AGN III - primordial activity in nuclei of late-type galaxies with pseudobulges

Abstract

1. Based on observational data on evolution of quasars and galaxies of different types along with the results of numerical simulations we make a conclusion that on low redshifts ($z<0.5$) QSOI/II objects in massive elliptical and spiral galaxies with classical bulges cannot be in late single activity event (be "primordial"). Instead of it they have had events of activity earlier in their evolution. It means that their presence on low redshifts is connected with the recurrence phenomenon, sequential wet minor mergings, because timescale of the activity does not exceed several units of $10^7$ years. 2. We define a new class - "AGN III" as active galactic nuclei in isolated late-type spirals with low-mass rapidly rotating pseudobulges. We also state that only such objects can be in the primordial phase of activity at low redshifts. Black holes in such galaxies have masses $M_{BH}<10^7M_\odot$ and also, probably very high spin. Such properties can explain their peculiar emission spectra. A good representative of AGN III might be the galaxies with narrow (${\rm FWHM}(H\beta)\leq1200$ km/s) broad permitted emission lines - NLS. It is believed that their black hole masses are less than $M_{BH}<10^7M_\odot$ and their host galaxies have pseudobulges instead of the classical ones. Because host galaxies of NLS have pseudobulges and BLS (Broad-Line Seyfert galaxies) have classical bulges these two types of objects cannot have evolutionary connection. Presumably, the parent population of NLS are the quasars of "population A".