Abstract Details

Name: RAHUL GUPTA
Affiliation: ARYABHATTA RESEARCH INSTITUTE OF OBSERVATIONAL SCIENCES
Conference ID: ASI2021_215
Title : Observational properties of VHE detected GRB 180720B, GRB 190114C, and GRB 190829A
Authors and Co-Authors : Rahul Gupta, S. B. Pandey, A. J. Castro-Tirado, K. Misra, and V. Bhalerao 1. Aryabhatta Research Institute of Observational Sciences (ARIES), Manora Peak, Nainital-263002, India. 2. Aryabhatta Research Institute of Observational Sciences (ARIES), Manora Peak, Nainital-263002, India. 3. Instituto de Astrofisica de Andalucia (IAA-CSIC), Glorieta de la Astronomia s/n, E-18008, Granada, Spain. 4. Aryabhatta Research Institute of Observational Sciences (ARIES), Manora Peak, Nainital-263002, India. 5. Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
Abstract Type : Poster
Abstract Category : Extragalactic Astronomy
Abstract : Recent observations of very high energy (VHE) photons from Gamma-ray bursts (GRBs) afterglows using MAGIC and HESS telescopes has open a new window in the field of GRBs research. By now, at least three GRBs (GRB 180720B, GRB 190114C, and GRB 190829A) have confirmed VHE detections. It is still an unsolved question whether VHE detected GRBs require special environments for this VHE emission to occur at sufficient strength to be observable or whether all GRBs have VHE emission (and we missed due to the observational limitations) and it is solely related to the released GRB emission. In this work, we present the results of a detailed investigation of the prompt and afterglow emission of all three VHE detected GRBs based on multi-wavelength observations. We find some similarities between GRB 180720B and GRB 190114C, however, GRB 190829A is a peculiar low luminous burst. GRB 190829A consists of two isolated sub bursts or episodes, separated by a quiescent phase. The first episode, which has a higher spectral peak of 120 keV and low isotropic energy $10^{50}$ erg is an outlier to the Amati correlation and marginally satisfies the Yonetoku correlation. However, the energetically dominant second episode has lower peak energy and is consistent with the above correlations. We compared this GRB to other low-luminosity GRBs (LLGRBs). We also analyzed the late time Fermi-LAT emission that encapsulates the H.E.S.S. and MAGIC detection for these VHE detected GRBs. Some of the LAT photons are likely to be associated with the GRBs and they could have an Inverse Compton mechanism origin. Furthermore, our results show that teraelectronvolt-energy photons seem common in both high-luminosity GRBs and LLGRBs.