Kiloparsec-scale gaseous clumps and star formation at z = 5-7
Date Issued
2018
Author(s)
Carniani, S.
•
Maiolino, R.
•
Amorin, R.
•
•
Pallottini, A.
•
Ferrara, A.
•
Willott, C. J.
•
Smit, R.
•
Matthee, J.
•
Sobral, D.
•
•
•
De Barros, S.
•
•
•
Guaita, L.
Abstract
We investigate the morphology of the [C II] emission in a sample of `normal' star-forming galaxies at 5 < z < 7.2 in relation to their UV (rest-frame) counterpart. We use new Atacama Large Millimetre/submillimetre Array (ALMA) observations of galaxies at z ∼ 6-7, as well as a careful re-analysis of archival ALMA data. In total 29 galaxies were analysed, 21 of which are detected in [C II]. For several of the latter the [C II] emission breaks into multiple components. Only a fraction of these [C II] components, if any, is associated with the primary UV systems, while the bulk of the [C II] emission is associated either with fainter UV components, or not associated with any UV counterpart at the current limits. By taking into account the presence of all these components, we find that the L_[C II]-SFR (star formation rate) relation at early epochs is fully consistent with the local relation, but it has a dispersion of 0.48 ± 0.07 dex, which is about two times larger than observed locally. We also find that the deviation from the local L_[C II]-SFR relation has a weak anticorrelation with the EW(Ly α). The morphological analysis also reveals that [C II] emission is generally much more extended than the UV emission. As a consequence, these primordial galaxies are characterized by a [C II] surface brightness generally much lower than expected from the local Σ _[C II]-Σ _{SFR} relation. These properties are likely a consequence of a combination of different effects, namely gas metallicity, [C II] emission from obscured star-forming regions, strong variations of the ionization parameter, and circumgalactic gas in accretion or ejected by these primeval galaxies.
Volume
478
Issue
1
Start page
1170
Issn Identifier
0035-8711
Ads BibCode
2018MNRAS.478.1170C
Rights
open.access
File(s)![Thumbnail Image]()
![Thumbnail Image]()
Loading...
Name
1712.03985.pdf
Description
preprint
Size
965.73 KB
Format
Adobe PDF
Checksum (MD5)
b7b755ccfe921e11f5c88481548a7ece
Loading...
Name
sty1088.pdf
Description
pdf editoriale
Size
2.31 MB
Format
Adobe PDF
Checksum (MD5)
631cd8dbb1bc5115011d9e6d910f2914