Observations of pulsars at 9 millimetres

¹ Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany e-mail: jessner@mpifr-bonn.mpg.de
² University of Manchester, Jodrell Bank Centre for Astrophysics, Manchester M13 9PL, UK
³ J. Kepler Institute of Astronomy, University of Zielona Gora, Poland

Received: 24 November 2006
Accepted: 11 December 2007

Abstract

Aims.The behaviour of the pulsar spectrum at high radio frequencies can provide decisive information about the nature of the radio emission mechanism.

Methods.We report recent observations of a selected sample of pulsars at  mm (32 GHz) with the 100-m Effelsberg radio telescope.

Results.Three pulsars, PSR B0144+59, PSR B0823+26, and PSR B2022+50, were detected for the first time at this frequency. We confirm the earlier flux density measurements for a sample of six pulsars, and we are able to place upper flux density limits for another 12 pulsars. We find that all pulsar spectra have a simple form that can be described using only three parameters, one of which is the lifetime of short nano-pulses in the emission region. The study of the transition region from coherent to incoherent emission needs further and more sensitive observations at even higher radio frequencies.