ASKAP commissioning observations of the GAMA 23 field

Authors

Denis A. Leahy, University of Calgary
A. M. Hopkins, Macquarie University
R. P. Norris, Western Sydney University
J. Marvil, Australia Telescope National Facility
J. D. Collier, Western Sydney University
E. N. Taylor, Swinburne University of Technology
J. R. Allison, University of Oxford
C. Anderson, Australia Telescope National Facility
M. Bell, University of Technology Sydney
M. Bilicki, Center for Theoretical Physics of the Polish Academy of Sciences
J. Bland-Hawthorn, The University of Sydney
S. Brough, UNSW Sydney
M. J.I. Brown, Monash University
S. Driver, The University of Western Australia
G. Gurkan, CSIRO Astronomy and Space Science
L. Harvey-Smith, Western Sydney University
I. Heywood, University of Oxford
Benne W. Holwerda, University of LouisvilleFollow
J. Liske, Universität Hamburg
A. R. Lopez-Sanchez, Macquarie University
D. McConnell, Australia Telescope National Facility
A. Moffett, Vanderbilt University
M. S. Owers, Macquarie University
K. A. Pimbblet, University of Hull
W. Raja, Australia Telescope National Facility
N. Seymour, Curtin University
M. A. Voronkov, Australia Telescope National Facility
L. Wang, SRON Netherlands Institute for Space Research

Document Type

Article

Publication Date

1-1-2019

Department

Physics and Astronomy

Abstract

We have observed the G23 field of the Galaxy AnMass Assembly (GAMA) survey using the Australian Square Kilometre Array Pathfinder (ASKAP) in its commissioning phase to validate the performance of the telescope and to characterise the detected galaxy populations. This observation covers ∼48 deg2 with synthesised beam of 32.7 arcsec by 17.8 arcsec at 936MHz, and ∼39 deg2 with synthesised beam of 15.8 arcsec by 12.0 arcsec at 1320MHz. At both frequencies, the root-mean-square (r.m.s.) noise is ∼0.1 mJy/beam. We combine these radio observations with the GAMA galaxy data, which includes spectroscopy of galaxies that are i-band selected with a magnitude limit of 19.2. Wide-field Infrared Survey Explorer (WISE) infrared (IR) photometry is used to determine which galaxies host an active galactic nucleus (AGN). In properties including source counts, mass distributions, and IR versus radio luminosity relation, the ASKAP-detected radio sources behave as expected. Radio galaxies have higher stellar mass and luminosity in IR, optical, and UV than other galaxies. We apply optical and IR AGN diagnostics and find that they disagree for ∼30% of the galaxies in our sample. We suggest possible causes for the disagreement. Some cases can be explained by optical extinction of the AGN, but for more than half of the cases we do not find a clear explanation. Radio sources are more likely (∼6%) to have an AGN than radio quiet galaxies (∼1%), but the majority of AGN are not detected in radio at this sensitivity.

ThinkIR Citation

Leahy, Denis A.; Hopkins, A. M.; Norris, R. P.; Marvil, J.; Collier, J. D.; Taylor, E. N.; Allison, J. R.; Anderson, C.; Bell, M.; Bilicki, M.; Bland-Hawthorn, J.; Brough, S.; Brown, M. J.I.; Driver, S.; Gurkan, G.; Harvey-Smith, L.; Heywood, I.; Holwerda, Benne W.; Liske, J.; Lopez-Sanchez, A. R.; McConnell, D.; Moffett, A.; Owers, M. S.; Pimbblet, K. A.; Raja, W.; Seymour, N.; Voronkov, M. A.; and Wang, L., "ASKAP commissioning observations of the GAMA 23 field" (2019). Faculty and Staff Scholarship. 491.
https://ir.library.louisville.edu/faculty/491

DOI

10.1017/pasa.2019.16

ORCID

0000-0002-4884-6756