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IISER Pune alumnus in the discovery of orbiting black holes  Jul 05, 2017

Karishma Bansal, an IISER Pune alumnus, is part of a team of researchers that detected for the first time, two supermassive black holes orbiting each other, in a galaxy about 750 million light years away from Earth. She is also the lead author of the paper 'Constraining the Orbit of the Supermassive Black Hole Binary 0402+379', recently published in The Astrophysical Journal.

Supermassive black holes (SMBHs) are the largest types of black holes, whose formation is still a mystery. The two SMBHs observed in the galaxy 0402+379 are separated by a distance of about 24 light years. On the cosmic scale this separation is very small, and thus hard to detect which marks the technical achievement of this discovery.

This work is the first instance where a supermassive binary black hole system has been imaged as two distinct objects which are orbiting each other. This was done with the VLBA (Very Long Baseline Array), a system of 10 radio telescopes that has been observing signals emitted by this system for many years now.

"In the initial stages of the project, I started learning how to reduce radio data. Later I began to analyse data that my advisor, Dr. Greg Taylor, and team had been gathering for over 10 years”, said Bansal, now a graduate student at the University of New Mexico. “It was very exciting to be able to see black holes in an image for the first time.”

Regarding how this finding would further our knowledge of the universe, she said, “It will enable us to understand formation and evolution of galaxies in general and how supermassive black holes affect them. As we know that (the galaxies) Andromeda and Milky Way are on a collision course, this discovery enables us to see our future from billions of years from now, today.”

On learning about this contribution, Prof. G. Ambika, Dean, Graduate Studies, said, “I am delighted to note that Karishma is a part of this exciting discovery on the orbital motion between two supermassive black holes hundreds of millions of light years from Earth. It is a matter of great pride for all of us at IISER Pune”.

We congratulate Karishma Bansal on this achievement and wish her the very best for her future endeavours.

You can learn more about this work here.

- Reported by Harshini Tekur