Skip to main content

Research Repository

Advanced Search

ALMA resolves turbulent, rotating [CII] emission in a young starburst galaxy at z = 4.8

De Breuck, C.; Williams, R.J.; Swinbank, M.; Caselli, P.; Coppin, K.; Davis, T.A.; Maiolino, R.; Nagao, T.; Smail, I.; Walter, F.; Weiß, A.; Zwaan, M.A.

ALMA resolves turbulent, rotating [CII] emission in a young starburst galaxy at z = 4.8 Thumbnail


Authors

C. De Breuck

R.J. Williams

M. Swinbank

P. Caselli

K. Coppin

T.A. Davis

R. Maiolino

T. Nagao

F. Walter

A. Weiß

M.A. Zwaan



Abstract

We present spatially resolved Atacama Large Millimeter/submillimeter Array (ALMA) [Cii] observations of the z = 4.7555 submillimetre galaxy, ALESS 73.1. Our 0.̋5 FWHM map resolves the [Cii] emitting gas which is centred close to the active galactic nucleus (AGN). The gas kinematics are dominated by rotation but with high turbulence, vrot/σint ~ 3.1, and a Toomre Q parameter <1 throughout the disk. By fitting three independent thin rotating disk models to our data, we derive a total dynamical mass of 3 ± 2 × 1010 M⊙. This is close to the molecular gas mass derived from previous CO(2-1) observations, and implies a CO to H2 conversion factor αCO < 2.3 M⊙ (K km s-1 pc2)-1. The mass budget also constrains the stellar mass to <3.1 × 1010 M⊙, and entails a gas fraction of fgas ≳ 0.4. The diameter of the dust continuum emission is <2 kpc, while the star-formation rate is as high as 1000 M⊙ yr-1. Combined with our stellar mass constraint, this implies an extreme specific star formation rate >80 Gyr-1, especially since there are no clear indications of recent merger activity. Finally, our high signal-to-noise [Cii] measurement revises the observed [Nii]/[Cii] ratio, which suggests a close to solar metallicity, unless the [Cii] flux contains significant contributions from Hii regions. Our observations suggest that ALESS73.1 is a nascent galaxy undergoing its first major burst of star formation, embedded within an unstable but metal-rich gas disk.

Citation

De Breuck, C., Williams, R., Swinbank, M., Caselli, P., Coppin, K., Davis, T., …Zwaan, M. (2014). ALMA resolves turbulent, rotating [CII] emission in a young starburst galaxy at z = 4.8. Astronomy & Astrophysics, 565, https://doi.org/10.1051/0004-6361/201323331

Journal Article Type Article
Publication Date May 12, 2014
Deposit Date Nov 17, 2014
Publicly Available Date Mar 29, 2024
Journal Astronomy and astrophysics.
Print ISSN 0004-6361
Electronic ISSN 1432-0746
Publisher EDP Sciences
Peer Reviewed Peer Reviewed
Volume 565
DOI https://doi.org/10.1051/0004-6361/201323331
Keywords Galaxies: high-redshift, Galaxies: starburst, Galaxies: kinematics and dynamics, Galaxies: ISM.

Files

Published Journal Article (560 Kb)
PDF

Copyright Statement
Reproduced with permission from Astronomy & Astrophysics, © ESO 2014.





You might also like



Downloadable Citations