First Identification of 10-kpc Scale [CII] 158um Halos around Star-Forming Galaxies at z=5-7. (arXiv:1902.06760v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Fujimoto_S/0/1/0/all/0/1">Seiji Fujimoto</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ouchi_M/0/1/0/all/0/1">Masami Ouchi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ferrara_A/0/1/0/all/0/1">Andrea Ferrara</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pallottini_A/0/1/0/all/0/1">Andrea Pallottini</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ivison_R/0/1/0/all/0/1">R. J. Ivison</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Behrens_C/0/1/0/all/0/1">Christoph Behrens</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gallerani_S/0/1/0/all/0/1">Simona Gallerani</a>
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.
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.
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