Related papers: Time-evolution of Peak Energy and Luminosity Relat…
Employing a sample presented by Kaneko et al. (2006) and Kocevski et al. (2003), we select 42 individual tracking pulses (here we defined tracking as the cases in which the hardness follows the same pattern as the flux or count rate time…
The temporal evolution of the spectral break in the time resolved spectral energy density of the broad band afterglow of gamma ray bursts (GRBs) 091127 and 080319B was shown recently to be inconsistent with that expected for the cooling…
We study the spectral evolution on second and sub--second timescales in 11 long and 12 short Gamma Ray Bursts (GRBs) with peak flux >8.5e-6 erg/cm2 s (8 keV-35 MeV) detected by the Fermi satellite. The peak flux correlates with the…
Using a theoretical model describing pulse shapes, we have clarified the relations between the observed pulses and their corresponding timescales, such as the angular spreading time, the dynamic time as well as the cooling time. We find…
The spectral properties of a composite thermal emission arising from a relativistic expanding fireball can be remarkably different from the Planck function. We perform a detailed study of such a system to explore the features of the prompt…
We report test results of the correlation between time variability and peak luminosity of Gamma-Ray Bursts (GRBs), using a larger sample (32) of GRBs with known redshift than that available to Reichart et al. (2001), and using as…
We develop a new method for simultaneous timing and spectral studies of Gamma Ray Burst (GRB) prompt emission and apply it to make a pulse-wise description of the prompt emission of GRB 090618, the brightest GRB detected in the Fermi era.…
Despite the great variation in the light curves of Gamma Ray Burst (GRB) prompt emission, their spectral energy distribution is generally curved and broadly peaked. In particular, their spectral evolution is well described by the…
The $h\nu_{peak}/100 KeV \sim [E_{iso}/10^{52} \rm{erg}]^{1/2}$ correlation reported recently by Amati et al. (2002) and Lamb et al. (2003) for long GRB's can be interpreted as a viewing angle effect if the emitting region of the fireball…
A time-resolved spectral analysis for a sample of 22 intense, broad GRB pulses from the BATSE GRB sample is presented. We fit the spectra with the Band function and investigate the correlation between the observed flux (F) and the peak…
We use a nearly complete sample of Gamma Ray Bursts (GRBs) detected by the Swift satellite to study the correlations between the spectral peak energy Ep of the prompt emission, the isotropic energetics Eiso and the isotropic luminosity…
This paper presents a study on the spectral evolution of gamma-ray burst (GRB) prompt emissions observed with the Suzaku Wide-band All-sky Monitor (WAM). By making use of the WAM data archive, 6 bright GRBs exhibiting 7 well-separated…
We present the relation between the ($z-$ and $k-$corrected) spectral lags, $\tau$, for the standard Swift energy bands 50-100 keV and 100-200 keV and the peak isotropic luminosity, $L_{\mathrm{iso}}$ (a relation reported first by Norris et…
Well-sampled optical lightcurves of 146 gamma-ray bursts (GRBs) are complied from the literature. Multiple optical emission components are extracted with power-law function fits to these lightcurves. We present a systematical analysis for…
We present a time-resolved spectral analysis of 51 long and 11 short bright GRBs observed with the {\em Femri}/GBM, paying special attention to $E_{\rm p}$ evolution within a same burst. Among 8 single-pulse long GRBs, 5 show hard-to-soft…
A correlation between the peak luminosity and the peak energy has been found by Yonetoku et al. as $L_{p}\propto E_{p,i}^{2.0}$ for 11 pre-Swift long gamma-ray bursts. In this study, for a greatly expanded sample of 148 long gamma-ray…
Gamma-ray burst (GRB) emission is believed to originate in highly relativistic fireballs. Currently, only lower limits were securely set to the initial fireball Lorentz factor Gamma_0. We aim to provide a direct measure of Gamma_0. The…
We report results of a systematic study of the broad band (2--2000 keV) time resolved prompt emission spectra of a sample of gamma-ray bursts (GRBs) detected with both Wide Field Cameras on board the \sax\ satellite and the \batse\…
We report a correlation based on a spectral simulation study of the prompt emission spectra of gamma-ray bursts (GRBs) detected by the Swift Burst Alert Telescope (BAT). The correlation is between the Epeak energy, which is the peak energy…
Spectral evolution of gamma-ray burst pulses assumed to arise from emission of fireballs is explored. It is found that, due to the curvature effect, the integrated flux and peak energy are well related by a power law in the decaying phase…