The Murchison Widefield Array Commissioning Survey: A Low-Frequency Catalogue of 14 110 Compact Radio Sources over 6 100 Square Degrees

Abstract We present the results of an approximately 6 100 deg2 104–196 MHz radio sky survey performed with the Murchison Widefield Array during instrument commissioning between 2012 September and 2012 December: the MWACS. The data were taken as meridian drift scans with two different 32-antenna sub-arrays that were available during the commissioning period. The survey covers approximately 20.5 h < RA < 8.5 h, − 58° < Dec < −14°over three frequency bands centred on 119, 150 and 180 MHz, with image resolutions of 6–3 arcmin. The catalogue has 3 arcmin angular resolution and a typical noise level of 40 mJy beam− 1, with reduced sensitivity near the field boundaries and bright sources. We describe the data reduction strategy, based upon mosaicked snapshots, flux density calibration, and source-finding method. We present a catalogue of flux density and spectral index measurements for 14 110 sources, extracted from the mosaic, 1 247 of which are sub-components of complexes of sources.

Roger Cappallo | Alan Whitney | Mark Waterson | Lu Feng | Steven Tingay | Melanie Johnston-Hollitt | Bryna J. Hazelton | Natasha Hurley-Walker | Randall B. Wayth | Judd D. Bowman | Benjamin McKinley | Lincoln Greenhill | David Emrich | Martin E. Bell | Gianni Bernardi | Avinash A. Deshpande | Luke Hindson | Eric Kratzenberg | Nadia Kudryavtseva | Miguel F. Morales | Divya Oberoi | Pietro Procopio | David L. Kaplan | Aaron Ewall-Wice | K. Srivani | Daniel C. Jacobs | Ramesh Bhat | Emil Lenc | Stephen Ord | Thiagaraj Prabu | B. M. Gaensler | Brian Corey | Ravi Subrahmanyan | E. Lenc | D. Kaplan | J. Hewitt | B. Pindor | R. Webster | Lu Feng | S. Tingay | M. Morales | E. Morgan | D. Oberoi | Andrew J. Williams | A. Rogers | B. Corey | R. Cappallo | A. Whitney | R. Wayth | P. Procopio | J. Kasper | A. Offringa | G. Bernardi | J. Bowman | A. Ewall-Wice | B. Hazelton | D. Jacobs | R. Goeke | P. Hancock | R. Subrahmanyan | M. Johnston-Hollitt | F. Briggs | B. Gaensler | D. Mitchell | L. Greenhill | S. Ord | C. Lonsdale | A. Deshpande | M. Lynch | M. Waterson | M. Bell | L. Hindson | R. Bhat | D. Emrich | N. Hurley-Walker | K. Srivani | R. McWhirter | J. Morgan | B. McKinley | E. Kratzenberg | A. Roshi | N. Kudryavtseva | T. Prabu | J. Riding | U. Shankar | Andrew Williams | Jacqueline Hewitt | John Morgan | Robert Goeke | Anish Roshi | Bart Pindor | Paul J. Hancock | Alan Rogers | Edward Morgan | Frank Briggs | Justin Kasper | Rachel Webster | Colin Lonsdale | Daniel Mitchell | André Offringa | Jennifer Riding | Mervyn Lynch | Russell McWhirter | Udaya Shankar | Chris Williams | C. Williams

[1]  A. R. Whitney,et al.  A survey for transients and variables with the Murchison Widefield Array 32-tile prototype at 154 MHz , 2013, 1311.2989.

[2]  A. R. Whitney,et al.  The giant lobes of Centaurus A observed at 118 MHz with the Murchison Widefield Array , 2013, 1309.0916.

[3]  A. R. Whitney,et al.  A 189 MHz, 2400 deg2 POLARIZATION SURVEY WITH THE MURCHISON WIDEFIELD ARRAY 32-ELEMENT PROTOTYPE , 2013, 1305.6047.

