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Title: The Lyman Continuum Escape Fraction of Emission Line-selected z ∼ 2.5 Galaxies Is Less Than 15%

Abstract

Recent work suggests that strong emission line, star-forming galaxies (SFGs) may be significant Lyman continuum leakers. We combine archival Hubble Space Telescope broadband ultraviolet and optical imaging (F275W and F606W, respectively) with emission line catalogs derived from WFC3 IR G141 grism spectroscopy to search for escaping Lyman continuum (LyC) emission from homogeneously selected z ∼ 2.5 SFGs. We detect no escaping Lyman continuum from SFGs selected on [O ii] nebular emission ( N = 208) and, within a narrow redshift range, on [O iii]/[O ii]. We measure 1 σ upper limits to the LyC escape fraction relative to the non-ionizing UV continuum from [O ii] emitters, f {sub esc} ≲ 5.6%, and strong [O iii]/[O ii] > 5 ELGs, f {sub esc} ≲ 14.0%. Our observations are not deep enough to detect f {sub esc} ∼ 10% typical of low-redshift Lyman continuum emitters. However, we find that this population represents a small fraction of the star-forming galaxy population at z ∼ 2. Thus, unless the number of extreme emission line galaxies grows substantially to z ≳ 6, such galaxies may be insufficient for reionization. Deeper survey data in the rest-frame ionizing UV will be necessary to determine whether strong linemore » ratios could be useful for pre-selecting LyC leakers at high redshift.« less

Authors:
;  [1]; ;  [2]; ; ;  [3]; ;  [4];  [5];  [6];  [7]
  1. Department of Astronomy, AlbaNova University Centre, Stockholm University, SE-10691 Stockholm (Sweden)
  2. Minnesota Institute for Astrophysics, University of Minnesota, 116 Church Street SE, Minneapolis, MN 55455 (United States)
  3. Space Telescope Science Institute, Baltimore, MD 21218 (United States)
  4. School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85281 (United States)
  5. Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States)
  6. DiSAT, Università dellInsubria, via Valleggio 11, I-22100 Como (Italy)
  7. Department of Physics, University of California, Riverside, CA 92521 (United States)
Publication Date:
OSTI Identifier:
22654465
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 841; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; CATALOGS; EMISSION; GALAXIES; LYMAN LINES; RED SHIFT; SPACE; SPECTROSCOPY; STARS; TELESCOPES; ULTRAVIOLET RADIATION

Citation Formats

Rutkowski, Michael J., Hayes, Matthew, Scarlata, Claudia, Mehta, Vihang, Henry, Alaina, Hathi, Nimish, Koekemoer, Anton M., Cohen, Seth, Windhorst, Rogier, Teplitz, Harry I., Haardt, Francesco, and Siana, Brian. The Lyman Continuum Escape Fraction of Emission Line-selected z ∼ 2.5 Galaxies Is Less Than 15%. United States: N. p., 2017. Web. doi:10.3847/2041-8213/AA733B.
Rutkowski, Michael J., Hayes, Matthew, Scarlata, Claudia, Mehta, Vihang, Henry, Alaina, Hathi, Nimish, Koekemoer, Anton M., Cohen, Seth, Windhorst, Rogier, Teplitz, Harry I., Haardt, Francesco, & Siana, Brian. The Lyman Continuum Escape Fraction of Emission Line-selected z ∼ 2.5 Galaxies Is Less Than 15%. United States. doi:10.3847/2041-8213/AA733B.
Rutkowski, Michael J., Hayes, Matthew, Scarlata, Claudia, Mehta, Vihang, Henry, Alaina, Hathi, Nimish, Koekemoer, Anton M., Cohen, Seth, Windhorst, Rogier, Teplitz, Harry I., Haardt, Francesco, and Siana, Brian. Thu . "The Lyman Continuum Escape Fraction of Emission Line-selected z ∼ 2.5 Galaxies Is Less Than 15%". United States. doi:10.3847/2041-8213/AA733B.
@article{osti_22654465,
title = {The Lyman Continuum Escape Fraction of Emission Line-selected z ∼ 2.5 Galaxies Is Less Than 15%},
author = {Rutkowski, Michael J. and Hayes, Matthew and Scarlata, Claudia and Mehta, Vihang and Henry, Alaina and Hathi, Nimish and Koekemoer, Anton M. and Cohen, Seth and Windhorst, Rogier and Teplitz, Harry I. and Haardt, Francesco and Siana, Brian},
abstractNote = {Recent work suggests that strong emission line, star-forming galaxies (SFGs) may be significant Lyman continuum leakers. We combine archival Hubble Space Telescope broadband ultraviolet and optical imaging (F275W and F606W, respectively) with emission line catalogs derived from WFC3 IR G141 grism spectroscopy to search for escaping Lyman continuum (LyC) emission from homogeneously selected z ∼ 2.5 SFGs. We detect no escaping Lyman continuum from SFGs selected on [O ii] nebular emission ( N = 208) and, within a narrow redshift range, on [O iii]/[O ii]. We measure 1 σ upper limits to the LyC escape fraction relative to the non-ionizing UV continuum from [O ii] emitters, f {sub esc} ≲ 5.6%, and strong [O iii]/[O ii] > 5 ELGs, f {sub esc} ≲ 14.0%. Our observations are not deep enough to detect f {sub esc} ∼ 10% typical of low-redshift Lyman continuum emitters. However, we find that this population represents a small fraction of the star-forming galaxy population at z ∼ 2. Thus, unless the number of extreme emission line galaxies grows substantially to z ≳ 6, such galaxies may be insufficient for reionization. Deeper survey data in the rest-frame ionizing UV will be necessary to determine whether strong line ratios could be useful for pre-selecting LyC leakers at high redshift.},
doi = {10.3847/2041-8213/AA733B},
journal = {Astrophysical Journal Letters},
number = 2,
volume = 841,
place = {United States},
year = {Thu Jun 01 00:00:00 EDT 2017},
month = {Thu Jun 01 00:00:00 EDT 2017}
}