J/ApJ/693/1484 Early optical afterglow catalog (Cenko+, 2009)
Dark bursts in the Swift era: the Palomar 60 Inch-Swift early optical afterglow
catalog.
Cenko S.B., Kelemen J., Harrison F.A., Fox D.B., Kulkarni S.R.,
Kasliwal M.M., Ofek E.O., Rau A., Gal-Yam A., Frail D.A., Moon D.-S.
<Astrophys. J., 693, 1484-1493 (2009)>
=2009ApJ...693.1484C 2009ApJ...693.1484C (SIMBAD/NED BibCode)
ADC_Keywords: Gamma rays ; Photometry, RI ; Photometry, ugriz ; X-ray sources
Keywords: gamma rays: bursts
Abstract:
We present multicolor optical observations of long-duration
γ-ray bursts (GRBs) made over a three-year period with the
robotic Palomar 60 inch telescope (P60). Our sample consists of all 29
events discovered by Swift for which P60 began observations less than
1hr after the burst trigger. We were able to recover 80% of the
optical afterglows from this prompt sample, and we attribute this high
efficiency to our red coverage. Like Melandri et al. (2008, Cat.
J/ApJ/686/1209), we find that a significant fraction (∼50%) of Swift
events show a suppression of the optical flux with regard to the X-ray
emission (the so-called "dark" bursts). Our multicolor photometry
demonstrates this is likely due in large part to extinction in the
host galaxy. We argue that previous studies, by selecting only the
brightest and best-sampled optical afterglows, have significantly
underestimated the amount of dust present in typical GRB environments.
Description:
The P60-Swift early optical afterglow catalog is shown in Table 1.
Here, we have included all optical afterglows of events localized by
Swift in the three year period from 2005 April 1-2008 March 31
(roughly coinciding with the beginning of real-time GRB alerts and
narrow-field instrument follow up) for which we began P60 observations
within 1hr after the BAT trigger.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 65 878 P60-Swift early optical afterglow catalog
table3.dat 127 29 P60-Swift early optical afterglow sample
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See also:
J/ApJ/690/163 : The first Swift UV-Opt GRB afterglow catalog (Roming+, 2009)
J/MNRAS/397/1177 : Swift-XRT observations of GRBs (Evans+, 2009)
J/ApJ/686/1209 : Optical properties of GRB afterglows (Melandri+, 2008)
J/ApJ/654/L21 : R-band light curves of GRB 060206 and GRB 060210 (Stanek+,
2007)
J/AJ/133/1027 : Positions for 179 Swift X-ray afterglows (Butler+, 2007)
J/A+A/448/L9 : Position catalogue of Swift XRT afterglows (Moretti+, 2006)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- --- [GRB]
4- 10 A7 --- GRB GRB name (YYMMDDA)
12 A1 --- r_GRB Reference flag on GRB (1)
14- 28 A15 "datime" ObsDate Date of observation in "YYYY/MM/DD.DDDD" format
UT at beginning of exposure
30- 39 E10.4 s Time Time since burst (2)
41- 42 A2 --- Filt Filter used in observation (Ic,Rc,g,i,i',z,z')
46- 51 F6.1 s Exp Exposure time
53 A1 --- l_mag Limit flag on mag
54- 58 F5.2 mag mag Observed magnitude
60- 63 F4.2 mag e_mag ? Error in mag
65 A1 --- r_mag Reference for mag (3)
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Note (1): References as follows:
d = Soderberg et al. (2007ApJ...661..982S 2007ApJ...661..982S)
e = Cenko et al. (2006ApJ...652..490C 2006ApJ...652..490C);
f = Perley et al. (2008ApJ...688..470P 2008ApJ...688..470P).
Note (2): Time from mid-point of exposure to Swift-BAT trigger.
Note (3): References as follows:
1 = SDSS (Cat. II/294);
2 = ftp.aavso.org (American Association of Variable Star Observers);
3 = USNO-B1 (Monet et al. , 2003, Cat. I/284);
4 = Perley et al. (2008ApJ...688..470P 2008ApJ...688..470P);
5 = Covino et al. (2008MNRAS.388..347C 2008MNRAS.388..347C).
