Low-radio-frequency eclipses of the redback pulsar J2215+5135 observed in the image plane with LOFAR

J. W. Broderick (1) , R. P. Fender (1) , R.P. Breton (2) , A. J. Stewart (3) , A Rowlinson (4) , J. D. Swinbank (5) , J W T Hessels (6) , T. D. Staley (7) , A. J. Van der horst (8) , M.E. Bell (1) , D Carbone (5) , Y Cendes (5) , Stéphane Corbel (9, 10) , J Eislöffel (11) , H Falcke (12) , Jean-Mathias Griessmeier (13, 10) , T. E. Hassall (2) , P. Jonker (14) , M Kramer (15) , M Kuniyoshi (15) , C. J. Law (5) , S Markoff (5) , G. J. Molenaar (5) , M Pietka (16) , L.H.A. Scheers (16) , M Serylak (10) , B. W. Stappers (2) , S ter Veen (14) , J van Leeuwen (5) , R. A. M. J. Wijers (5) , R Wijnands (5) , M. W. Wise (5) , Philippe Zarka (10, 17)

1 University of Southampton
2 Jodrell Bank Centre for Astrophysics
3 LASP - Laboratory for Atmospheric and Space Physics [Boulder]
4 CSIRO Astronomy and Space Science
5 AI PANNEKOEK - Astronomical Institute Anton Pannekoek
6 ASTRON - Netherlands Institute for Radio Astronomy
7 Oxford Astrophysics
8 GW - The George Washington University
9 AIM (UMR7158 / UMR_E_9005 / UM_112) - Astrophysique Interprétation Modélisation
10 USN - Unité Scientifique de la Station de Nançay
11 TLS - Thüringer Landessternwarte Tautenburg
12 Radboud University [Nijmegen]
13 LPC2E - Laboratoire de Physique et Chimie de l'Environnement et de l'Espace
14 IMAPP - Institute for Mathematics, Astrophysics and Particle Physics
15 MPIFR - Max-Planck-Institut für Radioastronomie
16 Oxford Astrophysics
17 LESIA - Laboratoire d'études spatiales et d'instrumentation en astrophysique

The eclipses of certain types of binary millisecond pulsars (i.e. 'black widows' and 'redbacks') are often studied using high-time-resolution, 'beamformed' radio observations. However, they may also be detected in images generated from interferometric data. As part of a larger imaging project to characterize the variable and transient sky at radio frequencies <200 MHz, we have blindly detected the redback system PSR J2215+5135 as a variable source of interest with the Low-Frequency Array (LOFAR). Using observations with cadences of two weeks – six months, we find preliminary evidence that the eclipse duration is frequency dependent (∝ν −0.4), such that the pulsar is eclipsed for longer at lower frequencies, in broad agreement with beamformed studies of other similar sources. Furthermore, the detection of the eclipses in imaging data suggests an eclipsing medium that absorbs the pulsed emission, rather than scattering it. Our study is also a demonstration of the prospects of finding pulsars in wide-field imaging surveys with the current generation of low-frequency radio telescopes.

Keywords: binaries: eclipsing.; radio continuum: stars.; pulsars: individual: PSR J2215+5135; pulsars: general

Domains: Sciences of the Universe [physics]

J. W. Broderick, R. P. Fender, R.P. Breton, A. J. Stewart, A Rowlinson, et al.. Low-radio-frequency eclipses of the redback pulsar J2215+5135 observed in the image plane with LOFAR. Monthly Notices of the Royal Astronomical Society, 2016, 459, pp.2681-2689. ⟨10.1093/mnras/stw794⟩. ⟨insu-01338263⟩