J/ApJ/704/1405 Testing the Epeak-Eiso relation for GRBs (Krimm+, 2009)
Testing the Epeak-Eiso relation for GRBs detected by Swift and Suzaku-WAM.
Krimm H.A., Yamaoka K., Sugita S., Ohno M., Sakamoto T., Barthelmy S.D.,
Gehrels N., Hara R., Norris J.P., Ohmori N., Onda K., Sato G., Tanaka H.,
Tashiro M., Yamauchi M.
<Astrophys. J., 704, 1405-1432 (2009)>
=2009ApJ...704.1405K 2009ApJ...704.1405K
ADC_Keywords: Gamma rays ; Models ; Redshifts
Keywords: gamma rays: bursts
Abstract:
One of the most prominent, yet controversial associations derived from
the ensemble of prompt-phase observations of gamma-ray bursts (GRBs)
is the apparent correlation in the source frame between the peak
energy (Epeak) of the νF(ν) spectrum and the isotropic
radiated energy, Eiso. Since most GRBs have Epeak above the energy
range (15-150keV) of the Burst Alert Telescope (BAT) on Swift,
determining accurate Epeak values for large numbers of Swift bursts
has been difficult. However, by combining data from Swift/BAT and the
Suzaku Wide-band All-Sky Monitor (WAM), which covers the energy range
from 50 to 5000keV, for bursts which are simultaneously detected, one
can accurately fit Epeak and Eiso and test the relationship
between them for the Swift sample. Between the launch of Suzaku in
2005 July and the end of 2009 April, there were 48 GRBs that triggered
both Swift/BAT and WAM, and an additional 48 bursts that triggered
Swift and were detected by WAM, but did not trigger. A BAT-WAM team
has cross-calibrated the two instruments using GRBs, and we are now
able to perform joint fits on these bursts to determine their spectral
parameters. For those bursts with spectroscopic redshifts, we can also
calculate the isotropic energy. Here, we present the results of joint
Swift/BAT-Suzaku/WAM spectral fits for 91 of the bursts detected by
the two instruments.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 92 91 General properties of BAT/WAM bursts
table2.dat 114 192 Time-integrated spectral parameters of BAT/WAM
bursts
table3.dat 70 24 Spectral parameters for BAT/WAM bursts fitted
only by a power-law model
table4.dat 61 66 Fluence values for BAT/WAM bursts
table5.dat 104 432 Time-resolved spectral parameters of BAT/WAM bursts
refs.dat 40 67 References
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See also:
IX/36 : GRANAT/PHEBUS catalog of cosmic gamma-ray bursts (Terekhov+, 1994-2002)
J/ApJS/195/2 : The second Swift BAT GRB catalog (BAT2) (Sakamoto+, 2011)
J/A+A/525/A53 : GBM parameters for detected FERMI bursts (Guetta+, 2011)
J/MNRAS/407/2075 : Gamma-ray bursts spectral peak estimator (Shahmoradi+,
2010)
J/PAZh/35/10 : Gamma-ray bursts with known redshifts (Badjin+, 2009)
J/ApJS/175/179 : The BAT1 gamma-ray burst catalog (Sakamoto+, 2008)
J/other/APh/26.367 : GRB from RICE data (Besson+, 2007)
J/ApJS/169/62 : GRB database of spectral lags (Hakkila+, 2007)
J/ApJS/166/298 : Spectral catalog of bright BATSE gamma-ray bursts (Kaneko+
2006)
J/ApJ/609/935 : Gamma-ray burst formation rate (Yonetoku+, 2004)
J/ApJS/134/385 : Supplement to the BATSE gamma-ray burst catalogs (Kommers+
2001)
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- 7 A7 --- GRB GRB designation (YYMMDDA)
9- 13 F5.1 s T90 Values of T90 are from Sakamoto et al. (2008,
Cat. J/ApJS/175/179) unless otherwise indicated
