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The LBT Project V: Cosmological Implications of a New Determination of Primordial He
Tsung-Han Yeh, Keith A. Olive, Brian D. Fields +5
The primordial abundance of He plays a central role in big-bang nucleosynthesis (BBN) and in the cosmic microwave background (CMB). The LBT Project's new measuremen…
The LBT Y Project IV: A New Value of the Primordial Helium Abundance
Erik Aver, Evan D. Skillman, Richard W. Pogge +7
We present a new determination of the primordial helium abundance based on new, high-quality Large Binocular Telescope (LBT) observations of 54 metal-poor H II regions. These regio…
The LBT Project I: An Improved Determination of the Primordial Helium Abundance -- Project Description, Sample Selection, Observations, and Methodology
Evan D. Skillman, Richard W. Pogge, Erik Aver +9
Extremely low metallicity HII regions have been observed with the goal of determining the primordial helium abundance (). , combined with standard big bang nu…
Improving Helium Abundance Determinations with Leo P as a Case Study
Erik Aver, Danielle A. Berg, Keith A. Olive +3
Currently, the primordial helium abundance is best estimated through spectroscopic observations of H II regions in metal-poor galaxies. However these determinations are limited by…
The Size of the Narrow-Line Emitting Region in the Seyfert 1 Galaxy NGC 5548 from Emission-Line Variability
B. M. Peterson, K. D. Denney, G. De Rosa +8
The narrow [O III] 4959, 5007 emission-line fluxes in the spectrum of the well-studied Seyfert 1 galaxy NGC 5548 are shown to vary with time. From this we show that the narrow line…
Stellar Velocity Dispersion Measurements in High-Luminosity Quasar Hosts and Implications for the AGN Black Hole Mass Scale
C. J. Grier, P. Martini, L. C. Watson +7
We present new stellar velocity dispersion measurements for four luminous quasars with the NIFS instrument and the ALTAIR laser guide star adaptive optics system on the Gemini Nort…
ALFALFA Discovery of the Nearby Gas-Rich Dwarf Galaxy Leo~P. III. An Extremely Metal Deficient Galaxy
Evan D. Skillman, John J. Salzer, Danielle A. Berg +10
We present KPNO 4-m and LBT/MODS spectroscopic observations of an HII region in the nearby dwarf irregular galaxy Leo P discovered recently in the Arecibo ALFALFA survey. In both o…
The Low-Luminosity End of the Radius-Luminosity Relationship for Active Galactic Nuclei
Misty C. Bentz, Kelly D. Denney, Catherine J. Grier +15
We present an updated and revised analysis of the relationship between the Hbeta broad-line region (BLR) radius and the luminosity of the active galactic nucleus (AGN). Specificall…
CIV Line-Width Anomalies: The Perils of Low S/N Spectra
Kelly D. Denney, Richard W. Pogge, Roberto J. Assef +3
Comparison of six high-redshift quasar spectra obtained with the Large Binocular Telescope with previous observations from the Sloan Digital Sky Survey shows that failure to correc…
The Mid-Infrared and Optical Decay of SN 2011fe
Colin M. McClelland, Peter M. Garnavich, Peter A. Milne +2
We measure the decay rate of the mid-IR luminosity from type Ia supernova 2011fe between six months and one year after explosion using Spitzer/IRAC observations. The fading in the…
No Stripped Hydrogen in the Nebular Spectra of Nearby Type Ia Supernova 2011fe
Benjamin J. Shappee, K. Z. Stanek, R. W. Pogge +1
A generic prediction of the single-degenerate model for Type Ia supernovae (SNe Ia) is that a significant amount of material will be stripped from the donor star (~0.5 Msun for a g…
The Structure of the Broad Line Region in AGN: I. Reconstructed Velocity-Delay Maps
C. J. Grier, B. M. Peterson, Keith Horne +38
We present velocity-resolved reverberation results for five active galactic nuclei. We recovered velocity-delay maps using the maximum-entropy method for four objects: Mrk 335, Mrk…
Reverberation Mapping Results for Five Seyfert 1 Galaxies
C. J. Grier, B. M. Peterson, R. W. Pogge +40
We present the results from a detailed analysis of photometric and spectrophotometric data on five Seyfert 1 galaxies observed as a part of a recent reverberation mapping program.…
Probing the low-redshift star formation rate as a function of metallicity through the local environments of type II supernovae
R. Stoll, J. L. Prieto, K. Z. Stanek +1
Type II SNe can trace star formation to probe its global metallicity distribution at low-redshift. We present oxygen and iron abundance distributions of SN II progenitor regions th…
The Unusual Temporal and Spectral Evolution of the Type IIn Supernova 2011ht
P. W. A. Roming, T. A. Pritchard, J. L. Prieto +17
We present very early UV to optical photometric and spectroscopic observations of the peculiar Type IIn supernova (SN) 2011ht in UGC 5460. The UV observations of the rise to peak a…
A Reverberation Lag for the High-Ionization Component of the Broad Line Region in the Narrow-Line Seyfert 1 Mrk 335
C. J. Grier, B. M. Peterson, R. W. Pogge +37
We present the first results from a detailed analysis of photometric and spectrophotometric data on the narrow-line Seyfert 1 galaxy Mrk 335, collected over a 120-day span in the f…
SN 2010jl in UGC 5189: Yet another luminous type IIn supernova in a metal-poor galaxy
R. Stoll, J. L. Prieto, K. Z. Stanek +5
We present ASAS data starting 25 days before the discovery of the recent type IIn SN 2010jl, and we compare its light curve to other luminous IIn SNe, showing that it is a luminous…
Black Hole Mass Estimates Based on CIV are Consistent with Those Based on the Balmer Lines
R. J. Assef, K. D. Denney, C. S. Kochanek +39
Using a sample of high-redshift lensed quasars from the CASTLES project with observed-frame ultraviolet or optical and near-infrared spectra, we have searched for possible biases b…
Reverberation Mapping Measurements of Black Hole Masses in Six Local Seyfert Galaxies
K. D. Denney, B. M. Peterson, R. W. Pogge +40
We present the final results from a high sampling rate, multi-month, spectrophotometric reverberation mapping campaign undertaken to obtain either new or improved Hbeta reverberati…
Reverberation Mapping Results from MDM Observatory
Kelly D. Denney, B. M. Peterson, R. W. Pogge +6
We present results from a multi-month reverberation mapping campaign undertaken primarily at MDM Observatory with supporting observations from around the world. We measure broad li…
Diverse Broad Line Region Kinematic Signatures From Reverberation Mapping
K. D. Denney, B. M. Peterson, R. W. Pogge +40
A detailed analysis of the data from a high sampling rate, multi-month reverberation mapping campaign, undertaken primarily at MDM Observatory with supporting observations from tel…
XMM-Newton observations of SDSS J143030.22001115.1: an unusually flat spectrum AGN
S. Mathur, E. C. Golowacz, R. Williams +3
We present XMM observations of the AGN SDSS 1430-0011. The low S/N spectrum of this source obtained in a snap shot Chandra observation showed an unusually flat continuum. With the…