Abstract:
The radio sky at lower frequencies, particularly below 20 MHz, is expected to be a combination of increasingly bright non-thermal emission
and significant absorption from intervening thermal plasma. The sky maps at these frequencies cannot therefore be obtained by simple
extrapolation of those at higher frequencies. However, due to severe constraints in ground-based observations, this spectral window still
remains greatly unexplored. In this paper, we propose and study, through simulations, a novel minimal configuration for a space interferometer system which would enable imaging of the radio sky at frequencies well below 20 MHz with angular resolutions comparable to those
achieved at higher radio frequencies in ground-based observations by using the aperture synthesis technique. The minimal configuration
consists of three apertures aboard Low Earth Orbit (LEO) satellites orbiting the Earth in mutually orthogonal orbits. Orbital periods for the
satellites are deliberately chosen to differ from each other so as to obtain maximum (u,v) coverage in short time spans with baselines greater
than 15 000 km, thus, giving us angular resolutions finer than 10 arcsec even at these low frequencies. The sensitivity of the (u,v) coverage is
assessed by varying the orbit and the initial phase of the satellites. We discuss the results obtained from these simulations and highlight the
advantages of such a system
