[en] We present a theoretical description of different types of accretion disks and jets near supermassive black holes (SMBHs) that can be observed in the (sub)millimeter wave band. Special attention is paid to the possible formation of the shadow of a black hole illuminated by an accretion disk or a jet. We suggest a simple criterion for identifying such a shadow in current and planned SMBH observations using very long baseline interferometry (VLBI). As an example, we propose a number of potential SMBH candidates satisfying this criterion for observations with the future Millimetron space observatory in the VLBI regime and with the Event Horizon Telescope. (reviews of topical problems)

[en] This paper reviews a wide range of questions in astrophysics and cosmology that can be answered by astronomical observations in the far-IR to millimeter wavelength range and which include the formation and evolution of stars and planets, galaxies, and the interstellar medium, the study of black holes, and the development of the cosmological model. These questions are considered in relation to the Millimetron Space Observatory (Spectrum-M project), which is equipped with a 10 m aperture cooled telescope and can operate both as a single-dish telescope and as part of a space-ground very long baseline interferometer. (physics of our days)