A survey for transients and variables with the Murchison Widefield Array 32-tile prototype at 154 MHz
Author(s)Bowman, Judd D.; Goeke, Robert F.; Hewitt, Jacqueline N.; Morgan, Edward H.; Remillard, Ronald Alan; Williams, Christopher Leigh; ... Show more Show less
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We present a search for transient and variable radio sources at 154 MHz with the Murchison Widefield Array 32-tile prototype. 51 images were obtained that cover a field of view of 1430 deg[superscript 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 min and there was additional temporal information on day and year time-scales. 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 time-scale variability (26 min). We conclude that this variability is likely caused by simplifications in the calibration strategy or ionospheric effects. On the time-scale of 1 yr 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 ρ < 7.5 × 10[superscript −5] deg[superscript −2] with flux densities >5.5 Jy, and characteristic time-scales of both 26 min and 1 yr.
DepartmentHaystack Observatory; MIT Kavli Institute for Astrophysics and Space Research
Monthly Notices of the Royal Astronomical Society
Oxford University Press
Bell, M. E., T. Murphy, D. L. Kaplan, P. Hancock, B. M. Gaensler, J. Banyer, K. Bannister, et al. “A Survey for Transients and Variables with the Murchison Widefield Array 32-Tile Prototype at 154 MHz.” Monthly Notices of the Royal Astronomical Society 438, no. 1 (February 11, 2014): 352–367.
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