Dust heating as a method for detecting black holes

Heating of interstellar dust in Galaxy by Hawking photon radiation is studied. Based on this process, constraints on the fraction of primordial black holes (PBH) in dark matter (DM) is calculated. These constraints estimates for two destributions of PBHs, in which PBHs is homogeniously distributed in the Universe and have the same distributon as DM in the Galaxy. For second distributon we use the spherically symmetric Navarro-Frenk-White profile. In both cases, it is assumed that interstellar dust is uniformly distributed n the Galaxy. The heating of interstellar dust in a molecular cloud located in the Central Molecular Zone of the Galaxy (CMZ) is also studied. The dust temperature in the molecular cloud is calculated depending on the distance to the PBH and the emission spectrum of dust grains is constructed.