Isro's black hole mission XPoSat begins active observation, looks at Crab pulsar

[Ajay0]

ISRO's Polix instrument onboard its satellite  XPoSat  (X-ray Polarimeter Satellite ) has started active observation of the Crab pulsar.

https://www.indiatoday.in/science/story/isro-black-hole-mission-xposat-begins-active-observation-looks-at-crab-pulsar-2501428-2024-02-13

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The Crab Pulsar, the central star in the Crab Nebula, is a neutron star that emits beams of radiation detectable from Earth, much like a cosmic lighthouse. It spins at an astonishing rate of about 30 rotations per second, making it one of the most fascinating objects for astrophysical studies.

XPoSat's mission is to enhance our understanding of the dynamics of bright astronomical X-ray sources under extreme conditions.

Alongside POLIX, the mission carries another scientific payload, XSPECT, which provides spectroscopic information and timing in soft X-rays. Together, these instruments will observe various celestial phenomena, including black holes, neutron stars, and active galactic nuclei, over the planned five-year lifetime of the mission.

The commencement of POLIX's active observation phase marks a significant step forward for India's first dedicated polarimetry mission. The data collected will help unravel the complexities of emission mechanisms from astronomical sources and contribute to the global scientific community's efforts to understand the universe's high-energy processes.

 

 

[Ajay0]

XPoSat, launched by ISRO on January 1, has been operating in low earth orbit at an approximate altitude of 650

km.https://indianexpress.com/article/cities/bangalore/xposat-first-light-study-pulsars-black-holes-isro-9160755/

 

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XPoSat comprises two payloads – the Indian X-ray Polarimeter (POLIX) and X-ray Spectroscopy and Timing (XPECT) built by Raman Research Institute and ISRO’s UR Rao Satellite Centre, respectively.

Isro added POLIX, the world’s first instrument to operate in the medium energy band 8-30 kilo electron Volt (keV), was activated in two stages around January 10. Thereafter, this primary payload commenced scientific measurements of Crab nebula, the intended source. This is a supermassive remnant of a star and has been an object of great scientific interest.

The vital X-ray measurements using POLIX were taken during January 15 to 18. This is a first-of-its-kind pulse profile obtained from a celestial source from the medium energy band. The pulse profile showcases the time window (67 milliseconds in total) of X-rays scattered by the Beryllium scatterer inside POLIX. The plot also illustrates the timing on non-pulsed emissions from pulsar wind nebulae surrounding the Crab pulsar.

On the commencement of actual scientific measurements, an Isro scientist working on the mission said, “XPoSat is currently undergoing its performance verification phase. It could last for about three months after which the real science measurements would begin.”

Normally, post the launch of a mission, the payloads are tested for its health and extensive calibration exercises are undertaken. However, in the case of XPoSat, with no previous data ever obtained from missions in the medium energy band, no calibration can be performed. Thereby data and measurements obtained using XPoSat will be laying a bedrock foundation to the field of X-ray polarimetry used for studying pulsars and extremely bright celestial objects.