Sep 9 – 13, 2019
Rome
UTC timezone

First Identification of 10-kpc Scale [CII] 158um Halos around Star-Forming Galaxies at z=5-7 (Seiji Fujimoto)

Sep 11, 2019, 10:22 AM
18m
Rome

Rome

Accademia dei Lincei c/o Villa Farnesina Via della Lungara 10/230 00165 Roma
Talk Reionization and First Light

Description

We report the discovery of 10-kpc scale [CII] 158um halos surrounding star-forming galaxies in the early Universe. We choose deep ALMA data of 18 galaxies each with a star-formation rate of ~ 10-70 Msun with no signature of AGN whose [CII] lines are individually detected at z=5.153-7.142, and conduct stacking of the [CII] lines and dust-continuum in the uv-visibility plane. The radial profiles of the surface brightnesses show a 10-kpc scale [CII] halo at the 9.2sigma level significantly extended more than the HST stellar continuum data by a factor of ~5 on the exponential-profile scale length basis, as well as the dust continuum. We also compare the radial profiles of [CII] and Lya halos universally found in star-forming galaxies at this epoch, and find that the scale lengths agree within the 1sigma level. The existence of the extended [CII] halo is the evidence of outflow remnants in the early galaxies and suggest that the outflows may be dominated by cold-mode outflows, which challenges current galaxy evolution models.

Primary authors

Dr Seiji Fujimoto (The Cosmic Dawn Center) Dr Masami Ouchi (University of Tokyo) Prof. Andrea Ferrara (Scuola Normale Superiore) Dr Andrea Pallottini (Scuola Normale Superiore) Dr Rob Ivison (European Southern Observatory) Dr Christoph Behrens (Scuola Normale Superiore) Dr Simona Gallerani (Scuola Normale Superiore)

Presentation materials