Search for AGNs in Dwarf Galaxies in the the M81 Field with INTEGRAL Data

Using long-term INTEGRAL hard X-ray observations, we have put upper limits on the bolometric luminosity ( L_bol≲ 10^41 erg s ^-1 ) of the nuclei of 72 nearby dwarf galaxies located in the M81 field. This has allowed us to constrain the fraction of galaxies in which the central black hole accretes matter at a rate above 0.1 % of the critical one. Under simple assumptions about the distributions of black hole masses and accretion rates this fraction does not exceed 9 % . Reliable estimates of the central black hole masses are required to obtain more stringent constraints on the fraction of AGNs.