• Prospects for Detecting the 326.5MHz Redshifted 21-cm HI Signal with the Ooty Radio Telescope (ORT)

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      https://www.ias.ac.in/article/fulltext/joaa/035/02/0157-0182

    • Keywords

       

      Cosmology: large scale structure of Universe; intergalactic medium; diffuse radiation.

    • Abstract

       

      Observations of the redshifted 21-cm HI fluctuations promise to be an important probe of the post-reionization era (𝑧 ≤ 6). In this paper we calculate the expected signal and foregrounds for the upgraded Ooty Radio Telescope (ORT) which operates at frequency 𝑣𝑜 = 326.5MHz which corresponds to redshift 𝑧 = 3.35. Assuming that the visibilities contain only the HI signal and system noise, we show that a 3𝜎 detection of the HI signal (∼ 1 mK) is possible at angular scales 11' to 3° with ≈ 1000 h of observation. Foreground removal is one of the major challenges for a statistical detection of the redshifted 21 cm HI signal. We assess the contribution of different foregrounds and find that the 326.5MHz sky is dominated by the extragalactic point sources at the angular scales of our interest. The expected total foregrounds are 104−105 times higher than the HI signal.

    • Author Affiliations

       

      Sk. Saiyad Ali1 Somnath Bharadwaj2

      1. Department of Physics, Jadavpur University, Kolkata 700 032, India.
      2. Department of Physics and Meteorology & Centre for Theoretical Studies, IIT Kharagpur, Kharagpur 721 302, India.
    • Dates

       
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