Oral Presentation
Imaging the Structure of M87 using the Event Horizon Telescope
Presenter: Katie Bouman (Massachusetts Institute of Technology)
The Event Horizon Telescope (EHT) is a very long baseline interferometer capable of resolving structure on the scale of the Schwarzschild radius for the supermassive black hole in M87. VLBI measurements place a sparse set of constraints on the emission image’s spatial frequencies. The task of reconstructing an image from these constraints is highly ill-posed and relies heavily on priors to guide optimization. Current VLBI image reconstruction techniques have been reasonably successful in imaging large celestial sources with coarse angular resolution. However, as the demand for higher resolving power increases, particularly for imaging M87 using the EHT in mm/sub-mm wavelengths, traditional reconstruction algorithms are quickly approaching their limits. We present a novel Bayesian approach for VLBI image reconstruction. Our method is robust across different types of images, and produces good results under different settings such as low SNR and atmospheric noise. The success of our method is demonstrated on archival 7mm VLBA data as well as against other state-of-the-art methods on realistic synthetic experiments. Additionally, we present a new dataset website (vlbiimaging.csail.mit.edu) for easy access to data as well as to allow for controlled comparisons across algorithms.
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