Image credit: Samuele Ronchini

The origin of early gamma-ray radiation in gamma‑ray bursts (GRBs) is still highly debated. Our knowledge is based on the wide field telescopes operational in the range of 10 keV-10 MeV. However, at higher energies (above 100 GeV), it is challenging to catch the early emission due to the slew of the telescope. I will discuss the multi-messenger observational strategies focused on detecting the early VHE emission from compact binary mergers in the era of the third-generation gravitational wave detectors Einstein Telescope (ET) and Cosmic Explorer (CE).  Thanks to the proposed unprecedented low-frequency sensitivity, it is possible to detect and localize gravitational wave events in the inspiral phase and use the detection as an early warning alert for EM facilities. I will discuss the physical processes responsible for obtaining the VHE counterparts through the synchrotron self Compton model in the leptonic scenario, the high energy tail of the hadronic GRB model as well as external inverse Compton emission as viable candidates in the energy band of 10 GeV - 10 TeV. I will also briefly discuss the recent discovery of the GeV component from a compact binary merger, GRB 211211A, and how it boosted the possibility of having GeV to sub-TeV emission from these objects.

Breve CV del Dr. Biswajit Banerjee:

He is a postdoctoral researcher at Gran Sasso Science Institute, L’Aquila in the Gravity and Cosmology group. He is a member of the LIGO-VIRGO-KAGRA collaboration and an associate member of the MAGIC collaboration. His main research interest aligns with the hunt for the electromagnetic counterpart of gravitational waves. He led the analysis of the HE gamma-ray data from LAT from the source GRB 211211A, which was established as the first ever long GRB associated with a kilonova.