LOFAR 150-MHz observations of the Boötes field: catalogue and source counts

Journal article

We present the first wide area (19 deg 2 ), deep (≈120-150 μJy beam -1 ), high-resolution (5.6 � 7.4 arcsec) LOFAR High Band Antenna image of the Bo�tes field made at 130-169 MHz. This image is at least an order of magnitude deeper and 3-5 times higher in angular resolution than previously achieved for this field at low frequencies. The observations and data reduction, which includes full direction-dependent calibration, are described here. We present a radio source catalogue containing 6 276 sources detected over an area of 19 deg 2 , with a peak flux density threshold of 5σ. As the first thorough test of the facet calibration strategy, introduced by van Weeren et al., we investigate the flux and positional accuracy of the catalogue. We present differential source counts that reach an order of magnitude deeper in flux density than previously achieved at these low frequencies, and show flattening at 150-MHz flux densities below 10 mJy associated with the rise of the low flux density star-forming galaxies and radio-quiet AGN.

Authors: Williams, W; van Weeren, R; Röttgering, H; Best, P; Dijkema, T

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Oxford University Press
• Journal: Monthly Notices of the Royal Astronomical Society
• Volume: 460
• Issue: 3
• Pages: 2385-2412
• Publication date: 2016-05-29
• Acceptance date: 2016-05-03
• DOI: 10.1093/mnras/stw1056
• EISSN: 1365-2966
• ISSN: 0035-8711
• Keywords: surveys; techniques: interferometric; galaxies: active; radio continuum: galaxies