Very Long Baseline Interferometry (VLBI) at sub-millimeter waves has the potential to image the shadow of the black hole in the Galactic Center, Sagittarius A* (Sgr A*), and thereby test basic predictions of the theory of general relativity. We investigate the imaging prospects of a new Space VLBI mission concept. The setup consists of two satellites in polar or equatorial circular Medium-Earth Orbits with slightly different radii, resulting in a dense spiral-shaped uv-coverage with long baselines, allowing for extremely high-resolution and high-fidelity imaging of radio sources. We simulate observations of a general relativistic magnetohydrodynamics model of Sgr A* for this configuration with noise calculated from model system parameters. After gridding the uv-plane and averaging visibilities accumulated over multiple months of integration, images of Sgr A* with a resolution of up to 4 μas could be reconstructed, allowing for stronger tests of general relativity and accretion models than with ground-based VLBI.
@article{arxiv.2005.01339,
title = {On the prospects of imaging Sagittarius A* from space},
author = {Freek Roelofs and Heino Falcke and Christiaan Brinkerink and Monika Moscibrodzka and Leonid I. Gurvits and Manuel Martin-Neira and Volodymyr Kudriashov and Marc Klein-Wolt and Remo Tilanus and Michael Kramer and Luciano Rezzolla},
journal= {arXiv preprint arXiv:2005.01339},
year = {2020}
}
Comments
4 pages, 4 figures, published in Proceedings IAU Symposium No. 342, 2018