The C-Band All-Sky Survey (C-BASS): Constraining diffuse Galactic radio emission in the North Celestial Pole region

Clive Dickinson, Adam Barr, H C Chiang, C Copley, R. D. P. Grumitt, Stuart Harper, Heiko M. Heilgendorff, Luke R. P. Jew, J L Jonas, Michael Jones, John Leahy, J. Leech, E M Leitch, S J C Muchovej, T. J. Pearson, Michael Peel, A C S Readhead, J. Sievers, M. A. Stevenson, Angela C. Taylor

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    The C-Band All-Sky Survey (C-BASS) is a high-sensitivity all-sky radio survey at an angular resolution of 45 arcmin and a frequency of 4.7 GHz. We present a total intensity map of the North Celestial Pole (NCP) region of sky, above declination > +80, which is limited by source confusion at a level of ≈ 0:6mK rms.We apply the template-tting (cross-correlation) technique to WMAP and Planck data, using the C-BASS map as the synchrotron template, to investigate the contribution of diffuse foreground emission at frequencies 20{40 GHz. We quantify the anomalous microwave emission (AME) that is correlated with far-infrared dust emission. The AME amplitude does not change signicantly (< 10 %) when using the higher frequency C-BASS 4.7 GHz template instead of the traditional Haslam 408MHz map as a tracer of synchrotron radiation. We measure template coecients of 9:930:35 and 9:520:34K per unit 353 when using the Haslam and C-BASS synchrotron templates, respectively. The AME contributes 552 K rms at 22.8 GHz and accounts for 60% of the total foreground emission. Our results show that a harder (atter spectrum) component of synchrotron emission is not dominant at frequencies & 5 GHz; the best-tting synchrotron temperature spectral index is = &#x100000;2:91 0:04 from 4.7 to 22.8 GHz and = &#x100000;2:85 0:14 from 22:8 to 44.1 GHz. Free-free emission is weak, contributing 7 K rms ( 7%) at 22.8 GHz. The best explanation for the AME is still electric dipole emission from small spinning dust grains.
    Original languageEnglish
    JournalMonthly Notices of the Royal Astronomical Society
    Early online date22 Feb 2019
    Publication statusPublished - 2019


    • surveys { radiation mechanism
    • non-thermal { radiation mechanism
    • thermal { diuse radiation { radio continuum
    • ISM


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