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Session 74 - Pulsars.
Display session, Wednesday, January 15
Metropolitan Ballroom,
We have used signle pulse observations made with the Effelsberg radiotelescope at six different radiofrequencies in the microwave range to investigate the pulse to pulse intensity modulations as well as the manner in which single pulse profiles cobmine to form a stable integrated profile.
The modulation index is calculated for five sources at radio-frequencies of 1.4, 1.7, 2.3, 4.7, 8.5 and 10.5 GHz. High values of the modulation index are found to correlate with higher frequencies, suggesting the burst like nature of the emission at high radio frequencies. The burst nature of the emission is more evident in dual frequency measurements, where clearly the intensity fluctuations at the highest frequency (8.5GHz) are rare but very energetic while the low (2.3GHz) activity is always present. The occassional high activity burts do not seem to coinside in time at both frequencies.
Furthermore, an analysis of the characteristic time scales involed in the profile stabilization process is presented. Subaverages of shorter integrations are created and correlated with the average profile. Correlations between the average profile and those subaverages, show weak frequency dependence, indicating that the stabilization process is common for all frequencies.
