J/ApJ/731/103 Redshift catalog for Swift long GRBs (Xiao+, 2011)
Redshift catalog for Swift long gamma-ray bursts.
Xiao L., Schaefer B.E.
<Astrophys. J., 731, 103 (2011)>
=2011ApJ...731..103X 2011ApJ...731..103X
ADC_Keywords: Gamma rays ; Redshifts ; Spectroscopy
Keywords: gamma-ray burst: general
Abstract:
We present a catalog of the redshifts for most long-duration gamma-ray
bursts (GRBs) by Swift from 2004 December 20 to 2008 July 23 (258
bursts in total). All available information is collected, including
spectroscopic redshifts, photometric redshift limits, and redshifts
calculated from various luminosity relations. Error bars for the
redshifts derived from the luminosity relations are asymmetric, with
tails extended to the high-redshift end, and this effect is evaluated
by looking at the 30% of Swift bursts with spectroscopic redshifts. A
simulation is performed to eliminate this asymmetric effect, and the
resultant redshift distribution is deconvolved. We test and confirm
this simulation on the sample of bursts with known spectroscopic
redshifts and then apply it to the 70% of Swift bursts that do not
have spectroscopic measures. A final intrinsic redshift distribution
is then made for almost all Swift bursts, and the efficiency of the
spectroscopic detections is evaluated. The efficiency of spectroscopic
redshifts varies from near unity at low redshift to 0.5 at z=1, to
near 0.3 at z=4, and to 0.1 at z=6. We also find that the fraction of
GRBs with z>5 is ∼10%, and this fraction is compared with simulations
from a cosmological model.
Description:
We collect all the Swift GRBs from 2004 December 20 (GRB041220) to
2008 July 23 (GRB080723A). Most of the data are downloaded from the
Legacy ftp site (ftp://legacy.gsfc.nasa.gov/swift/data/obs).
Swift is a multi-wavelength GRB detection satellite that has three
instruments on board. The wide-field BAT, which covers a 15-150keV
energy band, can position a burst to 1'-4' accuracy. The narrow X-ray
telescope (XRT) and UV/Optical telescope (UVOT) start observing the
GRB within ∼100s after the trigger time and position it within the
arcsec level. With the analysis of the spectroscopic features (e.g.,
absorption lines) of the afterglows, redshifts of the GRBs are
measured with relatively high accuracy. We collected all the reported
spectroscopic redshift from GCN Circulars archive and the literature.
GRBs with multiple or conflicting reported redshifts are excluded from
our catalog.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 34 76 Bursts not included in our catalog
table3.dat 136 258 Luminosity indicators
table5.dat 72 263 Our redshifts and spectroscopic redshifts
refs.dat 86 282 References
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See also:
J/ApJS/195/2 : The second Swift BAT GRB catalog (BAT2) (Sakamoto+, 2011)
J/ApJ/720/1513 : The afterglows of Swift-era GRBs. I. (Kann+, 2010)
J/ApJ/690/163 : The first Swift UV-Opt GRB afterglow catalog (Roming+, 2009)
J/ApJ/704/1405 : Testing the Epeak-Eiso relation for GRBs (Krimm+, 2009)
J/ApJS/175/179 : The BAT1 gamma-ray burst catalog (Sakamoto+, 2008)
J/ApJ/642/L99 : R-band photometry of GRB 060206 (Wozniak+, 2006)
J/A+A/427/87 : List of GRBs (Gorosabel+, 2004)
http://swift.gsfc.nasa.gov/docs/swift/archive/grb_table/ : Swift GRB table
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 identification (YYMMDDA)
9- 33 A25 --- rej Rejection cause
34 A1 --- n_rej [a-e] Additional note (1)
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Note (1): Note as follows:
a = Suggested a probable Soft Gamma-Ray Repeater.
b = Possible incomplete light curve.
c = Swift BAT slew survey discovery.
d = Short-hard burst with long extended emissions.
e = Below Swift threshold.
