SIMBAD references

2021MNRAS.502.3045K - Mon. Not. R. Astron. Soc., 502, 3045-3056 (2021/April-1)

A new determination of the primordial helium abundance using the analyses of H II region spectra from SDSS.


Abstract (from CDS):

The precision measurement of the primordial helium abundance Yp is a powerful probe of the early Universe. The most common way to determine Yp is the analyses of observations of metal-poor H II regions found in blue compact dwarf galaxies. We present the spectroscopic sample of 100 H II regions collected from the Sloan Digital Sky Survey. The final analysed sample consists of our sample and HeBCD data base from Izotov et al. (2007). We use a self-consistent procedure to determine physical conditions, current helium abundances, and metallicities of the H II regions. From a regression to zero metallicity, we have obtained Yp = 0.2462 ± 0.0022, which is one of the most stringent constraints obtained with such methods up to date and is in a good agreement with the Planck result Y_ p_^Planck^ = 0.2471 ±0.0003. Using the determined value of Yp and the primordial deuterium abundance taken from Particle Data Group (Zyla et al. 2020) we put a constraint on the effective number of neutrino species Neff = 2.95 ± 0.16, which is consistent with the Planck one Neff = 2.99 ± 0.17. Further increase of statistics potentially allows us to achieve Planck accuracy, which in turn will become a powerful tool for studying the self-consistency of the standard cosmological model and/or physics beyond.

Abstract Copyright: © 2021 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society

Journal keyword(s): galaxies: abundances - galaxies: starburst - cosmological parameters - early Universe - primordial nucleosynthesis

CDS comments: The objects from Table 2 are not in SIMBAD (not enough information). HS 1700+5416 is a misprint for HS 1700+6416.

Simbad objects: 21

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