Lyman Continuum Emission Escaping from Luminous Green Pea Galaxies at z = 0.5

Compact starburst galaxies are thought to include many or most of the from which substantial Lyman continuum emission can escape into intergalactic medium. Li and Malkan (2018) used SDSS photometry find a population such at z~0.5. They were discovered by their extremely strong [OIII]4959+5007 lines, produce clearly detectable excess brightness in i bandpass, compared with surrounding filters. We therefore HST/COS spectrograph observe two newly i-band around limits. One has strongly detected below its limit, corresponding relative fraction ionizing photons 20+/-2%. The other, is less compact UV imaging, 2-sigma upper limit <5%. Before spectroscopy, existing data could not distinguish these galaxies. Although sample hardly sufficient for statistical analysis, it shows possibility that some [OIII] emitters as class have escaping. differences might be determined luck our particular viewing geometry. Obtaining HST revealed Lyman-continuum emitting galaxy differs having no central absorption prominent Ly{\alpha} line profile. other target, escaping continuum, more common double-peaked emission.