CaltechAUTHORS
Published August 20, 2008 | Version Published
Journal Article Open

A comprehensive study of GRB 070125, a most energetic gamma-ray burst

Creators

  • 1. ROR icon National Radio Astronomy Observatory
  • 2. ROR icon University of Virginia
  • 3. ROR icon California Institute of Technology
  • 4. ROR icon University of Bonn
  • 5. ROR icon Pennsylvania State University
  • 6. ROR icon University of Hawaii at Manoa
  • 7. ROR icon Princeton University
  • 8. ROR icon Carnegie Institution for Science
  • 9. ROR icon Weizmann Institute of Science
  • 10. ROR icon Mount Stromlo Observatory
  • 11. ROR icon Australian National University
  • 12. ROR icon Pomona College

Abstract

We present a comprehensive multiwavelength analysis of the bright, long-duration gamma-ray burst GRB 070125, comprised of observations in gamma-ray, X-ray, optical, millimeter, and centimeter wave bands. Simultaneous fits to the optical and X-ray light curves favor a break on day 3.78, which we interpret as the jet break from a collimated outflow. Independent fits to optical and X-ray bands give similar results in the optical bands but shift the jet break to around day 10 in the X-ray light curve. We show that for the physical parameters derived for GRB 070125, inverse Compton scattering effects are important throughout the afterglow evolution. While inverse Compton scattering does not affect radio and optical bands, it may be a promising candidate to delay the jet break in the X-ray band. Radio light curves show rapid flux variations, which are interpreted as due to interstellar scintillation and used to derive an upper limit of 2.4 × 10^(17) cm on the radius of the fireball in the lateral expansion phase of the jet. Radio light curves and spectra suggest a high synchrotron self-absorption frequency indicative of the afterglow shock wave moving in a dense medium. Our broadband modeling favors a constant density profile for the circumburst medium over a windlike profile (R^(−2)). However, keeping in mind the uncertainty of the parameters, it is difficult to unambiguously distinguish between the two density profiles. Our broadband fits suggest that GRB 070125 is a burst with high radiative efficiency (>60%).

Additional Information

© 2008 American Astronomical Society. Received 2008 January 18, accepted for publication 2008 April 30. Print publication: Issue 2 (2008 August 20). P. C. thanks the VLA staff for making radio observations, without which this work was not possible. P. C. is a Jansky Fellow at the National Radio Astronomy Observatory. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. We thank Sarah Yost for providing us with the GRB broadband modeling code and helping out in running the code. P. C. used the fussy calculator (http://fussy.googlecode.com) for error propagation calculations and wishes to thank its author, Sanjay Bhantagar. R. A. C. was supported in part by NASA grant NNG06GJ33G.

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Additional details

Identifiers

Eprint ID
14414
Resolver ID
CaltechAUTHORS:20090618-204832185

Funding

NASA
NNG06GJ33G
National Radio Astronomy Observatory
NSF

Dates

Created
2009-08-12
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Updated
2021-11-08
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Caltech Custom Metadata

Caltech groups
Space Radiation Laboratory, Division of Geological and Planetary Sciences (GPS)