The bulk of hydrogen-ionizing photons necessary to reionize the intergalactic
medium (IGM) by redshift z~6 is likely to have arisen from stars in low-mass
galaxies. Whether these galaxies were numerous enough at z>6 to reionize the
IGM entirely depends on their production rate of H-ionizing photons, xi_ion,
and the fraction of these escaping into the IGM. We derive a novel diagnostic
of xi_ion based on the equivalent width of the bright OIII4959,5007 line
doublet, which does not require measurements of H-recombination lines. We
calibrate this diagnostic through the analysis of the luminosities of 15
nebular emission lines in high-quality optical spectra of 10 low-redshift
analogs of primeval galaxies, using the new-generation spectral analysis tool
Beagle. The success of this analysis confirms the ability of the models to
constrain the ionized-gas properties of extreme star-forming regions, paving
the way to similar analyses at high redshift. The new xi_ion diagnostic can be
used to derive more accurate estimates of this parameter than currently
possible from the contamination by Hbeta+OIII4959,5007 of broad-band
photometry in distant galaxies, and, in the future, from direct observations of
OIII4959,5007 out to z~9.5 using JWST/NIRSpec.
Description
[1709.03503] The ionization properties of extreme nearby star-forming regions
%0 Generic
%1 chevallard2017ionization
%A Chevallard, Jacopo
%A Charlot, Stéphane
%A Senchyna, Peter
%A Stark, Daniel P.
%A Vidal-García, Alba
%A Feltre, Anna
%A Gutkin, Julia
%A Jones, Tucker
%A Mainali, Ramesh
%A Wofford, Aida
%D 2017
%K [OIII] formation ionisation lines region star
%T The ionization properties of extreme nearby star-forming regions
%U http://arxiv.org/abs/1709.03503
%X The bulk of hydrogen-ionizing photons necessary to reionize the intergalactic
medium (IGM) by redshift z~6 is likely to have arisen from stars in low-mass
galaxies. Whether these galaxies were numerous enough at z>6 to reionize the
IGM entirely depends on their production rate of H-ionizing photons, xi_ion,
and the fraction of these escaping into the IGM. We derive a novel diagnostic
of xi_ion based on the equivalent width of the bright OIII4959,5007 line
doublet, which does not require measurements of H-recombination lines. We
calibrate this diagnostic through the analysis of the luminosities of 15
nebular emission lines in high-quality optical spectra of 10 low-redshift
analogs of primeval galaxies, using the new-generation spectral analysis tool
Beagle. The success of this analysis confirms the ability of the models to
constrain the ionized-gas properties of extreme star-forming regions, paving
the way to similar analyses at high redshift. The new xi_ion diagnostic can be
used to derive more accurate estimates of this parameter than currently
possible from the contamination by Hbeta+OIII4959,5007 of broad-band
photometry in distant galaxies, and, in the future, from direct observations of
OIII4959,5007 out to z~9.5 using JWST/NIRSpec.
@misc{chevallard2017ionization,
abstract = {The bulk of hydrogen-ionizing photons necessary to reionize the intergalactic
medium (IGM) by redshift z~6 is likely to have arisen from stars in low-mass
galaxies. Whether these galaxies were numerous enough at z>6 to reionize the
IGM entirely depends on their production rate of H-ionizing photons, xi_ion,
and the fraction of these escaping into the IGM. We derive a novel diagnostic
of xi_ion based on the equivalent width of the bright [OIII]4959,5007 line
doublet, which does not require measurements of H-recombination lines. We
calibrate this diagnostic through the analysis of the luminosities of 15
nebular emission lines in high-quality optical spectra of 10 low-redshift
analogs of primeval galaxies, using the new-generation spectral analysis tool
Beagle. The success of this analysis confirms the ability of the models to
constrain the ionized-gas properties of extreme star-forming regions, paving
the way to similar analyses at high redshift. The new xi_ion diagnostic can be
used to derive more accurate estimates of this parameter than currently
possible from the contamination by Hbeta+[OIII]4959,5007 of broad-band
photometry in distant galaxies, and, in the future, from direct observations of
[OIII]4959,5007 out to z~9.5 using JWST/NIRSpec.},
added-at = {2017-09-13T11:52:49.000+0200},
author = {Chevallard, Jacopo and Charlot, Stéphane and Senchyna, Peter and Stark, Daniel P. and Vidal-García, Alba and Feltre, Anna and Gutkin, Julia and Jones, Tucker and Mainali, Ramesh and Wofford, Aida},
biburl = {https://www.bibsonomy.org/bibtex/232e8666a61f999f77abd6ef3fa131ba3/miki},
description = {[1709.03503] The ionization properties of extreme nearby star-forming regions},
interhash = {ba9138b51bdde8437aed2ccf1e0b3459},
intrahash = {32e8666a61f999f77abd6ef3fa131ba3},
keywords = {[OIII] formation ionisation lines region star},
note = {cite arxiv:1709.03503Comment: 6 pages, 5 figures, submitted to MNRAS Letters, comments welcome},
timestamp = {2017-09-13T11:52:49.000+0200},
title = {The ionization properties of extreme nearby star-forming regions},
url = {http://arxiv.org/abs/1709.03503},
year = 2017
}