Sub-MeV spectroscopy with AstroSat-CZT imager for gamma ray bursts

Cadmium–Zinc–Telluride Imager (CZTI) onboard AstroSat has been a prolific Gamma-Ray Burst (GRB) monitor. While the 2-pixel Compton scattered events (100–300 keV) are used to extract sensitive spectroscopic information, inclusion of low-gain pixels ( $$\sim $$ 20 $$\%$$ detector plane) after careful calibration extends energy range spectra 600 keV. The new feature also allows single-pixel spectroscopy GRBs sub-MeV which is otherwise limited 150 We introduced noise rejection algorithm in analysis (‘Compton noise’). These additions not only enhances sensitivity CZTI, but will allow proper characterization detected by Fermi. This article describes methodology single, event and veto 100–900 keV combined for first year operation. CZTI last five years bright GRBs. methodologies, when applied on spectral this large sample GRBs, potential improve results significantly help better understanding prompt emission mechanism.