2024-10-11 11:00  P5A-1

Accretion flow around black holes is ‘MAD’!

Dr. Ramiz Akhtar

Accretion process on to black hole is one of the most powerful phenomena in the universe. Black hole sources often exhibit jets and outflows. To understand how these jets are ejected from black holes, we need to study the accretion process in detail. Over the years, various accretion disk models have been proposed. In recent years, a significant accretion state called the ‘magnetically arrested disc (MAD)’ has garnered attention. The observations of M87 and Sgr A* by the Event Horizon Telescope (EHT) collaboration have highlighted the MAD state. It has been suggested that the accretion flow around these two black holes (AGNs) is in the MAD state, based on comparisons between radio images and post-processed GRMHD simulations. Additionally, the GRAVITY collaboration’s high angular resolution near-infrared (NIR) observations of flares in Sgr A* have confirmed that their origin lies in magnetic flux eruption events, which are characteristic of the MAD state. In this regard, we have developed a relativistic, radiation, magnetohydrodynamics (Rad-RMHD) simulation model to investigate the MAD state. We studied luminosity variation and energy spectrum for MAD state in AGNs based on our model and their possible astrophysical application.