J/MNRAS/448/2624 List of isolated emission episodes in GRB (Charisi+, 2015)
Catalogue of isolated emission episodes in gamma-ray bursts from
Fermi, Swift and BATSE.
Charisi M., Marka S., Bartos I.
<Mon. Not. R. Astron. Soc., 448, 2624-2633 (2015)>
=2015MNRAS.448.2624C 2015MNRAS.448.2624C (SIMBAD/NED BibCode)
ADC_Keywords: Gamma rays
Keywords: catalogues - gamma-ray burst: general
Abstract:
We report a comprehensive catalogue of emission episodes within long
gamma-ray bursts (GRBs) that are separated by a quiescent period
during which gamma-ray emission falls below the background level. We
use a fully automated identification method for an unbiased,
large-scale and expandable search. We examine a comprehensive sample
of long GRBs from the BATSE (Burst and Transient Source Experiment),
Swift and Fermi missions, assembling a total searched set of 2710
GRBs, the largest catalogue of isolated emission episodes so far. Our
search extends out to [-1000s,750s] around the burst trigger,
expanding the covered time interval beyond previous studies and far
beyond the nominal durations (T90) of most bursts. We compare
our results to previous works by identifying pre-peak emission (or
precursors), defined as isolated emission periods prior to the episode
with the highest peak luminosity of the burst. We also systematically
search for similarly defined periods after the burst's peak
emission. We find that the pre-peak and post-peak emission periods are
statistically similar, possibly indicating a common origin. For the
analysed GRBs, we identify 24 percent to have more than one isolated
emission episode, with 11 percent having at least one pre-peak event
and 15 percent having at least one post-peak event. We identify GRB
activity significantly beyond their T90, which can be important
for understanding the central engine activity as well as, e.g.
gravitational-wave searches.
Description:
We analysed GRB light curves from the three main GRB catalogues: (i)
the Gamma-ray Burst Monitor (GBM) on board Fermi Gamma-ray Space
Telescope (Meegan et al., 2009ApJ...702..791M 2009ApJ...702..791M), (ii) the Burst Alert
Telescope (BAT) on the Swift satellite (Gehrels et al.,
2004ApJ...611.1005G 2004ApJ...611.1005G), and (iii) the BATSE on board Compton Gamma-Ray
Observatory (Fishman et al., 1989, Its Max'91 Workshop 2:
Developments in Observations and Theory for Solar Cycle 22. Wingle R.
M., Dennis B. R., editors. 1989. p. 96.). We analysed GRBs detected
prior to 2014 January 01. The search was confined to long GRBs with
nominal duration T90 (T90>2s), where T90 is defined as the time
interval during which 90% of the GRB fluence was detected with 5%
fluence detected both before and after the interval. Note that T90 was
the only property considered in identifying long GRBs. The main reason
for this selection is the reduced accuracy of the search for
variability shorter than the bin size of the available light curves.
Fermi-GBM consists of 12 NaI detectors, sensitive to energies from
8keV to ∼1MeV, which cover the entire unocculted sky, along with two
BGO detectors sensitive to higher energy photons (∼200keV to ∼40MeV).
The GBM burst catalogue
(http://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html) consists
of 1276 GRBs (2008 July-2013 December) and the data are publicly
available (http://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/)
Swift-BAT is a sensitive gamma-ray detector with a wide field of view
(1.4sr) designed to provide GRB triggers with accurate localization.
During the considered observation period up to the end of 2013 (2004
Decembe-2013 December), Swift had detected 833 GRBs (Sakamoto et
al., 2011ApJS..195....2S 2011ApJS..195....2S, Cat. J/ApJS/195/2).
The data are retrieved from the public archive
(http://swift.gsfc.nasa.gov/archive/)
BATSE consisted of eight large NaI area detectors (LADs) covering the
energy range of ∼25keV to ∼2MeV, and was able to observe the
entire unobstructed sky. Over its nine years of operation (1991
April-2000 May), it detected 2702 GRBs
(http://gammaray.msfc.nasa.gov/batse/grb/catalog/current/).
For each burst, the daily LAD discriminator data (DISCLA) are
retrieved from the archive
(ftp://legacy.gsfc.nasa.gov/compton/data/batse/daily)
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
baste.dat 9 1275 BATSE Catalog -- Isolated Emission Episodes
fermi.dat 12 956 Fermi Catalog -- Isolated Emission Episodes
swift.dat 10 583 Swift Catalog -- Isolated Emission Episodes
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See also:
IX/20 : The Fourth BATSE Burst Revised Catalog (Paciesas+ 1999)
Byte-by-byte Description of file: baste.dat fermi.dat swift.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- Name GRB name (GRBNNNNNN, GRBNNNNNNNN or GRBNNNNNNA)
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 04-Sep-2015