Abstract:
We present preliminary results from an ongoing program of
accurate pulsar dispersion measure (DM) measurements using the GMRT. From
simultaneous dual frequency observations, we are able to determine OMs to
accuracies of 1 part in 104 and better. For 4 of the 12 pulsars studied, we find
our mean DM value to be significantly different from the expected value. For
most of the pulsars, we detect significant variations of the DM on time scales
of weeks to months.
