ArXiv HighEng

Gamma-Ray Burst (GRB)

 * The power-law temporal decays displayed by the radio, optical, and X-ray ﬂuxes of GRB afterglows ($F_{\nu}\prop t^{-{\alpha}}$) have provided strong support for the prediction (Meszaros & Rees 1997) that afterglows arise from the relativistic blast-wave generated as the GRB outﬂow ejecta interacts with the ambient medium.
 * If the GRB outﬂow is a collimated jet then a break in the smooth power-law decay of the afterglow is expected for both either a conical jet (Panaitescu, Meszaros & Rees 1998) or a sideways-spreading jet (by Rhoads 1999).

X-ray Binary

 * Vela X-1 (4U 0900-40) is a an eclipsing and persistently active high mass X-ray binary (HMXB) system consisting of a massive (23M⊙; 34R⊙) B0.5 1b supergiant HD 77581 (Brucato & Kristian 1972; Nagase 1989); and a 1.77M⊙ neutron star (Rawls et al. 2011). It has an orbital period of 8.964 days (van Kerkwijk et al. 1995) with a slightly eccentric orbit (e~0.1). Being a closely spaced binary system (Quaintrell et al. 2003), the neutron star is deeply embedded in the strong stellar wind of the companion. [arXiv:1212.1538]
 * A prototype candidate for accretion via stellar wind
 * It exhibits pulsations with a period 283 s