EduNe Bureau
Guwahati: In a breakthrough study, researchers from the Indian Institute of Technology (IIT) Guwahati, in collaboration with ISRO’s U. R. Rao Satellite Centre and Haifa University in Israel, have decoded a puzzling X-ray flickering pattern from a distant black hole, GRS 1915+105, located about 28,000 light-years away.
Using data from India’s space observatory AstroSat, the team found that the black hole’s X-ray brightness alternates between bright and dim phases, each lasting several hundred seconds. During the bright phases, they detected rapid flickers nearly 70 times per second, which vanished when the black hole dimmed.
“This is the first clear evidence of such rapid flickering tied to changes in the corona—the hot cloud of particles surrounding the black hole,” said Prof. Santabrata Das, Department of Physics, IIT Guwahati. “AstroSat’s unique capabilities made this discovery possible.”
The study shows that during brighter phases, the corona becomes more compact and hotter, producing the rapid flickers. In dimmer phases, it expands and cools, making the flickers disappear. This proves that the corona is a dynamic, changing structure rather than a fixed one.
Dr. Anuj Nandi from ISRO explained, “Our study provides direct evidence that X-ray flickering originates from modulations in the corona around the black hole.”
The findings, published in the Monthly Notices of the Royal Astronomical Society, not only help scientists understand the extreme conditions near black holes but also shed light on how they grow, release energy, and shape the evolution of galaxies.
