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86 GHz imaging of M87 with the ngEHT and ngVLA

Presentation #302.26 in the session Computation, Data Handling, Image Analysis — iPoster Session.

Published onJun 29, 2022
86 GHz imaging of M87 with the ngEHT and ngVLA

The coming decade will witness the inauguration of two major “next-generation” radio telescopes: the next-generation Very Large Array (ngVLA) and the next-generation Event Horizon Telescope (ngEHT). Though the primary observing frequency range of the ngEHT (~230-345 GHz) falls above the highest frequency targeted by the ngVLA (~115 GHz), the design specifications for the ngEHT are continuing to evolve and the potential exists for extending its frequency range down to ~86 GHz, which would permit overlap with the ngVLA. We aim to motivate development in this direction by exploring the improvements in imaging capabilities that could be achieved through joint 86 GHz observations with both the ngEHT and ngVLA arrays. Using synthetic observations of an M87-like source, we have compared the image reconstruction quality achievable with the ngEHT, ngVLA, and joint ngEHT+ngVLA arrays. We demonstrate that the joint array achieves an imaging dynamic range that is ~5 times higher than the standalone ngEHT and an angular resolution that is ~30% finer than the standalone ngVLA. We find that imaging algorithms designed for EHT data struggle to accommodate the larger data volumes and higher signal-to-noise ratios expected from an ngEHT+ngVLA joint observation, and the quality of our image reconstructions is currently limited by these algorithmic shortcomings. Nevertheless, we demonstrate that a joint ngEHT+ngVLA array would be able to simultaneously image the bright horizon-scale emission on ~40-microarcsecond scales as well as the much fainter extended jet emission expected out to at least ~1 milliarcsecond. If the accretion flow around the supermassive black hole in M87 is sufficiently optically thin at 86 GHz, then joint observations with the ngEHT and ngVLA should be able to image the central shadow feature.


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