Multi-wavelength emission from magnetically arrested disks around isolated black holes
Abstract
We discuss the prospects for identifying nearest isolated black holes (IBHs) in our Galaxy. IBHs accreting gas from the interstellar medium (ISM) likely form magnetically arrested disks (MADs). We show that thermal electrons in the MADs emit optical signals through the thermal synchrotron process while non-thermal electrons accelerated via magnetic reconnections emit a flat-spectrum synchrotron radiation in the X-ray to MeV gamma-ray ranges. The Gaia catalog will include at most a thousand of IBHs within kpc that are distributed on and around the cooling sequence of white dwarfs (WDs) in the Hertzsprung-Russell diagram. These IBH candidates should also be detected by eROSITA, with which they can be distinguished from isolated WDs and neutron stars. Followup observations with hard X-ray and MeV gamma-ray satellites will be useful to unambiguously identify IBHs.
Keywords
Cite
@article{arxiv.2109.14389,
title = {Multi-wavelength emission from magnetically arrested disks around isolated black holes},
author = {Shigeo S. Kimura and Kazumi Kashiyama and Kenta Hotokezaka},
journal= {arXiv preprint arXiv:2109.14389},
year = {2021}
}
Comments
10 pages, 4 figures, 1 table, accepted for publications in ApJL, discussions are added, conclusions are unchanged, a few typos are corrected