According to the ARIES study, what happens to the shock in the accretion disc when a black hole spins rapidly?
- A.It is pushed farther from the black hole, giving only low-frequency QPOs
- B.It is pulled closer to the black hole, producing QPOs over a wider range of frequencies
- C.It disappears completely and no QPOs are produced
- D.It becomes permanently stable and stops oscillating
Correct answer
Explanation
The correct answer is that the shock is pulled closer to the black hole, producing QPOs over a much wider range of frequencies. The simulations showed that as spin increases, the oscillating shock moves inward and its oscillations grow more pronounced, so the predicted frequencies can exceed 100 Hz for a black hole of about ten solar masses, which matches the fast variations observed in black hole X-ray binary systems. Option A describes the opposite case, a slowly spinning black hole, where viscosity pushes the average position of the shock farther out and mainly low-frequency QPOs result. Option C is wrong because the oscillations are precisely what produces the observed flickering. Option D is wrong because the shock becomes unstable, not permanently stable, once viscosity crosses its critical value. The study also reported a clear relation between QPO frequency and the photon index.
Read the full article: ARIES Study Explains High-Frequency QPOs Near Spinning Black Holes
Practice Questions
The study on the effect of black hole spin on quasi-periodic oscillations was led by scientists of which institute?
- A.Indian Institute of Astrophysics, Bengaluru
- B.Aryabhatta Research Institute of Observational Sciences (ARIES)
- C.Physical Research Laboratory, Ahmedabad
- D.Inter-University Centre for Astronomy and Astrophysics, Pune
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Its Numerical and Theoretical Astrophysics Group built the computer simulation of viscous accretion flows used in the work, which was led by Mr Sanit Debnath and Dr Indranil Chattopadhyay, with scientists from the Nicolaus Copernicus Astronomical Center in Poland and MJP Rohilkhand University, Bareilly.
Read the full explanation →In the context of black hole research, QPO stands for:
- A.Quantum Photon Oscillation
- B.Quasi-Periodic Oscillation
- C.Quadrupole Phase Orbit
- D.Quasar Polar Outflow
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Matter pulled towards a black hole forms an accretion flow that falls inward at high speed and emits non-thermal radiation, and the brightness of that radiation shows nearly regular variations known as quasi-periodic oscillations.
Read the full explanation →Which of the following was NOT named as a research area of the new C-DOT Centre of Excellence?
- A.Very large-scale MIMO systems
- B.Post-quantum communication
- C.Deep-sea mining equipment
- D.AI-native communication networks
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The Centre of Excellence at IIT (BHU), Varanasi has been given a brief in communication technology: wireless communications, quantum technologies, cybersecurity and communication systems driven by artificial intelligence, with advanced research in 5G Advanced and 6G technologies, very large-scale Multiple-Input Multiple-Output systems, sensing merged with communication, AI-native networks and devices…
Read the full explanation →C-DOT, which signed the agreement for the new Centre of Excellence, works under which ministry?
- A.Ministry of Electronics and Information Technology
- B.Ministry of Communications
- C.Ministry of Education
- D.Ministry of Science and Technology
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The Centre for Development of Telematics, or C-DOT, is the research and development centre of the Department of Telecommunications, which is a department of the Ministry of Communications, and it is in that capacity that it signed the agreement for a Centre of Excellence at IIT (BHU), Varanasi.
Read the full explanation →C-DOT's sixth Centre of Excellence has been set up at which institution?
- A.IIT Kanpur
- B.IISc Bengaluru
- C.IIT (BHU), Varanasi
- D.IIT Roorkee
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The Centre for Development of Telematics signed a Memorandum of Understanding with the Indian Institute of Technology (BHU), Varanasi to establish its sixth Centre of Excellence, and the signing was followed by the formal opening of the centre on the campus.
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