J/ApJ/686/1209 Optical properties of GRB afterglows (Melandri+, 2008)
The early-time optical properties of gamma-ray burst afterglows.
Melandri A., Mundell C.G., Kobayashi S., Guidorzi C., Gomboc A.,
Steele I.A., Smith R.J., Bersier D., Mottram C.J., Carter D., Bode M.F.,
O'Brien P.T., Tanvir N.R., Rol E., Chapman R.
<Astrophys. J., 686, 1209-1230 (2008)>
=2008ApJ...686.1209M 2008ApJ...686.1209M
ADC_Keywords: Gamma rays - Photometry, RI
Keywords: gamma rays: bursts
Abstract:
We present a multiwavelength analysis of 63 gamma-ray bursts observed
with the world's three largest robotic optical telescopes, the
Liverpool and Faulkes Telescopes (North and South). Optical emission
was detected for 24 GRBs with brightnesses ranging from R=10 to 22mag
in the first 10 minutes after the burst. By comparing optical and
X-ray light curves from t=100 to ∼106 seconds, we introduce four main
classes, defined by the presence or absence of temporal breaks at
optical and/or X-ray wavelengths. While 14/24 GRBs can be modeled with
the forward-shock model, explaining the remaining 10 is very
challenging in the standard framework even with the introduction of
energy injection or an ambient density gradient. Early X-ray
afterglows, even segments of light curves described by a power law,
may be due to additional emission from the central engine. Thirty-nine
GRBs in our sample were not detected and have deep upper limits
(R<22mag) at early time. Of these, only 10 were identified by other
facilities, primarily at near infrared wavelengths, resulting in a
dark burst fraction of ∼50%. Additional emission in the early-time
X-ray afterglow due to late-time central engine activity may also
explain some dark bursts by making the bursts brighter than expected
in the X-ray band compared to the optical band.
Description:
The sample was observed with the network of three 2m telescopes
RoboNet-1.0, formed by the Liverpool Telescope (LT, Canary Islands),
the Faulkes Telescope North (FTN; Haleakala, Hawaii), and the Faulkes
Telescope South (FTS; Siding Spring, Australia). Up to 2007 September
the network robotically reacted to 63 GRBs with 24 optical afterglow
detections and 39 upper limits. In this paper the optical photometry
of each optical afterglow was performed using Starlink GAIA photometry
tools.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 51 224 Optical photometry in the R-band of GRB afterglows
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See also:
J/ApJ/626/L5 : Photometric observations of GRB 041006 (Stanek+, 2005)
J/ApJ/642/L99 : R-band photometry of GRB 060206 (Wozniak+, 2006)
J/ApJ/654/L21 : R-band light curves of GRB 060206 and GRB 060210 (Stanek+,
2007)
J/ApJ/672/449 : GRB 061126 light curves (Perley+, 2008)
http://www.astro.livjm.ac.uk/RoboNet : Index of RoboNet
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- GRB GRB identification (1)
13- 20 F8.3 min Dt Mean time from the burst event
22- 28 F7.3 min Exp Total exposure time
30- 38 A9 --- Filter Filter (SDSS-R or Bessel-R)
40- 45 F6.3 mag Rcmag Rc band magnitude (2)
47- 51 F5.3 mag e_Rcmag 1-σ error in Rcmag
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Note (1): References for data published in previous papers, as follows:
GRB 050502A = Guidorzi, C., et al. 2005ApJ...630L.121G 2005ApJ...630L.121G
GRB 050713A = Guetta, D., et al. 2007A&A...461...95G 2007A&A...461...95G
GRB 050730 = Pandey, S. B., et al. 2006A&A...460..415P 2006A&A...460..415P
GRB 051111 = Guidorzi, C., et al. 2007A&A...463..539G 2007A&A...463..539G
GRB 060108 = Oates, S., et al. 2006MNRAS.372..327O 2006MNRAS.372..327O
GRB 060206 = Monfardini, A., et al. 2006ApJ...648.1125M 2006ApJ...648.1125M
GRB 060210 = Curran, P., et al. 2007A&A...467.1049C 2007A&A...467.1049C
GRB 060927 = Ruiz-Velasco, A. E., et al. 2007ApJ...669....1R 2007ApJ...669....1R
GRB 061007 = Mundell, C., et al. 2007ApJ...660..489M 2007ApJ...660..489M
GRB 061121 = Page, K., et al. 2007ApJ...663.1125P 2007ApJ...663.1125P
Note (2): Magnitude are not corrected for Galactic extinction.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 06-Jan-2011