Presentation #224.06 in the session Evolution of Galaxies IV.
The direct measurement of escaping Lyman continuum (LyC) radiation from high-redshift galaxies is key to unraveling the mystery of the cosmic reionization, but has been challenging. Using the new wide HST WFC3/F275W imaging obtained by UVCANDELS, we search for prominent individual LyC leakers at z>2.4 and constrain the escape fraction of the ionizing radiation. UVCANDELS is a cycle-26 Treasury Program that acquired 164 orbits of F275W+F435W imaging in four CANDELS fields: GOODS-N, GOODS-S, EGS, and COSMOS, covering a total area of ~430 arcmin2 and reaching a 5-σ depth of 27 ABmag in F275W and 28 ABmag in F435W. Our extensive LyC leaker search and stacking take advantage of the following catalogs of spectroscopic redshifts (spec-zs): (1) a compilation of ~6500 spec-zs published by various groups over the past >10 years (2) a re-analysis of the archival grism spectroscopy in the CANDELS fields, and (3) a dedicated visual inspection ranking the quality of the rest-frame UV/optical spectra for each source by 4-5 individuals. We obtain tentative candidates of LyC leaking galaxies and AGN with moderately strong F275W signals, which are potentially the escaping ionizing radiation at z>2.4. We will also present our preliminary upper limits on the z~2.4 escape fraction using an image stacking technique, and discuss their implications for cosmic reionization.