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dc.contributor.authorThyagarajan, Nithyanandanen
dc.contributor.authorCarilli, Christopheren
dc.contributor.authorNikolic, Bojanen
dc.date.accessioned2018-09-11T17:31:07Z
dc.date.available2018-09-11T17:31:07Z
dc.date.issued2018-06en
dc.identifier.issn0031-9007
dc.identifier.urihttps://www.repository.cam.ac.uk/handle/1810/280168
dc.description.abstractDetecting neutral Hydrogen (H\,{\sc i}) via the 21~cm line emission from the intergalactic medium at $z\gtrsim 6$ has been identified as one of the most promising probes of the epoch of cosmic reionization -- a major phase transition of the Universe. However, these studies face severe challenges imposed by the bright foreground emission from cosmic objects. Current techniques require precise instrumental calibration to separate the weak H\,{\sc i} line signal from the foreground continuum emission. We propose to mitigate this calibration requirement by using measurements of the interferometric bi-spectrum phase. Bi-spectrum phase is unaffected by antenna-based direction-independent calibration errors and hence for a compact array it depends on the sky brightness distribution only (subject to the usual thermal-like noise). We show that the bi-spectrum phase of foreground synchrotron continuum has a characteristically smooth spectrum relative to the cosmological line signal. The two can be separated effectively by exploiting this spectral difference using Fourier techniques, while eliminating the need for precise antenna-based calibration of phases introduced by the instrument, and the ionosphere, inherent in existing approaches. Using fiducial models for continuum foregrounds, and for the cosmological H\,{\sc i} signal, we show the latter should be detectable in bi-spectrum phase spectra, with reasonable significance at $|k_\parallel| \gtrsim 0.5\,h$~Mpc$^{-1}$, using existing instruments. Our approach will also benefit other H\,{\sc i} intensity mapping experiments that face similar challenges, such as those measuring Baryon Acoustic Oscillations (BAO).
dc.format.mediumPrinten
dc.languageengen
dc.publisherAPS
dc.titleDetecting Cosmic Reionization Using the Bispectrum Phase.en
dc.typeArticle
prism.issueIdentifier25en
prism.publicationDate2018en
prism.publicationNamePhysical review lettersen
prism.startingPage251301
prism.volume120en
dc.identifier.doi10.17863/CAM.27536
dcterms.dateAccepted2018-05-02en
rioxxterms.versionofrecord10.1103/physrevlett.120.251301en
rioxxterms.licenseref.urihttp://www.rioxx.net/licenses/all-rights-reserveden
rioxxterms.licenseref.startdate2018-06en
dc.contributor.orcidCarilli, Christopher [0000-0001-6647-3861]
dc.contributor.orcidNikolic, Bojan [0000-0001-7168-2705]
dc.identifier.eissn1079-7114
rioxxterms.typeJournal Article/Reviewen
rioxxterms.freetoread.startdate2019-06-30


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