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 [10.1111/j.1745-3933.2008.00451.x].

Are the black hole masses in narrow-line Seyfert 1 galaxies actually small?

DOTTI, MASSIMO;
2008

Abstract

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.
Articolo in rivista - Articolo scientifico
galaxies: active, galaxies: nuclei, galaxies: Seyfert
English
mag-2008
386
1
L15
L19
none
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 [10.1111/j.1745-3933.2008.00451.x].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/21526
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