Yu 2007 Shallow decay阶段的高能辐射

主要内容:
依然用星风泡作为能量注入方式，考虑逆康普顿散射，会产生大量的高能辐射。

精彩摘抄:


文章信息:

arXiv:0706.3741 [ps, pdf, other]

Title: Observational Signatures of High-Energy Emission during the Shallow Decay Phase of GRB X-Ray Afterglows

Authors: Y. W. Yu, X. W. Liu, Z. G. Dai

Comments: 21 pages, 7 figures

Subjects: Astrophysics (astro-ph)

The widely existing shallow decay phase of the X-ray afterglows of gamma-ray bursts (GRBs) is generally accepted to be due to long-lasting energy injection. The outflows carrying the injecting energy, based on their composition, could correspond to two types: baryon-dominated and lepton-dominated ones. The former-type outflows could be lagging materials in a wide GRB ejecta with a radial distribution of Lorentz factor, while the latter could be an electron-positron-pair wind that is driven by the post-burst central engine. We here provide a unified description for the dynamics of the two models of energy injection, and calculate the corresponding high-energy photon emission by considering the synchrotron radiation and inverse Compton scattering (including synchrotron self-Compton and combined inverse-Compton). We find that, for both models, there is a plateau (even a hump) in high-energy light curves during the X-ray shallow decay phase. In particular, a considerable fraction of the injecting energy in the leptonic-component-dominated model can be shared by the long-lasting reverse shock since it is relativistic. Furthermore, almost all of the energy of the reverse shock is carried by leptons and thus enhances the inverse-Compton emission dramatically. Therefore, this model predicts more significant high-energy afterglow emission than the baryonic-component-dominated model. We argue that these observational signatures would be used to discriminate between different energy-injection models in the upcoming {\em Gamma-ray Large Area Space Telescope} (GLAST) era.