Valerii M. Malofeev

Radio spectra of pulsars

AbstractThe results of flux pulsar radioemission measurements at meter wavelengths, made at Pushchino Radio Astronomical Observatory of the Lebedev Physical Institute, are presented. Flux densities at 102, 85, 61 and 39 MHz have been measured for 85, 29, 37 and 23 pulsars correspondingly. Some of them were performed at all frequencies simultaneously.On the basis of these data and high frequencies data obtained by other authors, spectra of 52 pulsars were plotted. In practically all investigated pulsars we have detected a turn-over frequency at which the flux density of pulsar radioemission attained its maximum. Its mean value isvm=130±80 MHz. Averaged on many pulsars, the spectral index is negative in the 39–61 MHz frequency range

Spectra of nine pulsars at 61 – 1420 MHz

(\bar \alpha _{39 - 61} = - 1.4 \pm 0.4)

Superdispersion Delay of Low-Frequency Pulsar Pulses

and passes through zero at frequencies of about 100 MHz, becoming positive in the 100–400 MHz frequency range. It was noticed that the spectral index in the 100–400 MHz interval depends upon such pulsar periods as α100−=0.7logp+0.9. Using the spectra, more precise radio luminosities of pulsars have been computed.

Pulsar Mean Pulse Profiles at 102.5-MHZ

With the DKR-1000 and BSA meter-band radio telescopes of the Physics Institute used for the study of pulsars, digital computing technology is employed for processing the results of observations in real time. For enhancing sensitivity and time resolution, a procedure of pulse buildup with prior compensation of a pulsar’s dispersion over a wide band is employed. A study of known pulsars is conducted with the help of analyzers of the “Neutron” type. To search for unknown pulsars, a system has been developed that processes observations with the on-line method, using an M-6000 electronic computer.