Abstract Details

Name: Santosh Vadawale
Affiliation: Physical Research Laboratory
Conference ID: ASI2017_1031
Title : Hard X-ray Polarimetry with AstroSat CZTI
Authors and Co-Authors : S. V. Vadawale(1), A. R. Rao(2), D. Bhattacharya(3), T.Chattopadhyay(1), Mithun, N. P. S.(1), V. Bhalerao(3), A. Vibhute(3), S. Sreekumar(4) + CZTI Team 1 - Physical Research Laboratory 2 - Tata Institute of Fundamental Research 3 - Inter University Center of Astronomy & Astrophysics 4 - Vikram Sarabhai Space Center
Abstract Type :
Abstract Category : Plenary
Abstract : The Cadmium Zinc Telluride Imager (CZTI) is a wide-field coded aperture mask instrument on AstroSat, sensitive to photons from 20 keV to over 150 keV. It is primarily designed for simultaneous hard X-ray imaging and spectroscopy of a variety of celestial X-ray sources such as, black hole binaries, neutron star binaries, pulsars, AGNs and GRBs. The detector plane of CZTI consists of a large array of pixilated CZT detectors with total 16384 pixels, each having size of 2.5 × 2.5 mm2 and thickness of 5 mm. The larger thickness and the fine pixilated nature of the detector plane of CZTI is also helpful in extending useful energy range to ~250 keV as well as to measure polarization in hard X-rays, by identifying the X-ray photons interacting by means of Compton scattering. As an added advantage of the extended energy range, CZTI is also sensitive to hard X-ray transients like gamma-ray bursts. CZTI has been operating successfully since the launch of AstroSat and has detected many bright X-ray sources. Apart from the regular imaging and spectroscopic measurements, CZTI has successfully measured hard X-ray polarization in a few sources including the standard candle source, the Crab nebula; a black hole binary Cygnus X-1 and a number of gamma-ray bursts. Here I will present the early results of the hard X-ray polarization measurements with the AstroSat CZTI carried out with observations during the performance verification phase and guaranteed time observations.