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dc.contributor.authorCarilli, Christopheren
dc.contributor.authorNikolic, Bojanen
dc.contributor.authorThyagarajan, Nen
dc.contributor.authorGale-Sides, Ken
dc.date.accessioned2018-09-08T06:27:39Z
dc.date.available2018-09-08T06:27:39Z
dc.date.issued2018-06-01en
dc.identifier.issn0048-6604
dc.identifier.urihttps://www.repository.cam.ac.uk/handle/1810/279703
dc.description.abstractNew massively redundant low frequency arrays allow for a novel investigation of closure relations in interferometry. We employ commissioning data from the Hydrogen Epoch of Reionization Array to investigate closure quantities in this densely packed grid array of 14m antennas operating at 100 MHz to 200 MHz. We investigate techniques that utilize closure phase spectra for redundant triads to estimate departures from redundancy for redundant baseline visibilities. We find a median absolute deviation from redundancy in closure phase across the observed frequency range of about 4.5deg. This value translates into a non-redundancy per visibility phase of about 2.6deg, using prototype electronics. The median absolute deviations from redundancy decrease with longer baselines. We show that closure phase spectra can be used to identify ill-behaved antennas in the array, independent of calibration. We investigate the temporal behavior of closure spectra. The Allan variance increases after a one minute stride time, due to passage of the sky through the primary beam of the transit telescope. However, the closure spectra repeat to well within the noise per measurement at corresponding local sidereal times (LST) from day to day. In future papers in this series we will develop the technique of using closure phase spectra in the search for the HI 21cm signal from cosmic reionization.
dc.publisherWiley-Blackwell
dc.titleH I 21-cm Cosmology and the Bispectrum: Closure Diagnostics in Massively Redundant Interferometric Arraysen
dc.typeArticle
prism.endingPage865
prism.issueIdentifier6en
prism.publicationDate2018en
prism.publicationNameRadio Scienceen
prism.startingPage845
prism.volume53en
dc.identifier.doi10.17863/CAM.27074
dcterms.dateAccepted2018-04-13en
rioxxterms.versionofrecord10.1029/2018RS006537en
rioxxterms.licenseref.urihttp://www.rioxx.net/licenses/all-rights-reserveden
rioxxterms.licenseref.startdate2018-06-01en
dc.contributor.orcidCarilli, Christopher [0000-0001-6647-3861]
dc.contributor.orcidNikolic, Bojan [0000-0001-7168-2705]
dc.identifier.eissn1944-799X
rioxxterms.typeJournal Article/Reviewen
pubs.funder-project-idSTFC (ST/P006280/1)
rioxxterms.freetoread.startdate2019-06-01


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