The stars of the HETDEX Survey. I. Radial velocities and metal-poor stars from lowresolution 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 SteinmetzJ. Craig Wheeler

Research output: Contribution to journalReview articlepeer-review

6 Scopus citations


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 ∼ 750) spectra of Lyα emitters. In its search for these galaxies, HETDEX will also observe a few times 105 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 ∼ 60°) Galactic latitudes. With these spectra, we measure radial velocities (RVs) for ∼42,000 unique FGK-type stars in the catalog and show that the HETDEX spectra are sufficient to constrain these RVs with a 1σ precision of 28.0 km s-1 and bias of 3.5 km s-1 with respect to the Large Sky Area Multi-Object Fibre Spectroscopic Telescope surveys and 1σ precision of 27.5 km s-1 and bias of 14.0 km s-1 compared to the Sloan Extension for Galactic Understanding and Exploration survey. Since these RVs are for faint (G . 16) stars, they will be complementary to Gaia. Using t-Distributed Stochastic Neighbor Embedding (tSNE), we also demonstrate that the HETDEX spectra can be used to determine a star's Teff, and log g and its [Fe/H]. With the tSNE 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.

Original languageEnglish (US)
Article numberabe9bd
JournalAstrophysical Journal
Issue number2
StatePublished - Apr 20 2021

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


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