Scientists led by ISRO detected quick X-ray flashes from the black hole GRS 1915+105 and released their results in Monthly Notices of the Royal Astronomical Society

What exactly is GRS 1915+105?

It is a stellar-mass black hole situated in a binary system, coupled with a normal star, and recognized for its highly variable X-ray emissions.

Found By: Identified in 1992 by the WATCH all-sky surveillance on the Granat

Situated at about 28,000 light-years from Earth in the Aquila constellation, inside the Milky Way galaxy.

Main Characteristics:

Mass: approximately 12 times the solar mass.

High Variability: Displays fluctuating X-ray dips and flares every several hundred seconds.

High Frequency QPOs Observed: Fast flashes at 70 Hz (Quasi-periodic Oscillations) during luminous stages.

Plasma Corona: Alternates between dense-hot and expanded-cool phases, influencing X-ray fluctuations.

Accretion Process: Draws in material from a companion star, creating a rotating accretion disk (1–10 million °C) and an extremely hot corona (~100 million °C).

Importance:

AstroSat Milestone: First Indian telescope to observe real-time dynamic behavior of the corona.

Theoretical Progress: Endorses the notion that compact corona surrounding black holes gives rise to high-frequency X-ray flickers.

Astrophysics Insight: Assists in unraveling the physical conditions adjacent to event horizons where gravitational forces are intense.