| Name: Arushi Kumar |
| Affiliation: Indian Institute of Space Science and Technology Thiruvananthapuram |
| Conference ID: ASI2026_702 |
| Title: Dust scattering of X-ray photons from Gamma ray bursts |
| Abstract Type: Poster |
| Abstract Category: High Energy Phenomena, Fundamental Physics and Astronomy |
| Author(s) and Co-Author(s) with Affiliation: Arushi Kumar(Indian Institute of Space Science and Technology, Thiruvananthapuram), L. Resmi(Indian Institute of Space Science and Technology, Thiruvananthapuram) |
| Abstract: Gamma-ray bursts (GRBs) are among the most energetic events in the universe. A longer-lasting and multi-wavelength afterglow follows the initial intense and highly energetic emissions in X-rays and gamma rays. When dust lies close to the progenitor, some of the prompt X-ray photons do not travel directly but instead scatter off dust grains before reaching the observer. These scattered X-ray prompt photons reach the observer with a time delay during the afterglow phase. In certain cases, this phenomenon may explain the shape of the observed X-ray afterglow light curves and the softening of the observed spectrum. Studying these effects can provide insights into both the GRB and its surrounding environment.
In this work, we applied a simple dust scattering model to study how different physical conditions affect the scattered emission. We focused on five key parameters: the distance R of the dust layer from the progenitor, the power-law index q describing the dust grain size distribution, the maximum grain size a+, the minimum grain size a-, and the scattering optical depth. We sampled the parameter space and produced synthetic light curves and spectra, to understand the role of the parameters in shaping the light curves and the spectral evolution.
Using the detector response matrix of the Swift XRT, we estimated the parameter ranges that would yield observable dust-scattered emission during the afterglow phase, with particular emphasis on R, the distance of the dust layer from the progenitor. We compare these ranges with the expected distances of dust shells around Wolf-Rayet stars, the most likely progenitors of GRBs. |
