{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,17]],"date-time":"2026-09-17T00:18:10Z","timestamp":1789604290329,"version":"build-2803163510"},"reference-count":33,"publisher":"American Astronomical Society","issue":"2","license":[{"start":{"date-parts":[[2022,1,19]],"date-time":"2022-01-19T00:00:00Z","timestamp":1642550400000},"content-version":"vor","delay-in-days":18,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2022,1,19]],"date-time":"2022-01-19T00:00:00Z","timestamp":1642550400000},"content-version":"tdm","delay-in-days":18,"URL":"https:\/\/iopscience.iop.org\/info\/page\/text-and-data-mining"}],"content-domain":{"domain":["iopscience.iop.org"],"crossmark-restriction":false},"short-container-title":["ApJ"],"published-print":{"date-parts":[[2022,1,1]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>\n                    We present a reanalysis of the Event Horizon Telescope 228  GHz observations of M87. We apply traditional hybrid mapping techniques to the publicly available\n                    <jats:italic>network-calibrated<\/jats:italic>\n                    data. We explore the impact on the final image of different starting models, including the following: a point source, a disk, an annulus, a Gaussian, and an asymmetric double Gaussian. The images converge to an extended source with a size \u223c44\n                    <jats:italic>\u03bc<\/jats:italic>\n                    as. Starting with the annulus and disk models leads to images with the lowest noise, smallest off-source artifacts, and better closure residuals. The source appears as a ring, or edge-brightened disk, with higher surface brightness in the southern half, consistent with previous results. Starting with the other models leads to a surface brightness distribution with a similar size, and an internal depression, but not as clearly ringlike. A consideration of visibility amplitudes versus UV-distance argues for a roughly circularly symmetric structure of \u223c50\n                    <jats:italic>\u03bc<\/jats:italic>\n                    as scale, with a sharp edge, based on a prominent minimum in the UV-distribution, and the amplitude of the secondary peak in the UV-plot is more consistent with an annular model than a flat disk model. With further processing, we find a possible modest extension from the ring toward the southwest, in a direction consistent with the southern limb of the jet seen on 3mm VLBI images on a factor of few larger scales. However, this extension appears along the direction of one of the principle sidelobes of the synthesized beam, and hence requires testing with better UV-coverage.\n                  <\/jats:p>","DOI":"10.3847\/1538-4357\/ac3cba","type":"journal-article","created":{"date-parts":[[2022,1,19]],"date-time":"2022-01-19T09:46:50Z","timestamp":1642585610000},"page":"125","update-policy":"https:\/\/doi.org\/10.1088\/crossmark-policy","source":"Crossref","is-referenced-by-count":20,"title":["Hybrid Mapping of the Black Hole Shadow in M87"],"prefix":"10.3847","volume":"924","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-6647-3861","authenticated-orcid":true,"given":"Chris L.","family":"Carilli","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1602-7868","authenticated-orcid":false,"given":"Nithyanandan","family":"Thyagarajan","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"2208","published-online":{"date-parts":[[2022,1,19]]},"reference":[{"key":"apjac3cbabib1","author":"Arras","year":"2020"},{"key":"apjac3cbabib2","doi-asserted-by":"publisher","first-page":"1691","DOI":"10.1086\/115988","volume":"102","author":"Carilli","year":"1991","journal-title":"AJ"},{"key":"apjac3cbabib3","first-page":"187","author":"Cornwell","year":"1999"},{"key":"apjac3cbabib4","doi-asserted-by":"publisher","first-page":"1067","DOI":"10.1093\/mnras\/196.4.1067","volume":"196","author":"Cornwell","year":"1981","journal-title":"MNRAS"},{"key":"apjac3cbabib5","first-page":"189","author":"Cotton","year":"1995"},{"key":"apjac3cbabib6","doi-asserted-by":"publisher","first-page":"L11","DOI":"10.3847\/2041-8213\/abef71","volume":"911","author":"EHT MWL Science Working Group","year":"2021","journal-title":"ApJL"},{"key":"apjac3cbabib7","doi-asserted-by":"publisher","first-page":"L4","DOI":"10.3847\/2041-8213\/ab0e85","volume":"875","author":"Event Horizon Telescope Collaboration","year":"2019a","journal-title":"ApJL"},{"key":"apjac3cbabib33","doi-asserted-by":"publisher","first-page":"L6","DOI":"10.3847\/2041-8213\/ab1141","volume":"875","author":"Event Horizon Telescope Collaboration","year":"2019b","journal-title":"ApJL"},{"key":"apjac3cbabib8","doi-asserted-by":"publisher","first-page":"L3","DOI":"10.3847\/2041-8213\/ab0c57","volume":"875","author":"Event Horizon Telescope Collaboration","year":"2019c","journal-title":"ApJL"},{"key":"apjac3cbabib9","doi-asserted-by":"publisher","first-page":"L12","DOI":"10.3847\/2041-8213\/abe71d","volume":"910","author":"Event Horizon Telescope Collaboration","year":"2021a","journal-title":"ApJL"},{"key":"apjac3cbabib10","doi-asserted-by":"publisher","first-page":"L13","DOI":"10.3847\/2041-8213\/abe4de","volume":"910","author":"Event Horizon Telescope Collaboration","year":"2021b","journal-title":"ApJL"},{"key":"apjac3cbabib11","doi-asserted-by":"publisher","first-page":"109","DOI":"10.1007\/0-306-48080-8_7","volume":"285","author":"Greisen","year":"2003","journal-title":"Astrophys. 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