Hostname: page-component-7c8c6479df-24hb2 Total loading time: 0 Render date: 2024-03-19T09:43:33.671Z Has data issue: false hasContentIssue false

An intrinsic correlation between GRB optical/UV afterglow brightness and decay rate

Published online by Cambridge University Press:  22 July 2013

S.R. Oates
Affiliation:
Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking Surrey, RH5 6NT, UK;. e-mail: sro@mssl.ucl.ac.uk
M.J. Page
Affiliation:
Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking Surrey, RH5 6NT, UK;. e-mail: sro@mssl.ucl.ac.uk
M. De Pasquale
Affiliation:
University of Nevada, Las Vegas, Department of Physics & Astronomy, Box 454002, 4505 Maryland Parkway, Las Vegas, NV 89154-4002, USA
P. Schady
Affiliation:
Max-Planck-Institut für Extraterrestrische Physik, Giessenbachstraße 1, 85748 Garching, Germany
A.A. Breeveld
Affiliation:
Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking Surrey, RH5 6NT, UK;. e-mail: sro@mssl.ucl.ac.uk
S.T. Holland
Affiliation:
Space Telescope Science Center, 3700 San Martin Dr., Baltimore, MD 21218, USA
N.P.M. Kuin
Affiliation:
Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking Surrey, RH5 6NT, UK;. e-mail: sro@mssl.ucl.ac.uk
F.E. Marshall
Affiliation:
Astrophysics Science Division, Code 660.1, NASA Goddard Space Flight Centre, 8800 Greenbelt Road, Greenbelt, Maryland 20771, USA
Get access

Abstract

We examine 48 Swift/UVOT long Gamma-ray Burst light curves and find a correlation between the logarithmic luminosity at 200 s and average decay rate determined from 200 s onwards, with a Spearman rank coefficient of −0.58 at a significance of 99.998% (4.2σ). We determine the log L200s − α > 200s correlation to be intrinsic and discuss two possible causes: there is a property of the central engine, outflow or external medium that effects the rate of energy release so that the bright afterglows release their energy more quickly and decay faster than the fainter afterglows; alternatively, the observers viewing angle may produce the correlation, with observers at large viewing angles observing fainter and slower decaying light curves.

Type
Research Article
Copyright
© EAS, EDP Sciences 2013

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Kendall, M., & Stuart, A., 1979, The advanced theory of statistics, Vol. 2, Inference and relationship
Oates, S.R., Page, M.J., Schady, P., et al., 2009, MNRAS, 395, 490 CrossRef
Panaitescu, A., & Vestrand, W.T., 2008, MNRAS, 387, 497 CrossRef
Roming, P.W.A., Koch, T.S., Oates, S.R., et al., 2013, in preparation
Zhang, B., Fan, Y., Dyks, J., et al., 2006, ApJ, 642, 354 CrossRef