Lyα Halos around [O iii]-selected Galaxies in HETDEX

Abstract

Abstract We present extended Lyα emission out to 800 kpc of 1034 [O iii]-selected galaxies at redshifts 1.9 < z < 2.35 using the Hobby–Eberly Telescope Dark Energy Experiment. The locations and redshifts of the galaxies are taken from the 3D-HST survey. The median-stacked surface brightness profile of the Lyα emission of the [O iii]-selected galaxies agrees well with that of 968 bright Lyα-emitting galaxies (LAEs) at r > 40 kpc from the galaxy centers. The surface brightness in the inner parts (r < 10 kpc) around the [O iii]-selected galaxies, however, is 10 times fainter than that of the LAEs. Our results are consistent with the notion that photons dominating the outer regions of the Lyα halos are not produced in the central galaxies but originate outside of them.