We describe a sample of low-mass Seyfert 2 galaxies selected from the Sloan Digital Sky Survey , having a median absolute magnitude of M _ { g } = -19.0 mag .
These galaxies are Type 2 counterparts to the Seyfert 1 galaxies with intermediate-mass black holes identified by Greene & Ho ( 2004 ) .
Spectra obtained with the Echellette Spectrograph and Imager at the Keck Observatory are used to determine the central stellar velocity dispersions and to examine the emission-line properties .
Overall , the stellar velocity dispersions are low ( \sim 40 - 90 km s ^ { -1 } ) , and we find 12 objects having \sigma _ { \star } < 60 km s ^ { -1 } , a range where very few Seyfert 2 galaxies were previously known .
The sample follows the correlation between stellar velocity dispersion and FWHM ( [ O iii ] ) seen in more massive Seyfert galaxies , indicating that the narrow-line FWHM values are largely determined by virial motion of gas in the central regions of the host galaxies , but the [ O iii ] emission lines exhibit a higher incidence of redward asymmetries and double-peaked profiles than what is found in typical Seyfert samples .
Using estimates of the black hole masses and AGN bolometric luminosities , we find that these galaxies are typically radiating at a high fraction of their Eddington rate , with a median L _ { \mathrm { bol } } / L _ { \mathrm { Edd } } = 0.4 .
We identify one galaxy , SDSS J110912.40+612346.7 , as a Type 2 analog of the nearby dwarf Seyfert 1 galaxy NGC 4395 , with a nearly identical narrow-line spectrum and a dwarf spiral host of only M _ { g } = -16.8 mag .
The close similarities between these two objects suggest that the obscuring torus of AGN unification models may persist even at the lowest luminosities seen among Seyfert galaxies , below L _ { \mathrm { bol } } = 10 ^ { 41 } ergs s ^ { -1 } .
Spectropolarimetry observations of four objects do not reveal any evidence for polarized broad-line emission , but SDSS J110912.40+612346.7 has a continuum polarization significantly in excess of the expected Galactic foreground polarization , possibly indicative of scattered light from a hidden nucleus .
Forthcoming observations of this sample , including X-ray and mid-infrared spectroscopy , can provide new tests of the obscuring torus model for active galaxies at low luminosities .