79 research outputs found
Finding Fermi GBM Counterparts to LIGO Gravitational-Wave Candidates
No abstract availabl
Background estimation in a wide-field background-limited instrument such as Fermi GBM
The supporting instrument on board the Fermi Gamma-ray Space Telescope, the
Gamma-ray Burst Monitor (GBM) is a wide-field gamma-ray monitor composed of 14
individual scintillation detectors, with a field of view which encompasses the
entire unocculted sky. Primarily designed as transient monitors, the
conventional method for background determination with GBM-like instruments is
to time interpolate intervals before and after the source as a polynomial. This
is generally sufficient for sharp impulsive phenomena such as Gamma-Ray Bursts
(GRBs) which are characterised by impulsive peaks with sharp rises, often
highly structured, and easily distinguishable against instrumental backgrounds.
However, smoother long lived emission, such as observed in solar flares and
some GRBs, would be difficult to detect in a background-limited instrument
using this method. We present here a description of a technique which uses the
rates from adjacent days when the satellite has approximately the same
geographical footprint to distinguish low-level emission from the instrumental
background. We present results from the application of this technique to GBM
data and discuss the implementation of it in a generalised background limited
detector in a non-equatorial orbit.Comment: Proceedings of SPIE, Vo. 8443, Paper No. 8443-3
Fermi GBM Counterparts to LIGO/Virgo Gravitational-Wave Candidates
No abstract availabl
BATSE Observations of Gamma-Ray Burst Tails
I discuss in this paper the phenomenon of post-burst emission in BATSE
gamma-ray bursts at energies traditionally associated with prompt emission. By
summing the background-subtracted signals from hundreds of bursts, I find that
tails out to hundreds of seconds after the trigger may be a common feature of
long events (duration greater than 2s), and perhaps of the shorter bursts at a
lower and shorter-lived level. The tail component appears independent of both
the duration (within the long GRB sample) and brightness of the prompt burst
emission, and may be softer. Some individual bursts have visible tails at
gamma-ray energies and the spectrum in at least a few cases is different from
that of the prompt emission.Comment: 33 Pages from LaTex including 7 figures, with aastex. To appear in
Astrophysical Journa
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