Physical Processes Shaping Gamma‐Ray Burst X‐Ray Afterglow Light Curves: Theoretical Implications from theSwiftX‐Ray Telescope Observations

The Synchrotron-self-Compton Radiation Accompanying Shallow Decaying X-Ray Afterglow: the Case of GRB 940217

“…Then, there is only one choice -the shock parameters should evolve with time. If we take q ∼ 0.5 (which is suggested by the recent Swift XRT data, see Zhang et al 2006), a ∼ 1, b ∼ 0, then the flux would be nearly a constant, which is agreement with the observation.…”

“…However, there are increasing evidences that the shock energy may increase with time during some period. One good example is the discovery of the "shallow decay phase" in the early X-ray light curves of many GRBs, which is usually attributed to the energy injection (Zhang et al 2006;Nousek et al 2006). Now we consider the case that there is significant continuous energy injection into the fireball, so the fireball decelerates less rapidly and the afterglow emission will show a shallow decline.…”

“…Now we consider the case that there is significant continuous energy injection into the fireball, so the fireball decelerates less rapidly and the afterglow emission will show a shallow decline. The dynamical evolution and the synchrotron radiation signature for energy injection have been discussed by many authors (Rees & Mészáros 1998;Dai & Lu 1998;Cohen & Piran 1999;Zhang & Mészáros 2001a;Zhang et al 2006;Nousek et al 2006;Fan & Xu 2006). …”

“…The successful launch of the Swift satellite did open a new window to reveal what happens in the early GRB afterglow phase. As summarized in Zhang et al (2006) and Nousek et al (2006), in a canonical Swift GRB X-ray afterglow lightcurve some interesting features are emerging, including the very early sharp decline (i.e., phase-I), a shallow decline of the X-ray afterglow (i.e., phase-II), and the energetic X-ray flares (i.e., phase-V). The interpretation and the implication of these features have been discussed in great detail (see Mészáros 2006;Piran & Fan 2007;Zhang 2007 for recent reviews).…”

“…The interpretation and the implication of these features have been discussed in great detail (see Mészáros 2006;Piran & Fan 2007;Zhang 2007 for recent reviews). For Phase-II, which interests us here, a widely considered explanation is a significant energy injection dE inj /dt ∝ t −q (see Zhang et al 2006 andNousek et al 2006 and the references therein). However, the energy injection process, if there is, seems to be not all the story.…”