XPosat
Context:
- Recently, ISRO put its first polarimetry mission which is X-ray Polarimeter Satellite (XPoSat) in a precise circular orbit of 650 km.
- XPoSat is the world’s second satellite-based mission which is dedicated to making X-ray polarimetry measurements.
What is XPoSat?
- It is India’s maiden mission dedicated to analyse the polarisation of X-rays which emanates from bright celestial sources in the medium frequency band.
- It comprises two payloads which include Indian X-ray Polarimeter (POLIX) and X-ray Spectroscopy and Timing (XSPECT).
- Both the payloads have been built by the Raman Research Institute and UR Rao Satellite Centre.
- The estimated mission life is about five years during which it will observe sources that emit polarised X-rays.
- The observations will be taken when the magnetars or neutron are in transit through the Earth’s shadow.
About the payloads:
POLIX:
- It is the world’s first instrument which is designed to operate in the medium X-ray of 8 to 30 kilo electron Volt (keV) energy band.
- It consists of a collimator that is the key component to filter light originating from bright sources in the field of view.
- POLIX will observe a few tens of astronomical sources.
XSPECT:
- It is constructed to conduct fast timing and high spectroscopic resolution in a soft X-ray energy band (0.8-15 keV).
- It will observe a variety of sources similar to X-ray pulsars, black hole binaries, low-magnetic field neutron stars, active galactic nuclei or AGNs and magnetars.
Significance of XPosat Mission:
- Till the date, astronomers have largely depended on spectroscopic, imaging and timing based data obtained from either ground-based telescopes or satellite-based missions from the optical to the radio frequency band of the electromagnetic spectrum.
- XPoSat will facilitate X-ray polarisation measurements possible from bright sources in the medium energy band (8-30 keV) energy range which has never been attempted ever before.
- By studying the polarised X-rays which emanates from excellent sources like magnetars, black holes and their surrounding environments, and neutron stars, scientists can understand the nature of the radiations and the multitudes of processes involved in the generation of these radiations.
Polarisation of X-rays and their study:
- X-rays comprises of electric and magnetic waves which are constantly in motion.
- Due to their sinusoidal wave nature, they tend not to follow a patterned direction of motion.
- But a polarised X-ray is both organised and has two waves vibrating in the similar direction.
