Limits on Fast Radio Bursts and other transient sources at 182 MHz using the Murchison Widefield Array

Journal
Date Issued
2016
Author(s)
Rowlinson, A.
•
Bell, M. E.
•
Murphy, T.
•
Trott, C. M.
•
Hurley-Walker, N.
•
Johnston, S.
•
Tingay, S. J.
•
Kaplan, D. L.
•
Carbone, D.
•
Hancock, P. J.
•
Feng, L.
•
Offringa, A. R.
•
•
Bowman, J. D.
•
Briggs, F.
•
Cappallo, R. J.
•
Deshpande, A. A.
•
Gaensler, B. M.
•
Greenhill, L. J.
•
Hazelton, B. J.
•
Johnston-Hollitt, M.
•
Lonsdale, C. J.
•
McWhirter, S. R.
•
Mitchell, D. A.
•
Morales, M. F.
•
Morgan, E.
•
Oberoi, D.
•
Ord, S. M.
•
Prabu, T.
•
Udaya Shankar, N.
•
Srivani, K. S.
•
Subrahmanyan, R.
•
Wayth, R. B.
•
Webster, R. L.
•
Williams, A.
•
Williams, C. L.
DOI
Abstract
We present a survey for transient and variable sources, on time-scales from 28 s to ∼1 yr, using the Murchison Widefield Array (MWA) at 182 MHz. Down to a detection threshold of 0.285 Jy, no transient candidates were identified, making this the most constraining low-frequency survey to date and placing a limit on the surface density of transients of <4.1 × 10-7 deg-2 for the shortest time-scale considered. At these frequencies, emission from Fast Radio Bursts (FRBs) is expected to be detectable in the shortest time-scale images without any corrections for interstellar or intergalactic dispersion. At an FRB limiting flux density of 7980 Jy, we find a rate of <82 FRBs per sky per day for dispersion measures <700 pc cm-3. Assuming a cosmological population of standard candles, our rate limits are consistent with the FRB rates obtained by Thornton et al. if they have a flat spectral slope. Finally, we conduct an initial variability survey of sources in the field with flux densities ≳0.5 Jy and identify no sources with significant variability in their light curves. However, we note that substantial further work is required to fully characterize both the short-term and low-level variability within this field.
Volume
458
Issue
4
Start page
3506
Uri
Url
Issn Identifier
0035-8711
Ads BibCode
2016MNRAS.458.3506R
Rights
open.access
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