2022, Liu, Chenxu, Gebhardt, Karl, Kollatschny, Wolfram, Ciardullo, Robin, Mentuch Cooper, Erin, Davis, Dustin, Farrow, Daniel J., Finkelstein, Steven L., Gawiser, Eric, Gronwall, Caryl, Hill, Gary J., House, Lindsay, Schneider, Donald P., Urrutia, Tanya, Zeimann, Gregory R.

We report an active galactic nucleus (AGN) with an extremely high equivalent width (EW), EWLyα+N V,rest ≳921 Å, in the rest frame, at z ∼ 2.24 in the Hobby-Eberly Telescope Dark Energy Experiment Survey (HETDEX), as a representative case of the high-EW AGN population. The continuum level is a nondetection in the HETDEX spectrum; thus the measured EW is a lower limit. The source is detected with significant emission lines (>7σ) at Lyα + N v λ1241, C iv λ1549, and a moderate emission line (∼4σ) at He ii λ1640 within the wavelength coverage of HETDEX (3500-5500 Å). The r-band magnitude is 24.57 from the Hyper Suprime-Cam-HETDEX joint survey with a detection limit of r = 25.12 at 5σ. The Lyα emission line spans a clearly resolved region of ∼10″ (85 kpc) in diameter. The Lyα line profile is strongly double peaked. The spectral decomposed blue gas and red gas Lyα emission are separated by ∼1.″2 (10.1 kpc) with a line-of-sight velocity offset of ∼1100 km s−1. This source is probably an obscured AGN with powerful winds.

2023, Mentuch Cooper, Erin, Gebhardt, Karl, Davis, Dustin, Farrow, Daniel J., Liu, Chenxu, Zeimann, Gregory, Ciardullo, Robin, Feldmeier, John J., Drory, Niv, Jeong, Donghui, Benda, Barbara, Bowman, William P., Boylan-Kolchin, Michael, Chávez Ortiz, Óscar A., Debski, Maya H., Dentler, Mona, Fabricius, Maximilian, Farooq, Rameen, Finkelstein, Steven L., Gawiser, Eric, Gronwall, Caryl, Hill, Gary J., Hopp, Ulrich, House, Lindsay R., Janowiecki, Steven, Khoraminezhad, Hasti, Kollatschny, Wolfram, Komatsu, Eiichiro, Landriau, Martin, Niemeyer, Maja Lujan, Lee, Hanshin, MacQueen, Phillip, Mawatari, Ken, McKay, Brianna, Ouchi, Masami, Poppe, Jennifer, Saito, Shun, Schneider, Donald P., Snigula, Jan, Thomas, Benjamin P., Tuttle, Sarah, Urrutia, Tanya, Weiss, Laurel, Wisotzki, Lutz, Zhang, Yechi

We present the first publicly released catalog of sources obtained from the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX). HETDEX is an integral field spectroscopic survey designed to measure the Hubble expansion parameter and angular diameter distance at 1.88 < z < 3.52 by using the spatial distribution of more than a million Lyα-emitting galaxies over a total target area of 540 deg2. The catalog comes from contiguous fiber spectra coverage of 25 deg2 of sky from 2017 January through 2020 June, where object detection is performed through two complementary detection methods: one designed to search for line emission and the other a search for continuum emission. The HETDEX public release catalog is dominated by emission-line galaxies and includes 51,863 Lyα-emitting galaxy (LAE) identifications and 123,891 [O ii]-emitting galaxies at z < 0.5. Also included in the catalog are 37,916 stars, 5274 low-redshift (z < 0.5) galaxies without emission lines, and 4976 active galactic nuclei. The catalog provides sky coordinates, redshifts, line identifications, classification information, line fluxes, [O ii] and Lyα line luminosities where applicable, and spectra for all identified sources processed by the HETDEX detection pipeline. Extensive testing demonstrates that HETDEX redshifts agree to within Δz < 0.02, 96.1% of the time to those in external spectroscopic catalogs. We measure the photometric counterpart fraction in deep ancillary Hyper Suprime-Cam imaging and find that only 55.5% of the LAE sample has an r-band continuum counterpart down to a limiting magnitude of r ∼ 26.2 mag (AB) indicating that an LAE search of similar sensitivity to HETDEX with photometric preselection would miss nearly half of the HETDEX LAE catalog sample. Data access and details about the catalog can be found online at http://hetdex.org/. A copy of the catalogs presented in this work (Version 3.2) is available to download at Zenodo doi:10.5281/zenodo.7448504.

2021, Hill, Gary J., Lee, Hanshin, MacQueen, Phillip J., Kelz, Andreas, Drory, Niv, Vattiat, Brian L., Good, John M., Ramsey, Jason, Kriel, Herman, Peterson, Trent, DePoy, D. L., Gebhardt, Karl, Marshall, J. L., Tuttle, Sarah E., Bauer, Svend M., Chonis, Taylor S., Fabricius, Maximilian H., Froning, Cynthia, Häuser, Marco, Indahl, Briana L., Jahn, Thomas, Landriau, Martin, Leck, Ron, Montesano, Francesco, Prochaska, Travis, Snigula, Jan M., Zeimann, Greg, Bryant, Randy, Damm, George, Fowler, J. R., Janowiecki, Steven, Martin, Jerry, Mrozinski, Emily, Odewahn, Stephen, Rostopchin, Sergey, Shetrone, Matthew, Spencer, Renny, Mentuch Cooper, Erin, Armandroff, Taft, Bender, Ralf, Dalton, Gavin, Hopp, Ulrich, Komatsu, Eiichiro, Nicklas, Harald, Ramsey, Lawrence W., Roth, Martin M., Schneider, Donald P., Sneden, Chris, Steinmetz, Matthias

The Hobby-Eberly Telescope (HET) Dark Energy Experiment (HETDEX) is undertaking a blind wide-field low-resolution spectroscopic survey of 540 deg2 of sky to identify and derive redshifts for a million Lyα-emitting galaxies in the redshift range 1.9 < z < 3.5. The ultimate goal is to measure the expansion rate of the universe at this epoch, to sharply constrain cosmological parameters and thus the nature of dark energy. A major multiyear Wide-Field Upgrade (WFU) of the HET was completed in 2016 that substantially increased the field of view to 22′ diameter and the pupil to 10 m, by replacing the optical corrector, tracker, and Prime Focus Instrument Package and by developing a new telescope control system. The new, wide-field HET now feeds the Visible Integral-field Replicable Unit Spectrograph (VIRUS), a new low-resolution integral-field spectrograph (LRS2), and the Habitable Zone Planet Finder, a precision near-infrared radial velocity spectrograph. VIRUS consists of 156 identical spectrographs fed by almost 35,000 fibers in 78 integral-field units arrayed at the focus of the upgraded HET. VIRUS operates in a bandpass of 3500-5500 Å with resolving power R ≃ 800. VIRUS is the first example of large-scale replication applied to instrumentation in optical astronomy to achieve spectroscopic surveys of very large areas of sky. This paper presents technical details of the HET WFU and VIRUS, as flowed down from the HETDEX science requirements, along with experience from commissioning this major telescope upgrade and the innovative instrumentation suite for HETDEX.