Hostname: page-component-84b7d79bbc-lrf7s Total loading time: 0 Render date: 2024-07-31T22:09:55.500Z Has data issue: false hasContentIssue false
  • English
  • Français

Blue Compact Galaxies and the Primordial Helium Abundance Determination

Published online by Cambridge University Press:  14 August 2015

Y.I. Izotov  and
T.X. Thuan
Y.I. Izotov
Affiliation:
Main Astronomical Observatory, Ukrainian National Academy of Sciences Goloseevo, Kiev-22, 252650, Ukraine
T.X. Thuan
Affiliation:
Astronomy Department, University of Virginia Charlottesville, VA 22903, USA

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

We use a sample of 45 low-metallicity H II regions to determine the primordial helium abundance Yp. We have carefully investigated the physical effects which may make the He I line intensities deviate from their recombination values such as collisional and fluorescent enhancements, underlying He I stellar absorption and absorption by Galactic interstellar Na, I. By extrapolating the Y vs. O/H linear regression to O/H = 0, we obtain Yp = 0.245±0.002. Our Yp gives 0.06±0.01.

Type
II. Joint Discussions
Information
Highlights of Astronomy , Volume 11 , Issue 1: Highlights of Astronomy. As presented at the XXIIIrd General Assembly of the IAU (Part A), 1997 , 1998 , pp. 137 - 138
Copyright
Copyright © Kluwer 1998

References

Izotov, Y.I., Thuan, T.X., & Lipovetsky, V.A. 1994, ApJ, 435, p. 647 Google Scholar
Izotov, Y.L., Thuan, T.X., & Lipovetsky, V.A. 1997, ApJS, 108, p. 1 Google Scholar
Izotov, Y.L., & Thuan, T.X. 1997, ApJ, in pressGoogle Scholar
Songaila, A., Cowie, L.L., Hogan, C.J., & Rugers, M. 1994, Nature, 368, p. 599 Google Scholar
Tytler, D., Fan, X.-M., & Buries, S. 1996, Nature, 381, p. 207 Google Scholar