| Name: AYUSH GARG |
| Affiliation: Indian Institute of Technology, Indore |
| Conference ID: ASI2026_114 |
| Title: Time-resolved Spectroscopic study of Ultra-long GRBs |
| Abstract Type: Poster |
| Abstract Category: High Energy Phenomena, Fundamental Physics and Astronomy |
| Author(s) and Co-Author(s) with Affiliation: AYUSH GARG(Indian Institute of Technology, Indore), Dr. Amit Shukla(Indian Institute of Technology, Indore), Dr. Dorottya Szecsi(Nicolaus Copernicus University, Toruń, Poland) |
| Abstract: The ultra-relativistic, highly collimated jets generated by Gamma-Ray Bursts (GRBs) provide crucial insights into particle emission. These jets also reveal the physical mechanisms driving the rapid release of high-energy gamma-ray photons. We discuss time-resolved spectroscopy and flux variability for the ultra-long GRB 220627A. We are also comparing the time-resolved spectroscopy for three different ultra-long GRBs observed by Fermi-GBM/LAT. For each ultra-long GRB, there are two different episodes observed by Fermi and other satellites, which are hundreds of seconds apart from each other. Using time-resolved spectroscopy, we can comment on the spectral contributions from different time-resolved flares in both the temporal and spectral domains. Due to its unique characteristics, GRB 220627A serves as an excellent source for studying particle emission processes, small-scale variability, and the properties of its central engine. To investigate the gravitational lensing of GRB 220627A, the time bins of the first episode were correlated with those of the second episode. A coherent relationship was observed between flux and photon spectral distribution. This relationship was modelled using an exponentially cut-off power law model for both episodes. The discrepancy in MeV-to-GeV fluence detection by LAT further rules out gravitational lensing but suggests that the progenitor is undergoing a burst that evolves into an ultra-long GRB with two episodes. Isotropic energy, spectral signatures, and burst duration parameters for GRB 220627A align with the established limits for a blue supergiant progenitor, as described in the literature. |
