LOFAR MSSS: Detection of a low-frequency radio transient in 400 hrs of monitoring of the North Celestial Pole
Creators: name: Stewart, A. J.
name: Fender, R. P.
name: Broderick, J. W.
name: Hassall, T. E.
name: Muñoz-Darias, T.
name: Rowlinson, A.
name: Swinbank, J. D.
name: Staley, T. D.
name: Molenaar, G. J.
name: Scheers, B.
name: Grobler, T. L.
name: Pietka, M.
name: Heald, G.
name: McKean, J. P.
name: Bell, M. E.
name: Bonafede, A.
name: Breton, R. P.
name: Carbone, D.
name: Cendes, Y.
name: Clarke, A. O.
name: Corbel, S.
name: de Gasperin, F.
name: Eislöffel, J.
name: Falcke, H.
name: Ferrari, C.
name: Grießmeier, J. -M.
name: Hardcastle, M. J.
name: Heesen, V.
name: Hessels, J. W. T.
name: Horneffer, A.
name: Iacobelli, M.
name: Jonker, P.
name: Karastergiou, A.
name: Kokotanekov, G.
name: Kondratiev, V. I.
name: Kuniyoshi, M.
name: Law, C. J.
name: van Leeuwen, J.
name: Markoff, S.
name: Miller-Jones, J. C. A.
name: Mulcahy, D.
name: Orru, E.
name: Pandey-Pommier, M.
name: Pratley, L.
name: Rol, E.
name: Röttgering, H. J. A.
name: Scaife, A. M. M.
name: Shulevski, A.
name: Sobey, C. A.
name: Stappers, B. W.
name: Tasse, C.
name: van der Horst, A. J.
name: van Velzen, S.
name: van Weeren, R. J.
name: Wijers, R. A. M. J.
name: Wijnands, R.
name: Wise, M.
name: Zarka, P.
name: Alexov, A.
name: Anderson, J.
name: Asgekar, A.
name: Avruch, I. M.
name: Bentum, M. J.
name: Bernardi, G.
name: Best, P.
name: Breitling, F.
name: Brüggen, M.
name: Butcher, H. R.
name: Ciardi, B.
name: Conway, J. E.
name: Corstanje, A.
name: de Geus, E.
name: Deller, A.
name: Duscha, S.
name: Frieswijk, W.
name: Garrett, M. A.
name: Gunst, A. W.
name: van Haarlem, M. P.
name: Hoeft, M.
name: Hörandel, J.
name: Juette, E.
name: Kuper, G.
name: Loose, M.
name: Maat, P.
name: McFadden, R.
name: McKay-Bukowski, D.
name: Moldon, J.
name: Munk, H.
name: Norden, M. J.
name: Paas, H.
name: Polatidis, A. G.
name: Schwarz, D.
name: Sluman, J.
name: Smirnov, O.
name: Steinmetz, M.
name: Thoudam, S.
name: Toribio, M. C.
name: Vermeulen, R.
name: Vocks, C.
name: Wijnholds, S. J.
name: Wucknitz, O.
name: Yatawatta, S.
Publisher: name: arXiv
Year: 2015
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: We present the results of a four-month campaign searching for low-frequency radio transients near the North Celestial Pole with the Low-Frequency Array (LOFAR), as part of the Multifrequency Snapshot Sky Survey (MSSS). The data were recorded between 2011 December and 2012 April and comprised 2149 11-minute snapshots, each covering 175 deg^2. We have found one convincing candidate astrophysical transient, with a duration of a few minutes and a flux density at 60 MHz of 15-25 Jy. The transient does not repeat and has no obvious optical or high-energy counterpart, as a result of which its nature is unclear. The detection of this event implies a transient rate at 60 MHz of 3.9 (+14.7, -3.7) x 10^-4 day^-1 deg^-2, and a transient surface density of 1.5 x 10^-5 deg^-2, at a 7.9-Jy limiting flux density and ~10-minute time-scale. The campaign data were also searched for transients at a range of other time-scales, from 0.5 to 297 min, which allowed us to place a range of limits on transient rates at 60 MHz as a function of observation duration.
description: 23 pages, 16 figures, 5 tables, accepted for publication in MNRAS