Narrow-line Seyfert 1 galaxies (NLS1s) are generally considered peculiar objects among the broad class of type 1 active galactic nuclei, due to the relatively small width of the broad lines, strong X-ray variability, soft X-ray continua, weak [OIII], and strong FeII line intensities. The mass MBH of the central massive black hole (MBH) is claimed to be lighter than expected from known MBH-host galaxy scaling relations, while the accretion rate on to the MBH larger than the average value appropriate to Seyfert 1 galaxies. In this Letter, we show that NLS1 peculiar MBH and L/LEdd turn out to be fairly standard, provided that the broad-line region is allowed to have a disc-like, rather than isotropic, geometry. Assuming that NLS1s are rather `normal' Seyfert 1 objects seen along the disc axis, we could estimate the typical inclination angles from the fraction of Seyfert 1 classified as NLS1s, and compute the geometrical factor relating the observed full width at half-maximum of broad lines to the virial mass of the MBH. We show that the geometrical factor can fully account for the `black hole mass deficit' observed in NLS1s, and that L/LEdd is (on average) comparable to the value of the more common broad-line Seyfert 1 galaxies.
Decarli, R., Dotti, M., Fontana, M., & Haardt, F. (2008). Are the black hole masses in narrow-line Seyfert 1 galaxies actually small?. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY. LETTERS, 386(1), L15-L19.
|Citazione:||Decarli, R., Dotti, M., Fontana, M., & Haardt, F. (2008). Are the black hole masses in narrow-line Seyfert 1 galaxies actually small?. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY. LETTERS, 386(1), L15-L19.|
|Tipo:||Articolo in rivista - Articolo scientifico|
|Carattere della pubblicazione:||Scientifica|
|Titolo:||Are the black hole masses in narrow-line Seyfert 1 galaxies actually small?|
|Autori:||Decarli, R; Dotti, M; Fontana, M; Haardt, F|
|Data di pubblicazione:||mag-2008|
|Rivista:||MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY. LETTERS|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1111/j.1745-3933.2008.00451.x|
|Appare nelle tipologie:||01 - Articolo su rivista|