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dc.contributor.authorReid, Mark J.
dc.contributor.authorBroderick, Avery E.
dc.contributor.authorLoeb, Abraham
dc.contributor.authorHonma, Mareki
dc.contributor.authorBrunthaler, Andreas
dc.date.accessioned2019-09-24T12:05:04Z
dc.date.issued2008
dc.identifier.citationReid, Mark J., Avery E. Broderick, Abraham Loeb, Mareki Honma, and Andreas Brunthaler. 2008. “Limits on the Position Wander of Sgr A*.” The Astrophysical Journal 682 (2): 1041–46. https://doi.org/10.1086/588603.
dc.identifier.issn0004-637X
dc.identifier.issn1538-4357
dc.identifier.urihttp://nrs.harvard.edu/urn-3:HUL.InstRepos:41393459*
dc.description.abstractWe present measurements with the Very Long Baseline Array of the variability in the centroid position of Sgr A* relative to a background quasar at 7 mm wavelength. We find an average centroid wander of 71 +/- 45 mu as for timescales between 50 and 100 minutes and 113 +/- 50 mu as for timescales between 100 and 200 minutes, with no secular trend. These are sufficient to begin constraining the viability of the accretion hot spot model for the radio variability of Sgr A*. It is possible to rule out hot spots with orbital radii above 15GM(Sgr) (A*)/c(2) that contribute more than 30% of the total 7 mm flux. However, closer or less luminous hot spots remain unconstrained. Since the fractional variability of Sgr A* during our observations was similar to 20% on timescales of hours, the hot spot model for Sgr A*'s radio variability remains consistent with these limits. Improved monitoring of Sgr A*'s centroid position has the potential to place significant constraints on the existence and morphology of inhomogeneities in a supermassive black hole accretion flow.
dc.language.isoen_US
dc.publisherAmerican Astronomical Society
dash.licenseLAA
dc.titleLimits on the Position Wander of Sgr A*
dc.typeJournal Article
dc.description.versionVersion of Record
dc.relation.journalThe Astrophysical Journal
dash.depositing.authorLoeb, Abraham::9975df1f269ab49c1ad5a328a1ec1476::600
dc.date.available2019-09-24T12:05:04Z
dash.workflow.comments1Science Serial ID 97851
dc.identifier.doi10.1086/588603
dash.source.volume682;2
dash.source.page1041-1046


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