The Hobby–Eberly Telescope Dark Energy Experiment (HETDEX) Survey Design, Reductions, and Detections*

Gebhardt, Karl; Cooper, Erin Mentuch; Ciardullo, Robin; Acquaviva, Viviana; Bender, R.; Bowman, W. Paul; Castanheira, B. G.; Dalton, Gavin; Davis, Dustin; Jong, Roelof S. de; DePoy, D. L.; Devarakonda, Yaswant; Sun, Dongsheng; Drory, Niv; Fabricius, Maximilian; Farrow, Daniel J.; Feldmeier, John J.; Finkelstein, Steven L.; Froning, Cynthia S.; Gawiser, Eric; Grönwall, C.; Herold, Laura; Hill, Gary J.; Hopp, U.; House, Lindsay R.; Janowiecki, Steven; Jarvis, Matthew; Jeong, Donghui; Jogee, Shardha; Kakuma, Ryota; Kelz, Andreas; Kollatschny, W.; Komatsu, Eiichiro; Krumpe, M.; Landriau, Martin; Liu, Chenxu; Niemeyer, Maja Lujan; MacQueen, Phillip J.; Marshall, J. L.; Mawatari, Ken; McLinden, Emily; Mukae, Shiro; Nagaraj, Gautam; Ono, Yoshiyasu; Ouchi, Masami; Papovich, Casey; Sakai, Nao; Saito, Shun; Schneider, Donald P.; Schulze, Andreas; Shanmugasundararaj, Khavvia; Shetrone, M.; Sneden, Chris; Snigula, J.; Steinmetz, Matthias; Thomas, B. P.; Thomas, Brianna; Tuttle, Sarah; Urrutia, T.; Wisotzki, L.; Wold, Isak; Zeimann, Gregory R.; Zhang, Yechi

doi:10.3847/1538-4357/ac2e03

Cited by 77 publications

(164 citation statements)

References 108 publications

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“…The data-processing pipeline is described in Gebhardt et al (2021). A crucial aspect for detecting low surface brightness Lyα emission is the sky subtraction.…”

Section: Data and Data Processingmentioning

confidence: 99%

“…Multiple independent techniques show that the PSF of VIRUS is well modeled by a Moffat function with β ä [3, 3.5] in good seeing conditions (Gebhardt et al 2021;Hill et al 2021). To test this, we measure the median radial profile of Gaia stars observed by VIRUS in the same observations as the LAEs.…”

Section: Shape Of the Point-spread Functionmentioning

confidence: 99%

“…Because the dominant origin of the Lyα halo photons depends on, among other things, the distance to the galaxies (Byrohl et al 2021;Mitchell et al 2021), observations of Lyα profiles out to larger distances will be helpful. An ideal data set for this is provided by the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX; Hill et al 2008;Gebhardt et al 2021;Hill et al 2021), which is designed to detect more than one million LAEs at redshifts 1.9 < z < 3.5 in a 10.9 Gpc 3 volume to measure their clustering and thereby constrain cosmological parameters. HETDEX detects emission lines by simultaneously acquiring tens of thousands of spectra without any preselection of targets.…”

Section: Introductionmentioning

confidence: 99%

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Surface Brightness Profile of Lyman-α Halos out to 320 kpc in HETDEX

Niemeyer

Komatsu

Byrohl

et al. 2022

ApJ

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We present the median-stacked Lyman-α (Lyα) surface brightness profiles of 968 spectroscopically selected Lyα emitting galaxies (LAEs) at redshifts 1.9 < z < 3.5 in the early data of the Hobby-Eberly Telescope Dark Energy Experiment. The selected LAEs are high-confidence Lyα detections with high signal-to-noise ratios observed with good seeing conditions (point-spread function FWHM <1.″4), excluding active galactic nuclei. The Lyα luminosities of the LAEs are 1042.4–1043 erg s−1. We detect faint emission in the median-stacked radial profiles at the level of ( 3.6 ± 1.3 ) × 10 − 20 erg s − 1 cm − 2 arcsec − 2 from the surrounding Lyα halos out to r ≃ 160 kpc (physical). The shape of the median-stacked radial profile is consistent at r < 80 kpc with that of much fainter LAEs at 3 < z < 4 observed with the Multi Unit Spectroscopic Explorer (MUSE), indicating that the median-stacked Lyα profiles have similar shapes at redshifts 2 < z < 4 and across a factor of 10 in Lyα luminosity. While we agree with the results from the MUSE sample at r < 80 kpc, we extend the profile over a factor of two in radius. At r > 80 kpc, our profile is flatter than the MUSE model. The measured profile agrees at most radii with that of galaxies in the Byrohl et al. cosmological radiative transfer simulation at z = 3. This suggests that the surface brightness of a Lyα halo at r ≲ 100 kpc is dominated by resonant scattering of Lyα photons from star-forming regions in the central galaxy, whereas at r > 100 kpc, it is dominated by photons from galaxies in surrounding dark matter halos.

