The Stars of the HETDEX Survey. I. Radial Velocities and Metal-Poor Stars from Low-Resolution Stellar Spectra

Abstract

The Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) is an unbiased, massively multiplexed spectroscopic survey, designed to measure the expansion history of the universe through low-resolution ($R\sim 750$) spectra of Lyman-Alpha Emitters. In its search for these galaxies, HETDEX will also observe a few 10${}^5$ stars. In this paper, we present the first stellar value-added catalog within the internal second data release of the HETDEX Survey (HDR2). The new catalog contains 120,571 low-resolution spectra for 98,736 unique stars between $10<G<22$ spread across the HETDEX footprint at relatively high ($b\sim 60^{\circ }$) Galactic latitudes. With these spectra, we measure radial velocities (RVs) for $\sim$42,000 unique FGK-type stars in the catalog and show that the HETDEX spectra are sufficient to constrain these RVs with a 1$\sigma$ precision of 28.0 km/s and bias of 3.5 km/s with respect to the LAMOST surveys and 1$\sigma$ precision of 27.5 km/s and bias of 14.0 km/s compared to the SEGUE survey. Since these RVs are for faint ($G\ge 16$) stars, they will be complementary to Gaia. Using t-Distributed Stochastic Neighbor Embedding (t-SNE), we also demonstrate that the HETDEX spectra can be used to determine a star's T$\mathrm{eff}$, and log g and its [Fe/H]. With the t-SNE projection of the FGK-type stars with HETDEX spectra we also identify 416 new candidate metal-poor ([Fe/H] $<-1$~dex) stars for future study. These encouraging results illustrate the utility of future low-resolution stellar spectroscopic surveys.

arXiv comment18 Pages, 11 Figures, 2 Tables. Accepted to ApJ

References in corpus (46)

• SciPy 1.0--Fundamental Algorithms for Scientific Computing in Python
• Astropy: A Community Python Package for Astronomy
• The Sloan Digital Sky Survey: Technical Summary
• Gaia Data Release 2. Summary of the contents and survey properties
• A grid of MARCS model atmospheres for late-type stars I. Methods and general properties
• The Apache Point Observatory Galactic Evolution Experiment (APOGEE)
• The Sixteenth Data Release of the Sloan Digital Sky Surveys: First Release from the APOGEE-2 Southern Survey and Full Release of eBOSS Spectra
• SEGUE: A Spectroscopic Survey of 240,000 stars with g=14-20
• The First Stars
• The Radial Velocity Experiment (RAVE): first data release
• The First Data Release (DR1) of the LAMOST general survey
• The GALAH Survey: Scientific Motivation
• Near-Field Cosmology with Metal-Poor Stars
• Determining stellar atmospheric parameters and chemical abundances of FGK stars with iSpec
• The SEGUE Stellar Parameter Pipeline. I. Description and Initial Validation Tests
• Estimating distances from parallaxes
• A Search for Stars of Very Low Metal Abundance. VI. Detailed Abundances of 313 Metal-Poor Stars
• The GALAH Survey: Second Data Release
• The Most Metal-Poor Stars. II. Chemical Abundances of 190 Metal-Poor Stars Including 10 New Stars With [Fe/H] < -3.5
• The SEGUE Stellar Parameter Pipeline. II. Validation with Galactic Globular and Open Clusters
• The Pristine survey I: Mining the Galaxy for the most metal-poor stars
• The SEGUE Stellar Parameter Pipeline. III. Comparison with High-Resolution Spectroscopy of SDSS/SEGUE Field Stars
• Abundance Estimates for 16 Elements in 6 Million Stars from LAMOST DR5 Low-Resolution Spectra
• Pre-galactic metal enrichment - The chemical signatures of the first stars
• Cross-Correlation and Maximum Likelihood Analysis: A New Approach to Combine Cross-Correlation Functions
• The Sixth Data Release of the Radial Velocity Experiment (RAVE) -- I: Survey Description, Spectra and Radial Velocities
• The SEGUE Stellar Parameter Pipeline. IV. Validation with an Extended Sample of Galactic Globular and Open Clusters
• Estimating distances from parallaxes. II. Performance of Bayesian distance estimators on a Gaia-like catalogue
• The R-Process Alliance: First Release from the Northern Search for r-Process Enhanced Metal-Poor Stars in the Galactic Halo
• Carbon-Enhanced Metal-Poor Stars. III. Main-Sequence Turn-Off Stars from the SDSS/SEGUE Sample
• Identical or fraternal twins? : The chemical homogeneity of wide binaries from Gaia DR2
• LAMOST Spectroscopic Survey of the Galactic Anticentre (LSS-GAC): the second release of value-added catalogues
• Dissecting stellar chemical abundance space with t-SNE
• The Pristine Survey -- VI. The first three years of medium-resolution follow-up spectroscopy of Pristine EMP star candidates
• SkyMapper stellar parameters for Galactic Archaeology on a grand-scale
• Origins of the Thick Disk as Traced by the Alpha-Elements of Metal-Poor Giant Stars Selected from RAVE
• Prospects for Measuring Abundances of >20 Elements with Low-resolution Stellar Spectra
• Exploring the Star Formation History of Elliptical Galaxies: Beyond Simple Stellar Populations with a New Estimator of Line Strengths
• Very metal-poor stars observed by the RAVE survey
• On the Relative Ages of the $\alpha$-Rich and $\alpha$-Poor Stellar Populations in the Galactic Halo
• Properties of Radial Velocities measurement based on LAMOST-II Medium-Resolution Spectroscopic Observations
• The COMBS survey I: Chemical Origins of Metal-Poor Stars in the Galactic Bulge
• LAMOST DR1: Stellar parameters and chemical abundances with SP_Ace
• Replicated Spectrographs in Astronomy
• Climbing the cosmic ladder with stellar twins in RAVE with Gaia
• Extremely Metal-Poor Star Candidates in the SDSS

Cited by in corpus (10)

• The HETDEX Instrumentation: Hobby-Eberly Telescope Wide Field Upgrade and VIRUS
• The Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) Survey Design, Reductions, and Detections
• HETDEX Public Source Catalog 1: 220K Sources Including Over 50K Lyman Alpha Emitters from an Untargeted Wide-area Spectroscopic Survey
• The two-loop bispectrum of large-scale structure
• Exploring the chemodynamics of metal-poor stellar populations
• Identifying Active Galactic Nuclei at $z\sim 3$ from the HETDEX Survey Using Machine Learning
• Searching for Supernovae in HETDEX Data Release 3
• HETDEX Public Data Release 1: Source Catalog 2 and Data Cubes from ~90 sq deg of Integral-Field Optical Spectroscopy
• The GALAH Survey: A New Sample of Extremely Metal-Poor Stars Using A Machine Learning Classification Algorithm
• Golden and Silver Dark Sirens for precise H0 measurement with HETDEX