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Hot Accretion Flows

Nonthermal processes in hot accretion flows

Hot Accretion Flow Diagram

Research Questions

Overview

Hot accretion flows, also known as Radiatively Inefficient Accretion Flows (RIAFs), are a class of accretion flows where the accreting material has very high temperatures (close to the virial temperature) but low density. These flows are characterized by low radiative efficiency and are thought to be present in many low-luminosity Active Galactic Nuclei (AGNs) and X-ray binaries.

Understanding the physics of hot accretion flows is crucial for interpreting observations of supermassive black holes, such as those at the center of our Galaxy (Sagittarius A*) and M87, which have been recently imaged by the Event Horizon Telescope.

Research Focus

My research in this area focuses on the role of nonthermal particles in hot accretion flows. While the bulk of the plasma in these flows is thermal, a significant fraction of particles can be accelerated to relativistic energies through various mechanisms, including magnetic reconnection and turbulent acceleration.

Key research areas include:

Observational Connections

The theoretical models developed in this research are directly compared with multi-wavelength observations of low-luminosity AGNs. The nonthermal emission from relativistic particles can significantly affect the observed spectrum, particularly in the radio and X-ray bands, providing crucial diagnostics for understanding the physics of these extreme environments.

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