scholarly journals Primordial helium abundance determination using sulphur as metallicity tracer

2018 ◽  
Vol 478 (4) ◽  
pp. 5301-5319 ◽  
Author(s):  
Vital Fernández ◽  
Elena Terlevich ◽  
Angeles I Díaz ◽  
Roberto Terlevich ◽  
F F Rosales-Ortega
Keyword(s):  
Helium Abundance ◽  
Primordial Helium ◽  
Abundance Determination

scholarly journals Blue Compact Galaxies and the Primordial Helium Abundance Determination

1998 ◽  
Vol 11 (1) ◽  
pp. 137-138
Author(s):  
Y.I. Izotov ◽  
T.X. Thuan
Keyword(s):  
Linear Regression ◽  
H Ii Regions ◽  
Helium Abundance ◽  
Line Intensities ◽  
Low Metallicity ◽  
Physical Effects ◽  
Primordial Helium ◽  
Compact Galaxies ◽  
Abundance Determination

Abstract 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.

scholarly journals Systematic effects and self-consistency in the primordial helium abundance determination

2018 ◽  
Vol 1135 ◽  
pp. 012006
Author(s):  
Oleg A. Kurichin ◽  
Alexandre V. Ivanchik
Keyword(s):  
Helium Abundance ◽  
Systematic Effects ◽  
Primordial Helium ◽  
Self Consistency ◽  
Abundance Determination

scholarly journals Temperature Bias and the Primordial Helium Abundance Determination

2002 ◽  
Vol 565 (2) ◽  
pp. 668-680 ◽  
Author(s):  
Antonio Peimbert ◽  
Manuel Peimbert ◽  
Valentina Luridiana
Keyword(s):  
Helium Abundance ◽  
Temperature Bias ◽  
Primordial Helium ◽  
Abundance Determination

scholarly journals Measurement of the primordial helium abundance from the intergalactic medium

2018 ◽  
Vol 2 (12) ◽  
pp. 957-961 ◽  
Author(s):  
Ryan J. Cooke ◽  
Michele Fumagalli
Keyword(s):  
Intergalactic Medium ◽  
Helium Abundance ◽  
Primordial Helium

Very Metal-Poor Galaxies and the Primordial Helium Abundance

1994 ◽  
pp. 182-191
Author(s):  
Elena Terlevich ◽  
Evan Skillman ◽  
Roberto Terlevich
Keyword(s):  
Helium Abundance ◽  
Primordial Helium

scholarly journals Determination of the Primordial Helium Abundance Based on NGC 346, an H ii Region of the Small Magellanic Cloud

2019 ◽  
Vol 876 (2) ◽  
pp. 98 ◽  
Author(s):  
Mabel Valerdi ◽  
Antonio Peimbert ◽  
Manuel Peimbert ◽  
Andrés Sixtos
Keyword(s):  
Magellanic Cloud ◽  
Helium Abundance ◽  
Small Magellanic Cloud ◽  
H Ii Region ◽  
Primordial Helium

Spectrophotometry of 12 metal-poor galaxies - Implications for the primordial helium abundance

1983 ◽  
Vol 273 ◽  
pp. 81 ◽  
Author(s):  
D. Kunth ◽  
W. L. W. Sargent
Keyword(s):  
Helium Abundance ◽  
Primordial Helium

On determining the primordial helium abundance from the spectra of H II galaxies

1992 ◽  
Vol 401 ◽  
pp. 157 ◽  
Author(s):  
Alison Campbell
Keyword(s):  
Helium Abundance ◽  
Primordial Helium
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