Spatially Resolved Spectroscopy of Narrow-line Seyfert 1 Host Galaxies

Abstract

We present optical integral field spectroscopy for five $z\lt 0.062$ narrow-line Seyfert 1 (NLS1) galaxies, probing their host galaxies at $\gtrsim 2\mbox{--}3\,\mathrm{kpc}$ scales. Emission lines from the active galactic nucleus (AGN) and the large-scale host galaxy are analyzed separately, based on an AGN–host decomposition technique. The host galaxy gas kinematics indicates large-scale gas rotation in all five sources. At the probed scales of $\gtrsim 2\mbox{--}3\,\mathrm{kpc}$, the host galaxy gas is found to be predominantly ionized by star formation without any evidence of a strong AGN contribution. None of the five objects shows specific star formation rates (SFRs) exceeding the main sequence of low-redshift star-forming galaxies. The specific SFRs for MCG-05-01-013 and WPVS 007 are roughly consistent with the main sequence, while ESO 399-IG20, MS 22549-3712, and TON S180 show lower specific SFRs, intermediate to the main sequence and the red quiescent galaxies. The host galaxy metallicities, derived for the two sources with sufficient data quality (ESO 399-IG20 and MCG-05-01-013), indicate central oxygen abundances just below the low-redshift mass–metallicity relation. Based on this initial case study, we outline a comparison of AGN and host galaxy parameters as a starting point for future extended NLS1 studies with similar methods. Show more