STUDIES OF PULSAR RADIO EMISSION WITH THE GURT RADIO TELESCOPE SUBARRAY

Abstract

Purpose: Finding the possibility of pulsar radio emission studies in the meter wavelength range with a small-sized subarray of the low-frequency GURT radio telescope of new generation. Development of the joint pulsar radio emission observations technique for the meter and decameter wavelength ranges at the GURT and UTR-2 radio telescopes, respectively, for studying the radio emission properties in a wide frequency range. Design/methodology/approach: The unique location of the two radio telescopes with overlapping frequency ranges at the same observatory area, and therefore under the conditions of the same propagation medium influence on the pulsar radio emission propagation recorded with these radio telescopes allows to determine the radiation flux spectra of these sources within a wide frequency range. The pulsar pulses averaged over 2-4 h are studied here. The UTR-2 structure flexibility and simultaneous using of several radio astronomy receivers allow analyzing the signals received with the whole radio telescope in the typical additive mode and with its separate subarrays, too. Simultaneous signal recording in these configurations allows controlling the influence of ionosphere on the signal propagation within the UTR-2 frequency range. Findings: With the GURT radio telescope subarray consisting of 25 active antenna elements the emission of 16 known pulsars within the 30÷70 MHz range was detected. Jointly with the UTR-2 two sessions of simultaneous wideband observations of pulsar radio emission were made within the 16.5÷70 MHz range. In the range of 16.5÷70 MHz, the average values of flux density and dispersion measures, as well as variations of these parameters for pulsars В1133+16, В1508+55 and В1919+21 were obtained. Conclusions: The studies made confirm the possibility of effective usage of the separate GURT radio telescope subarrays for radio astronomy observations, and in particular for pulsar radio emission studies. Long-term observations of pulsars in a wide frequency range allow obtaining the average values of pulsar radio emission flux densities, their spectral indices and the pulsar dispersion measures, as well as the variations of these values.

Keywords

• flux
• pulsed pulsar emission
• decameter and meter wavelengths
• radio telescope