Observational signatures from clusters of stellar black holes in supercritical AGNs

LEANDRO ABAROA

San Juan

Congreso; Reunión Anual de la Asociación Argentina de Astronomía; 2023

Asociación Argentina de Astronomía

Active galactic nuclei (AGNs) are powered by accretion onto supermassive black holes (SMBHs) with69masses in the range 10 − 10 M⊙. These SMBHs are fed by accretion disks radiating from the IR/optical bands to the X-rays. Different types of objects can orbit the SMBHs, including massive stars, neutron stars, clouds from broad- and narrow-line regions, and X-ray binaries. Isolated stellar mass black holes (BHs of ∼ 10M⊙) should also be present in large numbers within the central parsec of the galaxies. These BHs are expected to form a cluster around the SMBH as a result of the enhanced star formation rate in the inner galaxy and black hole migration caused by gravitational dynamical friction. In this talk, we will explore the possibility of detecting electromagnetic signatures of a central cluster of BHs in a supercritical AGN, that is, an AGN where the accretion rate onto the central SMBH is greater than the Eddington rate. In these supercritical nuclei, the accretion disk launches powerful winds that interact with the objects orbiting the SMBH. Isolated BHs can capture matter from this dense wind, leading to the formation of small accretion disks around them. If jets are produced in these non-stellar microquasars, they might be sites of particle acceleration up to relativistic energies. These particles, in turn, should cool by different radiative processes. Therefore, the wind of the SMBH can eventually illuminate the BHs through the production of nonthermal radiation.