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“…The data-processing pipeline is described in Gebhardt et al (2021). A crucial aspect for detecting low surface brightness Lyα emission is the sky subtraction.…”

Section: Data and Data Processingmentioning

confidence: 99%

Section: Shape Of the Point-spread Functionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Surface Brightness Profile of Lyman-α Halos out to 320 kpc in HETDEX

Niemeyer

Komatsu

Byrohl

et al. 2022

ApJ

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“…HETDEX (Hill et al 2008;Gebhardt et al 2021) is a spectroscopic survey without target preselection on the 10 m Hobby-Eberly Telescope (HET; Ramsey et al 1998;Hill et al 2021). It uses the Visible Integral-field Replicable Unit Spectrograph (VIRUS; Hill et al 2018Hill et al , 2021 to record spectra for all targets within its field of view.…”

Section: The Hetdex Surveymentioning

confidence: 99%

“…The data processing of HETDEX frames is detailed in Gebhardt et al (2021). Briefly, bias frames, pixel flats, twilight sky flats, and the background on the science frames themselves are used to produce a wavelength calibrated, sky-subtracted spectrum for each fiber in the array.…”

Section: The Hetdex Surveymentioning

confidence: 99%

The Active Galactic Nuclei in the Hobby–Eberly Telescope Dark Energy Experiment Survey (HETDEX). I. Sample Selection

Liu¹,

Gebhardt²,

Cooper³

et al. 2022

ApJS

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We present the first active galactic nuclei (AGN) catalog of the Hobby–Eberly Telescope Dark Energy Experiment Survey (HETDEX) observed between 2017 January and 2020 June. HETDEX is an ongoing spectroscopic survey (3500–5500 Å) with no target preselection based on magnitudes, colors or morphologies, enabling us to select AGN based solely on their spectral features. Both luminous quasars and low-luminosity Seyferts are found in our catalog. AGN candidates are selected with at least two significant AGN emission lines, such as the Lyα and C iv λ1549 line pair, or with a single broad emission line with FWHM > 1000 km s−1. Each source is further confirmed by visual inspections. This catalog contains 5322 AGN, covering an effective sky coverage of 30.61 deg2. A total of 3733 of these AGN have secure redshifts, and we provide redshift estimates for the remaining 1589 single broad-line AGN with no crossmatched spectral redshifts from the Sloan Digital Sky Survey Data Release 14 of QSOs. The redshift range of the AGN catalog is 0.25 < z < 4.32, with a median of z = 2.1. The bolometric luminosity range is 109–1014 L ☉ with a median of 1012 L ☉. The median r-band magnitude of our AGN catalog is 21.6 mag, with 34% having r > 22.5, and 2.6% reaching the detection limit at r ∼ 26 mag of the deepest imaging surveys we searched. We also provide a composite spectrum of the AGN sample covering 700–4400 Å.

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Revisiting the emission line source detection problem in integral field spectroscopic data

Herenz

2023

Astron Nachr

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We present a 3-dimensional matched filtering approach for the blind search of faint emission-line sources in integral-field spectroscopic datasets. The filter is designed to account for the spectrally rapidly varying background noise due to the telluric air glow spectrum. A software implementation of this matched filtering search is implemented in an updated version of the Line Source Detection Cataloguing tool (LSDCat2.0). Using public data from the MUSE-Wide survey we show how the new filter design provides higher detection significances for faint emission line sources buried in between atmospheric [OH]-bands at 𝜆 ≳ 7000 Å. We also show how, for a given source parameterization, the selection function of the improved algorithm can be derived analytically from the variances of the data. We verify this analytic solution against source insertion and recovery experiments in the recently released dataset of the MUSE eXtreme Deep Field (MXDF). We then illustrate how the selection function has to be rescaled for 3D emission line source profiles that are not fully congruent with the template. This procedure alleviates the construction of realistic selection functions by removing the need for computationally cumbersome source insertion and recovery experiments.

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The Hobby–Eberly Telescope Dark Energy Experiment (HETDEX) Survey Design, Reductions, and Detections*

Cited by 77 publications

References 108 publications

Surface Brightness Profile of Lyman-α Halos out to 320 kpc in HETDEX

Surface Brightness Profile of Lyman-α Halos out to 320 kpc in HETDEX

The Active Galactic Nuclei in the Hobby–Eberly Telescope Dark Energy Experiment Survey (HETDEX). I. Sample Selection

Revisiting the emission line source detection problem in integral field spectroscopic data

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