Black Hole Imaging with Space-Based Telescopes

The Event Horizon Telescope (EHT) is a millimeter-wavelength arrayusing very long baseline interferometry (VLBI) to image the supermassiveblack holes at the center of galaxies. The EHT has enough angularresolution to image the shadow of the supermassive black hole in thecenter of our galaxy as well as in the nearby giant elliptical galaxyM87. With baselines approaching an Earth diameter, the EHT is near thelimit of the resolution achievable from ground-based VLBI. This posterexplores the potential benefits of adding telescopes in extended orbitsto the EHT, allowing for higher-fidelity imaging of current targetsources as well as the addition of new target sources with smallershadows. To test the effectiveness of orbital patterns, we firstgenerate models of sources with various black hole shadow sizes, thencreate model telescope arrays that include telescopes in differentorbits. We then reconstruct model images using simulated data from thesetelescope arrays. We determine that, by including a geostationary Earthorbiting satellite and a high-inclination medium Earth orbitingsatellite, we can successfully reconstruct high-fidelity images of thenext tier of shadow sources down to a shadow diameter of ~3microarcseconds. This would allow the array to image the shadow of theblack hole in the Sombrero Galaxy, among others, and would allow the EHTto study the fine structure of jet launch and collimation in M87 andother active galactic nuclei. This work is made possible by funding fromthe National Science Foundation (AST-1659420, AST-1614868, andAST-1440254).