Open AccessPrimordial 4He abundance refinement using sample of SDSS DR15 galaxies
Author(s) -
Oleg A. Kurichin,
A. V. Ivanchik,
В. В. Клименко
Publication year - 2019
Publication title -
journal of physics. conference series
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.21
H-Index - 85
eISSN - 1742-6596
pISSN - 1742-6588
DOI - 10.1088/1742-6596/1400/2/022051
Subject(s) - sky , astrophysics , abundance (ecology) , metallicity , galaxy , physics , spectral line , astronomy , biology , fishery
We present spectroscopic data on metal-deficient HII regions from dwarf galaxies of the Local Volume on the basis of Sloan Digital Sky Survey (SDSS) Data Release 15 observations. Using the data on the intensities of the optical emission lines of the HII regions, one can determine their chemical composition, as well as other physical properties, such as temperature and electron density. Oxygen abundance (and thus the metallicity) of the source is determined using direct method by using strong [OIII] lines. Here we present only sources with oxygen abundance below 12 + logO/H = 8.5. These data is used to determine primordial helium abundance, which value should be determined with as little errors as possibles. The main way to reduce errors is to use the spectroscopic data of the highest quality possible. On the other hand one can statistically decrease evaluation errors by using large dataset. Main focus of this paper is studying if we can decrease errors in Y p determination by combining HeBCD sample with SDSS spectra of lower quallity.