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

Rowlinson, A.A.RowlinsonBell, M. E.M. E.BellMurphy, T.T.MurphyTrott, C. M.C. M.TrottHurley-Walker, N.N.Hurley-WalkerJohnston, S.S.JohnstonTingay, S. J.S. J.TingayKaplan, D. L.D. L.KaplanCarbone, D.D.CarboneHancock, P. J.P. J.HancockFeng, L.L.FengOffringa, A. R.A. R.OffringaBERNARDI, GIANNIGIANNIBERNARDIBowman, J. D.J. D.BowmanBriggs, F.F.BriggsCappallo, R. J.R. J.CappalloDeshpande, A. A.A. A.DeshpandeGaensler, B. M.B. M.GaenslerGreenhill, L. J.L. J.GreenhillHazelton, B. J.B. J.HazeltonJohnston-Hollitt, M.M.Johnston-HollittLonsdale, C. J.C. J.LonsdaleMcWhirter, S. R.S. R.McWhirterMitchell, D. A.D. A.MitchellMorales, M. F.M. F.MoralesMorgan, E.E.MorganOberoi, D.D.OberoiOrd, S. M.S. M.OrdPrabu, T.T.PrabuUdaya Shankar, N.N.Udaya ShankarSrivani, K. S.K. S.SrivaniSubrahmanyan, R.R.SubrahmanyanWayth, R. B.R. B.WaythWebster, R. L.R. L.WebsterWilliams, A.A.WilliamsWilliams, C. L.C. L.Williams2020-07-062020-07-0620160035-8711http://hdl.handle.net/20.500.12386/26337We 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.STAMPAenLimits on Fast Radio Bursts and other transient sources at 182 MHz using the Murchison Widefield ArrayArticle10.1093/mnras/stw4512-s2.0-84965028216000375799500010https://academic.oup.com/mnras/article/458/4/3506/26138022016MNRAS.458.3506RFIS/05 - ASTRONOMIA E ASTROFISICAERC sectors::Physical Sciences and Engineering::PE9 Universe sciences: astro-physics/chemistry/biology; solar systems; stellar, galactic and extragalactic astronomy, planetary systems, cosmology, space science, instrumentation::PE9_6 Stars and stellar systems