The LOFAR pilot surveys for pulsars and fast radio transients

Thijs Coenen (1) , Joeri van Leeuwen (2) , Jason W. T. Hessels (2) , Ben W. Stappers (3) , Vladislav I. Kondratiev (1) , A. Alexov (1) , R. P. Breton (4) , A. Bilous (5) , S. Cooper (3) , H. Falcke (1, 6, 7) , R. A. Fallows (1) , V. Gajjar (3) , Jean-Mathias Griessmeier (8, 9) , T. E. Hassall (3) , A. Karastergiou (10) , E. F. Keane (6) , M. Kramer (6, 3) , M. Kuniyoshi (6) , A. Noutsos (6) , S. Osłowski (11) , M. Pilia (1) , M. Serylak (9) , C. Schrijvers , C. Sobey (6) , S. ter Veen (5) , J. Verbiest (6) , P. Weltevrede (3) , S. Wijnholds (1) , K. Zagkouris (10) , A. S. van Amesfoort (1) , J. Anderson (12) , A. Asgekar (1) , I. M. Avruch (13) , M. E. Bell (4) , M. J. Bentum (1) , G. Bernardi (14) , P. Best (15) , A. Bonafede (16) , F. Breitling (12) , J. Broderick (4) , M. Brüggen (17) , H. R. Butcher (1) , B. Ciardi (18) , A. Corstanje (7) , A. Deller , S. Duscha , J. Eislöffel (19) , R. Fender (4) , C. Ferrari (20) , W. Frieswijk , M. A. Garrett (1, 21) , F. de Gasperin , E. de Geus (1) , A. W. Gunst (1) , J. P. Hamaker , G. Heald (1) , M. Hoeft (19) , A. van Der Horst , E. Juette (22) , G. Kuper (1) , C. Law (23) , G. Mann (12) , R. Mcfadden (1) , D. Mckay-Bukowski (24) , J. P. Mckean (1) , H. Munk (1) , E. Orru (1) , H. Paas (1) , M. Pandey-Pommier (25) , A. G. Polatidis (1) , W. Reich (6) , A. Renting , H. Röttgering (21) , A. Rowlinson , A. M. M. Scaife (26) , D. Schwarz (11) , J. Sluman (1) , O. Smirnov (27) , J. Swinbank (23) , Michel Tagger (9) , Y. Tang , C. Tasse (28) , S. Thoudam (7) , C. Toribio , R. Vermeulen , C. Vocks , R. J. van Weeren (1) , O. Wucknitz (6) , P. Zarka (28) , A. Zensus (6)

1 ASTRON - Netherlands Institute for Radio Astronomy
2 UvA - University of Amsterdam [Amsterdam]
3 JBCA - Jodrell Bank Centre for Astrophysics
4 University of Southampton
5 IMAPP - Institute for Mathematics, Astrophysics and Particle Physics
6 MPIFR - Max-Planck-Institut für Radioastronomie
7 Radboud University [Nijmegen]
8 USN - Unité Scientifique de la Station de Nançay
9 LPC2E - Laboratoire de Physique et Chimie de l'Environnement et de l'Espace
10 University of Oxford
11 Universität Bielefeld
12 AIP - Leibniz-Institut für Astrophysik Potsdam
13 SRON - SRON Netherlands Institute for Space Research
14 CfA - Harvard-Smithsonian Center for Astrophysics
15 University of Edinburgh
16 Jacobs University [Bremen]
17 UHH - Universität Hamburg
18 Max Planck Institute for Astrophysics
19 TLS - Thüringer Landessternwarte Tautenburg
20 LAGRANGE - Joseph Louis LAGRANGE
21 Leiden Observatory [Leiden]
22 Ruhr-Universität Bochum [Bochum]
23 AI PANNEKOEK - Astronomical Institute Anton Pannekoek
24 University of Oulu
25 CRAL - Centre de Recherche Astrophysique de Lyon
26 School of Physics and Astronomy [Southampton]
27 Rhodes University, Grahamstown
28 LESIA - Laboratoire d'études spatiales et d'instrumentation en astrophysique

We have conducted two pilot surveys for radio pulsars and fast transients with the Low-Frequency Array (LOFAR) around 140 MHz and here report on the first low-frequency fast-radio burst limit and the discovery of two new pulsars. The first survey, the LOFAR Pilot Pulsar Survey (LPPS), observed a large fraction of the northern sky, ~1.4 x 10^4 sq. deg, with 1-hr dwell times. Each observation covered ~75 sq. deg using 7 independent fields formed by incoherently summing the high-band antenna fields. The second pilot survey, the LOFAR Tied-Array Survey (LOTAS), spanned ~600 sq. deg, with roughly a 5-fold increase in sensitivity compared with LPPS. Using a coherent sum of the 6 LOFAR "Superterp" stations, we formed 19 tied-array beams, together covering 4 sq. deg per pointing. From LPPS we derive a limit on the occurrence, at 142 MHz, of dispersed radio bursts of < 150 /day/sky, for bursts brighter than S > 107 Jy for the narrowest searched burst duration of 0.66 ms. In LPPS, we re-detected 65 previously known pulsars. LOTAS discovered two pulsars, the first with LOFAR or any digital aperture array. LOTAS also re-detected 27 previously known pulsars. These pilot studies show that LOFAR can efficiently carry out all-sky surveys for pulsars and fast transients, and they set the stage for further surveying efforts using LOFAR and the planned low-frequency component of the Square Kilometer Array.

Keywords: pulsars: general; telescopes; surveys

Domains: Solar and Stellar Astrophysics [astro-ph.SR]; Physics [physics]; Astrophysics [astro-ph]

Thijs Coenen, Joeri van Leeuwen, Jason W. T. Hessels, Ben W. Stappers, Vladislav I. Kondratiev, et al.. The LOFAR pilot surveys for pulsars and fast radio transients. Astronomy and Astrophysics - A&A, 2014, 570, ⟨10.1051/0004-6361/201424495⟩. ⟨insu-01277801⟩