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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 identification (YYMMDDA)
9- 13 F5.2 s tauLag ? Spectral lag
15- 18 F4.2 s e_tauLag ? Uncertainty in tauLag
20- 25 F6.3 --- Var ? Variability indicator (4)
27- 31 F5.3 --- e_Var ? Uncertainty in Var
33- 37 F5.2 s tauRT ? Minimum rise time in the light curve
39- 42 F4.2 s e_tauRT ? Uncertainty in tauRT
45 A1 --- l_Np Limit flag on Npeak
46- 47 I2 --- Np ? Number of peaks in the light curve
49- 52 I4 keV Epeak Photon energy spectrum is brightest
54- 57 I4 keV E_Epeak Upper limit uncertainty in Epeak
59- 61 I3 keV e_Epeak Lower limit uncertainty in Epeak
63 A1 --- f_Epeak [c] conservative estimation of uncertainty (1)
65- 70 F6.3 --- alpha [-5/1] The α power law index (see refs)
72- 75 F4.2 --- E_alpha ? Upper limit uncertainty in alpha
77- 80 F4.2 --- e_alpha Uncertainty in alpha (2)
82 A1 --- f_alpha [c] conservative estimation of uncertainty (1)
84- 88 F5.2 --- beta [-4/2.1] The β power law index (see refs)
90- 93 F4.2 --- E_beta ? Upper limit uncertainty in beta
95- 98 F4.2 --- e_beta Uncertainty in beta (2)
100 A1 --- f_beta [c] conservative estimation of uncertainty (1)
102-106 A5 --- refs Reference(s) for the power law indices (see
refs.dat file)
108 A1 --- l_tJet Limit flag on tJet
109-115 F7.4 d tJet ? Optical jet break time
117-122 F6.4 d e_tJet ? Uncertainty in tJet
124-125 A2 --- n_tJet Individual notes on tJet (3)
127-136 A10 --- r_tJet Reference(s) for tJet (see refs.dat file)
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Note (1): Indicates a conservative estimation of uncertainty not reported
in the original paper.
Note (2): This is a lower limit when the upper limit in the previous column
is provided otherwise it is the symmetric uncertainty.
Note (3): Flag as follows:
b = Jet break time reported from X-ray data only, not being used in
this work.
c = Multi-values for jet break reported, due to the confusing condition
of the afterglow light curve, not using any of these values in
this work.
d = Grupe et al. (2006ApJ...645..464G 2006ApJ...645..464G) shows no break between 0.4-2.5day,
with the slope of the light curve suggesting a break before 0.4day,
while both Ghirlanda et al. (2007A&A...466..127G 2007A&A...466..127G) and Campana et al.
(2007A&A...472..395C 2007A&A...472..395C) suggest a break after 2.5day, based on Ghirlanda's
relation.
e = Value obtained from Liang et al. (2008ApJ...675..528L 2008ApJ...675..528L ) figure and text,
table 4 misreported it.
f = With a pre-break slope too shallow for the forward shock model, not
being used as a jet break time.
g = Only one post-break data reported.
h = Optical break not restrictive.
i = Break not detected in X-ray data.
j = Optical data confusing, not able to make decision where the
jet break lies.
k = Only taking R band jet break, as later data is lacked in V band.
Note (4): the variability indicator V measures whether a light curve
is spiky (large V) or smooth; see Fennimore and Ramirez-Ruiz 2000,
0004176
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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 identification (YYMMDDA)
9 A1 --- l_zsp Limit flag on zsp
11- 16 F6.3 --- zsp ? Spectroscopic redshift
18- 20 F3.1 --- e_zsp ? Uncertainty in zsp
22- 24 A3 --- r_zsp Reference for zsp (see refs.dat file)
26 A1 --- l_zbest Limit flag on zbest
28- 33 F6.3 --- zbest ? Best estimated redshift
35- 38 F4.2 --- e_zbest ? The 1σ lower limit on zbest
40- 45 F6.3 --- E_zbest ? The 1σ upper limit on zbest
47- 50 F4.2 --- zph ? Upper limit from photometric redshift
52- 60 A9 --- r_zph Reference for zph (see refs.dat file)
62 A1 --- l_z Limit flag on z
64- 68 F5.2 --- z Final redshift
70- 72 F3.1 --- e_z ? Uncertainty in z
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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- 4 A4 --- Ref Reference code
6- 24 A19 --- BibCode Bibcode
26- 49 A24 --- Aut Author's name(s)
51- 86 A36 --- Comm Comment
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 22-Oct-2012