ARIES study links black hole spin to quasi-periodic oscillations
Why in the news
The Ministry of Science and Technology said on 23 October 2026 that ARIES researchers have explained how the spin of a black hole changes the quasi-periodic oscillations seen in X-ray binaries.
Key facts
- Researchers: Sanit Debnath and Dr Indranil Chattopadhyay of ARIES, with collaborators from the Nicolaus Copernicus Astronomical Center, Poland, and MJP Rohilkhand University, Bareilly.
- QPOs: near-regular flickering in the X-rays given off by matter in the accretion disc around a black hole.
- Mechanism: above a critical viscosity, the normally steady shock in the accretion flow becomes unstable and oscillates, producing QPOs.
- Role of spin: slowly spinning black holes mainly give low-frequency QPOs; fast spinners pull the shock inward, giving QPOs over a much wider frequency range.
- High frequencies: for very high spin and a black hole of about 10 solar masses, frequencies can top 100 Hz, similar to signals seen in X-ray binaries.
- A clear relation was found between QPO frequency and the photon index.
- Journal: Journal of High Energy Astrophysics (JHEAP).
About the study and ARIES
The team describes its simulation, which conserves mass, momentum and energy, as the first numerical study of a viscous accretion flow that also applies the thermodynamics of a relativistic fluid. ARIES (Aryabhatta Research Institute of Observational Sciences) is an autonomous institute under the Department of Science and Technology (DST), Government of India.
Exam angle
- ARIES works under DST.
- QPOs are flickers in X-ray light from accretion discs, studied in X-ray binaries.
- Faster spin widens the QPO frequency range; above 100 Hz possible for about 10 solar-mass black holes.