Observations of Pulsars at 7 Millimeters

Abstract

We report the Ðrst observations of a selected sample of pulsars at 43 GHz (7 mm). All four pulsars (B0329]54, B0355]54, B1929]10, and B2021]51) were successfully detected with pulse shapes and widths similar to those at lower frequencies. For B0329]54, we see the well-known proÐle mode changing behavior observed at low frequencies. The triple-frequency receiver system used for the observations allowed a spectral study spanning almost 30 GHz, using bands centered at 15, 23, and 43 GHz. Our results strengthen the claim for unusual spectral behavior of pulsars, i.e., a Ñattening (or possible upturn) of the pulsar spectrum at millimeter wavelengths.