Zusammenfassung
We present the HST WFC3/F275W UV imaging observations of A2218-Flanking, a
lensed compact dwarf galaxy at redshift $z\approx2.5$. The stellar mass of
A2218-Flanking is $łog(M/M_ødot=9.14$ and SFR is 12.5~$M_ødot$~yr$^-1$
after correcting the magnification. This galaxy has a young galaxy age of
127~Myr and a compact galaxy size of $r_1/2=2.4$~kpc. The HST UV imaging
observations cover the rest-frame Lyman continuum (LyC) emission
($\sim800$\AA) from A2218-Flanking. We firmly detect ($14\sigma$) the LyC
emission in A2218-Flanking in the F275W image. Together with the HST F606W
images, we find that the absolute escape fraction of LyC is $f_\rm
abs,esc>28-57\%$ based on the flux density ratio between 1700\AA and
800\AA ($f_1700/f_800$). The morphology of the LyC emission in the F275W
images is extended and well follows the morphology of the UV continuum
morphology in the F606W images, suggesting that the $f_800$ is not from
foreground contaminants. We find that the region with a high star formation
rate surface density has a lower $f_1700/f_800$ (higher $f_800/f_1700$)
ratio than the diffused regions, suggesting that LyC photons are more likely to
escape from the region with the intensive star-forming process. We compare the
properties of galaxies with and without LyC detections and find that LyC
photons are easier to escape in low mass galaxies.
Nutzer