278 citations · 958 across the 20 of their papers we have counts for
12 papers · 1 filter
Powerful flares from recoiling black holes in quasars
G. A. Shields, E. W. Bonning
Mergers of spinning black holes can give recoil velocities from gravitational radiation up to several thousand km/s. A recoiling supermassive black hole in an AGN retains the inner…
Quasars with a Kick -- Black Hole Recoil in Quasars
G. A. Shields, E. W. Bonning, S. Salviander
Mergers of spinning black holes can give recoil velocities from gravitational radiation up to several thousand km/s. A recoiling supermassive black hole in an AGN can retain the in…
Evolution of the Black Hole - Bulge Relationship in QSOs
G. A. Shields, S. Salviander, E. W. Bonning
QSOs allow study of the evolution of the relationship between black holes in galactic nuclei and their host galaxies. The black hole mass can be derived from the widths of the broa…
The Black Hole - Bulge Relationship for QSOs at High Redshift
G. A. Shields, K. L. Menezes, C. A. Massart +1
We examine the black hole mass - galaxy bulge relationship in high-redshift QSOs. Black hole masses are derived from the broad emission lines, and the host galaxy stellar velocity…
QSO Host Galaxy Luminosity and [OIII] Line Width as a Surrogate for Stellar Velocity Distribution
E. W. Bonning, G. A. Shields, S. Salviander +1
Supermassive black holes in galactic nuclei show a close relationship between the black hole mass, luminosity, and stellar velocity dispersion (sigma_*) of the host galaxy bulge. P…
How Massive Are BALQSO Winds?
F. Hamann, B. Sabra, V. Junkkarinen +2
We are involved in a program to derive properties of broad absorption line (BAL) winds in quasars using combined UV and X-ray observations. A major obstacle is large uncertainties…
The Puzzle of the Lyman Continuum Polarization of QSOs
Gregory Shields, E. Agol, Omer Blaes
Recent spectropolarimetry of QSOs has revealed a surprising rise in polarization in the Lyman continuum of several objects. We discuss several recent attempts to interpret this fea…
The Lyman Continuum Polarization Rise in the QSO PG 1222+228
Gregory A. Shields
Some QSOs show an abrupt, strong rise in polarization near rest wavelength 750 A. If this arises in the atmosphere of an accretion disk around a supermassive black hole, it may hav…
A Brief History of AGN
Gregory A. Shields
Astronomers knew early in the twentieth century that some galaxies have emission-line nuclei. However, even the systematic study by Seyfert (1943) was not enough to launch active g…
Novae and BAL QSOs: The Aluminum Test
Gregory A. Shields
Novae have been proposed as the explanation of high reported abundances of heavy elements in the gas producing the broad absorption lines (BALs) of QSOs. High abundances of odd num…
The Extraordinary Abundances of QSO Broad Absorption Line Regions: A Matter of Novae?
Gregory A. Shields
The broad absorption lines (BALs) of QSOs indicate abundances of heavy elements, relative to hydrogen, that are 1 to 2 orders of magnitude higher than the solar values. In at least…
Chemical Abundances in Virgo Spiral Galaxies II: Effects of Cluster Environment
Evan D. Skillman, Robert C. Kennicutt, Gregory A. Shields +1
We present new measurements of chemical abundances in H II regions in spiral galaxies of the Virgo cluster and a comparison of Virgo galaxies and field spirals. With these new data…