Details

Autor(en) / Beteiligte

• Cracco, V.
• Ciroi, S.
• Berton, M.
• Di Mille, F.
• Foschini, L.
• La Mura, G.
• Rafanelli, P.

Titel

A spectroscopic analysis of a sample of narrow-line Seyfert 1 galaxies selected from the Sloan Digital Sky Survey

Ist Teil von

• Monthly notices of the Royal Astronomical Society, 2016-10, Vol.462 (2), p.1256-1280

Ort / Verlag

London: Oxford University Press

Erscheinungsjahr

2016

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• We revisited the spectroscopic characteristics of narrow-line Seyfert 1 galaxies (NLS1s) by analysing a homogeneous sample of 296 NLS1s at redshift between 0.028 and 0.345, extracted from the Sloan Digital Sky Survey (SDSS-DR7) public archive. We confirm that NLS1s are mostly characterized by Balmer lines with Lorentzian profiles, lower black hole masses and higher Eddington ratios than classic broad-line Seyfert 1 (BLS1s), but they also appear to be active galactic nuclei (AGNs) contiguous with BLS1s and sharing with them common properties. Strong Fe ii emission does not seem to be a distinctive property of NLS1s, as low values of Fe ii/Hβ are equally observed in these AGNs. Our data indicate that Fe ii and Ca ii kinematics are consistent with the one of Hβ. On the contrary, O i λ8446 seems to be systematically narrower and it is likely emitted by gas of the broad-line region more distant from the ionizing source and showing different physical properties. Finally, almost all NLS1s of our sample show radial motions of the narrow-line region highly ionized gas. The mechanism responsible for this effect is not yet clear, but there are hints that very fast outflows require high continuum luminosities (>1044 erg s−1) or high Eddington ratios (log (L bol/L Edd) > −0.1).