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    • Keywords


      Cosmology: dark ages, reionization, first stars; instrumentation: interferometer; telescopes.

    • Abstract


      A key science project for SKA-Low is the interferometer imaging of spatio-temporal fluctuations in the hydrogen ionization fraction and spin temperature as a diagnostic of cosmic dawn (CD) and epoch of reionization (EoR) in the redshift range $6 \lesssim z \lesssim 28$. However, detection of the global CD/EoR signal, which provides the differential HI 21-cm brightness temperature with respect to the background radiation temperature, is outside the current purview of SKA-Low observing in interferometer mode. This global CD/EoR signal can provide the critical zero-spacing measurement vital for establishing the base level of fluctuations measured by SKA-Low interferometers. We present here, a concept to detect the global CD/EoR signal as a supplement to the CD/EoR key science of SKA-Low. This would be enabled by adding a compact array of outrigger antennas interspersed between the core stations of SKA-Low. The autocorrelations of the outrigger antennas would form the measurement set for the global CD/EoR. The visibilities measured between outriggers and SKA stations would be `blind' to the global CD/EoR signal and would provide a Global Sky Model and calibration of the bandpass and mode-coupling in the primary beam of the outriggers. The global signal measurement capabilitywill strengthen the SKA-Low CD/EoR program.

    • Author Affiliations



      1. Astronomy and Astrophysics, Raman Research Institute, Bangalore 560080, India.
      2. Space and Astronomy CSIRO, 26 Dick Perry Ave., Kensington, WA 6151, Australia.
    • Dates

  • Journal of Astrophysics and Astronomy | News

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