Title:	A minimal space interferometer configuration for imaging at low radio frequencies
Authors:	Jaini, Akhil Deshpande, A.A. Bitragunta, Sainath
Keywords:	radio astronomy radio interferometers space telescopes very long baseline interferometry artificial satellites space observatories
Issue Date:	Aug-2021
Publisher:	Published by Cambridge University Press on behalf of the Astronomical Society of Australia
Citation:	Publications of the Astronomical Societyof Australia, 2021, Vol.38, Articel Number : e040
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.
Description:	Restricted Access. An open-access version is available at arXiv.org (one of the alternative locations)
URI:	http://hdl.handle.net/2289/7824
ISSN:	1323-3580 1448-6083 (Online)
Alternative Location:	https://ui.adsabs.harvard.edu/abs/2021PASA...38...40J/abstract https://arxiv.org/abs/2108.03113 https://doi.org/10.1017/pasa.2021.34
Copyright:	2021 The Author(s)
Appears in Collections:	Research Papers (A&A)

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