A High-Resolution Hubble Space Telescope Study of Lyman Continuum
Leakers at $z\sim3$
R. Mostardi, A. Shapley, C. Steidel, R. Trainor, N. Reddy, und B. Siana. (2015)cite arxiv:1506.08201Comment: 30 pages, 5 tables, 19 figures. Submitted to ApJ. Version with full-resolution figures is available at: http://www.astro.ucla.edu/~aes/Mostardi_HST_LyC.pdf.
Zusammenfassung
We present $U_336V_606J_125H_160$ follow-up $HST$ observations of 16
$z\sim3$ candidate LyC emitters in the HS1549+1933 field. With these data, we
obtain high spatial-resolution photometric redshifts of all sub-arcsecond
components of the LyC candidates in order to eliminate foreground contamination
and identify robust candidates for leaking LyC emission. Of the 16 candidates,
we find one object with a robust LyC detection that is not due to foreground
contamination. This object (MD5) resolves into two components; we refer to the
LyC-emitting component as MD5b. MD5b has an observed 1500\AA\ to 900\AA\
flux-density ratio of $(F_UV/F_LyC)_obs=4.0\pm2.0$, compatible with
predictions from stellar population synthesis models. Neglecting IGM
absorption, this ratio corresponds to lower limits to the relative (absolute)
escape fraction of $f_esc,rel^MD5b=75\%\pm38\%$
($f_esc,abs^MD5b=14\%\pm7\%$). The stellar population fit to MD5b indicates
an age of $łesssim50$Myr, which is in the youngest 10% of the $HST$ sample and
the youngest third of typical $z\sim3$ Lyman break galaxies, and may be a
contributing factor to its LyC detection. We obtain a revised,
contamination-free estimate for the comoving specific ionizing emissivity at
$z=2.85$, indicating (with large uncertainties) that star-forming galaxies
provide roughly the same contribution as QSOs to the ionizing background at
this redshift. Our results show that foreground contamination prevents
ground-based LyC studies from obtaining a full understanding of LyC emission
from $z\sim3$ star-forming galaxies. Future progress in direct LyC searches is
contingent upon the elimination of foreground contaminants through high
spatial-resolution observations, and upon acquisition of sufficiently deep LyC
imaging to probe ionizing radiation in high-redshift galaxies.
Beschreibung
[1506.08201] A High-Resolution Hubble Space Telescope Study of Lyman Continuum Leakers at $z\sim3$
cite arxiv:1506.08201Comment: 30 pages, 5 tables, 19 figures. Submitted to ApJ. Version with full-resolution figures is available at: http://www.astro.ucla.edu/~aes/Mostardi_HST_LyC.pdf
%0 Generic
%1 mostardi2015highresolution
%A Mostardi, Robin E.
%A Shapley, Alice E.
%A Steidel, Charles C.
%A Trainor, Ryan F.
%A Reddy, Naveen A.
%A Siana, Brian
%D 2015
%K continuum escape fraction highz lyman
%T A High-Resolution Hubble Space Telescope Study of Lyman Continuum
Leakers at $z\sim3$
%U http://arxiv.org/abs/1506.08201
%X We present $U_336V_606J_125H_160$ follow-up $HST$ observations of 16
$z\sim3$ candidate LyC emitters in the HS1549+1933 field. With these data, we
obtain high spatial-resolution photometric redshifts of all sub-arcsecond
components of the LyC candidates in order to eliminate foreground contamination
and identify robust candidates for leaking LyC emission. Of the 16 candidates,
we find one object with a robust LyC detection that is not due to foreground
contamination. This object (MD5) resolves into two components; we refer to the
LyC-emitting component as MD5b. MD5b has an observed 1500\AA\ to 900\AA\
flux-density ratio of $(F_UV/F_LyC)_obs=4.0\pm2.0$, compatible with
predictions from stellar population synthesis models. Neglecting IGM
absorption, this ratio corresponds to lower limits to the relative (absolute)
escape fraction of $f_esc,rel^MD5b=75\%\pm38\%$
($f_esc,abs^MD5b=14\%\pm7\%$). The stellar population fit to MD5b indicates
an age of $łesssim50$Myr, which is in the youngest 10% of the $HST$ sample and
the youngest third of typical $z\sim3$ Lyman break galaxies, and may be a
contributing factor to its LyC detection. We obtain a revised,
contamination-free estimate for the comoving specific ionizing emissivity at
$z=2.85$, indicating (with large uncertainties) that star-forming galaxies
provide roughly the same contribution as QSOs to the ionizing background at
this redshift. Our results show that foreground contamination prevents
ground-based LyC studies from obtaining a full understanding of LyC emission
from $z\sim3$ star-forming galaxies. Future progress in direct LyC searches is
contingent upon the elimination of foreground contaminants through high
spatial-resolution observations, and upon acquisition of sufficiently deep LyC
imaging to probe ionizing radiation in high-redshift galaxies.
