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Astron. Astrophys. 364, L71-L74 (2000)

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Letter to the Editor

Search for discrete refractive scattering events

R. Ramachandran 1, A.A. Deshpande 2,3 and B.W. Stappers 4

1 Netherlands Foundation for Research in Astronomy, Postbus 2, 7990 AA Dwingeloo, The Netherlands (ramach@astro.uva.nl)
2 Raman Research Institute, C.V. Raman Avenue, Bangalore - 560 080, India (desh@rri.ernet.in)
3 Australia Telescope National Facility, CSIRO, Narrabri, NSW, Australia
4 Universiteit van Amsterdam, Sterrenkundig Instituut, 1098 SJ Amsterdam, The Netherlands (bws@astro.uva.nl)

Received 13 April 2000 / Accepted 15 November 2000


We have searched for discrete refractive scattering events (including effects due to possible non-multiple diffractive scattering) at meter wavelengths in the direction of two close by pulsars B0950+08 and B1929+10, where we looked for spectral signatures associated with the multiple imaging of pulsars due to scattering in the interstellar medium. We do not find any signatures of such events in the direction of either source over a spectral periodicity range of 50 KHz to 5 MHz. Our analysis puts strong upper limits on the column density contrast associated with a range of spatial scales of the interstellar electron density irregularities along these lines of sight.

Key words: stars: neutron – stars: pulsars: general – ISM: structure

Send offprint requests to: ramach@astro.uva.nl

© European Southern Observatory (ESO) 2000

Online publication: January 29, 2001