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http://hdl.handle.net/20.500.12386/25130| Title: | LOFAR discovery of a quiet emission mode in PSR B0823+26 | Authors: | Sobey, C. Young, N. J. Hessels, J. W. T. Weltevrede, P. Noutsos, A. Stappers, B. W. Kramer, M. Bassa, C. Lyne, A. G. Kondratiev, V. I. Hassall, T. E. Keane, E. F. Bilous, A. V. Breton, R. P. Grießmeier, J. -M. Karastergiou, A. PILIA, Maura Serylak, M. Veen, S. ter van Leeuwen, J. Alexov, A. Anderson, J. Asgekar, A. Avruch, I. M. Bell, M. E. Bentum, M. J. BERNARDI, GIANNI Best, P. Bîrzan, L. Bonafede, A. Breitling, F. Broderick, J. Brüggen, M. Corstanje, A. Carbone, D. de Geus, E. de Vos, M. van Duin, A. Duscha, S. Eislöffel, J. Falcke, H. Fallows, R. A. Fender, R. Ferrari, C. Frieswijk, W. Garrett, M. A. Gunst, A. W. Hamaker, J. P. Heald, G. Hoeft, M. Hörandel, J. Jütte, E. Kuper, G. Maat, P. Mann, G. Markoff, S. McFadden, R. McKay-Bukowski, D. McKean, J. P. Mulcahy, D. D. Munk, H. Nelles, A. Norden, M. J. Orrù, E. Paas, H. Pandey-Pommier, M. Pandey, V. N. Pietka, G. Pizzo, R. Polatidis, A. G. Rafferty, D. Renting, A. Röttgering, H. Rowlinson, A. Scaife, A. M. M. Schwarz, D. Sluman, J. Smirnov, O. Steinmetz, M. Stewart, A. Swinbank, J. Tagger, M. Tang, Y. Tasse, C. Thoudam, S. Toribio, C. Vermeulen, R. Vocks, C. van Weeren, R. J. Wijers, R. A. M. J. Wise, M. W. Wucknitz, O. Yatawatta, S. Zarka, P. |
Issue Date: | 2015 | Journal: | MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY | Number: | 451 | Issue: | 3 | First Page: | 2493 | Abstract: | PSR B0823+26, a 0.53-s radio pulsar, displays a host of emission phenomena over time-scales 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 (Low-Frequency Array) 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. | Acknowledgments: | We thank the Deutsche Forschungsgemeinschaft (DFG) for funding this work within the research unit FOR 1254 ‘Magnetisation of Interstellar and Intergalactic Media: The Prospects of Low-Frequency Radio Observations’. NY acknowledges support from the National Research Foundation (NRF). JWTH acknowledges funding from an NWO Vidi fellowship and ERC Starting Grant ‘DRAGNET’ (337062). The LOFAR was designed and constructed by ASTRON, the Netherlands Institute for Radio Astronomy, and has facilities in several countries that are owned by various parties (each with their own funding sources), and that are collectively operated by the International LOFAR Telescope (ILT) foundation under a joint scientific policy. The WSRT is operated by ASTRON/NWO. Observations with the Lovell Telescope are supported through an STFC consolidated grant. This work is partly based on observations with the 100-m telescope of the Max-Planck-Institut für Radioastronomie at Effelsberg. We would like to thank R. Karuppusamy for his help with the Effelsberg observations. CF acknowledges financial support by the Agence Nationale de la Recherche through grant ANR-09-JCJC-0001-01. The majority of the plots were created using the PSRCHIVE python interface, and the python package matplotlib (Hunter 2007 ). | URI: | http://hdl.handle.net/20.500.12386/25130 | URL: | https://academic.oup.com/mnras/article/451/3/2493/1182101 | ISSN: | 0035-8711 | DOI: | 10.1093/mnras/stv1066 | Bibcode ADS: | 2015MNRAS.451.2493S | Fulltext: | open |
| Appears in Collections: | 1.01 Articoli in rivista |
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|---|---|---|---|---|
| Sobey2015.pdf | 3.84 MB | Adobe PDF | View/Open |
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