On the detection of emission near the event horizons of accreting stellar-mass black holes

We discuss the possibility of detecting signs of the existence of stellar-mass black hole (BH) event horizons in the emission of interstellar gas accreting on them. We consider a sample of invisible compact objects detected as companions of Main Sequence stars in wide binaries. Theoretical luminosities and accretion rates of the interstellar gas were obtained within the framework of the spherical accretion model. BH velocities estimated from binary system dynamics, as well as the density of the surrounding ISM, were used in the calculations. Based on the sensitivity data of existing and projected ground-based and space-based telescopes (JWST, GMT, TMT, ELT, MILLIMETRON), we estimated the possibility of direct detection of both stationary and variable halo emission around the BHs.