The HETDEX Survey: The Lyα Escape Fraction from 3D-HST Emission-Line Galaxies at z ∼ 2

Laurel H. Weiss, William P. Bowman, Robin Ciardullo, Gregory R. Zeimann, Caryl Gronwall, Erin Mentuch Cooper, Karl Gebhardt, Gary J. Hill, Guillermo A. Blanc, Daniel J. Farrow, Steven L. Finkelstein, Eric Gawiser, Steven Janowiecki, Shardha Jogee, Donald P. Schneider, Lutz Wisotzki

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12 Citations (SciVal)


In this work, we measure the Lyα escape fraction of 935 [O iii]-emitting galaxies between 1.9 < z < 2.35 by comparing stacked spectra from the Hubble Space Telescope/WFC3's near-IR grism to corresponding stacks from the Hobby-Eberly Telescope Dark Energy Experiment's Internal Data Release 2. By measuring the stacks' Hβ to Lyα ratios, we determine the Lyα escape fraction as a function of stellar mass, star-formation rate, internal reddening, size, and [O iii]/Hβ ratio. We show that the escape fraction of Lyα correlates with a number of parameters, such as galaxy size, star-formation rate, and nebular excitation. However, we also demonstrate that most of these relations are indirect, and that the primary variables controlling the escape of Lyα are likely to be stellar mass and internal extinction. Overall, the escape of Lyα declines from ⪆16% in galaxies with to ≲1% for systems with, with the sample's mean escape fraction being.

Original languageEnglish (US)
Article number100
JournalAstrophysical Journal
Issue number2
StatePublished - May 10 2021

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


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