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 Society
F. Walter
Max Planck Society
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 Millimétrique (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 Society
J. M. Simpson
Durham University
E. Schinnerer
Max Planck Society
J. L. Wardlow
University of California at Irvine (UCI)
A. Weiss
Max Planck Society
P. van der Werf
Leiden University
Monthly Notices of the Royal Astronomical Society
0035-8711 (ISSN) 1365-2966 (eISSN)
Vol. 427 2 1066-1074Subject Categories
Astronomy, Astrophysics and Cosmology
Roots
Basic sciences
DOI
10.1111/j.1365-2966.2012.22048.x