New-generation radio interferometer

Abstract

Studies of physical conditions in active galactic nuclei and cosmological studies require low-frequency observations of compact radio sources with high sensitivity and resolution. To advance considerably in this research, observations in the meter wavelength range with a sensitivity of about 1 mJy are needed. The sensitivity of low-frequency observations of extragalactic radio sources is limited by the confusion effect. To suppress it to a 1 mJy level, one needs antennas with apertures of 300–400 km. Currently, new-generation SKA and LOFAR radio telescopes are developed, which are aperture-synthesis systems based on small antennas which have dimensions of several hundreds of kilometers. Such measuring complexes will allow one to achieve a sensitivity of 1 mJy. In this work, we propose to make an interferometer with baseline exceeding 5000 km on the basis of in-phase kilometer antenna arrays. It is shown that such a system will have a sensitivity of about 1 mJy at a frequency of 100 MHz. Along with the high sensitivity, the proposed interferometer based on diffraction gratings will make it possible to form a multilobe directional pattern that will cover the entire observable hemisphere in terms of inclination. This opens up new opportunities for fast surveys of weak small-size radio sources.