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Session 13 - Large Scale Structure & Cosmology.
Display session, Monday, January 13
Metropolitan Ballroom,
We report progress on observational and theoretical work related to a more accurate determination of the primordial helium abundance.
WHT and Calar Alto 3.5m double spectrograph observations of the very low metallicity galaxy SBS 0335-052 are presented. Simultaneous measurement of several helium emission lines with two independent telescope/spectrograph configurations allow us to derive a very accurate helium abundance for this object.
We have also carried out a detailed comparison of two atomic data sets (Almog amp; Netzer 1989; Smits 1996) for calculating the recombination spectrum of helium. This resultant atomic data has been combined with the recently calculated collision strengths of Sawey amp; Berrington (1993). Differences in the resultant emission line intensities from previous works are illustrated, and the significance for observational studies is discussed.
