主要内容:
Prochter et al. 2006说对MgII吸收体的分析发现用GRB余辉和用QSO作背景光源得到的结果不同。作者对C IV做的分析发现没有不同。
精彩摘抄:
文章信息:
Intervening Metal Systems in GRB and QSO sight-lines: The Mgii and Civ Question
主要内容:
如题。
精彩摘抄:
文章信息:
Simulation of prompt emission from GRBs with a photospheric component and its detectability by GLAST
Abstract: The prompt emission from gamma-ray bursts (GRBs) still requires a physical explanation. Studies of time-resolved GRB spectra, observed in the keV-MeV range, show that a hybrid model consisting of two components, a photospheric and a non-thermal component, in many cases fits bright, single-pulsed bursts as well as, and in some instances even better than, the Band function. With an energy coverage from 8 keV up to 300 GeV, GLAST will give us an unprecedented opportunity to further investigate the nature of the prompt emission. In particular, it will give us the possibility to determine whether a photospheric component is the determining feature of the spectrum or not. Here we present a short study of the ability of GLAST to detect such a photospheric component in the sub-MeV range for typical bursts, using simulation tools developed within the GLAST science collaboration.
主要内容:
一篇Science上的小综述（没看出来这篇文章的价值，哎）。
精彩摘抄:
文章信息:
Abstract: A study of gamma rays produced when stars collapse or collide reveals details of the explosion mechanism, particularly the role of magnetic fields.
主要内容:
认为回落盘激波产生的辐射比Ni的衰变产生的要强（一般认为超新星的光变是Ni的衰变产生的）。
精彩摘抄:
文章信息:
Light Curve Calculations of Supernovae from Fallback Gamma-Ray Bursts
Abstract: The currently-favored model for long-duration gamma-ray bursts (GRBs) invokes explosions from the collapse of a massive star down to a black hole: either directly or through fallback. Those GRBs forming via fallback will produce much less radioactive nickel, and hence it has been argued (without any real calculation) that these systems produce dim supernovae. These fallback black-hole GRBs have been recently been argued as possible progenitors of a newly discovered set of GRBs lacking any associated supernovae. Here we present the first ever radiation-hydrodynamics calculations of the light-curves produced in the hypernova explosion by a delayed-fallback gamma-ray burst. We find that the bolometric light-curve is dominated by shock-deposited energy, not the decay of radioactive elements. As such, observations of such bursts actually probe the density in the progenitor wind more than it does the production of radioactive nickel.
主要内容:
查看路上C IV的含量。
精彩摘抄:
文章信息:
On the Incidence of C IV Absorbers Along the Sightlines to Gamma-Ray Bursts
主要内容:
作者考虑用统计关系将伽玛暴普遍用的八个独立参量缩小为三个，分别是z, \alpha, \beta, AG_break, E_peak, AG_\alpha, T_90 and fluence，三个独立参量是T90， fluence， the fluence on the highest energy channel, 所用到的统计关有log T90 - log(1+z)
(p = 66.49%), log(1 + z) - \alpha (p = 99.75%), log Fluence - log T90 (p = 95.49%), logEpeak- log T90 (p = 97.98%) and log Epeak - log Fluence (p = 99.72%). 其中p是可信度。
精彩摘抄:
文章信息:
Principal Component Analysis of Gamma-Ray Bursts' Spectra
Abstract: Principal component analysis is a statistical method, which lowers the number of important variables in a data set. The use of this method for the bursts' spectra and afterglows is discussed in this paper. The analysis indicates that three principal components are enough among the eight ones to describe the variablity of the data. The correlation between spectral index alpha and the redshift suggests that the thermal emission component becomes more dominant at larger redshifts.
主要内容:
只给出了上限。
精彩摘抄:
文章信息:
A Search for CO(J=3-2) Emission from the Host Galaxy of GRB 980425 with the Atacama Submillimeter Telescope Experiment
主要内容:
类似于Panaitescu，对暴进行批量分析。主要是BeppoSAX的暴。
精彩摘抄:
文章信息:
Gamma-Ray Burst Afterglows as Probes of Environment and Blastwave Physics II: the Distribution of p and Structure of the Circumburst Medium
主要内容:
显示二者可能并不是暗暴。
精彩摘抄:
文章信息:
GRB 050410 and GRB 050412: are they really dark GRBs?
Abstract: We present a detailed analysis of the prompt and afterglow emission of GRB 050410 and GRB 050412 detected by Swift for which no optical counterpart was observed. The 15-150 keV energy distribution of the GRB 050410 prompt emission shows a peak energy at 53 keV. The XRT light curve of this GRB decays as a power law with a slope of alpha=1.06+/-0.04. The spectrum is well reproduced by an absorbed power law with a spectral index Gamma_x=2.4+/-0.4 and a low energy absorption N_H=4(+3;-2)x10^21 cm^(-2) which is higher than the Galactic value. The 15-150 keV prompt emission in GRB 050412 is modelled with a hard (Gamma=0.7+/-0.2) power law. The XRT light curve follows a broken power law with the first slope alpha_1=0.7+/-0.4, the break time T_break=254(-41;+79) s and the second slope alpha_2=2.8(-0.8;+0.5). The spectrum is fitted by a power law with spectral index Gamma_x=1.3+/-0.2 which is absorbed at low energies by the Galactic column. The GRB 050410 afterglow reveals the expected characteristics of the third component of the canonical Swift light curve. Conversely, a complex phenomenology was detected in the GRB 050412 because of the presence of the very early break. The light curve in this case can be interpreted as being the last peak of the prompt emission. The two bursts present tight upper limits for the optical emission, however, neither of them can be clearly classified as dark. For GRB 050410, the suppression of the optical afterglow could be attributed to a low density interstellar medium surrounding the burst. For GRB 050412, the evaluation of the darkness is more difficult due to the ambiguity in the extrapolation of the X-ray afterglow light curve.
主要内容:
主要是讨论仪器。
精彩摘抄:
文章信息:
Spectral Analysis of GRBs Measured by RHESSI
Abstract: The Ge spectrometer of the RHESSI satellite is sensitive to Gamma Ray Bursts (GRBs) from about 40 keV up to 17 MeV, thus ideally complementing the Swift/BAT instrument whose sensitivity decreases above 150 keV. We present preliminary results of spectral fits of RHESSI GRB data. After describing our method, the RHESSI results are discussed and compared with Swift and Konus.
