On the Lack of Correlation Between [OIII]/[OII] and Lyman-Continuum Escape Fraction. (arXiv:1812.04129v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Bassett_R/0/1/0/all/0/1">R. Bassett</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ryan_Weber_E/0/1/0/all/0/1">E. V. Ryan-Weber</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cooke_J/0/1/0/all/0/1">J. Cooke</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Diaz_C/0/1/0/all/0/1">C. G. Diaz</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nanayakkara_T/0/1/0/all/0/1">T. Nanayakkara</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yuan_T/0/1/0/all/0/1">T.-T. Yuan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Spitler_L/0/1/0/all/0/1">L. R. Spitler</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mestric_U/0/1/0/all/0/1">U. Me&#x161;tri&#x107;</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Garel_T/0/1/0/all/0/1">T. Garel</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sawicki_M/0/1/0/all/0/1">M. Sawicki</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gwyn_S/0/1/0/all/0/1">S. Gwyn</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Golob_A/0/1/0/all/0/1">A. Golob</a>

We present the first results of our pilot study of 8 photometrically selected
Lyman continuum (LyC) emitting galaxy candidates from the COSMOS field and
focus on their optical emission line ratios. Observations were performed in the
H and K bands using the Multi-Object Spectrometer for Infra-Red Exploration
(MOSFIRE) instrument at the Keck Observatory, targeting the [OII], H$beta$,
and [OIII] emission lines. We find that photometrically selected LyC emitting
galaxy candidates have high ionization parameters, based on their high
[OIII]/[OII] ratios (O32), with an average ratio for our sample of 2.5$pm$0.2.
Preliminary results of our companion Low Resolution Imaging Spectrometer (LRIS)
observations, targeting LyC and Ly$alpha$, show that those galaxies with the
largest O32 are typically found to also be Ly$alpha$ emitters. High O32
galaxies are also found to have tentative non-zero LyC escape fractions
($f_{esc}(LyC)$) based on $u$ band photometric detections. These results are
consistent with samples of highly ionized galaxies, including confirmed LyC
emitting galaxies from the literature. We also perform a detailed comparison
between the observed emission line ratios and simulated line ratios from
density bounded H$_{textrm{II}}$ regions modeled using the photoionization
code MAPPINGS V. Estimates of $f_{esc}(LyC)$ for our sample fall in the range
from 0.0-0.23 and suggest possible tension with published correlations between
O32 and $f_{esc}(LyC)$, adding weight to dichotomy of arguments in the
literature. We highlight the possible effects of clumpy geometry and mergers
that may account for such tension.

We present the first results of our pilot study of 8 photometrically selected
Lyman continuum (LyC) emitting galaxy candidates from the COSMOS field and
focus on their optical emission line ratios. Observations were performed in the
H and K bands using the Multi-Object Spectrometer for Infra-Red Exploration
(MOSFIRE) instrument at the Keck Observatory, targeting the [OII], H$beta$,
and [OIII] emission lines. We find that photometrically selected LyC emitting
galaxy candidates have high ionization parameters, based on their high
[OIII]/[OII] ratios (O32), with an average ratio for our sample of 2.5$pm$0.2.
Preliminary results of our companion Low Resolution Imaging Spectrometer (LRIS)
observations, targeting LyC and Ly$alpha$, show that those galaxies with the
largest O32 are typically found to also be Ly$alpha$ emitters. High O32
galaxies are also found to have tentative non-zero LyC escape fractions
($f_{esc}(LyC)$) based on $u$ band photometric detections. These results are
consistent with samples of highly ionized galaxies, including confirmed LyC
emitting galaxies from the literature. We also perform a detailed comparison
between the observed emission line ratios and simulated line ratios from
density bounded H$_{textrm{II}}$ regions modeled using the photoionization
code MAPPINGS V. Estimates of $f_{esc}(LyC)$ for our sample fall in the range
from 0.0-0.23 and suggest possible tension with published correlations between
O32 and $f_{esc}(LyC)$, adding weight to dichotomy of arguments in the
literature. We highlight the possible effects of clumpy geometry and mergers
that may account for such tension.

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