Journal ArticleAbsorption Troughs of Lyα Emitters in HETDEXWeiss, Laurel H; Davis, Dustin; Gebhardt, Karl; Gazagnes, Simon; Mirza_Khanlari, Mahan; Mentuch_Cooper, Erin; Chisholm, John; Berg, Danielle; Bowman, William P; Byrohl, Chris; Ciardullo, Robin; Fabricius, Maximilian; Farrow, Daniel; Gronwall, Caryl; Hill, Gary J; House, Lindsay R; Jeong, Donghui; Khoraminezhad, Hasti; Kollatschny, Wolfram; Komatsu, Eiichiro; Lujan_Niemeyer, Maja; Saito, Shun; Schneider, Donald P; Zeimann, Gregory R<title>Abstract</title> <p>The Hobby–Eberly Telescope Dark Energy Experiment (HETDEX) is designed to detect and measure the redshifts of more than 1 million Ly<italic>α</italic>emitting galaxies (LAEs) 1.88 <<italic>z</italic>< 3.52. In addition to its cosmological measurements, these data enable studies of Ly<italic>α</italic>spectral profiles and the underlying radiative transfer. Using the roughly half a million LAEs in the HETDEX Data Release 3, we stack various subsets to obtain the typical Ly<italic>α</italic>profile for the<italic>z</italic>∼ 2–3 epoch and to understand their physical properties. We find clear absorption wings around Ly<italic>α</italic>emission, which extend ∼2000 km s⁻¹both redward and blueward of the central line. Using far-UV spectra of nearby (0.002 <<italic>z</italic>< 0.182) LAEs in the COS Legacy Archive Spectroscopic Survey treasury and optical/near-IR spectra of 2.8 <<italic>z</italic>< 6.7 LAEs in the Multi Unit Spectroscopic-Wide survey, we observe absorption profiles in both redshift regimes. Dividing the sample by volume density shows that the troughs increase in higher-density regions. This trend suggests that the depth of the absorption is dependent on the local density of objects near the LAE, a geometry that is similar to damped Ly<italic>α</italic>systems. Simple simulations of Ly<italic>α</italic>radiative transfer can produce similar troughs due to absorption of light from background sources by H<sc>i</sc>gas surrounding the LAEs.</p>ApJ2024-02-0110564573The Astrophysical Journal96221020004-637Xhttps://doi.org/10.3847/1538-4357/ad1b512008793National Science Foundation