Tsukuba Uchu Forum

124th Uchu Forum

UV & Ly-alpha halos of LAEs across environments at z=2.84

Satoshi Kikuta

University of Tsukuba, Center for Computational Sciences

Diffuse Lyα emission around galaxies, or Lyα halo (LAH), is a valuable probe of their circumgalactic medium which regulate galaxy evolution. We present UV & Lyα radial surface brightness (SB) profiles of Lyα emitters (LAEs) at z = 2.84 detected with the HSC on the Subaru Telescope. UV and Lyα images of 3490 LAEs are extracted, and stacking the images yields SB sensitivity of ~1e−20 erg/s/cm^2/arcsec^2 in Lyα. Fitting of the two component exponential function gives the halo scalelength of ~10 pkpc. Dividing the sample according to their photometric properties, we find that while the dependence of halo scalelength on environment outside of the protocluster core is not clear, LAEs in the central regions of protoclusters have very large LAHs and may be related to diffuse Lyα emission from abundant cool gas in the protocluster core irradiated by active members. For the first time, we identify "UV halos" around bright LAEs which are probably due to a few lower-mass satellites. Through comparison with recent simulations, we discuss the possible origins of LAHs. (Talk is presented in Japanese. 発表は日本語で行われます。) Image