A survey for transients and variables with the Murchison Widefield Array 32-tile prototype at 154 MHz
Abstract
We present a search for transient and variable radio sources at 154 MHz with the Murchison Widefield Array 32-tile prototype. Fifty-one images were obtained that cover a field of view of 1430 deg^2 centred on Hydra A. The observations were obtained over three days in 2010 March and three days in 2011 April and May. The mean cadence of the observations was 26 minutes and there was additional temporal information on day and year timescales. We explore the variability of a sample of 105 low frequency radio sources within the field. Four bright (S > 6 Jy) candidate variable radio sources were identified that displayed low levels of short timescale variability (26 minutes). We conclude that this variability is likely caused by simplifications in the calibration strategy or ionospheric effects. On the timescale of one year we find two sources that show significant variability. We attribute this variability to either refractive scintillation or intrinsic variability. No radio transients were identified and we place an upper limit on the surface density of sources rho < 7.5 x 10^-5 deg^-2 with flux densities > 5.5 Jy, and characteristic timescales of both 26 minutes and one year.
Keywords
Cite
@article{arxiv.1311.2989,
title = {A survey for transients and variables with the Murchison Widefield Array 32-tile prototype at 154 MHz},
author = {M. E. Bell and T. Murphy and D. L. Kaplan and P. Hancock and B. M. Gaensler and J. Banyer and K. Bannister and C. Trott and N. Hurley-Walker and R. B. Wayth and J. -P. Macquart and W. Arcus and D. Barnes and G. Bernardi and J. D. Bowman and F. Briggs and J. D. Bunton and R. J. Cappallo and B. E. Corey and A. Deshpande and L. deSouza and D. Emrich and R. Goeke and L. J. Greenhill and B. J. Hazelton and D. Herne and J. N. Hewitt and M. Johnston-Hollitt and J. C. Kasper and B. B. Kincaid and R. Koenig and E. Kratzenberg and C. J. Lonsdale and M. J. Lynch and S. R. McWhirter and D. A. Mitchell and M. F. Morales and E. Morgan and D. Oberoi and S. M. Ord and J. Pathikulangara and T. Prabu and R. A. Remillard and A. E. E. Rogers and A. Roshi and J. E. Salah and R. J. Sault and N. Udaya Shankar and K. S. Srivani and J. Stevens and R. Subrahmanyan and S. J. Tingay and M. Waterson and R. L. Webster and A. R. Whitney and A. Williams and C. L. Williams and J. S. B. Wyithe},
journal= {arXiv preprint arXiv:1311.2989},
year = {2015}
}
Comments
18 pages, 12 figures