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Even after more than fifty years of the discovery of gamma-ray bursts, the production of the early phase of emission is still highly debated. Our knowledge so far is acquired from the wide field of view gamma‑ray instruments in the range of 10 keV-10 MeV. However, at the high-energy/very-high-energy gamma rays (above 100 GeV), it is challenging to catch these events in action. I will discuss the multi-messenger observational strategies to detect the early emission of short GRBs at very-high-energies (VHE; E > 30 GeV) in the era of the third-generation gravitational wave detectors Einstein Telescope (ET) and Cosmic Explorer (CE) and the synergy with Cherenkov Telescope Array (CTA). I will present the GW simulation tool developed in GSSI, GWFISH that enables us to evaluate the detection and parameter estimation capabilities of GW detectors. I will discuss the unprecedented low-frequency sensitivity of ET that will allow us to detect and localize gravitational wave events in the inspiral phase of the compact binaries and provide pre-merger alerts for the upcoming short GRBs. I will discuss possible VHE components from the synchrotron self Compton components in the leptonic GRB model, 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 briefly touch upon our recent discovery of the GeV component from a compact binary merger that boosted the possibility of having GeV to sub-TeV emission from compact binary merging events. I will briefly discuss our ongoing project on detecting the newly discovered GeV counterparts of binary neutron stars/ neutron star black-hole mergers from past LIGO-VIRGO-KAGRA runs. |