Kanpur: A team of scientists from the Inter-University Centre for Astronomy and Astrophysics (IUCAA), Pune and the Indian Institute of Technology, Kanpur studied the X-ray emission from a well known black hole binary GRS 1915+105 using the Indian space Observatory AstroSat launched by ISRO.

They analysed data from the Large Area X-ray Proportional Counter (LAXPC) and the Soft X-ray Telescope (SXT) instruments which were both developed in TIFR Mumbai.

Using the unique capability of these instruments, they were able to estimate simultaneously the frequency of the oscillation, the inner accretion disk radius and the accretion rate which is the amount of matter going into the black hole per second. They found that the frequency varies with inner radius and accretion rate in the very same manner as the dynamic frequency, i e inverse of the time taken by sound waves to travel from the inner radius to the black hole, as predicted four decades ago by the General Relativistic theory of accretion disks. This identification paves the way to make such system laboratories to test General Relativity.