• The AstroSat mass model: Imaging and flux studies of off-axis sources with CZTI

• # Fulltext

https://www.ias.ac.in/article/fulltext/joaa/042/0093

• # Keywords

Gamma-ray bursts; AstroSat; Cadmium Zinc Telluride Imager; mass model simulation.

• # Abstract

The Cadmium Zinc Telluride Imager (CZTI) on AstroSat is a hard X-ray coded-aperture mask instrument with a primary field-of-view of $4.6^{\circ} \times 4.6^{\circ}$ (FWHM).The instrument collimators become increasinglytransparent at energies above $\sim$100 keV, making CZTI sensitive to radiation from the entire sky. While this has enabled CZTI to detect a large number of off-axis transient sources, calculating the source flux or spectrum requires knowledge of the direction and energy dependent attenuation of the radiation incident upon the detector. Here, we present a GEANT4-based mass model of CZTI and AstroSat that can be used to simulate the satellite response to the incident radiation, and to calculate an effective ‘‘response file’’ for converting the source counts into fluxes and spectra. We provide details of the geometry and interaction physics, and validate the model by comparing the simulations of imaging and flux studies with observations. Spectroscopic validation of the massmodel is discussed in a companion paper, Chattopadhyay et al. (J. Astrophys. Astr., vol. 42 (2021) https://doi.org/10.1007/s12036-021-09718-2).

• # Author Affiliations

1. Indian Institute of Technology Bombay, Mumbai 400 076, India.
2. IRAP, CNES, CNRS, UPS, Universite´ de Toulouse, Toulouse, France.
3. Department of Physics, Stanford University, 382 Via Pueblo Mall, Stanford, CA 94305, USA.
4. Kavli Institute of Astrophysics and Cosmology, 452 Lomita Mall, Stanford, CA 94305, USA.
5. Physical Research Laboratory, Ahmedabad 380 009, India.
6. Department of Physics and Astronomy, Texas Tech University, Box 1051, Lubbock, TX 79409-1051, USA.
7. The Inter-University Centre for Astronomy and Astrophysics, Pune 411 007, India.
8. Tata Institute of Fundamental Research, Mumbai 400 005, India.

• # Journal of Astrophysics and Astronomy

Volume 44, 2023
All articles
Continuous Article Publishing mode

• # Continuous Article Publication

Posted on January 27, 2016

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