J/ApJ/744/141 Shapes of GRB light curves (Bhat+, 2012)
Temporal deconvolution study of long and short gamma-ray burst light curves.
Bhat P.N., Briggs M.S., Connaughton V., Kouveliotou C., van der Horst A.J.,
Paciesas W., Meegan C.A., Bissaldi E., Burgess M., Chaplin V., Diehl R.,
Fishman G., Fitzpatrick G., Foley S., Gibby M., Giles M.M., Goldstein A.,
Greiner J., Gruber D., Guiriec S., von Kienlin A., Kippen M., McBreen S.,
Preece R., Rau A., Tierney D., Wilson-Hodge C.
<Astrophys. J., 744, 141 (2012)>
=2012ApJ...744..141B 2012ApJ...744..141B
ADC_Keywords: Gamma rays
Keywords: gamma-ray burst: general - methods: data analysis -
relativistic processes
Abstract:
The light curves of gamma-ray bursts (GRBs) are believed to result
from internal shocks reflecting the activity of the GRB central
engine. Their temporal deconvolution can reveal potential differences
in the properties of the central engines in the two populations of
GRBs which are believed to originate from the deaths of massive stars
(long) and from mergers of compact objects (short). We present here
the results of the temporal analysis of 42 GRBs detected with the
Gamma-ray Burst Monitor onboard the Fermi Gamma-ray Space Telescope.
We deconvolved the profiles into pulses, which we fit with lognormal
functions. The distributions of the pulse shape parameters and
intervals between neighboring pulses are distinct for both burst types
and also fit with lognormal functions. We have studied the evolution
of these parameters in different energy bands and found that they
differ between long and short bursts. We discuss the implications of
the differences in the temporal properties of long and short bursts
within the framework of the internal shock model for GRB prompt
emission.
Description:
The Fermi/Gamma-ray Burst Monitor (GBM) is an uncollimated all-sky
(field of view ≥8sr) monitoring instrument. During the three years
since its launch (2008 June 11) GBM has collected over 700 GRBs.
During the first year, GBM detected 225 GRBs of which 59 were BGO
bright bursts (Bissaldi et al. 2011ApJ...733...97B 2011ApJ...733...97B). This is to ensure
the burst is sufficiently hard to allow pulse decomposition analysis
in different energy channels. Out of the latter data set we chose long
bursts with the product of fluence and peak flux (1.024s) values
greater than 1.0x10-4 and 5.0x10-6 erg photons/cm4/s for long
and short bursts, respectively. Burst fluences and peak fluxes
estimated in the energy range 10-1000keV are taken from the GBM
Gamma-ray burst catalog (Paciesas et al. 2012, Cat. J/ApJS/199/18).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 33 42 List of GRBs, chosen for the present analysis
table3.dat 112 754 Shape parameters of pulses fitted to full energy
light curves of GRBs
table4.dat 109 2341 Shape parameters of pulses fitted to GRB light
curves in different energy ranges
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See also:
J/ApJS/199/18 : The Fermi GBM catalog (Paciesas+, 2012)
J/A+A/525/A53 : GBM parameters for detected FERMI bursts (Guetta+, 2011)
J/A+A/530/A21 : Spectral properties of 438 GRBs (Nava+, 2011)
J/A+A/385/377 : 319 gamma-ray bursts BATSE triggers (Quilligan+, 2002)
J/ApJS/126/19 : BATSE gamma-ray burst spectral catalog. I. (Preece+, 2000)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 5 A5 --- Type "long" or "short" GRB
7- 8 A2 --- --- [bn]
9- 17 I09 --- ID Trigger identification as in Paciesas et al.,
2012, Cat. J/ApJS/199/18 (YYMMDDNNN; bn)
19- 25 F7.3 s T90 [0.192/176.2] Duration T90
27- 30 F4.2 s e_T90 [0.14/8.51] T90 uncertainty
32- 33 I2 --- N [2/32] Number of fitted pulses
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 2 A2 --- --- [bn]
3- 11 I09 --- ID Trigger identification
13- 17 F5.3 s bin [0.001/0.15] Bin width
19- 21 A3 --- Det Detector (BGO or NaI)
23- 24 I2 --- Num [1/32] Pulse number
26- 35 F10.5 --- Amp [0.00967/1980] Pulse amplitude (number/bin)
37- 46 F10.6 s Time [-13.1/141] Time since trigger
48- 58 F11.8 s Rise [3.7e-07/22.4] Rise time
60- 69 F10.8 s e_Rise Error in Rise
71- 80 F10.6 s Decay [0.00012/174] Decay time
82- 91 F10.7 s e_Decay Error in Decay
93-102 F10.7 s FWHM [8.82e-05/51.6] Pulse Full-Width at Half-Maximum
104-112 F9.6 s e_FWHM [1.1e-05/21] Error in FWHM
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 2 A2 --- --- [bn]
3- 11 I09 --- ID Trigger identification
13- 18 F6.1 keV E [12.5/1016.1] Mean energy
20- 21 I2 --- Num [1/34] Pulse number
23- 32 F10.5 --- Amp [0.00222/1160] Pulse amplitude; number/bin
34- 43 F10.6 s Time [-16.6/291] Time since trigger
45- 52 F8.5 s Rise [0.00101/44.3] Rise time
54- 65 F12.9 s e_Rise Error in Rise
67- 75 F9.5 s Decay [0.00101/124] Decay time
77- 88 F12.9 s e_Decay Error in Decay
90- 97 F8.5 s FWHM [0.0014/88.6] Pulse Full-Width at Half-Maximum
99-109 F11.8 s e_FWHM [0/53] Error in FWHM
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 20-Jun-2013