Erin Mentuch Cooper, K. Gebhardt, Dustin Davis, Robin Ciardullo, Chris Byrohl, Chenxu 辰旭 Liu 刘, Maya H. Debski, Óscar A. Chávez Ortiz, Maximilian Fabricius, Daniel J. Farrow, Steven L. Finkelstein, C. Gronwall, Gary J. Hill, Maja Lujan Niemeyer, Brianna McKay, Shiro Mukae, Masami Ouchi, H. Röttgering, D. Schneider, Sarah Tuttle, Lutz Wisotzki, Gregory R. Zeimann, Sai Zhai
Abstract The Hobby–Eberly Dark Energy Experiment (HETDEX) is an untargeted ∼540 deg 2 spectroscopic survey of Ly α emission in the 1.9 < z < 3.5 Universe. In surface brightness, this survey reaches 1 σ Ly α sensitivities of ∼2–5 × 10 −18 erg s −1 cm − 2 arcsec − 2 , allowing large samples of extended Ly α nebulae (LAN) to be studied. We selected a sample of 70,691 Ly α -emitting galaxies (LAEs) with an emission-line signal-to-noise ratio greater than 6 and modeled the Ly α emission as a point-source component with an optional exponential envelope. Half (∼47.5%) of the LAE sample (33,612 objects) exhibits significant extended emission and is best fit by the two-component model. The fraction of resolved sources increases with Ly α flux and luminosity. Their isophotal areas range from 10 to 130 arcsec 2 (median 15 arcsec 2 ), with integrated Ly α fluxes from 6 to 2000 × 10 −17 erg s −1 cm −2 (median 20 × 10 −17 erg s −1 cm −2 ). Comparison between point-spread function-weighted and isophotal flux measurements shows that the HETDEX pipeline underestimates the total Ly α flux by ∼30% on average, reflecting the substantial halo contribution in extended sources. Approximately 420 LANs are found per deg 2 over 79.5 deg 2 of noncontiguous sky. About 12% of resolved sources show active galactic nuclei signatures and are bright in Ly α and continuum. The remaining 88% span a wide range of morphologies and often lack continuum counterparts. Exponential scale lengths show no strong correlation with Ly α flux or luminosity (median 11.6 ± 1.9 kpc). Only 2.9% of the full S/N > 6 LAE population with ancillary data have radio counterparts, but 64% of those are found to be extended, with the radio fraction increasing with Ly α size. We present a catalog of all modeled sources, with their positions, redshifts, luminosities, and structural parameters for over 70,000 LAEs consisting of 33,000 spatially extended LAN. The catalog can be found at https://hetdex.org/data-results/ and in the online version of this paper.