IIT Guwahati researchers decode black hole signals

Researchers at the Indian Institute of Technology Guwahati (IIT Guwahati) have decoded X-ray signals from the black hole GRS 1915+105. The researchers have collaborated with the UR Rao Satellite Centre at the Indian Space Research Organisation (ISRO) and Haifa University, Israel, for this discovery.

The IIT Guwahati researchers used the Indian space observatory, AstroSat, to observe that the brightness from the black hole flickered between bright and dim phases, each lasting for about a few hundred seconds. During the bright phase, the corona of the black hole became compact and hot, with the flickers increasing in frequency. During the dim phase, the corona expands and cools down, making the flickers disappear.

The IIT Guwahati scientists concluded that the signals appeared only during the bright phase of the black hole, due to the oscillating corona. They deduced that a black hole is not a fixed structure, but rather something which is constantly changing its shape and energy based on the gases that flow into it.

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IIT Guwahati Research: Conclusions

The black hole signals study sheds light on the gravitational intensity and high temperature which exist at a black hole’s edge. This contributes to the understanding of how black holes grow and release energy, and how they affect their surroundings. This information helps scientists uncover how black holes influence the evolution of entire galaxies.

The IIT Guwahati black hole research has been published in the journal ‘Monthly Notices of the Royal Astronomical Society’. The paper is co-authored by Santabrata Das, professor at the department of physics, and his research scholar, Seshadri Majumder, along with Anuj Nandi from the UR Rao Satellite Centre, and Sreehari Harikesh from the University of Haifa.

Speaking about the research, Das said, “We have found the first evidence of rapid X-ray flickering, repeating nearly 70 times per second, occurring during the high-brightness phases of the source. Interestingly, these fast flickers disappear during the low-brightness phases.”