Journal Article

A note on black hole masses estimated by the second moment in narrow-line Seyfert 1 Galaxies

Wei-Hao Bian, Chen Hu, Qiu-Sheng Gu and Jian-Min Wang

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 390, issue 2, pages 752-758
Published in print October 2008 | ISSN: 0035-8711
Published online October 2008 | e-ISSN: 1365-2966 | DOI:
A note on black hole masses estimated by the second moment in narrow-line Seyfert 1 Galaxies

Show Summary Details


The second moment of the Hβ emission line is calculated for 329 narrow-line Seyfert 1 galaxies (NLS1s) selected from the Sloan Digital Sky Survey (SDSS), which is used to calculate the central supermassive black hole (SMBH) mass of each. We find that the second moment depends strongly on the broader component of the Hβ line profile. We find that for the NLS1s requiring two Gaussians to fit the Hβ line, the mean value of the SMBH mass from the Hβ second moment is larger by about 0.50 dex than that from the full width at half-maximum. Using the gas velocity dispersion of the core/narrow component of [O iii]λ5007 to estimate the stellar velocity dispersion σ*, the new mass makes NLS1s fall very close to the MBH–σ* relation for normal active galactic nuclei. By using σ* measured directly from SDSS spectra with a simple stellar population synthesis method, we find that for NLS1s with mass lower than 107M, they fall only marginally below the MBH–σ* relation considering the large scatter in the mass calculation.

Keywords: black hole physics; galaxies: active; galaxies: nuclei

Journal Article.  5322 words.  Illustrated.

Subjects: Astronomy and Astrophysics

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