[4]  Alan E. E. Rogers,et al.  Science with the Murchison Widefield Array , 2012, Publications of the Astronomical Society of Australia.

[5]  A. R. Whitney,et al.  The Murchison Widefield Array: The Square Kilometre Array Precursor at Low Radio Frequencies , 2012, Publications of the Astronomical Society of Australia.

[6]  James R. Curran,et al.  blobcat: software to catalogue flood‐filled blobs in radio images of total intensity and linear polarization , 2012, 1205.5313.

[7]  Christopher L. Williams,et al.  LOW-FREQUENCY IMAGING OF FIELDS AT HIGH GALACTIC LATITUDE WITH THE MURCHISON WIDEFIELD ARRAY 32 ELEMENT PROTOTYPE , 2012, 1203.5790.

[8]  Andrew Hopkins,et al.  Compact continuum source finding for next generation radio surveys , 2012, 1202.4500.

[9]  J. Roerdink,et al.  A morphological algorithm for improving radio-frequency interference detection , 2012, 1201.3364.

[10]  M. C. Toribio,et al.  LOFAR: The LOw-Frequency ARray , 2013, 1305.3550.

[11]  David F. Moore,et al.  NEW 145 MHz SOURCE MEASUREMENTS BY PAPER IN THE SOUTHERN SKY , 2011, 1105.1367.

[12]  W. A. Coles,et al.  Interferometric Imaging with the 32 Element Murchison Wide-Field Array , 2010, 1010.1733.

[13]  R. Davies,et al.  Astronomical Society of the Pacific Conference Series , 2010 .

[14]  S. Zaroubi,et al.  Foregrounds for observations of the cosmological 21 cm line - I. First Westerbork measurements of Galactic emission at 150 MHz in a low latitude field , 2009, 0904.0404.

[15]  Christopher L. Williams,et al.  The Murchison Widefield Array: Design Overview , 2009, Proceedings of the IEEE.

[16]  A. Lee Swindlehurst,et al.  IEEE Journal of Selected Topics in Signal Processing Inaugural Issue: [editor-in-chief's message] , 2007, J. Sel. Topics Signal Processing.

[17]  R. Hunstead,et al.  The Molonglo Southern 4 Jy Sample (MS4). I. Definition , 2005, astro-ph/0512588.

[18]  R. Perley,et al.  The VLA Low-Frequency Sky Survey , 2005, 0706.1191.

[19]  J. Curran,et al.  SUMSS: a wide-field radio imaging survey of the southern sky – II. The source catalogue , 2003, astro-ph/0303188.

[20]  Carlos De Breuck,et al.  A sample of ultra steep spectrum sources selected from the Westerbork In the Southern Hemisphere (WISH) survey , 2002, astro-ph/0208054.

[21]  D. Bock,et al.  SUMSS: A Wide-Field Radio Imaging Survey of the Southern Sky. I. Science Goals, Survey Design, and Instrumentation , 1998, astro-ph/9812083.

[22]  C. Carilli,et al.  Synthesis Imaging in Radio Astronomy II , 1999 .

[23]  James J. Condon,et al.  ERRORS IN ELLIPTICAL GAUSSIAN FITS , 1997 .

[24]  R. Sault,et al.  An approach to interferometric mosaicing , 1996 .

[25]  E. Greisen,et al.  Representations of celestial coordinates in FITS , 2002, astro-ph/0207413.

[26]  E. Greisen,et al.  The NRAO VLA Sky Survey , 1996 .

[27]  M. I. Large,et al.  The Molonglo Reference Catalogue of radio sources. , 1981 .

[28]  O. Slee.  Culgoora-3 list of radio source measurements. , 1977 .

[29]  J. Condon,et al.  Confusion and flux-density error distributions , 1974 .

[30]  A. Wright,et al.  Australian Journal of Physics Astrophysical Supplement , 1973 .