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An Improved Method for Using MgII to Estimate Black Hole Masses in Active Galactic Nuclei
Christopher A. Onken, Juna A. Kollmeier
We present a method for obtaining accurate black hole (BH) mass estimates from the MgII emission line in active galactic nuclei (AGNs). Employing the large database of AGN measurem…
The Black Hole Mass of NGC 4151: Comparison of Reverberation Mapping and Stellar Dynamical Measurements
Christopher A. Onken, Monica Valluri, Bradley M. Peterson +11
We present a stellar dynamical estimate of the black hole (BH) mass in the Seyfert 1 galaxy, NGC 4151. We analyze ground-based spectroscopy as well as imaging data from the ground…
NGC 5548 in a Low-Luminosity State: Implications for the Broad-Line Region
Misty C. Bentz, Kelly D. Denney, Edward M. Cackett +15
We describe results from a new ground-based monitoring campaign on NGC 5548, the best studied reverberation-mapped AGN. We find that it was in the lowest luminosity state yet recor…
The Mass of the Black Hole in the Seyfert 1 Galaxy NGC 4593 from Reverberation Mapping
Kelly D. Denney, Misty C. Bentz, Bradley M. Peterson +15
We present new observations leading to an improved black hole mass estimate for the Seyfert 1 galaxy NGC 4593 as part of a reverberation-mapping campaign conducted at the MDM Obser…
A Reverberation-Based Mass for the Central Black Hole in NGC 4151
Misty C. Bentz, Kelly D. Denney, Edward M. Cackett +15
We have undertaken a new ground-based monitoring campaign to improve the estimates of the mass of the central black hole in NGC 4151. We measure the lag time of the broad H beta li…
The Mass of the Central Black Hole in the Seyfert Galaxy NGC 4151
Kyle G. Metzroth, Christopher A. Onken, Bradley M. Peterson
In order to improve the reverberation-mapping based estimate of the mass of the central supermassive black hole in the Seyfert 1 galaxy NGC 4151, we have reanalyzed archival ultrav…
The Radius-Luminosity Relationship for Active Galactic Nuclei: The Effect of Host-Galaxy Starlight on Luminosity Measurements
Misty C. Bentz, Bradley M. Peterson, Richard W. Pogge +2
We have obtained high resolution images of the central regions of 14 reverberation-mapped active galactic nuclei (AGN) using the Hubble Space Telescope Advanced Camera for Surveys…
Black Hole Masses and Eddington Ratios at 0.3<z<4
Juna A. Kollmeier, Christopher A. Onken, Christopher S. Kochanek +9
We study the distribution of Eddington luminosity ratios, L_bol/L_edd, of active galactic nuclei (AGNs) discovered in the AGN and Galaxy Evolution Survey (AGES). We combine H-beta,…
Central Masses and Broad-Line Region Sizes of Active Galactic Nuclei. II. A Homogeneous Analysis of a Large Reverberation-Mapping Database
B. M. Peterson, L. Ferrarese, K. M. Gilbert +9
We present improved black hole masses for 35 active galactic nuclei (AGNs) based on a complete and consistent reanalysis of broad emission-line reverberation-mapping data. From obj…
Supermassive Black Holes in Active Galactic Nuclei. II. Calibration of the M-sigma Relationship for AGNs
Christopher A. Onken, Laura Ferrarese, David Merritt +5
We calibrate reverberation-based black hole masses in active galactic nuclei (AGNs) by using the correlation between black hole mass, M, and bulge/spheroid stellar velocity dispers…
History of Hydrogen Reionization in the Cold Dark Matter Model
Christopher A. Onken, Jordi Miralda-Escude
We calculate the reionization history in Cold Dark Matter (CDM) models. The epoch of the end of reionization and the Thomson scattering optical depth to the cosmic microwave backgr…
Black Hole Masses in Three Seyfert Galaxies
C. A. Onken, B. M. Peterson, M. Dietrich +2
We analyze published reverberation mapping data for three Seyfert galaxies (NGC 3227, NGC 3516, and NGC 4593) to refine the mass estimate for the supermassive black hole in the cen…
Steps Toward Determination of the Size and Structure of the Broad-Line Region in Active Galactic Nuclei. XVI. A Thirteen-Year Study of Spectral Variability in NGC 5548
B. M. Peterson, the International AGN Watch
We present the final installment of an intensive 13-year study of variations of the optical continuum and broad H-beta emission line in the Seyfert 1 galaxy NGC 5548. The data base…
The Mass of the Central Black Hole in the Seyfert Galaxy NGC 3783
Christopher A. Onken, Bradley M. Peterson
Improved analysis of ultraviolet and optical monitoring data on the Seyfert 1 galaxy NGC 3783 provides evidence for the existence of a supermassive, (8.7+/-1.1)x10^6 M_sun, black h…
CCD Photometry of the Globlular Cluster NGC 5986 and its Post-Asymptotic-Giant-Branch and RR Lyrae Stars
D. R. Alves, H. E. Bond, C. Onken
We have obtained new CCD BV photometry of the little-studied southern Galactic globular cluster NGC 5986, including light curves of 5 of its RR Lyrae variables. The cluster's red g…