Curtin University Homepage
  • Library
  • Help
    • Admin

    espace - Curtin’s institutional repository

    JavaScript is disabled for your browser. Some features of this site may not work without it.
    View Item 
    • espace Home
    • espace
    • Curtin Research Publications
    • View Item
    • espace Home
    • espace
    • Curtin Research Publications
    • View Item

    Comparison of Observing Modes for Statistical Estimation of the 21 cm Signal from the Epoch of Reionisation

    Access Status
    Open access via publisher
    Authors
    Trott, Cathryn
    Date
    2014
    Type
    Journal Article
    
    Metadata
    Show full item record
    Citation
    Trott, C. 2014. Comparison of Observing Modes for Statistical Estimation of the 21 cm Signal from the Epoch of Reionisation. Publications of the Astronomical Society of Australia. 31: Article ID e026.
    Source Title
    Publications of the Astronomical Society of Australia
    DOI
    10.1017/pasa.2014.23
    ISSN
    1323-3580
    School
    Department of Imaging and Applied Physics
    URI
    http://hdl.handle.net/20.500.11937/42970
    Collection
    • Curtin Research Publications
    Abstract

    Noise considerations for experiments that aim to statistically estimate the 21 cm signal from high redshift neutral hydrogen during the Epoch of Reionisation (EoR) using interferometric data are typically computed assuming a tracked observation, where the telescope pointing centre and instrument phase centre are the same over the observation. Current low frequency interferometers use aperture arrays of fixed dipoles, which are steered electronically on the sky, and have different properties to mechanically-steered single apertures, such as reduced sensitivity away from zenith, and discrete pointing positions on the sky. These properties encourage the use of two additional observing modes: (1) zenith drift, where the pointing centre remains fixed at the zenith, and the phase centre tracks the sky, and (2) drift + shift, a hybrid mode where the telescope uses discrete pointing centres, and the sky drifts during each fixed pointing.These three observing modes view the sky differently and therefore yield different uncertainties in the power spectrum according to the balance of radiometric noise and cosmic variance. The coherence of measurements made by the instrument in these modes dictates the optimal reduction in thermal noise by combination of coherent modes, and the reduction in cosmic variance by combination of incoherent modes (views of different patches of the sky). Along with calibration and instrument stability considerations, the balance between these noise components provides one measure for the utility of these three modes for measuring a statistical signature of the EoR signal.We provide a general framework for estimating the uncertainty in the power spectrum for a given observing mode, telescope beam shape, and interferometer antenna distribution. We then apply this framework to the Murchison Widefield Array (MWA) using an analysis of the two-dimensional (2D) and one-dimensional (1D) power spectra for 900 hours of observing. We demonstrate that zenith drift scans can yield marginally lower uncertainty in the signal power compared with tracked scans for the MWA EoR experiment, and that moderately higher signal-to-noise ratio (S/N) estimates of the amplitude (3%) and slope (1%) of the 1D power spectrum are accessible, translating directly into a reduction in the required observing time to reach the same estimation precision. We find that the additional sensitivity of pointing at zenith, and the reduction in cosmic variance available with a zenith drift scan, makes this an attractive observing mode for current and future arrays.

    Related items

    Showing items related by title, author, creator and subject.

    • A study of fundamental limitations to statistical detection of redshifted H I from the epoch of reionization
      Thyagarajan, Nithyanandan; Udaya Shankar, N.; Subrahmanyan, Ravi; Arcus, Wayne; Bernardi, Gianni; Bowman, Judd; Briggs, Frank; Bunton, John; Cappallo, Roger; Corey, Brian; deSouza, Ludi; Emrich, David; Gaensler, Brian; Goeke, Robert; Greenhill, Lincoln; Hazelton, Bryna; Herne, David; Hewitt, Jacqueline; Johnston-Hollitt, Melanie; Kaplan, David; Kasper, Justin; Kincaid, Barton; Koenig, Ronald; Kratzenberg, Eric; Lonsdale, Colin; Lynch, Mervyn; McWhirter, S. Russell; Mitchell, Daniel; Morales, Miguel; Morgan, Edward; Oberoi, Divya; Ord, Stephen; Pathikulangara, Joseph; Remillard, Ronald; Rogers, Alan; Roshi, D. Anish; Salah, Joseph; Sault, Robert; Srivani, K.; Stevens, Jamie; Thiagaraj, Prabu; Tingay, Steven; Wayth, Randall; Waterson, Mark; Webster, Rachel; Whitney, Alan; Williams, Andrew; Williams, Christopher; Wyithe, J. Stuart (2013)
      In this paper, we explore for the first time the relative magnitudes of three fundamental sources of uncertainty, namely, foreground contamination, thermal noise, and sample variance, in detecting the H I power spectrum ...
    • The impact of realistic foreground and instrument models on 21 cm epoch of reionization experiments
      Nasirudin, Ainulnabilah ; Murray, Steven ; Trott, Cathryn ; Greig, B.; Joseph, Ronniy C. ; Power, C. (2020)
      Predictions for the ability of 21 cm interferometric experiments to discriminate Epoch of Reionization (EoR) signal models are typically limited by the simplicity of data models, whereby foreground signals and characteristics ...
    • The Impact of Point-Source Subtraction Residuals on 21 cm Epoch of Reionization Estimation
      Trott, Cathryn; Wayth, Randall; Tingay, Steven (2012)
      Precise subtraction of foreground sources is crucial for detecting and estimating 21 cm H I signals from the Epoch of Reionization (EoR). We quantify how imperfect point-source subtraction due to limitations of the ...
    Advanced search

    Browse

    Communities & CollectionsIssue DateAuthorTitleSubjectDocument TypeThis CollectionIssue DateAuthorTitleSubjectDocument Type

    My Account

    Admin

    Statistics

    Most Popular ItemsStatistics by CountryMost Popular Authors

    Follow Curtin

    • 
    • 
    • 
    • 
    • 

    CRICOS Provider Code: 00301JABN: 99 143 842 569TEQSA: PRV12158

    Copyright | Disclaimer | Privacy statement | Accessibility

    Curtin would like to pay respect to the Aboriginal and Torres Strait Islander members of our community by acknowledging the traditional owners of the land on which the Perth campus is located, the Whadjuk people of the Nyungar Nation; and on our Kalgoorlie campus, the Wongutha people of the North-Eastern Goldfields.