GUWAHATI: Researchers from the Indian Institute of Technology Guwahati (IIT Guwahati) and the UR Rao Satellite Centre, Indian Space Research Organisation (ISRO), Bengaluru, have successfully detected polarised emissions from a black hole source situated beyond our Milky Way Galaxy.
This pioneering feat was accomplished through the use of X-ray polarimetry, marking a significant advancement in our understanding of highly energetic celestial objects.
The focus of the study was the Large Magellanic Cloud X-3 (LMC X3), a binary star system comprising a black hole and a “normal” star, the latter being hotter, larger, and more massive than the Sun. LMC X3 is located in a satellite galaxy of our Milky Way, nearly 200,000 light-years away from Earth. While it has been observed since its discovery in 1971, the polarisation properties of the X-rays emitted by such energetic objects remained a gap in scientific understanding.
The emitted X-rays from LMC X-3, being 10,000 times more powerful than those from the Sun, interact with surrounding material, changing polarisation characteristics. This alteration aids in comprehending how matter is drawn toward black holes in the presence of intense gravitational forces.
The researchers utilised the Imaging X-ray Polarimetry Explorer (IXPE), NASA's first mission to study the polarisation of X-rays from celestial objects, along with the simultaneous broad-band coverage of the Neutron Star Interior Composition Explorer (NICER) Mission and Nuclear Spectroscopic Telescope Array (NuSTAR) Mission to analyse LMC X-3 and constrain its spin.
Published in the Monthly Notices of the Royal Astronomical Society: Letters, the study was funded by the Science and Engineering Research Board (SERB), Department of Science and Technology, India. The research team, led by Prof. Santabrata Das and Anuj Nandi, included research scholars Seshadri Majumder (IIT Guwahati) and Ankur Kushwaha (URSC).
These findings open a new frontier for investigating and understanding the nature of astrophysical black hole sources.