column density to the dust extinction, N^{rest}_{H}/A^{rest}_{V}, in the rest frame of each SGRB. We found that the distribution of N^{rest}_{H}/A^{rest}_{V} is systematically smaller than the one for long GRBs, and is roughly consistent with the …
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…
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.
Gamma-ray bursts (GRBs) are among the most luminous sources in the universe. The nature of their emission at TeV energies is one of the most relevant open issues related to these events. The temporal and spectral features inferred from the early and late emissions usually known as prompt and afterglow, respectively, can be interpreted within the context of the fireball model. The synchrotron self-Compton process is expected during the afterglow phase. We explain how the theoretical SSC light curves can be compared with hypothetical upper limit located at z=0.3. We show the allowed parameter sp…
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 …
Probing Pre-galactic Metal Enrichment with High-Redshift Gamma-Ray Bursts
我们探讨高红移伽马射线暴（GRB）作为有前途的工具，探测前银河系金属富集。利用原始矮星系中爆发的Pop III GRB的明亮余辉作为发光背景源，计算了星系际介质（IGM）中第一重元素留下的金属吸收线的强度。为了得到伽玛射线暴吸收线的诊断，我们使用了一个现有的高分辨率模拟的第一个星系的形成，其特征是在一个维里温度>10^4 K的晕中氢原子冷却的开始。我们探索不寻常的环爆环境内的系统，举办流行III星，模拟密度演化与自相似的解决方案的香槟流。对于接近冷却阈值的微晕，环爆流密度大致与（1+z）成正比，其值约为几cm^{-3}。在质量更大的晕中，对应于第一个星系，密度可能更大，n>100 cm^{-3}。由此产生的余辉通量可以分别在近红外和无线电波段用JWST和VLA检测到，直到红移z>20。我们预测，余辉发射的最大值从近红外到毫米波段移动，峰值通量从mJy到Jy在不同的观测时间。伽玛暴具有高亮度和无特征的幂律谱，是探测IGM早期金属富集的理想工具。由第一颗超新星（SN）爆炸产生的第一个星系中的金属可能处于低电离阶段。我们表明，如果余辉可以观察到足够早，分析的金属线可以区分是否产生的第一个重元素的PISN，或核心塌陷（II型）SN，从而约束的初始质量函数的第一个恒星。
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…
