AGN III-primordial activity in the nuclei of disk galaxies with pseudobulges

作者：Komberg B V^*; Ermash A A

来源：Astronomy Reports, 2013, 57(6): 401-409.

DOI：10.1134/S1063772913060036

Observational data on the evolution of quasars and galaxies of various morphological types and numerical simulations carried out by various groups are used to argue that low-redshift (z < 0.5) quasars of types I and II, identified with massive elliptical and spiral galaxies with classical bulges, cannot be undergoing a single, late phase of activity; i.e., their activity cannot be "primordial," and must have "flared up" at multiple times in the past. This means that their appearance at low z is associated with recurrence of their activity-i.e., with major mergers of gas-rich galaxies (so-called wet major mergers)-since their lifetimes in the active phase do not exceed a few times 10(7) yrs. Only objects we have referred to earlier as AGN III, which are associated with the nuclei of isolated, late-type spiral galaxies with low-mass, rapidly-rotating "pseudobulges," could represent primordial AGNs at low z. The black holes in such galaxies have masses M (BH) < 10(7) M (aS (TM)), and the peculiarities of their nuclear spectra suggest that they may have very high specific rotational angular momenta per unit mass. Type I narrow-line (widths less than 2000 km/s) Seyfert galaxies (NLSyIs) with pseudobulges and black-hole masses M (BH) < 10(7) M (aS (TM)) may be characteristic representatives of the AGN III population. Since NLSyI galaxies have pseudobulges while Type I broad-line Seyfert galaxies have classical bulges, these two types of galaxies cannot represent different evolutionary stages of a single type of object. It is possible that the precursors of NLSyIs are "Population A" quasars.

• 出版日期2013-6