%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 }