An ALMA survey of submillimetre galaxies in the Extended Chandra Deep Field South: radio properties and the far-infrared/radio correlation

Author(s)

A. P. Thomson, Rob J. Ivison, J. M. Simpson, Helmut Dannerbauer, A. Mark Swinbank, Ian R. Smail, V. Arumugam, David M Alexander, A. Beelen, W. N. Brandt, I. Chandra, T. R. Greve, J. A. Hodge, E. Ibar, A. Karim, E. J. Murphy, E. Schinnerer, S. Sirothia, F Walter, J. L. Wardlow, Paul, van der Werf

Abstract

We present a study of the radio properties of 870 μm-selected submillimetre galaxies (SMGs), observed at high resolution with Atacama Large Millimeter Array (ALMA) in the Extended Chandra Deep Field South. From our initial sample of 76 ALMA SMGs, we detect 52 SMGs at >3σ significance in Karl G. Jansky Very Large Array 1400 MHz imaging, of which 35 are also detected at >3σ in new 610 MHz Giant Metre-Wave Radio Telescope imaging. Within this sample of radio-detected SMGs, we measure a median radio spectral index α

₆₁₀

¹⁴⁰⁰ = -0.79 ± 0.06, (with inter-quartile range α = [-1.16, -0.56]) and investigate the far-infrared/radio correlation via the parameter q

_IR, the logarithmic ratio of the rest-frame 8-1000 μm flux and monochromatic radio flux. Our median q

_IR = 2.56 ± 0.05 (inter-quartile range q

_IR = [2.42, 2.78]) is higher than that typically seen in single-dish 870 μm-selected sources (q

_IR ~ 2.4), which may reflect the fact that our ALMA-based study is not biased to radio-bright counterparts, as previous samples were. Finally, we search for evidence that q

_IR and α evolve with age in a codependent manner, as predicted by starburst models: the data populate the predicted region of parameter space, with the stellar mass tending to increase along tracks of q

_IR versus a in the direction expected, providing the first observational evidence in support of these models.

Organisation(s)

Department of Astrophysics

External organisation(s)

Durham University, European Southern Observatory (Germany), Tata Institute of Fundamental Research (TIFR), Université Paris XI - Paris-Sud, Pennsylvania State University, Max-Planck-Institut für Astronomie, National Radio Astronomy Observatory, Charlottesville, Rheinische Friedrich-Wilhelms-Universität Bonn, California Institute of Technology (Caltech), University of Edinburgh, University College London, Universidad de Valparaíso, Pontificia Universidad Católica de Chile, University of Copenhagen, Leiden University

Journal

Monthly Notices of the Royal Astronomical Society

Volume

442

Pages

577-588

No. of pages

12

ISSN

0035-8711

DOI

https://doi.org/10.1093/mnras/stu839

Publication date

07-2014

Peer reviewed

Yes

Austrian Fields of Science 2012

103003 Astronomy, 103004 Astrophysics

Keywords

ASJC Scopus subject areas

Astronomy and Astrophysics, Space and Planetary Science

Portal url

https://ucrisportal.univie.ac.at/en/publications/an-alma-survey-of-submillimetre-galaxies-in-the-extended-chandra-deep-field-south-radio-properties-and-the-farinfraredradio-correlation(7d02d5ea-53b7-473a-844f-45a54b548aee).html