Imaging the Schwarzschild-radius-scale Structure of M87 with the Event Horizon Telescope Using Sparse Modeling
Name
Akiyama-2017-Imaging the Schwarzschild-radius-.pdf
Size
2.08 MB
Format
Adobe PDF
Checksum (MD5)
97833dd2a0a0f8e3ded5dd9077a6d48d
Author(s)
Kuramochi, Kazuki
Ikeda, Shiro
Tazaki, Fumie
Honma, Mareki
Broderick, Avery E.
Dexter, Jason
Mościbrodzka, Monika
Chael, Andrew A.
Zaizen, Masamichi
Akiyama, Kazunori
Date Issued
March 2017
Journal
Astrophysical Journal
Publisher
IOP Publishing
Citation
Akiyama, Kazunori, Kazuki Kuramochi, Shiro Ikeda, Vincent L. Fish, Fumie Tazaki, Mareki Honma, Sheperd S. Doeleman, et al. “Imaging the Schwarzschild-Radius-Scale Structure of M87 with the Event Horizon Telescope Using Sparse Modeling.” The Astrophysical Journal 838, no. 1 (March 17, 2017): 1. © 2017 The American Astronomical Society
Version
Final published version
Abstract
We propose a new imaging technique for radio and optical/infrared interferometry. The proposed technique reconstructs the image from the visibility amplitude and closure phase, which are standard data products of short-millimeter very long baseline interferometers such as the Event Horizon Telescope (EHT) and optical/infrared interferometers, by utilizing two regularization functions: the ℓ [subscript 1]-norm and total variation (TV) of the brightness distribution. In the proposed method, optimal regularization parameters, which represent the sparseness and effective spatial resolution of the image, are derived from data themselves using cross-validation (CV). As an application of this technique, we present simulated observations of M87 with the EHT based on four physically motivated models. We confirm that ℓ [subscript 1] + TV regularization can achieve an optimal resolution of ~20%–30% of the diffraction limit λ/D max, which is the nominal spatial resolution of a radio interferometer. With the proposed technique, the EHT can robustly and reasonably achieve super-resolution sufficient to clearly resolve the black hole shadow. These results make it promising for the EHT to provide an unprecedented view of the event-horizon-scale structure in the vicinity of the supermassive black hole in M87 and also the Galactic center Sgr A*.
MIT Department
Haystack Observatory
Massachusetts Institute of Technology. Computer Science and Artificial Intelligence Laboratory
Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science
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Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
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DOI of Published Version
https://doi.org/10.3847/1538-4357/aa6305
