• DOI:10.1111/j.1365-2966.2006.11182.x
• Corpus ID: 18528485

The size of broad-line regions of low-luminosity active galactic nuclei

@article{Xueguang2007TheSO,
  title={The size of broad-line regions of low-luminosity active galactic nuclei},
  author={Zhang Xue-guang and Deborah Dultzin-Hacyan and Wang Ting-gui},
  journal={Monthly Notices of the Royal Astronomical Society},
  year={2007},
  volume={374},
  pages={691-696}
}

• Zhang Xue-guang, D. Dultzin-Hacyan, Wang Ting-gui
• Published 10 October 2006
• Physics
• Monthly Notices of the Royal Astronomical Society

We study the size of broad-line regions (BLRs) of low-luminosity active galactic nuclei (AGN), also called 'dwarf AGN',defined as having L Hα ≤ 10 41 erg s- 1 . We more than double the sample size analysed previously by Wang & Zhang. In this study we first confirm our previous result -that the sizes of BLRs of low-luminosity AGN are larger than those expected from the empirical relation R BLRs -L Hα valid for 'normal' AGN (Seyfert Is and quasars), except for objects with accretion rate m Hα > 10 -5.5 . Secondly, we find a positive correlation between the linewidth of the narrow emission lines (as a tracer of velocity dispersion and thus bulge and black hole mass) and the size of BLRs for both normal and low-luminosity AGN. In this paper we find a non-linear dependence of the BLR sizes of low-luminosity AGN on black hole masses. We also show that the sizes of BLRs are more strongly dominated by the 'specific accretion rate' m Hα , defined as m Hα = L Hα /L Edd , than by the masses of their central black holes. An expected result of this is that the size of the emission regions of low-ionization broad Ha of NGC 4395 should be consistent with the value from the empirical relation of R BLRs -L Hα , according to the high accretion rate.