AstroSat-CZTI as a hard X-ray pulsar monitor

The Cadmium–Zinc–Telluride Imager (CZTI) is an imaging instrument onboard AstroSat. This instrument operates as a nearly open all-sky detector above 60 keV, making possible long integrations irrespective of the spacecraft pointing. We present a technique based on the AstroSat-CZTI data to explore the hard X-ray characteristics of the γ-ray pulsar population. We report highly significant (∼30σ) detection of hard X-ray (60–380 keV) pulse profile of the Crab pulsar using ∼5000 ks of CZTI observations within 5 to 70 ∘ of Crab position in the sky, using a custom algorithm developed by us. Using Crab as our test source, we estimate the off-axis sensitivity of the instrument and establish AstroSat-CZTI as a prospective tool in investigating hard X-ray characteristics of γ-ray pulsars as faint as 10 mCrab.