J/ApJ/727/73 High S/N composite spectrum of GRB afterglows (Christensen+, 2011)
A high signal-to-noise ratio composite spectrum of gamma-ray burst afterglows.
Christensen L., Fynbo J.P.U., Prochaska J.X., Thone C.C.,
de Ugarte Postigo A., Jakobsson P.
<Astrophys. J., 727, 73 (2011)>
=2011ApJ...727...73C 2011ApJ...727...73C
ADC_Keywords: Gamma rays ; Spectroscopy
Keywords: galaxies: high-redshift - gamma-ray burst: general
Abstract:
We present a composite spectrum of 60 long duration gamma-ray burst
(GRB) afterglows with redshifts in the range 0.35<z<6.7 observed with
low-resolution optical spectra. The composite spectrum covers the
wavelength range 700-6600Å in the rest frame and has a mean
signal-to-noise ratio of 150 per 1Å pixel and reaches a maximum of
∼300 in the range 2500-3500Å. Equivalent widths are measured from
metal absorption lines from the Lyα line to ∼5200Å, and
associated metal and hydrogen lines are identified between the Lyman
break and Lyα line. The average transmission within the Lyman
forest is consistent with that found along quasar lines of sight.
Description:
The low spectral resolution data from the sample in Fynbo et al.
(2009ApJS..185..526F 2009ApJS..185..526F) provide the basis for this present follow-up
study. From the full sample of spectra, we here focus on the 66
afterglows which were observed with low-resolution optical
spectroscopy using the following instruments: FORS1 and FORS2 on the
VLT, AlFOSC on the Nordic Optical Telescope, GMOS-N and GMOS-S on the
Gemini North and South, respectively, and finally LRIS on the Keck
Telescope. Depending on the grating or grism chosen for the
observations, these instruments provided spectra with resolutions
between 315 and 2140.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 22 5900 Weighted composite afterglow spectrum
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See also:
J/A+A/530/A21 : Spectral properties of 438 GRBs (Nava+, 2011)
J/ApJ/720/1146 : Spectral analysis of GRBs (Lu+, 2010)
J/ApJ/701/824 : Afterglows of short and long-duration GRBs (Nysewander+, 2009)
J/ApJ/686/1209 : Optical properties of GRB afterglows (Melandri+, 2008)
J/ApJS/169/62 : GRB database of spectral lags (Hakkila+, 2007)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 6 F6.1 0.1nm lambda [701/6600] Wavelength (Å)
8- 13 F6.4 --- RFlux Relative flux
15- 22 F8.4 --- e_RFlux Uncertainty in RFlux
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 27-Aug-2012