Intermediate resolution H-beta spectroscopy and photometric monitoring of 3C 390.3 I. Further evidence of a nuclear accretion disk

TL;DR

This study presents long-term spectroscopic and photometric monitoring of AGN 3C 390.3, revealing variable H-beta profiles, outbursts, and evidence supporting an inclined accretion disk model, leading to a revised black hole mass estimate.

Contribution

It provides new observational evidence of accretion disk features in 3C 390.3 and refines the black hole mass estimate using reverberation mapping.

Findings

Detected two major outbursts in continuum and H-beta light.

Observed variable H-beta line profiles with asymmetric and symmetric wings.

Estimated black hole mass is approximately 2.1 x 10^9 solar masses.

Abstract

We have monitored the AGN 3C390.3 between 1995 and 2000.Two large amplitude outbursts, of different duration, in continuum and H beta light were observed ie.: in October 1994 a brighter flare that lasted about 1000 days and in July 1997 another one that lasted about 700 days were detected. The flux in the H beta wings and line core vary simultaneously, a behavior indicative of predominantly circular motions in the BLR.Important changes of the Hbeta emission profiles were detected: at times, we found profiles with prominent asymmetric wings, as those normaly seen in Sy1s, while at other times, we observe profiles with weak almost symmetrical wings, similar to those seen in Sy1.8s. We found that the radial velocity difference between the red and blue bumps is anticorrelated with the light curves of H beta and continuum radiation.e found that the radial velocity difference between the red and blue bumps is anticorrelated with the light curves of H-beta and continuum radiation. Theoretical H-beta profiles were computed for an accretion disk, the observed profiles are best reproduced by an inclined disk (25 deg) whose region of maximum emission is located roughly at 200 Rg. The mass of the black hole in 3C 390.3, estimated from the reverberation analysis is Mrev = 2.1 x 10^9 Msun, ie. 5 times larger than previous estimates