Limits on radio emission from pulsar wind nebulae |
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| Authors: | B M Gaensler † B W Stappers D A Frail D A Moffett ‡ S Johnston S Chatterjee |
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| Institution: | Center for Space Research, Massachusetts Institute of Technology, 70 Vassar Street, Cambridge, MA 02139, USA;Astronomical Institute 'Anton Pannekoek', Kruislaan 403, 1098 SJ Amsterdam, the Netherlands;National Radio Astronomy Observatory, PO Box 0, Socorro, NM 87801, USA;Physics Department, University of Tasmania, GPO Box 252-21, Hobart, Tasmania 7001, Australia;Research Centre for Theoretical Astrophysics, University of Sydney, NSW 2006, Australia;Department of Astronomy and Space Sciences, Cornell University, Ithaca, NY 14853, USA |
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| Abstract: | We report on a sensitive survey for radio pulsar wind nebulae (PWN) towards 27 energetic and/or high-velocity pulsars. Observations were carried out at 1.4 GHz using the Very Large Array and the Australia Telescope Compact Array and utilized pulsar-gating to search for off-pulse emission. These observing parameters resulted in a considerably more sensitive search than previous surveys and could detect PWN over a much wider range of spatial scales (and hence ambient densities and pulsar velocities). However, no emission clearly corresponding to a PWN was discovered. Based on these non-detections we argue that the young and energetic pulsars in our sample have winds which are typical of young pulsars, but produce unobservable PWN because they reside in low-density ( n ～0.003 cm?3) regions of the interstellar medium. However, non-detection of PWN around older and less energetic pulsars can only be explained if the radio luminosity of their winds is less than 10?5 of their spin-down luminosity, implying an efficiency at least an order of magnitude smaller than that seen for young pulsars. |
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| Keywords: | pulsars: general ISM: general supernova remnants radio continuum: ISM |
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