4 papers
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 III: LUCI Spectra of Metal-Poor Nebulae
Miqaela K. Weller, Richard W. Pogge, Evan D. Skillman +6
Accurately determining the elemental abundances of a low metallicity nebula strongly depends on measuring the density (n) and temperature (T) of the gas. Because these two…
The LBT Project II: MODS Spectra, Physical Conditions, and Oxygen Abundances in Local Metal-Poor Nebulae
Noah S. J. Rogers, Evan D. Skillman, Richard W. Pogge +7
Empirically measuring the primordial He mass fraction, , requires a significant number of low-metallicity nebulae with direct constraints on He/H and O/H abundances. Thi…
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…