The hetdex pilot survey. I. Survey design, performance, and catalog of emission-line galaxies

Joshua J. Adams, Guillermo A. Blanc, Gary J. Hill, Karl Gebhardt, Niv Drory, Lei Hao, Ralf Bender, Joyce Byun, Robin Ciardullo, Mark E. Cornell, Steven L. Finkelstein, Alex Fry, Eric Gawiser, Caryl Gronwall, Ulrich Hopp, Donghui Jeong, Andreas Kelz, Ralf Kelzenberg, Eiichiro Komatsu, Phillip J. MacQueenJeremy Murphy, P. Samuel Odoms, Martin Roth, Donald P. Schneider, Joseph R. Tufts, Christopher P. Wilkinson

Research output: Contribution to journalReview articlepeer-review

56 Scopus citations


We present a catalog of emission-line galaxies selected solely by their emission-line fluxes using a wide-field integral field spectrograph. This work is partially motivated as a pilot survey for the upcoming Hobby-Eberly Telescope Dark Energy Experiment. We describe the observations, reductions, detections, redshift classifications, line fluxes, and counterpart information for 397 emission-line galaxies detected over 169 □′ with a 3500-5800 Å bandpass under 5 Å full-width-half-maximum (FWHM) spectral resolution. The survey's best sensitivity for unresolved objects under photometric conditions is between 4 and 20 × 10-17 erg s-1 cm-2 depending on the wavelength, and Lya luminosities between 3 × 10 42 and 6 × 1042 erg s-1 are detectable. This survey method complements narrowband and color-selection techniques in the search of high-redshift galaxies with its different selection properties and large volume probed. The four survey fields within the COSMOS, GOODS-N, MUNICS, and XMM-LSS areas are rich with existing, complementary data. We find 105 galaxies via their high-redshift Lya emission at 1.9 < z < 3.8, and the majority of the remainder objects are low-redshift [Oii]3727 emitters at z < 0.56. The classification between low-and high-redshift objects depends on rest-frame equivalent width (EW), as well as other indicators, where available. Based on matches to X-ray catalogs, the active galactic nuclei fraction among the Lya emitters is 6%. We also analyze the survey's completeness and contamination properties through simulations. We find five high-z, highly significant, resolved objects with FWHM sizes >44 □″ which appear to be extended Lyα nebulae. We also find three high-z objects with rest-frame Lya EW above the level believed to be achievable with normal star formation, EW0 > 240 Å. Future papers will investigate the physical properties of this sample.

Original languageEnglish (US)
JournalAstrophysical Journal, Supplement Series
Issue number1
StatePublished - Jan 2011

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


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