Flux sensitivity requirements for the detection of Lyman continuum radiation drop-ins from star-forming galaxies below redshifts of 3

Abstract

Flux estimates for ionizing radiation escaping from star-forming galaxies with characteristic UV luminosities ($L_{1500(1+z)}^{\ast }$) derived from GALEX and the VIMOS-VLT Deep Survey, are presented as a function of redshift and assumed escape fraction. These estimates offer guidance to the design of instrumentation and observing strategies, be they spectroscopic or photometric, attempting to detect LyC escaping star-forming galaxies for redshifts $z<3$. Examples are given that relate the absolution escape fraction ($f_{LyC}^e$) of ionizing photons, integrated over the entire extreme UV (EUV) bandpass, to the relative escape fraction ($f_{900}^e$) observed just shortward of the ionization edge at 911.8 Å as a function of HI, HeI, and HeII column densities. We find that for $\log N_{HI}(c{m}^{-2})\gtrsim 17.0$ $f_{LyC}^e$ is significantly greater than $f_{900}^e$. Detection of LyC "drop-ins" in the rest-frame EUV will provide enhanced fidelity to determinations of the integrated fraction of ionizing photons $f_{LyC}^e$ that escape star-forming galaxies and contribute to the meta-galactic ionizing background.

15 pages, 10 figures, Published ApJ August 2017, astro-ph revised to align with apj post-proof (most significant two corrected inline equations section 4 para 6)

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Cited by in corpus (5)

• Conditions for Reionizing the Universe with A Low Galaxy Ionizing Photon Escape Fraction
• The Low-Redshift Lyman Continuum Survey. Unveiling the ISM properties of low-$z$ Lyman continuum emitters
• Intense CIV and HeII Emission in z~0 Galaxies: Probing High-Energy Ionizing Photons
• The contribution from stars stripped in binaries to cosmic reionization of hydrogen and helium
• Ionizing Radiation Escape from Low-Redshift Galaxies and Its Connection to Cosmic Reionization