SIMBAD references

Narrow-line Seyfert 1 galaxies (NLS1s) are arguably one of the key active galactic nucleus (AGN) subclasses in investigating the origin of the black hole mass-stellar velocity dispersion (M_BH - σ_*) relation because of their high accretion rate and significantly low M_BH. Currently, it is under discussion whether present-day NLS1s offset from the M_BH - σ_* relation. Using the directly measured stellar velocity dispersion of 93 NLS1s at z < 0.1, and M_BH estimates based on the updated mass estimators, we investigate the M_BH - σ_* relation of NLS1s in comparison with broad-line AGNs. We find no strong evidence that the NLS1s deviates from the M_BH - σ_* relation, which is defined by reverberation-mapped type 1 AGNs and quiescent galaxies. However, there is a clear trend of the offset with the host galaxy morphology, i.e., galaxies that are more inclined toward the LOS have higher stellar velocity dispersions, suggesting that the rotational broadening plays a role in measuring stellar velocity dispersion based on the single-aperture spectra from the Sloan Digital Sky Survey. In addition, we provide the virial factor log f = 0.05 ± 0.12 (f = 1.12), for M_BH estimators based on the FWHM of Hβ, by jointly fitting the M_BH - σ_* relation using quiescent galaxies and reverberation-mapped AGNs.