15- 16 I2 --- r_T90 ? Other reference for T90 (see refs.dat file)
17 A1 --- f_T90 [S] S: short burst
19- 24 F6.4 --- z ? Redshift
26- 27 I2 --- r_z ? Redshift reference (see refs.dat file)
29 A1 --- f_Trig [u] u: untrig
30- 35 I6 --- Trig ? BAT trigger number
37 A1 --- f_TrigW [u] u: untrig
38- 41 I4 --- TrigW ? WAM trigger number
43- 44 I2 --- Det WAM detector number (1)
45 A1 --- f_Det [c-g] only one side of WAM detectors used (2)
47- 53 F7.2 s ti.0 ? Total burst interval, start (3)
54 A1 --- --- [-]
55- 60 F6.2 s ti.1 ? Total burst interval, end (3)
62- 65 A4 --- f_ti.1 [sl,h ] Total burst peculiarity (4)
67- 73 F7.2 s si.0 ? Segment interval, start (3)
74 A1 --- --- [-]
75- 80 F6.2 s si.1 ? Segment interval, end (3)
81- 82 A2 --- f_si.1 [sl] Burst segment peculiarity (4)
85- 91 A7 --- Seg Segment: portion of the burst used for the time-
integrated spectral fit
92 A1 --- f_Seg [d] precursor to main burst (5)
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Note (1): "WAM dets": the identifier of the WAM detector or a pair of
detectors in which the burst was detected; cases where only one of a
pair was used in the fits are noted.
Note (2): Flag on Det as follows:
c = Only WAM side 0 used for fits.
e = Only WAM side 3 used for fits.
f = Only WAM side 1 used for fits.
g = Only WAM side 2 used for fits.
Note (3): Total interval and Segment interval: times are with respect to
the Swift/BAT trigger time. Time-resolved burst segments
Note (4): Flag as follows:
h = This burst did not trigger BAT, but was discovered as part of the BAT
slew survey. For this burst, T0 is the start of the spacecraft slew.
sl = The time interval included all or part of a spacecraft slew maneuver.
Note (5):
d = BAT triggered on a precursor to the main burst. Analysis was done using
BAT survey ("dph") data.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- GRB GRB designation (YYMMDDA)
9 A1 --- f_GRB [a] Flag for GRB 080218A (1)
11- 15 F5.2 --- alpha Photon spectral index α (2)
17- 20 F4.2 --- e_alpha alpha uncertainty
22- 26 F5.2 --- beta ? 2d photon spectral index β (2)
28- 32 F5.2 --- E_beta ? Positive error in beta
34- 37 F4.2 --- e_beta ? Negative error in beta
39- 42 I4 keV Epk ? Energy peak Epeak (2)
44- 47 I4 keV E_Epk ? Positive error in Epk
49- 51 I3 keV e_Epk ? Negative error in Epk
53- 59 F7.3 10+45J Eiso ? Isotropic energy (in 1052erg)
61- 66 F6.3 10+45J e_Eiso ? Eiso uncertainty
68- 71 F4.2 --- WAMA WAM A norm: dimensionless constant C (2)
73- 77 F5.2 --- E_WAMA Positive error in WAM A
79- 82 F4.2 --- e_WAMA Negative error in WAM A
84- 87 F4.2 --- WAMB ? WAM B norm: dimensionless constant C (2)
89- 92 F4.2 --- E_WAMB ? Positive error in WAM B
94- 97 F4.2 --- e_WAMB ? Negative error in WAM B
99-104 F6.2 --- chi2 χ2 test
106-108 I3 --- dof Degree of freedom
110-113 A4 --- Mod Model (G1)
114 A1 --- f_Mod [*] *: best-fit model (by Δχ2 test)
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Note (1):
a = Since the WAM normalization is anomalously large, we quote fit parameters
derived from the BAT data alone for this burst.
Note (2): The two-component model (Band et al., 1993ApJ...413..281B 1993ApJ...413..281B) is
defined in section 2 with β, a second photon spectral index
for the higher energy E>Ec where
Ec=(α-β)Epeak/(2+α).
