The XSPECT instrument captures a detailed spectrum of the supernova remnant Cassiopeia A (Cas A), encompassing both the Galactic Cosmic Ray (GCR) background and the Cosmic X-ray Background (CXB). The flux observed above 8 keV predominantly results from the combined contributions of CXB and GCR. The presented spectrum, depicted in the figure, is derived from a cumulative integration time of 20 ksec, collected across multiple orbits, providing valuable insights into the X-ray emissions associated with Cas A.
XPoSat, India’s inaugural X-ray polarimetric mission, has achieved a significant as the XSPECT instrument captures its initial observations from the Cassiopeia A (Cas A) supernova remnant. Launched on January 1, 2024, XPoSat is equipped with two co-aligned instruments, namely the POLarimeter Instrument in X-rays (POLIX) and X-ray SPECtroscopy and Timing (XSPECT). This mission is designed to unravel the mysteries of cosmic X-ray sources. While POLIX focuses on examining X-ray polarization in medium-energy X-rays, XSPECT engages in continuous and extended spectral and temporal studies of X-ray sources within the soft X-ray band.
In its performance verification phase, XSPECT was pointed towards Cassiopeia A, serving as a benchmark celestial source for instrument evaluation. The observation, initiated on January 5, 2024, successfully recorded emission lines from the supernova remnant, highlighting elements such as Magnesium, Silicon, Sulphur, Argon, Calcium, and Iron.
The XSPECT payload is a creation of the Space Astronomy Group at U R Rao Satellite Centre (URSC)/ISRO in Bengaluru. Leveraging XSPECT’s extended observational capabilities, the continuous studies are poised to make substantial contributions to our comprehension of high-energy phenomena in the universe.