1. RRI Digital Repository
  2. 04. Astronomy and Astrophysics
  3. Research Papers (A&A)
Please use this identifier to cite or link to this item: http://hdl.handle.net/2289/7420
Full metadata record
DC FieldValueLanguage
dc.contributor.authorPatwa, Akash Kumar-
dc.contributor.authorSethi, S.K.-
dc.date.accessioned2020-01-31T09:32:16Z-
dc.date.available2020-01-31T09:32:16Z-
dc.date.issued2019-12-10-
dc.identifier.citationThe Astrophysical Journal, 2019, Vol.887, p16en_US
dc.identifier.issn0004-637X-
dc.identifier.issn1538-4357(Online)-
dc.identifier.urihttp://hdl.handle.net/2289/7420-
dc.descriptionOpen Access.en_US
dc.description.abstractWe present a formalism to extract the EoR HI power spectrum for drift scans using radio interferometers. Our main aim is to determine the coherence time scale of time-ordered visibilities. We compute the two-point correlation function of the HI visibilities measured at different times to address this question. We determine, for a given baseline, the decorrelation of the amplitude and the phase of this complex function. Our analysis uses primary beams of four ongoing and future interferometers---PAPER, MWA, HERA, and SKA1-Low. We identify physical processes responsible for the decorrelation of the HI signal and isolate their impact by making suitable analytic approximations. The decorrelation time scale of the amplitude of the correlation function lies in the range of 2--20~minutes for baselines of interest for the extraction of the HI signal. The phase of the correlation function can be made small after scaling out an appropriate term, which also causes the coherence time scale of the phase to be longer than the amplitude of the correlation function. We find that our results are insensitive to the input HI power spectrum and therefore they are directly applicable to the analysis of the drift scan data. We also apply our formalism to a set of point sources and statistically homogeneous diffuse correlated foregrounds. We find that point sources decorrelate on a time scale much shorter than the HI signal. This provides a novel mechanism to partially mitigate the foregrounds in a drift scan.en_US
dc.language.isoenen_US
dc.publisherIOP Sciences for The American Astronomical Societyen_US
dc.relation.urihttps://ui.adsabs.harvard.edu/abs/2019arXiv190505772P/abstracten_US
dc.relation.urihttps://arxiv.org/abs/1905.05772en_US
dc.relation.urihttps://doi.org/10.3847/1538-4357/ab5185en_US
dc.rights2019, The American Astronomical Societyen_US
dc.titleDetecting the 21cm Signal from the Epoch of Reionization Using Drift Scans: Correlation of Time-ordered Visibilitiesen_US
dc.typeArticleen_US
Appears in Collections:Research Papers (A&A)

Files in This Item:
File Description SizeFormat 
2019_ApJ_887_Article No.52.pdfOpen Access1.86 MBAdobe PDFView/Open
Show simple item record


Items in RRI Digital Repository are protected by copyright, with all rights reserved, unless otherwise indicated.