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dc.contributor.authorLu, Ru-Sen
dc.contributor.authorKrichbaum, Thomas P.
dc.contributor.authorRoy, Alan L.
dc.contributor.authorFish, Vincent L.
dc.contributor.authorDoeleman, Sheperd S.
dc.contributor.authorJohnson, Michael D.
dc.contributor.authorAkiyama, Kazunori
dc.contributor.authorPsaltis, Dimitrios
dc.contributor.authorAlef, Walter
dc.contributor.authorAsada, Keiichi
dc.contributor.authorBeaudoin, Christopher
dc.contributor.authorBertarini, Alessandra
dc.contributor.authorBlackburn, Lindy
dc.contributor.authorBlundell, Ray
dc.contributor.authorBower, Geoffrey C.
dc.contributor.authorBrinkerink, Christiaan
dc.contributor.authorBroderick, Avery E.
dc.contributor.authorCappallo, Roger
dc.contributor.authorCrew, Geoffrey B.
dc.contributor.authorDexter, Jason
dc.contributor.authorDexter, Matt
dc.contributor.authorFalcke, Heino
dc.contributor.authorFreund, Robert
dc.contributor.authorFriberg, Per
dc.contributor.authorGreer, Christopher H.
dc.contributor.authorGurwell, Mark A.
dc.contributor.authorHo, Paul T. P.
dc.contributor.authorHonma, Mareki
dc.contributor.authorInoue, Makoto
dc.contributor.authorKim, Junhan
dc.contributor.authorLamb, James
dc.contributor.authorLindqvist, Michael
dc.contributor.authorMacmahon, David
dc.contributor.authorMarrone, Daniel P.
dc.contributor.authorMartí-Vidal, Ivan
dc.contributor.authorMenten, Karl M.
dc.contributor.authorMoran, James M.
dc.contributor.authorNagar, Neil M.
dc.contributor.authorPlambeck, Richard L.
dc.contributor.authorPrimiani, Rurik A.
dc.contributor.authorRogers, Alan E. E.
dc.contributor.authorRos, Eduardo
dc.contributor.authorRottmann, Helge
dc.contributor.authorSooHoo, Jason
dc.contributor.authorSpilker, Justin
dc.contributor.authorStone, Jordan
dc.contributor.authorStrittmatter, Peter
dc.contributor.authorTilanus, Remo P. J.
dc.contributor.authorTitus, Michael
dc.contributor.authorVertatschitsch, Laura
dc.contributor.authorWagner, Jan
dc.contributor.authorWeintroub, Jonathan
dc.contributor.authorWright, Melvyn
dc.contributor.authorYoung, Ken H.
dc.contributor.authorZensus, J. Anton
dc.contributor.authorZiurys, Lucy M.
dc.date.accessioned2018-07-23T23:51:20Z
dc.date.available2018-07-23T23:51:20Z
dc.date.issued2018-05-20
dc.identifier.citationRu-Sen Lu et al 2018 ApJ 859 60en_US
dc.identifier.issn1538-4357
dc.identifier.doi10.3847/1538-4357/aabe2e
dc.identifier.urihttp://hdl.handle.net/10150/628283
dc.description.abstractWe report results from very long baseline interferometric (VLBI) observations of the supermassive black hole in the Galactic center, Sgr A*, at 1.3 mm (230 GHz). The observations were performed in 2013 March using six VLBI stations in Hawaii, California, Arizona, and Chile. Compared to earlier observations, the addition of the APEX telescope in Chile almost doubles the longest baseline length in the array, provides additional uv coverage in the N-S direction, and leads to a spatial resolution of similar to 30 mu as (similar to 3 Schwarzschild radii) for Sgr A*. The source is detected even at the longest baselines with visibility amplitudes of similar to 4%-13% of the total flux density. We argue that such flux densities cannot result from interstellar refractive scattering alone, but indicate the presence of compact intrinsic source structure on scales of similar to 3 Schwarzschild radii. The measured nonzero closure phases rule out point-symmetric emission. We discuss our results in the context of simple geometric models that capture the basic characteristics and brightness distributions of disk-and jet-dominated models and show that both can reproduce the observed data. Common to these models are the brightness asymmetry, the orientation, and characteristic sizes, which are comparable to the expected size of the black hole shadow. Future 1.3 mm VLBI observations with an expanded array and better sensitivity will allow more detailed imaging of the horizon-scale structure and bear the potential for a deep insight into the physical processes at the black hole boundary.en_US
dc.description.sponsorshipEuropean Research Council (ERC) Synergy Grant "BlackHoleCam" [610058]; Spanish MINECO [AYA2012-38491-C02-01, AYA2015-63939-C2-2-P]; Generalitat Valenciana [PROMETEOII/2014/057]; Atacama Pathfinder EXperiment (APEX) telescope [091.F-9312(A)]; Smithsonian Institution; Academia Sinica; NSF; CARMAen_US
dc.language.isoenen_US
dc.publisherIOP PUBLISHING LTDen_US
dc.relation.urlhttp://stacks.iop.org/0004-637X/859/i=1/a=60?key=crossref.829e0d52c38924fa45ceda6afaf631dben_US
dc.rights© 2018. The American Astronomical Society.en_US
dc.subjectGalaxy: centeren_US
dc.subjectsubmillimeter: generalen_US
dc.subjecttechniques: high angular resolutionen_US
dc.subjecttechniques: interferometricen_US
dc.titleDetection of Intrinsic Source Structure at ∼3 Schwarzschild Radii with Millimeter-VLBI Observations of SAGITTARIUS A*en_US
dc.typeArticleen_US
dc.contributor.departmentUniv Arizona, Steward Observen_US
dc.identifier.journalASTROPHYSICAL JOURNALen_US
dc.description.collectioninformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.en_US
dc.eprint.versionFinal published versionen_US
dc.source.journaltitleThe Astrophysical Journal
dc.source.volume859
dc.source.issue1
dc.source.beginpage60
refterms.dateFOA2018-07-23T23:51:20Z


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