English

Observations and Theoretical Implications of GRB 970228

Astrophysics 2009-10-30 v3

Abstract

GRB 970228 is the first gamma ray burst for which prolonged post-burst transient x-ray, optical, and infrared emission has been detected. Recent Hubble Space Telescope observations show that the transient consists of two components: a point source, which is known to be fading, and an extended source, which is possibly fading. I fit standard fireball remnant models to the first month of x-ray, optical, and infrared measurements, which may be done without assuming a GRB distance scale. I show that its emission is consistent with that of the remnant of a relativistically expanding impulsive fireball in which a forward shock dominates the emission of the GRB event: the piston model. However, two discrepant measurements may indicate that the post-burst flux varies by factors of approximately 3 on timescales of days or weeks. Furthermore, using the HST observations and the fitted model, I show that the extended object probably is fading, which may place GRB 970228 at galactic halo distances.

Keywords

Cite

@article{arxiv.astro-ph/9704198,
  title  = {Observations and Theoretical Implications of GRB 970228},
  author = {Daniel E. Reichart},
  journal= {arXiv preprint arXiv:astro-ph/9704198},
  year   = {2009}
}

Comments

Accepted to the Astrophysical Journal Letters, 11 pages, LaTeX