@misc{mostardi2015highresolution,
abstract = {We present $U_{336}V_{606}J_{125}H_{160}$ follow-up $HST$ observations of 16
$z\sim3$ candidate LyC emitters in the HS1549+1933 field. With these data, we
obtain high spatial-resolution photometric redshifts of all sub-arcsecond
components of the LyC candidates in order to eliminate foreground contamination
and identify robust candidates for leaking LyC emission. Of the 16 candidates,
we find one object with a robust LyC detection that is not due to foreground
contamination. This object (MD5) resolves into two components; we refer to the
LyC-emitting component as MD5b. MD5b has an observed 1500\AA\ to 900\AA\
flux-density ratio of $(F_{UV}/F_{LyC})_{obs}=4.0\pm2.0$, compatible with
predictions from stellar population synthesis models. Neglecting IGM
absorption, this ratio corresponds to lower limits to the relative (absolute)
escape fraction of $f_{esc,rel}^{MD5b}=75\%\pm38\%$
($f_{esc,abs}^{MD5b}=14\%\pm7\%$). The stellar population fit to MD5b indicates
an age of $\lesssim50$Myr, which is in the youngest 10% of the $HST$ sample and
the youngest third of typical $z\sim3$ Lyman break galaxies, and may be a
contributing factor to its LyC detection. We obtain a revised,
contamination-free estimate for the comoving specific ionizing emissivity at
$z=2.85$, indicating (with large uncertainties) that star-forming galaxies
provide roughly the same contribution as QSOs to the ionizing background at
this redshift. Our results show that foreground contamination prevents
ground-based LyC studies from obtaining a full understanding of LyC emission
from $z\sim3$ star-forming galaxies. Future progress in direct LyC searches is
contingent upon the elimination of foreground contaminants through high
spatial-resolution observations, and upon acquisition of sufficiently deep LyC
imaging to probe ionizing radiation in high-redshift galaxies.},
added-at = {2015-06-30T09:25:40.000+0200},
author = {Mostardi, Robin E. and Shapley, Alice E. and Steidel, Charles C. and Trainor, Ryan F. and Reddy, Naveen A. and Siana, Brian},
biburl = {https://www.bibsonomy.org/bibtex/2e4ab82d63ee9888a0db491026bf9dae8/miki},
description = {[1506.08201] A High-Resolution Hubble Space Telescope Study of Lyman Continuum Leakers at $z\sim3$},
interhash = {1a33a97cea7fb0e476e98d823266f335},
intrahash = {e4ab82d63ee9888a0db491026bf9dae8},
keywords = {continuum escape fraction highz lyman},
note = {cite arxiv:1506.08201Comment: 30 pages, 5 tables, 19 figures. Submitted to ApJ. Version with full-resolution figures is available at: http://www.astro.ucla.edu/~aes/Mostardi_HST_LyC.pdf},
timestamp = {2015-06-30T09:25:47.000+0200},
title = {A High-Resolution Hubble Space Telescope Study of Lyman Continuum
Leakers at $z\sim3$},
url = {http://arxiv.org/abs/1506.08201},
year = 2015
}