115 research outputs found
The second Konus-Wind catalog of short gamma-ray bursts
In this catalog, we present the results of a systematic study of 295 short
gamma-ray bursts (GRBs) detected by Konus-Wind (KW) from 1994 to 2010. From the
temporal and spectral analyses of the sample, we provide the burst durations,
the spectral lags, the results of spectral fits with three model functions, the
total energy fluences and the peak energy fluxes of the bursts. We discuss
evidence found for an additional power-law spectral component and the presence
of extended emission in a fraction of the KW short GRBs. Finally, we consider
the results obtained in the context of the Type I (merger-origin) / Type II
(collapsar-origin) classifications.Comment: Accepted to the Astrophysical Journal Supplement Series (7 Figures, 8
Tables
Konus-Wind and Helicon-Coronas-F Observations of Solar Flares
Results of solar flare observations obtained in the Konus-Wind experiment
from November, 1994 to December, 2013 and in the Helicon Coronas-F experiment
during its operation from 2001 to 2005, are presented. For the periods
indicated Konus-Wind detected in the trigger mode 834 solar flares, and
Helicon-Coronas-F detected more than 300 solar flares.
A description of the instruments and data processing techniques are given. As
an example, the analysis of the spectral evolution of the flares
SOL2012-11-08T02:19 (M 1.7) and SOL2002-03-10T01:34 (C5.1) is made with the
Konus-Wind data and the flare SOL2003-10-26T06:11 (X1.2) is analyzed in the
2.223 MeV deuterium line with the Helicon-Coronas-F data.Comment: Published version. A list of the Konus-Wind solar flare triggers and
figures of their time profiles are available at
http://www.ioffe.ru/LEA/Solar
Spectral Cross-calibration of the Konus-Wind, the Suzaku/WAM, and the Swift/BAT Data using Gamma-Ray Bursts
We report on the spectral cross-calibration results of the Konus-Wind, the
Suzaku/WAM, and the Swift/BAT instruments using simultaneously observed
gamma-ray bursts (GRBs). This is the first attempt to use simultaneously
observed GRBs as a spectral calibration source to understand systematic
problems among the instruments. Based on these joint spectral fits, we find
that 1) although a constant factor (a normalization factor) agrees within 20%
among the instruments, the BAT constant factor shows a systematically smaller
value by 10-20% compared to that of Konus-Wind, 2) there is a systematic trend
that the low-energy photon index becomes steeper by 0.1-0.2 and Epeak becomes
systematically higher by 10-20% when including the BAT data in the joint fits,
and 3) the high-energy photon index agrees within 0.2 among the instruments.
Our results show that cross-calibration based on joint spectral analysis is an
important step to understanding the instrumental effects which could be
affecting the scientific results from the GRB prompt emission data.Comment: 82 pages, 88 figures, accepted for publication in PAS
GRB spectral parameters within the fireball model
Fireball model of the GRBs predicts generation of numerous internal shocks,
which then efficiently accelerate charged particles and generate magnetic and
electric fields. These fields are produced in the form of relatively
small-scale stochastic ensembles of waves, thus, the accelerated particles
diffuse in space due to interaction with the random waves and so emit so called
Diffusive Synchrotron Radiation (DSR) in contrast to standard synchrotron
radiation they would produce in a large-scale regular magnetic fields. In this
paper we present first results of comprehensive modeling of the GRB spectral
parameters within the fireball/internal shock concept. We have found that the
non-perturbative DSR emission mechanism in a strong random magnetic field is
consistent with observed distributions of the Band parameters and also with
cross-correlations between them; this analysis allowed to restrict GRB physical
parameters from the requirement of consistency between the model and observed
distributions.Comment: 14 pages, 17 figures, MNRAS in pres
On the Fast Spectral Variability of GRBs
Fast spectral variability of gamma-ray burst emission is considered for a
number of events seen by the Konus-Wind experiment. The variability manifests
itself as a strong correlation between instantaneous energy flux and peak
energy . In the () plane, the correlation produces distinct tracks
in the form of branches and loops representing the different parts of a burst
time history. Despite the variety of features seen in different events, the
main characteristics of the spectral evolution produce a quite consistent
pattern.Comment: 3 pages with 2 figures; to appear in the Proceedings of the workshop
"Gamma-Ray Bursts in the Afterglow Era: 2nd Workshop", held in Rome, October
17-20, 200
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