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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- 7 A7 --- GRB GRB designation (YYMMDDA)
9- 13 F5.2 --- alpha Photon spectral index
15- 18 F4.2 --- e_alpha alpha uncertainty
20- 22 I3 keV Epk ? Energy peak (1)
24- 26 I3 keV E_Epk ? Positive error on Epeak
28- 30 I3 keV e_Epk ? Negative error on Epeak
31 A1 --- f_Epk [a] a: this burst has a fit Epeak from
Sakamoto, 2008ApJS..175..179S 2008ApJS..175..179S
33- 36 F4.2 --- WAMA WAM A norm: dimensionless constant C
38- 41 F4.2 --- E_WAMA Positive error in WAM A
43- 46 F4.2 --- e_WAMA Negative error in WAM A
48- 51 F4.2 --- WAMB ? WAM B norm: dimensionless constant C
53- 56 F4.2 --- E_WAMB ? Positive error in WAM B
58- 61 F4.2 --- e_WAMB ? Negative error in WAM B
63- 67 F5.2 --- chi2 χ2 test
69- 70 I2 --- dof Degrees of freedom
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Note (1): For all bursts except those noted, Epeak values are estimated from
the Sakamoto et al. (2009ApJ...693..922S 2009ApJ...693..922S) α-Epeak relation.
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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- 7 A7 --- GRB GRB designation (YYMMDDA)
9- 13 F5.2 nJ/m2 Flu1 15-150keV energy fluence (in 10-6erg/cm2)
15- 18 F4.2 nJ/m2 E_Flu1 Flu1 positive uncertainty
20- 23 F4.2 nJ/m2 e_Flu1 Flu1 negative uncertainty
25- 29 F5.1 nJ/m2 Flu2 15-2000keV energy fluence (in 10-6erg/cm2)
31- 35 F5.2 nJ/m2 E_Flu2 Flu2 positive uncertainty
37- 41 F5.2 nJ/m2 e_Flu2 Flu2 negative uncertainty
43- 47 F5.1 nJ/m2 Flu3 1-10000keV energy fluence (in 10-6erg/cm2)
49- 54 F6.2 nJ/m2 E_Flu3 Flu3 positive uncertainty
56- 61 F6.2 nJ/m2 e_Flu3 Flu3 negative uncertainty
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- GRB GRB name (YYMMDDA)
9- 16 A8 --- Seq Sequence
18- 30 A13 --- Int Interval: times are with respect to the
Swift/BAT trigger
31- 32 A2 --- f_Int [sl]
34- 38 F5.2 --- alpha Spectral photon index α
40- 43 F4.2 --- e_alpha alpha uncertainty
45- 49 F5.2 --- beta ? Spectral photon index β
51- 55 F5.2 --- E_beta ? Positive error in beta
57- 60 F4.2 --- e_beta ? Negative error in beta
62- 65 I4 keV Epk ? Energy peak
67- 70 I4 keV E_Epk ? Positive error in Epeak
72- 75 I4 keV e_Epk ? Negative error in Epeak
77- 81 F5.2 10+45J Eiso ? Isotropic energy (in 1052ergs units)
83- 87 F5.2 10+45J e_Eiso ? Eiso uncertainty
89- 94 F6.2 --- chi2 χ2 test
96- 98 I3 --- dof Degree of freedom
100-103 A4 --- Mod Model (G1)
104 A1 --- f_Mod [*] best-fit model (by the Δχ2 test)
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Ref Reference number
4- 22 A19 --- BibCode Bibcode
24- 40 A17 --- Aut First author's name
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Global notes:
Note (G1): For each time interval, joint fits were made to the BAT and WAM
data. Data were fit using xspec11.3 to a simple power-law (PL) model,
a power-law model with an exponential cutoff (CPL), and the
two-component (Band) model (Band et al. 1993ApJ...413..281B 1993ApJ...413..281B).
See section 2 for further details.
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History:
From electronic version of the journal
(End) Emmanuelle Perret [CDS] 24-Nov-2011