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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 name (YYMMDDA)
8 A1 --- f_GRB [fg] Flag on object (1)
10- 12 A3 --- P60OT? [Yes/No ] Optical transient observed with the
Palomar 60 inch telescope (P60)
14- 16 A3 --- Ref Other reference for Optical or IR transient (2)
18- 24 F7.5 --- z ? Redshift
25 A1 --- r_z Redshift reference (3)
27- 31 F5.2 --- alpha1 ? Spectral decay indice α (4)
33- 36 F4.2 --- E_alpha1 ? Positive error on alpha1
38- 41 F4.2 --- e_alpha1 ? Negative error on alpha1
43- 47 F5.3 --- alpha2 ? Spectral decay indice α (4)
49- 53 F5.3 --- E_alpha2 ? Positive error on alpha2
55- 59 F5.3 --- e_alpha2 ? Negative error on alpha2
61- 66 F6.3 ks tb ? Burst trigger time (4)
68- 73 F6.3 ks E_tb ? Positive error on tb
75- 79 F5.3 ks e_tb ? Negative error on tb
81- 85 F5.2 --- betaO ? Spectral decay indice β (4)
87- 90 F4.2 --- E_betaO ? Positive error on betaO
92- 95 F4.2 --- e_betaO ? Negative error on betaO
97-100 F4.2 --- chi2 ? Best fit χ2 (4)
102-104 I3 --- dof ? Degree of Freedom (4)
106 A1 --- l_betaOX Limit flag on betaOX
107-111 F5.2 --- betaOX Optical-to-X-ray spectral index (5)
113 A1 --- l_AV Limit flag on AV
114-117 F4.2 mag AV ? Host extinction (6)
119-122 F4.2 mag E_AV ? Positive error on AV
124-127 F4.2 mag e_AV ? Negative error on AV
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Note (1): Flags as follows:
f = The optical light curve of GRB 050820A consists of many power-law
segments. See Cenko et al. (2006ApJ...652..490C 2006ApJ...652..490C) for details.
g = The optical light curve of GRB 060906 is not well described by either
a single or broken power-law. The spectral index was calculated over
only a small period of relatively flat evolution (t>104s).
Note (2): Optical (OT) and Infrared (IRT) transient references as follows:
GRB 050607 = Rhoads (2005GCN..3527....1R 2005GCN..3527....1R);
GRB 050915A = Bloom & Alatalo (2005GCN..3984....1B 2005GCN..3984....1B);
GRB 060923A = Tanvir et al. (2006GCN..5587....1T 2006GCN..5587....1T);
GRB 061222A = Cenko & Fox (2006GCN..5975....1C 2006GCN..5975....1C).
Note (3): Redshift reference as follows:
h = Soderberg et al. (2007ApJ...661..982S 2007ApJ...661..982S);
i = Prochaska et al. (2007ApJS..168..231P 2007ApJS..168..231P);
j = Fugazza et al. (2005GCN..3948....1F 2005GCN..3948....1F);
k = Cucchiara et al. (2006GCN..4729....1C 2006GCN..4729....1C);
l = Cucchiara et al. (2006GCN..5052....1C 2006GCN..5052....1C);
m = Price et al. (2007ApJ...663L..57P 2007ApJ...663L..57P);
n = Jakobsson et al. (2006A&A...460L..13J 2006A&A...460L..13J);
o = Rol et al. (2006GCN..5555....1R 2006GCN..5555....1R);
p = Cucchiara et al. (2007GCN..6083....1C 2007GCN..6083....1C);
q = Cenko et al. (2007GCN..6322....1C 2007GCN..6322....1C);
r = Perley et al. (2008ApJ...688..470P 2008ApJ...688..470P);
s = Jakobsson et al. (2007GCN..6952....1J 2007GCN..6952....1J);
t = Cucchiara et al. (2007GCN..7124....1C 2007GCN..7124....1C);
u = Prochaska et al. (2008GCN..7388....1P 2008GCN..7388....1P);
v = Vreeswijk et al. (2008GCN..7444....1V 2008GCN..7444....1V);
w = Wiersema et al. (2008GCN..7517....1W 2008GCN..7517....1W)
Note (4): We fitted the flux density to a single or broken power-law model
of the form Fν=t-α.ν-β.
Note (5): The optical-to-X-ray spectral index, measured at t=103s.
See section 3.4.
Note (6): We fitted for the host galaxy reddening by fixing the spectral
index to β=0.6 and assuming an SMC-like extinction law (Pei,
1992ApJ...395..130P 1992ApJ...395..130P).
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 15-Mar-2011