Multifrequency Study of Giant Radio Pulses from the Crab Pulsar with the K5 VLBI Recording Terminal

Abstract

Abstract Simultaneous multifrequency observations of Crab pulsar giant pulses (GPs) were performed with the 64-m Kalyazin radio telescope at four frequency ($\nu$$=$ 0.6, 1.4, 2.2, and 8.3 GHz) using the K5 VLBI recording terminal. The K5 terminal provided continuous recording in 16 $\times$ 4-MHz wide frequency channels distributed over 4 frequency bands. Several thousand GPs were detected during about 6 hours of observations on two successive days in 2005 July. The radio spectra of single GPs were analyzed at separate frequencies and over the whole frequency range. These spectra manifest notable modulation over the frequency ranges, $\Delta\nu$, both on large ($\Delta\nu/\nu$$\approx$ 0.5) and small ($\Delta\nu/$$\nu$$\approx$ 0.01) frequency scales. A cross-correlation analysis of GPs at 2.2 GHz showed that their pulse shapes can be interpreted as being an ensemble of unresolved bursts grouped together on time scales of $\approx$1$ \mu$s, being well-correlated over a 60-MHz band. The corresponding GP cross-correlation functions do not obey the predictions of the amplitude-modulated noise model of Rickett (1975), thus indicating that unresolved components represent a small number of elementary emitters.