Mon. Not. R. Astron. Soc., 347, 607-612 (2004/January-2)
The black hole-bulge relation in active galactic nuclei.
BIAN W. and ZHAO Y.
Abstract (from CDS):
We have used the widths of Hβ and [O III] emission lines to investigate the black hole-bulge relation in radio-loud active galactic nuclei (AGNs), radio-quiet AGNs and narrow-line Seyfert 1 galaxies (NLS1s). The central black hole mass, Mbh, is estimated from the Hβ linewidth and the optical luminosity, and the bulge velocity dispersion, σ, is directly estimated from the width of the [O III] line. We have found that radio-quiet AGNs follow the established Mbh-σ relationship in nearby inactive galaxies, while radio-loud AGNs and NLS1s deviate from this relationship. There are two plausible interpretations for the deviation of radio-loud AGNs. One is that the size of broad-line regions (BLRs) emitting the Hβ line is overestimated because of the overestimation of optical luminosity. The other is that the dynamics of BLRs and/or narrow-line regions in radio-loud AGNs is different from that in radio-quiet AGNs. The deviation of NLS1s may be due to the small inclination of BLRs to the line of sight or the reliability of the [O III] linewidth as the indicator of stellar velocity dispersion because of its complex multiple components.
black hole physics - galaxies: active - galaxies: nuclei - quasars: general