Fast Radio Bursts (FRBs) are short lived (∼ msec), energetic transients (having a peak flux density of ∼ Jy) with no known prompt emission in other energy bands. We present results of a search for prompt X-ray emissions from 41 FRBs using the Cadmium Zinc Telluride Imager (CZTI) on AstroSat which continuously monitors ∼70% of the sky. Our searches on various timescales in the 20-200 keV range, did not yield any counterparts in this hard X-ray band. We calculate upper limits on hard X-ray flux, in the same energy range and convert them to upper bounds for η: the ratio X-ray to radio fluence of FRBs. We find η≤108−10 for hard X-ray emission. Our results will help constrain the theoretical models of FRBs as the models become more quantitative and nearer, brighter FRBs are discovered.
@article{arxiv.1911.00537,
title = {Prompt X-ray emission from Fast Radio Bursts -- Upper limits with AstroSat},
author = {Akash Anumarlapudi and Varun Bhalerao and Shriharsh P. Tendulkar and Arvind Balasubramanian},
journal= {arXiv preprint arXiv:1911.00537},
year = {2021}
}