Oral Presentation
Quasar Environment and Large-Scale Feedback at z~2.2 Probed with Lyα Emitters and Continuum Selected Galaxies
Presenter: Yuta Suzuki (Ehime University)
The photoevaporation effect refers to an ionization/heating process of surrounding material by intense ultraviolet (UV) radiation, which suppresses galaxy formation by preventing cooling and gravitational collapse of gas in the surrounding dark matter halos. This could be most effective for low-mass galaxies around luminous quasars. Here, we report on a statistical analysis of quasar photoevaporation at z ~ 2.2, which compares the density of Ly Alpha Emitters (LAEs) and photo-z galaxies. We select 18 quasars, which are covered by Hyper Suprime-Cam Subaru Strategic Program and CFHT Large Area U-band Deep Survey. We spatially normalize the surrounding LAE/photo-z galaxy distribution to the median quasar proximity zone, stack them, and then compare their shapes of density profiles. As a result, we find that the density of LAEs is significantly lower than that of photo-z galaxies within the quasar proximity zone. We further find that the LAEs with higher EWs are less dense than those with lower EWs, and that the fainter photo-z galaxies are significantly reduced in density. Finally, we create a control sample of photo-z galaxies with similar host halo mass to the quasars, and find that the number densities of both LAEs and (other) photo-z galaxies increase toward the control galaxies while the rate of increase is smaller toward the quasars. In this talk, we will present these results and discuss the presence and possible effects of the photoevaporation effect on galaxy formation.
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