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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…
Tip of the Red Giant Branch Distances to NGC 1316, NGC 1380, NGC 1404, & NGC 4457: A Pilot Study of a Parallel Distance Ladder Using Type Ia Supernovae in Early-Type Host Galaxies
Max J. B. Newman, Conor Larison, Saurabh W. Jha +10
Though type-Ia supernovae (SNe Ia) are found in all types of galaxies, recent local Hubble constant measurements have disfavored using SNe Ia in early-type or quiescent galaxies, a…
An Empirical Calibration of the Tip of the Red Giant Branch Distance Method in the Near Infrared. II. JWST NIRCam Wide Filters
Max J. B. Newman, Kristen B. W. McQuinn, Evan D. Skillman +4
The tip of the red giant (TRGB) is a standardizable candle and is identifiable as the discontinuity at the bright extreme of the red giant branch (RGB) stars in color-magnitude dia…
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…