The Far-Ultraviolet Continuum Slope as a Lyman Continuum Escape Estimator at High-redshift - INSU - Institut national des sciences de l'Univers Access content directly
Journal Articles Monthly Notices of the Royal Astronomical Society Year : 2022

The Far-Ultraviolet Continuum Slope as a Lyman Continuum Escape Estimator at High-redshift

J. Chisholm
  • Function : Author
A. Saldana-Lopez
  • Function : Author
S. Flury
  • Function : Author
A. Jaskot
  • Function : Author
R. Amorín
  • Function : Author
S. L. Finkelstein
  • Function : Author
B. Fleming
  • Function : Author
H. Ferguson
  • Function : Author
V. Fernández
  • Function : Author
M. Giavalisco
  • Function : Author
M. Hayes
  • Function : Author
T. Heckman
  • Function : Author
A. Henry
  • Function : Author
Z. Ji
  • Function : Author
R. Marques-Chaves
  • Function : Author
V. Mauerhofer
  • Function : Author
S. Mccandliss
  • Function : Author
M. S. Oey
  • Function : Author
G. Östlin
  • Function : Author
M. Rutkowski
  • Function : Author
C. Scarlata
  • Function : Author
T. Thuan
  • Function : Author
M. Trebitsch
  • Function : Author
B. Wang
  • Function : Author
G. Worseck
  • Function : Author
X. Xu
  • Function : Author

Abstract

Most of the hydrogen in the intergalactic medium (IGM) was rapidly ionized at high-redshifts. While observations have established that reionization occurred, observational constraints on the high-redshift ionizing emissivity remain elusive. Here, we present a new analysis of the Low-redshift Lyman Continuum Survey (LzLCS) and literature observations, a combined sample of 89 star-forming galaxies at redshifts near 0.3 with Hubble Space Telescope observations of their ionizing continua (or Lyman Continuum, LyC). We find a strong (6σ significant) inverse correlation between the continuum slope at 1550 Å (defined as F$_\lambda \propto \lambda ^{\beta ^{1550}_{\rm obs}}$) and both the LyC escape fraction (fesc, LyC) and fesc, LyC times the ionizing photon production efficiency (ξion). On average, galaxies with redder continuum slopes have smaller fesc, LyC than galaxies with bluer slopes mainly due to higher dust attenuation. More than 5% (20%) of the LyC emission escapes galaxies with $\beta _{\rm obs}^{1550}$ <-2.1 (-2.6). We find strong correlations between $\beta _{\rm obs}^{1550}$ and the [O III]/[O II] flux ratio (at 7.5σ significance), galaxy stellar mass (at 5.9σ), the gas-phase metallicity (at 4.6σ), and the observed FUV absolute magnitude (at 3.4σ). Using previous observations of $\beta _{\rm obs}^{1550}$ at high-redshift, we estimate the evolution of fesc, LyC with both redshift and galaxy magnitude. The LzLCS observations suggest that fainter and lower mass galaxies dominate the ionizing photon budget at higher redshift, possibly due to their rapidly evolving metal and dust content. Finally, we use our correlation between $\beta _{\rm obs}^{1550}$ and fesc, LyC × ξion to predict the ionizing emissivity of galaxies during the epoch of reionization. Our estimated emissivities match IGM observations, and suggest that star-forming galaxies emit sufficient LyC photons into the IGM to exceed recombinations near redshifts of 7-8.
Fichier principal
Vignette du fichier
stac2874.pdf (2.49 Mo) Télécharger le fichier
Origin : Publisher files allowed on an open archive

Dates and versions

insu-03839633 , version 1 (06-07-2023)

Identifiers

Cite

J. Chisholm, A. Saldana-Lopez, S. Flury, D. Schaerer, A. Jaskot, et al.. The Far-Ultraviolet Continuum Slope as a Lyman Continuum Escape Estimator at High-redshift. Monthly Notices of the Royal Astronomical Society, 2022, ⟨10.1093/mnras/stac2874⟩. ⟨insu-03839633⟩
23 View
17 Download

Altmetric

Share

Gmail Facebook X LinkedIn More