2009/02/16 by Rongrong Xue, R.-R. Xue, Yizhong Fan +3 · 1 citation
Physics and Astronomy · #Afterglow #Astronomy and Astrophysical Research #Astrophysics and Cosmic Phenomena #Gamma-ray burst #Gamma-ray bursts and supernovae #Interstellar medium #Light curve #Lorentz factor #Lorentz transformation #Shock (circulatory) #astro-ph.HE
paper · pdf · doi:10.1051/0004-6361/200811361
6 pages,1 figure,3 tables,accepted for publication in Astronomy & Astrophysics
arxiv created 2009/02/16 · openalex publication_date 2009/03/19 · arxiv updated 2015/05/12 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
<i>Aims. <i/>We intend to determine the type of circumburst medium and directly measure the initial Lorentz factor of GRB outflows.<i>Methods. <i/>If the early X-ray afterglow light curve has a peak and the whole profile across the peak is consistent with the standard external shock model, the early rise profile of light curves can be used to differentiate whether the burst was born in the interstellar medium (ISM) or in a stellar wind. In the thin shell case related to a subrelativistic reverse shock, the peak time occurring after the end of the prompt emission can be used to derive an accurate , especially for the ISM case. The afterglow light curves for a flat electron spectrum have been derived analytically.<i>Results. <i/>In our GRB sample, we obtained for the bursts born in ISM. We did not find any good case for bursts born in stellar wind and behaving as a thin shell that can be used to constrain reliably.