SDSS-IV MaStar: theoretical atmospheric parameters for the MaNGA stellar library
ABSTRACT

We calculate the fundamental stellar parameters effective temperature, surface gravity, and iron abundance – Teff, log g, [Fe/H] – for the final release of the Mapping Nearby Galaxies at APO (MaNGA) Stellar Library (MaStar), containing 59 266 per-visit-spectra for 24 290 unique stars at intermediate resolution (R ∼ 1800) and high S/N (median = 96). We fit theoretical spectra from model atmospheres by both MARCS and BOSZ-ATLAS9 to the observed MaStar spectra, using the full spectral fitting code pPXF. We further employ a Bayesian approach, using a Markov Chain Monte Carlo (MCMC) technique to map the parameter space and obtain uncertainties. Originally in this paper, we cross match MaStar observations with Gaia photometry, which enable us to set reliable priors and identify outliers according to stellar evolution. In parallel to the parameter determination, we calculate corresponding stellar population models to test the reliability of the parameters for each stellar evolutionary phase. We further assess our procedure by determining parameters for standard stars such as the Sun and Vega and by comparing our parameters with those determined in the literature from high-resolution spectroscopy (APOGEE and SEGUE) and from lower resolution matching template (LAMOST). The comparisons, considering the different methodologies and S/N of more »

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Award ID(s):
Publication Date:
NSF-PAR ID:
10379840
Journal Name:
Monthly Notices of the Royal Astronomical Society
Volume:
509
Issue:
3
Page Range or eLocation-ID:
p. 4308-4329
ISSN:
0035-8711
Publisher:
Oxford University Press
We present a Bayesian isochrone fitting machinery to derive distances, extinctions, and stellar parameters (Teff, log g, and $\rm [Fe/H]$) for stars in the SkyMapper data release 3 (DR3) survey. We complement the latter with photometry from Gaia, 2MASS, and AllWISE, in addition to priors on parallaxes and interstellar extinction. We find our results to be in agreement with smaller samples of literature values derived using spectroscopic/photometric method, with typical uncertainties of order 130 K in effective temperature and 0.2 dex in surface gravity and metallicity. We demonstrate the quality of our stellar parameters by benchmarking our results against various spectroscopic surveys. We highlight the potential that SkyMapper bears for stellar population studies showing how we are able to clearly differentiate metallicities along the Gaia red (∼−0.4 dex) and blue (∼−1.1 dex) sequences using both dwarf and giant stars.