Giant galaxy growing from recycled gas: ALMA maps the circumgalactic molecular medium of the Spiderweb in [C?i]

Emonts, B.H.C.; Lehnert, M.D.; Dannerbauer, H.; De Breuck, C.; Miley, G.K.; Allison, J.R.; Gullberg, B.; Hatch, N.A.; Guillard, P.; Mao, M.Y.; Norris, R.P.

doi:10.1093/mnrasl/sly034

Authors

B.H.C. Emonts

M.D. Lehnert

H. Dannerbauer

C. De Breuck

G.K. Miley

J.R. Allison

B. Gullberg

NINA HATCH nina.hatch@nottingham.ac.uk
Associate Professor

P. Guillard

M.Y. Mao

R.P. Norris

Abstract

The circumgalactic medium (CGM) of the massive Spiderweb Galaxy, a conglomerate of merging proto-cluster galaxies at z = 2.2, forms an enriched interface where feedback and recycling act on accreted gas. This is shown by observations of [C?i], CO(1-0), and CO(4-3) performed with the Atacama Large Millimeter Array and Australia Telescope Compact Array. [C?i] and CO(4-3) are detected across ?50?kpc, following the distribution of previously detected low-surface-brightness CO(1-0) across the CGM. This confirms our previous results on the presence of a cold molecular halo. The central radio galaxy MRC?1138-262 shows a very high global L?CO(4?3)/L?CO(1?0) ? 1, suggesting that mechanisms other than FUV-heating by star formation prevail at the heart of the Spiderweb Galaxy. Contrary, the CGM has L?CO(4?3)/L?CO(1?0) and L?[CI]/L?CO(1?0) similar to the ISM of five galaxies in the wider proto-cluster, and its carbon abundance, X[CI]/XH2?, resembles that of the Milky Way and star-forming galaxies. The molecular CGM is thus metal-rich and not diffuse, confirming a link between the cold gas and in situ star formation. Thus, the Spiderweb Galaxy grows not directly through accretion of gas from the cosmic web, but from recycled gas in the CGM.

Citation

Emonts, B., Lehnert, M., Dannerbauer, H., De Breuck, C., Villar-Martín, M., Miley, G., …Norris, R. (2018). Giant galaxy growing from recycled gas: ALMA maps the circumgalactic molecular medium of the Spiderweb in [C i]. Monthly Notices of the Royal Astronomical Society: Letters, 477(1), L60-L65. https://doi.org/10.1093/mnrasl/sly034

Journal Article Type	Article
Acceptance Date	Feb 23, 2018
Online Publication Date	Mar 3, 2018
Publication Date	Jun 11, 2018
Deposit Date	Jan 8, 2019
Publicly Available Date	Jan 8, 2019
Journal	Monthly Notices of the Royal Astronomical Society: Letters
Electronic ISSN	1745-3933
Publisher	Oxford University Press
Peer Reviewed	Peer Reviewed
Volume	477
Issue	1
Pages	L60-L65
DOI	https://doi.org/10.1093/mnrasl/sly034
Public URL	https://nottingham-repository.worktribe.com/output/1451718
Publisher URL	https://academic.oup.com/mnrasl/article/477/1/L60/4919661