Observational Aspects of Gamma-ray Burst Afterglows

Abstract

For our understanding of the physics of GRB explosions as well as their implications on star formation and cosmology, it is crucial to observe the luminous afterglow emission. Optical/nearinfrared afterglow observations provide accurate physical scales to GRBs, and allow us to put constraints on the properties of the ultra-relativistic outflow. In the recent years, systematic follow-up campaigns have led to an increasing sample of high-quality afterglow light-curves, multi-wavelength SEDs and spectra. This new data shed light on the properties of the complete population of long GRBs, including those events that previously have escaped detection. I will give an overview of the state-of-the-art of the field and highlight new observational results.

Giant X-Ray Bump in GRB 121027a: Evidence for Fall-Back Disk Accretion

“…The redshift of this burst is provisionally implied to be z ∼ 1.77 by Gemini South spectroscopic observation, assuming the significant absorption feature at 7770Å in the optical spectrum as the MgII doublet 2796/2803Å (Tanvir et al 2012). It is later confirmed and accurately measured to be z = 1.773 by identifying several metal absorption lines with the X-shooter spectragraph (Kruehler et al 2012). The results of data analysis of the prompt BAT observation are as follows (Barthelmy et al 2012).…”

Variability of the giant X-ray bump in GRB 121027A and its possible origin

“…It is one of the typical ultra-long GRBs (e.g., Peng et al 2013;Levan et al 2014). The redshift was about 1.773 (Tanvir et al 2012;Kruehler et al 2012). Figure 1 shows the Swift/XRT lightcurve, in which the data is downloaded from the UK Swift Science Data Centre at the University of Leicester (Evans et al 2007(Evans et al , 2009.…”