Meet ISRO’s new X-ray eye in the sky

Meet ISRO’s new X-ray eye in the sky

Subject : Science and Tech

Section: Space tech

About XPoSat its component and its significance:

• XPoSat, India’s X-ray Polarimeter Satellite launched by ISRO, represents a significant leap in the study of polarized cosmic X-rays, aimed at unravelling the mysteries surrounding celestial phenomena such as black holes, neutron stars, and active galactic nuclei.
• The payload includes POLIX (Indian X-ray Polarimeter), developed at Raman Research Institute (RRI). Despite its relatively compact size of approximately 0.5 meters and 200 kilograms, this instrument stands out for its indigenous design, focusing on detecting the polarization of X-rays in space.
• Understanding X-ray polarization is crucial, particularly in stars boasting colossal magnetic fields like pulsars and regions adjacent to black holes, where the intricate interplay of matter and energy emits X-rays with distinct properties.
• POLIX’s innovative use of a beryllium disc enables the study of lower-energy X-rays compared to previous instruments, amplifying the breadth of knowledge acquisition in this domain.
• Accompanying POLIX on XPoSat is XSPECT, another instrument tailored to scrutinize the timing and spectral characteristics of X-ray-emitting cosmic entities.
• The limitations in focusing X-rays due to their high energy and the Earth’s atmosphere absorbing most cosmic X-rays necessitate space-based telescopes like XPoSat for in-depth observations.
• XPoSat’s mission signifies India’s shift from satellite deployment to planetary exploration, highlighted by recent missions like Chandrayaan-3 and Aditya-1, while also emphasizing collaborations with global space agencies like NASA.

Imaging X-ray Polarimetry Explorer (IXPE or SMEX-14) by NASA:

• It was only in December 2021 that the first instrument to study X-rays in space (IXPE) was launched into space by NASA and the Italian Space Agency (ASI).
• This instrument contains gas, whose atoms are stripped of electrons after interacting with incoming X-rays. Upon scrutiny, the direction of motion of these ejected electrons gives clues to the X-ray polarisation.

Key terms:

• Pulsars: A pulsar (from pulsating radio source) is a highly magnetized rotating neutron star that emits beams of electromagnetic radiation out of its magnetic poles.
• Black hole: A black hole is a region of spacetime where gravity is so strong that nothing, including light and other electromagnetic waves, has enough energy to escape it.
• Active galactic nuclei: An active galactic nucleus (AGN) is a compact region at the centre of a galaxy that emits a significant amount of energy across the electromagnetic spectrum, with characteristics indicating that the luminosity is not produced by stars.
  • Such excess, non-stellar emissions have been observed in the radio, microwave, infrared, optical, ultra-violet, X-ray and gamma ray wavebands.
  • A galaxy hosting an AGN is called an active galaxy. The non-stellar radiation from an AGN is theorized to result from the accretion of matter by a supermassive black hole at the centre of its host galaxy.
• X-rays: X-rays are a form of electromagnetic radiation, similar to visible light. Unlike light, however, x-rays have higher energy and can pass through most objects, including the body.