The C-Band All-Sky Survey (C-BASS): design and capabilities

Jones, Michael E.; Taylor, Angela C.; Aich, Moumita; Copley, Charles; Chiang, H. C.; Davis, R. J.; Dickinson, C.; Grumitt, R. D. P.; Hafez, Yaser A.; Heilgendorff, H. M.; Holler, C. M.; Irfan, Melis O.; Jew, Luke; John, J.; Jonas, J. L.; King, O. G.; Leahy, J. P.; Leech, J.; Leitch, E. M.; Muchovej, Stephen; Pearson, T. J.; Peel, M.; Readhead, A. C. S.; Sievers, Jonathan; Stevenson, M. A.; Zuntz, Joe

doi:10.1093/mnras/sty1956

Cited by 64 publications

(64 citation statements)

References 114 publications

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“…The C-Band All-Sky Survey (C-BASS) is a project to produce a high sensitivity all-sky map at 5 GHz in total intensity and polarization with a resolution of just under 1 • (Jones et al 2018). The primary science goal of C-BASS is to be E-mail: luke.jew@physics.ox.ac.uk used in combination with other data sets to produce maps of the cosmic microwave background (CMB) that are free from contaminating foreground Galactic emission in both total intensity and polarization.…”

Section: Introductionmentioning

confidence: 99%

The C-Band All-Sky Survey (C-BASS): Simulated parametric fitting in single pixels in total intensity and polarization

Jew

Taylor

Jones

et al. 2019

Monthly Notices of the Royal Astronomical Society

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The cosmic microwave background B-mode signal is potentially weaker than the diffuse Galactic foregrounds over most of the sky at any frequency. A common method of separating the CMB from these foregrounds is via pixel-based parametric-model fitting. There are not currently enough all-sky maps to fit anything more than the most simple models of the sky. By simulating the emission in seven representative pixels, we demonstrate that the inclusion of a 5 GHz data point allows for more complex models of low-frequency foregrounds to be fitted than at present. It is shown that the inclusion of the CBASS data will significantly reduce the uncertainties in a number of key parameters in the modelling of both the galactic foregrounds and the CMB. The extra data allow estimates of the synchrotron spectral index to be constrained much more strongly than is presently possible, with corresponding improvements in the accuracy of the recovery of the CMB amplitude. However, we show that to place good limits on models of the synchrotron spectral curvature will require additional low-frequency data.

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Section: Introductionmentioning

confidence: 99%

The C-Band All-Sky Survey (C-BASS): Simulated parametric fitting in single pixels in total intensity and polarization

Jew

Taylor

Jones

et al. 2019

Monthly Notices of the Royal Astronomical Society

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“…The C-BASS project is surveying the entire sky, in intensity and polarization, at a nominal frequency of 5 GHz and an angular resolution of ≈ 45 arcmin (Jones et al 2018). It uses two telescopes to obtain full-sky coverage; the northern telescope is a 6.1 m Gregorian antenna situated at the Owens Valley Radio Observatory, California, and the southern telescope is a 7.6 m Cassegrain antenna situated at Klerefontein, the MeerKAT/SKA South Africa support base.…”

Section: Observations and Data Analysismentioning

confidence: 99%

“…The C-Band All-Sky Survey (C-BASS) is a survey of the entire sky at 5 GHz, in intensity and polarization, at a resolution of 45 arcmin (King et al 2010;Jones et al 2018). The frequency chosen is ideal for CMB component separation studies, being much closer to observing frequencies used by CMB experiments, typically at 30 GHz and higher.…”

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confidence: 99%

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

Dickinson

Barr

Chiang

et al. 2019

Monthly Notices of the Royal Astronomical Society

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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 ≈ 0.6 mK rms. We apply the templatefitting (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 significantly (< 10 %) when using the higher frequency C-BASS 4.7 GHz template instead of the traditional Haslam 408 MHz map as a tracer of synchrotron radiation. We measure template coefficients of 9.93 ± 0.35 and 9.52 ± 0.34 K per unit τ 353 when using the Haslam and C-BASS synchrotron templates, respectively. The AME contributes 55 ± 2 µK rms at 22.8 GHz and accounts for ≈ 60% of the total foreground emission. Our results show that a harder (flatter spectrum) component of synchrotron emission is not dominant at frequencies 5 GHz; the best-fitting synchrotron temperature spectral index is β = −2.91 ± 0.04 from 4.7 to 22.8 GHz and β = −2.85 ± 0.14 from 22.8 to 44.1 GHz. Free-free emission is weak, contributing ≈ 7 µK rms (≈ 7%) at 22.8 GHz. The best explanation for the AME is still electric dipole emission from small spinning dust grains.

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“…The C-Band All Sky Survey (C-BASS) is a survey aimed at mapping the entire sky, both in total and polarized intensities, at 5 GHz (C-Band) with 45 arcmin angular resolution (Jones et al 2018). To cover the entire sky, C-BASS is being performed with two telescopes located in North and South hemispheres.…”

Section: A1 C-bassmentioning

confidence: 99%

CMB foreground measurements through broad-band radio spectro-polarimetry: prospects of the SKA-MPG telescope

Basu

Schwarz

Klöckner

et al. 2019

Monthly Notices of the Royal Astronomical Society

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Precise measurement of the foreground synchrotron emission, which contaminates the faint polarized cosmic microwave background radiation (CMB), is a major challenge for the next-generation of CMB experiments. To address this, dedicated foreground measurement experiments are being undertaken at radio frequencies between 2 and 40 GHz. Foreground polarized synchrotron emission measurements are particularly challenging, primarily due to the complicated frequency dependence in the presence of Faraday rotation, and are best recovered through broad fractional-bandwidth polarization measurements at frequencies 5 GHz. A unique opportunity for measuring the foreground polarized synchrotron emission will be provided by the 15-m SKA-MPG telescope operating in the frequency range 1.7 to 3.5 GHz (S-Band). Here, we present the scope of a Southern sky survey in S-Band at 1 degree angular resolution and explore its added advantage for application of powerful techniques, such as, Stokes Q, U fitting and RM-synthesis. A full Southern-sky polarization survey with this telescope, when combined with other on-going efforts at slightly higher frequencies, will provide an excellent frequency coverage for modeling and extrapolating the foreground polarized synchrotron emission to CMB frequencies ( 80 GHz) with rms brightness temperature better than 10 nK per 1 degree 2 . We find that this survey will be crucial for understanding the effects of Faraday depolarization, especially in low Galactic latitude regions. This will allow better foreground cleaning and thus will contribute significantly in further improving component separation analyses and increase usable sky area for cosmological analysis of the Planck data, and the LiteBIRD mission in the future.

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The C-Band All-Sky Survey (C-BASS): design and capabilities

Cited by 64 publications

References 114 publications

The C-Band All-Sky Survey (C-BASS): Simulated parametric fitting in single pixels in total intensity and polarization

The C-Band All-Sky Survey (C-BASS): Simulated parametric fitting in single pixels in total intensity and polarization

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

CMB foreground measurements through broad-band radio spectro-polarimetry: prospects of the SKA-MPG telescope

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