9 papers
Quasars and Narrow-Line Seyfert 1s: Trends and Selection Effects
Joseph C. Shields, Anca Constantin
The SDSS has opened a new era for the study of AGN spectroscopic properties and how these depend on luminosity and time. In this presentation we review some of the current issues a…
The Nuclei of Late-type Spiral Galaxies
T. Boeker, C. -J. Walcher, H. -W. Rix +8
We summarize some recent results from our observational campaign to study the central regions of spiral galaxies of late Hubble type (Scd - Sm). These disk-dominated, bulgeless gal…
Measuring Black Hole Masses Using Ionized Gas Kinematics
Aaron J. Barth, Marc Sarzi, Luis C. Ho +5
We describe techniques for measuring the central masses of galaxies using emission-line kinematics observed with the Hubble Space Telescope. For accurate results, it is necessary t…
X-Ray Absorption Associated with High-Velocity UV Absorbers
B. M. Sabra, F. Hamann, J. C. Shields +2
We present Chandra observations of two radio-quiet QSOs, PG 2302+029 and PG 1254+047. PG 2302+029 has an ultra high-velocity UV absorption system -56,000 km/s, while PG 1254+047 is…
Calibrating nebular diagnostics of T_* and abundance
M. S. Oey, J. C. Shields, M. A. Dopita +1
We obtained nebular spectroscopy of LMC HII regions having classified stellar populations, thereby strongly constraining the ionization input parameters. Using photoionization mode…
Supermassive Black Holes from the SUNNS survey
Marc Sarzi, Hans-Walter Rix, Joseph C. Shields +5
We report three new accurate mass measurements for the supermassive black holes hosted by the early-type disk galaxies NGC2787, NGC4459 and NGC4596. The targets were selected from…