An ALMA survey of submillimetre galaxies in the Extended Chandra Deep Field-South: detection of C II at z=4.4
Journal article, 2012

We present Atacama Large Millimeter Array (ALMA) 870-mu m (345-GHz) observations of two submillimetre galaxies (SMGs) drawn from an ALMA study of the 126 submillimetre sources from the LABOCA Extended Chandra Deep Field-South Survey (LESS). The ALMA data identify the counterparts to these previously unidentified submillimetre sources and serendipitously detect bright emission lines in their spectra which we show are most likely to be [CII] 157.74 mu m emission yielding redshifts of z = 4.42 and 4.44. This blind detection rate within the 7.5-GHz bandpass of ALMA is consistent with the previously derived photometric redshift distribution of SMGs and suggests a modest, but not dominant (less than or similar to 25 per cent), tail of 870-mu m selected SMGs at z greater than or similar to 4. We find that the ratio of L-[CII]/L-FIR in these SMGs is much higher than seen for similarly far-infrared-luminous galaxies at z similar to 0, which is attributed to the more extended gas reservoirs in these high-redshift ultraluminous infrared galaxies (ULIRGs). Indeed, in one system we show that the [C II] emission shows hints of extended emission on greater than or similar to 3 kpc scales. Finally, we use the volume probed by our ALMA survey to show that the bright end of the [CII] luminosity function evolves strongly between z = 0 and similar to 4.4, reflecting the increased interstellar medium cooling in galaxies as a result of their higher star formation rates. These observations demonstrate that even with short integrations, ALMA is able to detect the dominant fine-structure cooling lines from high-redshift ULIRGs, measure their energetics and spatially resolved properties and trace their evolution with redshift.

galaxies: starburst

interstellar-medium

photodissociation regions

iso-lws spectroscopy

galaxies: evolution

midinfrared counterparts

micron line

mu-m

galaxies: high-redshift

high-redshift

deficit

laboca survey

star-formation

ultraluminous infrared galaxies

Author

A. M. Swinbank

Durham University

A. Karim

Durham University

I. Smail

Durham University

J. Hodge

Max Planck Institute

F. Walter

Max Planck Institute

F. Bertoldi

University of Bonn

A. D. Biggs

European Southern Observatory (ESO)

C. De Breuck

European Southern Observatory (ESO)

S. C. Chapman

University of Cambridge

K. E. K. Coppin

McGill University

P. Cox

Institut de RadioAstronomie Millimetrique (IRAM)

A. L. R. Danielson

Durham University

H. Dannerbauer

University of Vienna

R. J. Ivison

University of Edinburgh

Royal Observatory

T. R. Greve

University College London (UCL)

Kirsten Kraiberg Knudsen

Chalmers, Earth and Space Sciences, Radio Astronomy and Astrophysics

K. M. Menten

Max Planck Institute

J. M. Simpson

Durham University

E. Schinnerer

Max Planck Institute

J. L. Wardlow

University of California at Irvine (UCI)

A. Weiss

Max Planck Institute

P. van der Werf

Leiden University

Monthly Notices of the Royal Astronomical Society

0035-8711 (ISSN) 1365-2966 (eISSN)

Vol. 427 2 1066-1074

Subject Categories

Astronomy, Astrophysics and Cosmology

Roots

Basic sciences

DOI

10.1111/j.1365-2966.2012.22048.x

More information

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2/20/2019