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

Keith Hawkins*, Greg Zeimann, Chris Sneden, Erin Mentuch Cooper, Karl Gebhardt, Howard E. Bond, Andreia Carrillo, Caitlin M. Casey, Barbara G. Castanheira, Robin Ciardullo, Dustin Davis, Daniel J. Farrow, Steven L. Finkelstein, Gary J. Hill, Andreas Kelz, Chenxu Liu, Matthew Shetrone, Donald P. Schneider, Else Starkenburg, Matthias SteinmetzCraig Wheeler

*Corresponding author for this work

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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($R\sim750$) 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 ($b\sim60^\circ$) 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 of3.5 km/s with respect to the LAMOST surveys and 1$\sigma$ precision of27.5 km/s and bias of 14.0 km/s compared to the SEGUE survey. Since these RVs are for faint ($G\geq16$) stars, they will be complementary toGaia. Using t-Distributed Stochastic Neighbor Embedding (t-SNE), we also demonstrate that the HETDEX spectra can be used to determine a star'sT${\rm{eff}}$, and log g and its [Fe/H]. With the t-SNE projection of the FGK-type stars with HETDEX spectra we also identify 416 newc andidate metal-poor ([Fe/H] $< -1$~dex) stars for future study.These encouraging results illustrate the utility of future low-resolution stellar spectroscopic surveys.
Original languageEnglish
Article number108
Number of pages13
JournalThe Astrophysical Journal
Issue number2
Publication statusPublished - 22-Apr-2021


  • Astrophysics - Astrophysics of Galaxies
  • Astrophysics - Solar and Stellar Astrophysics

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