LOFAR discovery of a quiet emission mode in PSR B0823+26

C. Sobey (1) , N. J. Young (2) , J. W. T. Hessels (3) , P. Weltevrede (4) , A. Noutsos (1) , B. W. Stappers (4) , M. Kramer (1, 5) , C. Bassa (6) , A. G. Lyne (4) , V. I. Kondratiev (7) , T. E. Hassall (4) , E. F. Keane (8) , A. V. Bilous (9) , R. P. Breton (4) , Jean-Mathias Griessmeier (10, 11) , A. Karastergiou (12, 13) , M. Pilia (7) , M. Serylak (10, 11) , S. ter Veen (9) , J. van Leeuwen (3) , A. Alexov (7) , J. Anderson (14) , A. Asgekar (7) , I. M. Avruch (15) , M. E. Bell (16) , M. J. Bentum (7) , G. Bernardi (17) , P. Best (18) , L. Bîrzan (19) , A. Bonafede (20) , F. Breitling (21) , J. Broderick (22) , M. Brüggen (20) , A. Corstanje (23) , D. Carbone (3) , E. de Geus (24) , M. de Vos (7) , A. van Duin (7) , S. Duscha (7) , J. Eislöffel (25) , H. Falcke (23) , R. A. Fallows (26) , R. Fender (22) , C. Ferrari (27) , W. Frieswijk (7) , M. A. Garrett (19) , A. W. Gunst (7) , J. P. Hamaker (7) , G. Heald (7) , M. Hoeft (25) , J. Hörandel (23) , E. Jütte (28) , G. Kuper (7) , P. Maat (7) , G. Mann (21) , S. Markoff (29) , R. Mcfadden (7) , D. Mckay-Bukowski (30) , J. P. Mckean (7) , D. D. Mulcahy (22) , H. Munk (7) , A. Nelles (23) , M. J. Norden (7) , E. Orrù (7) , H. Paas (31) , M. Pandey-Pommier (32) , V. N. Pandey (33) , G. Pietka (13) , R. Pizzo (7) , A. G. Polatidis (7) , D. Rafferty (34) , A. Renting (7) , H. Röttgering (19) , A. Rowlinson (16) , A. M. M. Scaife (35) , D. Schwarz (36) , J. Sluman (7) , O. Smirnov (12) , M. Steinmetz (37) , A. Stewart (38) , J. Swinbank (29) , Michel Tagger (10) , Y. Tang (39) , C. Tasse (40, 41) , S. Thoudam (23) , C. Toribio (7) , R. Vermeulen (7) , C. Vocks (21) , R. J. van Weeren (42) , R. A. M. J. Wijers (29) , M. W. Wise (29) , O. Wucknitz (43) , S. Yatawatta (7) , P. Zarka (40)

1 MPIFR - Max-Planck-Institut für Radioastronomie
2 UMN - University of Minnesota [Twin Cities]
3 UvA - University of Amsterdam [Amsterdam] = Universiteit van Amsterdam
4 Jodrell Bank Centre for Astrophysics
5 CAL - Columbia Astrophysics Laboratory
6 Cornell University [New York]
7 ASTRON - Netherlands Institute for Radio Astronomy
8 CAS - Centre for Astrophysics and Supercomputing [Swinburne]
9 IMAPP - Institute for Mathematics, Astrophysics and Particle Physics
10 LPC2E - Laboratoire de Physique et Chimie de l'Environnement et de l'Espace
11 USN - Unité Scientifique de la Station de Nançay
12 Rhodes University, Grahamstown
13 Oxford Astrophysics
14 Institute for Mathematics Applied to Geoscience
15 SRON - SRON Netherlands Institute for Space Research
16 CSIRO Astronomy and Space Science
17 LPNHE - Laboratoire de Physique Nucléaire et de Hautes Énergies
18 Edin. - University of Edinburgh
19 Leiden Observatory [Leiden]
20 Jacobs University = Constructor University [Bremen]
21 AIP - Leibniz-Institut für Astrophysik Potsdam
22 University of Southampton
23 Radboud University [Nijmegen]
24 Medstar Research Institute
25 TLS - Thüringer Landessternwarte Tautenburg
26 Institute of Mathematical and Physical Sciences
27 Département de Géologie
28 RUB - Ruhr University Bochum = Ruhr-Universität Bochum
29 AI PANNEKOEK - Astronomical Institute Anton Pannekoek
30 University of Oulu
31 Center for Information Technology CIT
32 CRAL - Centre de Recherche Astrophysique de Lyon
33 NRAO - National Radio Astronomy Observatory [Charlottesville]
34 Department of Astronomy and Astrophysics [PennState]
35 School of Physics and Astronomy [Southampton]
36 Interactions Son Musique Mouvement
37 DSMZ - Leibniz-Institut DSMZ-Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH / Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures
38 LASP - Laboratory for Atmospheric and Space Physics [Boulder]
39 UP11 - Université Paris-Sud - Paris 11
40 LESIA - Laboratoire d'études spatiales et d'instrumentation en astrophysique
41 SKA South Africa
42 CfA - Harvard-Smithsonian Center for Astrophysics
43 AlfA - Argelander-Institut für Astronomie

PSR B0823+26, a 0.53-s radio pulsar, displays a host of emission phenomena over timescales of seconds to (at least) hours, including nulling, subpulse drifting, and mode-changing. Studying pulsars like PSR B0823+26 provides further insight into the relationship between these various emission phenomena and what they might teach us about pulsar magnetospheres. Here we report on the LOFAR discovery that PSR B0823+26 has a weak and sporadically emitting 'quiet' (Q) emission mode that is over 100 times weaker (on average) and has a nulling fraction forty-times greater than that of the more regularly-emitting 'bright' (B) mode. Previously, the pulsar has been undetected in the Q-mode, and was assumed to be nulling continuously. PSR B0823+26 shows a further decrease in average flux just before the transition into the B-mode, and perhaps truly turns off completely at these times. Furthermore, simultaneous observations taken with the LOFAR, Westerbork, Lovell, and Effelsberg telescopes between 110 MHz and 2.7 GHz demonstrate that the transition between the Q-mode and B-mode occurs within one single rotation of the neutron star, and that it is concurrent across the range of frequencies observed.

Mots clés: PSR B0823+26-radio telescopes; individual; stars; neutron- pulsars; magnetosphere-pulsars

Domaines: Planète et Univers [physics]

C. Sobey, N. J. Young, J. W. T. Hessels, P. Weltevrede, A. Noutsos, et al.. LOFAR discovery of a quiet emission mode in PSR B0823+26. Monthly Notices of the Royal Astronomical Society, 2015, 451 (3), pp.2493-2506. ⟨10.1093/mnras/stv1066⟩. ⟨insu-01323239⟩