The Southern Hemisphere Narrow-Line Seyfert 1 Infrared Survey
  We present a near-infrared spectroscopic survey of narrow-line Seyfert 1
galaxies in the southern hemisphere (using the SOFI instrument on the ESO-NTT
telescope), sampled from optical surveys. We examine the kinematics of the
broad-line region, probed by the emission line width of hydrogen (Pa$\alpha$
and H$\beta$). We observed 57 objects, of which we could firmly measure
Pa$\alpha$ in 49 cases. We find that a single Lorentzian fit (preferred on
theoretical grounds) is preferred over multi-component Gaussian fits to the
line profiles; a lack of narrow-line region emission, overwhelmed by the
pole-on view of the broad line region (BLR) light, supports this. We recompute
the catalog black hole (BH) mass estimates, using the values of FWHM and
luminosity of H$\beta$, both from catalog values and re-fitted Lorentzian
values. We find a relationship slope greater than unity compared to the catalog
values. We ascribe this to contamination by galactic light or difficulties with
line flux measurements. However, the comparison of masses computed by the
fitted Lorentzian and Gaussian measurements show a slope close to unity.
Comparing the BH masses estimated from both Pa$\alpha$ and H$\beta$, the line
widths and fluxes shows deviations from expected; in general, however, the
computed BH masses are comparable. We posit a scenario where an intermixture of
dusty and dust-free clouds (or alternately a structured atmosphere)
differentially absorbs the line radiation of the BLR, due to dust absorption
and hydrogen bound-free absorption.
