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dc.contributor.authorMedeiros, Lia
dc.contributor.authorChan, Chi-Kwan
dc.contributor.authorÖzel, Feryal
dc.contributor.authorPsaltis, Dimitrios
dc.contributor.authorKim, Junhan
dc.contributor.authorMarrone, Daniel P.
dc.contributor.authorSa̧dowski, Aleksander
dc.date.accessioned2017-08-09T18:59:38Z
dc.date.available2017-08-09T18:59:38Z
dc.date.issued2017-07-19
dc.identifier.citationVariability in GRMHD Simulations of Sgr A*: Implications for EHT Closure Phase Observations 2017, 844 (1):35 The Astrophysical Journalen
dc.identifier.issn1538-4357
dc.identifier.doi10.3847/1538-4357/aa7751
dc.identifier.urihttp://hdl.handle.net/10150/625164
dc.description.abstractClosure phases along different baseline triangles carry a large amount of information regarding the structures of the images of black holes in interferometric observations with the Event Horizon Telescope. We use long time span, high cadence, GRMHD+radiative transfer models of Sgr A* to investigate the expected variability of closure phases in such observations. We find that, in general, closure phases along small baseline triangles show little variability, except in the cases when one of the triangle vertices crosses one of the small regions of low visibility amplitude. The closure phase variability increases with the size of the baseline triangle, as larger baselines probe the small-scale structures of the images, which are highly variable. On average, the funnel-dominated MAD models show less closure phase variability than the disk-dominated SANE models, even in the large baseline triangles, because the images from the latter are more sensitive to the turbulence in the accretion flow. Our results suggest that image reconstruction techniques need to explicitly take into account the closure phase variability, especially if the quality and quantity of data allow for a detailed characterization of the nature of variability. This also implies that, if image reconstruction techniques that rely on the assumption of a static image are utilized, regions of the u-v space that show a high level of variability will need to be identified and excised.
dc.description.sponsorshipNSF GRFP [DGE 1144085]; NASA/NSF TCAN [NNX14AB48G]; NSF [TM6-17006X, AST 1312034, AST-1207752, 1228509]; John Simon Guggenheim Memorial Foundation; Radcliffe Institute for Advanced Study at Harvard Universityen
dc.language.isoenen
dc.publisherIOP PUBLISHING LTDen
dc.relation.urlhttp://stacks.iop.org/0004-637X/844/i=1/a=35?key=crossref.20ebd670c96d05f16a64002ef7e91ea1en
dc.rights© 2017. The American Astronomical Society. All rights reserved.en
dc.subjectaccretion, accretion disksen
dc.subjectblack hole physicsen
dc.subjectGalaxy: centeren
dc.subjectradiative transferen
dc.titleVariability in GRMHD Simulations of Sgr A*: Implications for EHT Closure Phase Observationsen
dc.typeArticleen
dc.contributor.departmentUniv Arizona, Steward Observen
dc.contributor.departmentUniv Arizona, Dept Astronen
dc.identifier.journalThe Astrophysical Journalen
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
dc.eprint.versionFinal published versionen
refterms.dateFOA2018-09-11T22:05:51Z
html.description.abstractClosure phases along different baseline triangles carry a large amount of information regarding the structures of the images of black holes in interferometric observations with the Event Horizon Telescope. We use long time span, high cadence, GRMHD+radiative transfer models of Sgr A* to investigate the expected variability of closure phases in such observations. We find that, in general, closure phases along small baseline triangles show little variability, except in the cases when one of the triangle vertices crosses one of the small regions of low visibility amplitude. The closure phase variability increases with the size of the baseline triangle, as larger baselines probe the small-scale structures of the images, which are highly variable. On average, the funnel-dominated MAD models show less closure phase variability than the disk-dominated SANE models, even in the large baseline triangles, because the images from the latter are more sensitive to the turbulence in the accretion flow. Our results suggest that image reconstruction techniques need to explicitly take into account the closure phase variability, especially if the quality and quantity of data allow for a detailed characterization of the nature of variability. This also implies that, if image reconstruction techniques that rely on the assumption of a static image are utilized, regions of the u-v space that show a high level of variability will need to be identified and excised.


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