Angular momentum alignment of dark matter haloes |
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| Authors: | Steve Hatton Stéphane Ninin |
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| Institution: | Astronomical Institute 'Anton Pannekoek', Kruislaan 403, 1098 SJ Amsterdam, the Netherlands;Research School of Astronomy and Astrophysics, Institute of Advanced Studies, Australian National University, Mount Stromlo Observatory, Private Bag, Weston Creek Post Office, ACT 2611, Australia;Centre for Astrophysics and Supercomputing, Swinburne University of Technology, PO Box 218, Hawthorn, Victoria 3122, Australia;University of Manchester, Jodrell Bank Observatory, Macclesfield, Cheshire SK11 9DL;Columbia Astrophysics Laboratory, Columbia University, 550 West 120th Street, New York, NY 10027, USA;Australia Telescope National Facility, CSIRO, PO Box 76, Epping, NSW 1710, Australia;California Institute of Technology, MS 105-24, Pasadena, CA 91125, USA;Physics Department, University of Melbourne, Parkville, Victoria 3052, Australia |
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| Abstract: | In the three years following the discovery of PSR J2051?0827, we have observed a large number of eclipse traverses over a wide frequency range. These data show that the pulsar usually undergoes complete eclipse at frequencies below 1 GHz. At higher frequencies the pulsar is often detected throughout this low-frequency eclipse region with pulse times of arrival being significantly delayed relative to the best-fitting timing model. Variability in the magnitude of the delay is clearly seen and occurs on time-scales shorter than the orbital period. Simultaneous dual frequency observations highlight the difference in the eclipse behaviour for two widely separated frequencies. The low-frequency eclipses are accompanied by a significant decrease in pulsed flux density, while the flux density variations during higher frequency eclipses are not well defined. We consider a number of eclipse mechanisms and find that scattering and cyclotron absorption in the magnetosphere of the companion are consistent with the phenomena presented here. |
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| Keywords: | binaries: eclipsing stars: neutron pulsars: individual: PSR J2051?0827 |
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