C-Band All-Sky Survey (C-BASS): Simulated parametric fitting in single pixels in total intensity and polarization
Abstract
The cosmic microwave background (CMB) 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 C-BASS 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.
Additional Information
© 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model). Accepted 2019 September 11. Received 2019 September 6; in original form 2019 July 24. Published: 07 October 2019. The C-BASS project is a collaboration between Oxford and Manchester Universities in the UK, the California Institute of Technology in the USA, Rhodes University, University of KwaZulu-Natal and the South African Radio Observatory in South Africa, and the King Abdulaziz City for Science and Technology in Saudi Arabia. It has been supported by the NSF awards AST-0607857, AST-1010024, AST-1212217, and AST-1616227, and NASA award NNX15AF06G, the University of Oxford, the Royal Society, the Science and Technology Facilities Council, and the other participating institutions. This research was also supported by the South African Radio Astronomy Observatory, which is a facility of the National Research Foundation, an agency of the Department of Science and Technology. Clive Dickinson and Stuart Harper acknowledge support from an STFC Consolidated Grant (ST/P000649/1). Clive Dickinson acknowledges support from an ERC Starting (Consolidator) Grant (no. 307209). Michael Peel acknowledges funding from a FAPESP Young Investigator fellowship, grant 2015/19936-1. We made use of the PYTHON MATPLOTLIB, NUMPY, HEALPY (a python wrapper for the HEALPIX package; Gorski et al. 2005), SCIPY and PYMC packages. (http://cbass.web.ox.ac.uk). The authors would like to thank the anonymous reviewer for their thoughtful comments.Attached Files
Published - stz2697.pdf
Accepted Version - 1907.11642.pdf
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Additional details
- PMCID
- PMC6824519
- Eprint ID
- 99890
- Resolver ID
- CaltechAUTHORS:20191118-085234230
- NSF
- AST-0607857
- NSF
- AST-1010024
- NSF
- AST-1212217
- NSF
- AST-1616227
- NASA
- NNX15AF06G
- University of Oxford
- Royal Society
- Science and Technology Facilities Council (STFC)
- ST/P000649/1
- South African Radio Astronomy Observatory
- National Research Foundation (South Africa)
- Department of Science and Technology (South Africa)
- European Research Council (ERC)
- 307209
- