Turn-over in pulsar spectra around 1 GHz

Abstract

Aims. The main aim is to investigate the possibility of a high frequency turn-over in the radio spectrum of pulsars. Methods. Using the GMRT, multi-frequency flux density measurements of several candidate pulsars have been carried out and their spectra have been extended to lower frequencies. Results. We present the first direct evidence for turn-over in pulsar radio spectra at high frequencies. A total of 3 pulsars (including 2 new ones from this study) are now shown to have a turn-over frequency ≳1 GHz, and one is shown to have a turn-over at ∼600 MHz. © ESO 2007.