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

Michael J. Rutkowski, Claudia Scarlata, Alaina Henry, Matthew Hayes, Vihang Mehta, Nimish Hathi, Seth Cohen, Rogier Windhorst, Anton M. Koekemoer, Harry I. Teplitz, Francesco Haardt, Brian Siana

Research output: Contribution to journalArticle

13 Citations (Scopus)

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 1σ upper limits to the LyC escape fraction relative to the non-ionizing UV continuum from [O ii] emitters, f esc ≲ 5.6%, and strong [O iii]/[O ii] > 5 ELGs, f esc ≲ 14.0%. Our observations are not deep enough to detect f 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.

Original languageEnglish (US)
Article numberL27
JournalAstrophysical Journal Letters
Volume841
Issue number2
DOIs
StatePublished - Jun 1 2017

Fingerprint

escape
galaxies
continuums
stars
emitters
spectroscopy
Hubble Space Telescope
catalogs
broadband

Keywords

  • galaxies: general
  • galaxies: star formation
  • ultraviolet: galaxies

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Rutkowski, M. J., Scarlata, C., Henry, A., Hayes, M., Mehta, V., Hathi, N., ... Siana, B. (2017). The Lyman Continuum Escape Fraction of Emission Line-selected z ∼ 2.5 Galaxies Is Less Than 15%. Astrophysical Journal Letters, 841(2), [L27]. https://doi.org/10.3847/2041-8213/aa733b

The Lyman Continuum Escape Fraction of Emission Line-selected z ∼ 2.5 Galaxies Is Less Than 15%. / Rutkowski, Michael J.; Scarlata, Claudia; Henry, Alaina; Hayes, Matthew; Mehta, Vihang; Hathi, Nimish; Cohen, Seth; Windhorst, Rogier; Koekemoer, Anton M.; Teplitz, Harry I.; Haardt, Francesco; Siana, Brian.

In: Astrophysical Journal Letters, Vol. 841, No. 2, L27, 01.06.2017.

Research output: Contribution to journalArticle

Rutkowski, MJ, Scarlata, C, Henry, A, Hayes, M, Mehta, V, Hathi, N, Cohen, S, Windhorst, R, Koekemoer, AM, Teplitz, HI, Haardt, F & Siana, B 2017, 'The Lyman Continuum Escape Fraction of Emission Line-selected z ∼ 2.5 Galaxies Is Less Than 15%', Astrophysical Journal Letters, vol. 841, no. 2, L27. https://doi.org/10.3847/2041-8213/aa733b
Rutkowski, Michael J. ; Scarlata, Claudia ; Henry, Alaina ; Hayes, Matthew ; Mehta, Vihang ; Hathi, Nimish ; Cohen, Seth ; Windhorst, Rogier ; Koekemoer, Anton M. ; Teplitz, Harry I. ; Haardt, Francesco ; Siana, Brian. / The Lyman Continuum Escape Fraction of Emission Line-selected z ∼ 2.5 Galaxies Is Less Than 15%. In: Astrophysical Journal Letters. 2017 ; Vol. 841, No. 2.
@article{186b4b77707941ffa785b83a3f19d898,
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 1σ upper limits to the LyC escape fraction relative to the non-ionizing UV continuum from [O ii] emitters, f esc ≲ 5.6{\%}, and strong [O iii]/[O ii] > 5 ELGs, f esc ≲ 14.0{\%}. Our observations are not deep enough to detect f 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.",
keywords = "galaxies: general, galaxies: star formation, ultraviolet: galaxies",
author = "Rutkowski, {Michael J.} and Claudia Scarlata and Alaina Henry and Matthew Hayes and Vihang Mehta and Nimish Hathi and Seth Cohen and Rogier Windhorst and Koekemoer, {Anton M.} and Teplitz, {Harry I.} and Francesco Haardt and Brian Siana",
year = "2017",
month = "6",
day = "1",
doi = "10.3847/2041-8213/aa733b",
language = "English (US)",
volume = "841",
journal = "Astrophysical Journal Letters",
issn = "2041-8205",
publisher = "IOP Publishing Ltd.",
number = "2",

}

TY - JOUR

T1 - The Lyman Continuum Escape Fraction of Emission Line-selected z ∼ 2.5 Galaxies Is Less Than 15%

AU - Rutkowski, Michael J.

AU - Scarlata, Claudia

AU - Henry, Alaina

AU - Hayes, Matthew

AU - Mehta, Vihang

AU - Hathi, Nimish

AU - Cohen, Seth

AU - Windhorst, Rogier

AU - Koekemoer, Anton M.

AU - Teplitz, Harry I.

AU - Haardt, Francesco

AU - Siana, Brian

PY - 2017/6/1

Y1 - 2017/6/1

N2 - 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 1σ upper limits to the LyC escape fraction relative to the non-ionizing UV continuum from [O ii] emitters, f esc ≲ 5.6%, and strong [O iii]/[O ii] > 5 ELGs, f esc ≲ 14.0%. Our observations are not deep enough to detect f 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.

AB - 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 1σ upper limits to the LyC escape fraction relative to the non-ionizing UV continuum from [O ii] emitters, f esc ≲ 5.6%, and strong [O iii]/[O ii] > 5 ELGs, f esc ≲ 14.0%. Our observations are not deep enough to detect f 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.

KW - galaxies: general

KW - galaxies: star formation

KW - ultraviolet: galaxies

UR - http://www.scopus.com/inward/record.url?scp=85020274255&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85020274255&partnerID=8YFLogxK

U2 - 10.3847/2041-8213/aa733b

DO - 10.3847/2041-8213/aa733b

M3 - Article

VL - 841

JO - Astrophysical Journal Letters

JF - Astrophysical Journal Letters

SN - 2041-8205

IS - 2

M1 - L27

ER -