摘要：Context. It is not yet well known whether narrow line Seyfert 1 (NLS1)
galaxies follow the MBH −
σ⋆ relation found for
normal galaxies. Emission lines, such as [SII] or [OIII]λ5007, have been used as a
surrogate of the stellar velocity dispersion and various results have been obtained. On
the other hand, some active galactic nuclei (AGNs) have shown Balmer emission with an
additional intermediate component (IC) besides the well-known narrow and broad lines. The
properties of this IC have not yet been fully studied.
Aims. In order to re-examine the location of NLS1 in the MBH −
σ⋆ relation, we test
some emission lines, such as the narrow component (NC) of Hα and the forbidden
[NII]λλ6548,6584 and [SII]λλ6716,6731 lines, as
replacements for σ⋆. On the other
hand, we study the properties of the IC of Hα found in 14 galaxies of the sample to find a link
between this component, the central engine, and the remaining lines. We also compare the
emission among the broad component (BC) of Hα and those emitted at the narrow line region (NLR)
to detect differences in the ionizing source in each emitting region.
Methods. We have obtained and studied medium-resolution spectra (170
km s-1 FWHM at
Hα) of 36
NLS1 galaxies in the optical range ~5800−6800
Å. We performed a Gaussian decomposition of the Hα +[NII]λλ6548,6584 profile to
study the distinct components of Hα and [NII] lines. We also measured the [SII]
lines.
Results. We obtained black hole (BH) masses in the range log
(MBH/M⊙) =
5.4−7.5 for our sample. We found that, in general, most of the
galaxies lie below the MBH −
σ⋆ relation when the NC of
Hα and
[NII] lines are used as a surrogate of σ⋆. The objects are
closer to the relation when [SII] lines are used. Nevertheless, the galaxies are still
below this relation and we do not see a clear correlation between the BH masses and
FWHM[SII].
Besides this, we found that 13 galaxies show an IC, most of which are in the velocity
range ~700−1500 km s-1. This is same range as in AGN
types and is well correlated with the FWHM of BC and, therefore, with the BH mass. On the
other hand, we found that there is a correlation between the luminosity of the BC of
Hα and NC,
IC, [NII]λ6584, and [SII] lines.
关键词：galaxies: active;galaxies: Seyfert;galaxies: nuclei;galaxies: kinematics and dynamics
