Indian researchers detect X-Ray Polarization in Extragalactic black hole
Science & Technology
27th Nov, 2023
The research was led by Scientists from IIT Guwahati and U R Rao Satellite Centre (URSC) has discovered that X-Ray Polarization in Extragalactic black hole.
What is a Black Hole?
- A black hole is formed when stars collapse, leading to a space in the universe with an escape velocity — the speed at which an object must travel to override a planet or an object’s gravitational force.
- Because light cannot get out, black holes are invisible and can only be tracked with the help of spatial telescopes and special tools.
- The light cannot go out because the gravity inside a black hole is very strong as a result of a lot of matter being squeezed into a small space.
Extragalactic black hole:
- Extragalactic astronomy is the branch of astronomy concerned with objects outside the Milky Way galaxy. In other words, it is the study of all astronomical objects which are not covered by galactic astronomy.
- So, extragalactic black holes are found outside the Milky Way galaxy.
About the Study:
- Polarized emissions: For the first time, a team of researchers from the Indian Institute of Technology (IIT) Guwahati and the UR Rao Satellite Centre of the Indian Space Research Centre (ISRO) have detected polarized emissions from a black hole source that exists beyond our Milky Way Galaxy.
- Black hole sources: These findings open a new window to investigate and understand the nature of astrophysical black hole sources.
- Large Magellanic Cloud X-3 (LMC X3): It is a binary star system consisting of a black hole and a ‘normal’ star that is "much hotter, bigger, and more massive than the Sun.
- Location: The system is located in a satellite galaxy of the Milky Way, nearly 2,00,000 light years away from planet Earth.
- Satellite galaxy of Milky Way: Since its discovery in 1971, it has been observed by various satellites. However, there has been a gap in understanding the polarization properties of X-rays emitted by highly energetic objects like stellar mass black holes in the universe.
- The Imaging X-ray Polarimetry Explorer (IXPE): The researchers studied LMC X-3 using ‘The Imaging X-ray Polarimetry Explorer (IXPE)’, NASA’s first mission to study polarization of X-rays from celestial objects.
- Additional Data: They also used simultaneous broad-band coverage of the Neutron Star Interior Composition Explorer (NICER) Mission and the Nuclear Spectroscopic Telescope Array (NuSTAR) Mission to constrain the spin of LMC X-3.
Significance of the Study:
- X-ray polarimetry: It is a unique observational technique to identify where radiation comes from near black holes.
- Powerful X-rays: LMC X-3 emits X-rays that are 10,000 times more powerful than those from the Sun.
- Changes the polarization characteristics: When these X-rays interact with the material around black holes, specifically when they scatter, it changes the polarization characteristics, i.e. degree and angle.
- Behavior of matter drawing towards black hole: This helps in understanding how matter is drawn toward black holes in the presence of intense gravitational forces