Stellar parameters for the First Release of the MaStar Library: An Empirical Approach

Abstract

We report the stellar atmospheric parameters for 7503 spectra contained in the first release of the MaNGA stellar library (MaStar) in SDSS DR15. The first release of MaStar contains 8646 spectra measured from 3321 unique stars, each covering the wavelength range 3622 Å to 10354 Å with a resolving power of $R\sim$ 1800. In this work, we first determined the basic stellar parameters: effective temperature (${\mathrm{T}}_{\mathrm{eff}}$), surface gravity ($\log g$), and metallicity ($[Fe/H]$), which best fit the data using an empirical interpolator based on the Medium-resolution Isaac Newton Telescope library of empirical spectra (MILES), as implemented by the University of Lyon Spectroscopic analysis Software (Koleva et al. 2008, ULySS) package. While we analyzed all 8646 spectra from the first release of MaStar, since MaStar has a wider parameter-space coverage than MILES, not all of these fits are robust. In addition, not all parameter regions covered by MILES yield robust results, likely due to the non-uniform coverage of the parameter space by MILES. We tested the robustness of the method using the MILES spectra itself and identified a proxy based on the local density of the training set. With this proxy, we identified 7503 MaStar spectra with robust fitting results. They cover the range from 3179K to 20,517K in effective temperature (${\mathrm{T}}_{\mathrm{eff}}$), from 0.40 to 5.0 in surface gravity ($\log g$), and from $-$2.49 to $+$0.73 in metallicity ($[Fe/H]$).

14 pages, 13 figures

References in corpus (11)

• A grid of MARCS model atmospheres for late-type stars I. Methods and general properties
• Overview of the SDSS-IV MaNGA Survey: Mapping Nearby Galaxies at Apache Point Observatory
• Evolutionary Stellar Population Synthesis with MILES. Part I: The Base Models and a New Line Index System
• The Data Reduction Pipeline for the SDSS-IV MaNGA IFU Galaxy Survey
• Medium-resolution Isaac Newton Telescope library of empirical spectra - II. The stellar atmospheric parameters
• M dwarfs: effective temperatures, radii and metallicities
• Spectroscopic ages and metallicities of stellar populations: validation of full spectrum fitting
• Spectral models for solar-scaled and alpha-enhanced stellar populations
• The X-shooter Spectral Library (XSL): I. DR1. Near-ultraviolet through optical spectra from the first year of the survey
• The Extended IRTF Spectral Library: Expanded coverage in metallicity, temperature, and surface gravity
• To use or not to use synthetic stellar spectra in population synthesis models?

Cited by in corpus (6)

• SDSS-IV MaStar: Data-driven Parameter Derivation for the MaStar Stellar Library
• SDSS-IV MaStar: Stellar Parameter Determination with Continuum-Supplemented Full-Spectrum Fitting
• Carbon- and Oxygen-rich stars in MaStar: identification and classification
• A new code for low-resolution spectral identification of white dwarf binary candidates
• SDSS-IV MaStar: Determination of Stellar Parameters Using Bayesian Averaging
• SDSS-IV MaStar: Theoretical Atmospheric Parameters for the MaNGA Stellar Library