Wide-field broadband radio imaging with phased array feeds: a pilot multi-epoch continuum survey with ASKAP-BETA
Abstract
The Boolardy Engineering Test Array is a 6 x 12 m dish interferometer and the prototype of the Australian Square Kilometre Array Pathfinder (ASKAP), equipped with the first generation of ASKAP's phased array feed (PAF) receivers. These facilitate rapid wide-area imaging via the deployment of simultaneous multiple beams within a 30 square degree field of view. By cycling the array through 12 interleaved pointing positions and using 9 digitally formed beams we effectively mimic a traditional 1 hour x 108 pointing survey, covering 150 square degrees over 711 - 1015 MHz in 12 hours of observing time. Three such observations were executed over the course of a week. We verify the full bandwidth continuum imaging performance and stability of the system via self-consistency checks and comparisons to existing radio data. The combined three epoch image has arcminute resolution and a 1-sigma thermal noise level of 375 micro-Jy per beam, although the effective noise is a factor 3 higher due to residual sidelobe confusion. From this we derive a catalogue of 3,722 discrete radio components, using the 35 percent fractional bandwidth to measure in-band spectral indices for 1,037 of them. A search for transient events reveals one significantly variable source within the survey area. The survey covers approximately two-thirds of the Spitzer South Pole Telescope Deep Field. This pilot project demonstrates the viability and potential of using PAFs to rapidly and accurately survey the sky at radio wavelengths.
Keywords
Cite
@article{arxiv.1601.05857,
title = {Wide-field broadband radio imaging with phased array feeds: a pilot multi-epoch continuum survey with ASKAP-BETA},
author = {I. Heywood and K. W. Bannister and J. Marvil and J. R. Allison and L. Ball and M. E. Bell and D. C. -J. Bock and M. Brothers and J. D. Bunton and A. P. Chippendale and F. Cooray and T. J. Cornwell and D. DeBoer and P. Edwards and R. Gough and N. Gupta and L. Harvey-Smith and S. Hay and A. W. Hotan and B. Indermuehle and C. Jacka and C. A. Jackson and S. Johnston and A. E. Kimball and B. S. Koribalski and E. Lenc and A. Macleod and N. McClure-Griffiths and D. McConnell and P. Mirtschin and T. Murphy and S. Neuhold and R. P. Norris and S. Pearce and A. Popping and R. Y. Qiao and J. E. Reynolds and E. M. Sadler and R. J. Sault and A. E. T. Schinckel and P. Serra and T. W. Shimwell and J. Stevens and J. Tuthill and A. Tzioumis and M. A. Voronkov and T. Westmeier and M. T. Whiting},
journal= {arXiv preprint arXiv:1601.05857},
year = {2016}
}
Comments
20 pages, 13 figures, 4 tables. Accepted for publication in MNRAS