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

Journal Article · Thu Jun 01 04:00:00 EDT 2017 · Astrophysical Journal Letters

DOI:https://doi.org/10.3847/2041-8213/AA733B· OSTI ID:22654465

Rutkowski, Michael J.; Hayes, Matthew ^[1]; Scarlata, Claudia; Mehta, Vihang ^[2]; Henry, Alaina; Hathi, Nimish; Koekemoer, Anton M. ^[3]; Cohen, Seth; Windhorst, Rogier ^[4]; Teplitz, Harry I. ^[5]; Haardt, Francesco ^[6]; Siana, Brian ^[7]

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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)

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.

• OSTI ID: 22654465
• Journal Information: Astrophysical Journal Letters, Journal Name: Astrophysical Journal Letters Journal Issue: 2 Vol. 841; ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
CATALOGS
EMISSION
GALAXIES
LYMAN LINES
RED SHIFT
SPACE
SPECTROSCOPY
STARS
TELESCOPES
ULTRAVIOLET RADIATION