An update on MASIV: How intrinsic properties influence interstellar scintillation of AGN

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dc.contributor.authorBignall, Hayley
dc.contributor.authorKoay, Jun Yi
dc.contributor.authorLovell, Jim
dc.contributor.authorJauncey, Dave
dc.contributor.authorMacquart, Jean-Pierre
dc.contributor.authorPursimo, Tapio
dc.contributor.authorOjha, Roopesh
dc.contributor.authorRickett, Barney
dc.contributor.authorKedziora-Chudczer, Lucyna
dc.contributor.authorReynolds, Cormac
dc.contributor.authorKhoo, Sue
dc.date.accessioned2020-04-27T17:27:20Z
dc.date.available2020-04-27T17:27:20Z
dc.date.issued2012-04-17
dc.descriptionResolving the Sky - Radio Interferometry: Past, Present and Future -RTS2012 April 17-20, 2012 Manchester, UKen_US
dc.description.abstractMany flat-spectrum AGN exhibit short timescale variations when observed at radio wavelengths, due to interstellar scintillation (ISS). The observed variations depend on source angular size and "core dominance", as well as on the scattering properties of the intervening interstellar medium, both of which are highly non-uniform when considering large samples. ISS offers a powerful probe of source structure on micro-arcsecond angular scales. However, in order to use the statistics of ISS as a probe, it is necessary to understand the selection effects in the AGN samples under study. One initially surprising result of the MASIV 5 GHz VLA Survey was a drop-off in the ISS amplitudes of sources above z=2. In order to determine the cause of this effect, follow-up VLA observations were conducted at two frequencies. Our sample shows on average a steepening of source spectral index with redshift. Careful analysis shows that, after accounting for the redshift-spectral index correlation, the redshift dependence of ISS can be successfully modelled by the expected (1 + z)⁰˙⁵ scaling of intrinsic angular sizes of a flux- and intrinsic brightness temperature-limited sample. The MASIV follow-up observations allow limits to be placed on angular broadening due to interstellar and intergalactic scattering, beyond the resolution achievable with ground-based VLBI.en_US
dc.description.urihttps://pos.sissa.it/163/015/pdfen_US
dc.format.extent8 pagesen_US
dc.genreconference papers and proceedingsen_US
dc.identifierdoi:10.13016/m2qznj-yhxm
dc.identifier.citationBignall, Hayley; Koay, Jun Yi; Lovell, Jim; Jauncey, Dave; Macquart, Jean-Pierre; Pursimo, Tapio; Ojha, Roopesh; Rickett, Barney; Kedziora-Chudczer, Lucyna; Reynolds, Cormac; Khoo, Sue; An update on MASIV: How intrinsic properties influence interstellar scintillation of AGN; Resolving the Sky - Radio Interferometry: Past, Present and Future -RTS2012; https://pos.sissa.it/163/015/pdfen_US
dc.identifier.urihttp://hdl.handle.net/11603/18335
dc.language.isoen_USen_US
dc.publisherProceedings of Scienceen_US
dc.relation.isAvailableAtThe University of Maryland, Baltimore County (UMBC)
dc.relation.ispartofUMBC Physics Department Collection
dc.relation.ispartofUMBC Center for Space Sciences and Technology (CSST) / Center for Research and Exploration in Space Sciences & Technology II (CRSST II)
dc.rightsThis item is likely protected under Title 17 of the U.S. Copyright Law. Unless on a Creative Commons license, for uses protected by Copyright Law, contact the copyright holder or the author.
dc.rightsAttribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)*
dc.rights.urihttps://creativecommons.org/licenses/by-nc-nd/4.0/*
dc.titleAn update on MASIV: How intrinsic properties influence interstellar scintillation of AGNen_US
dc.typeTexten_US

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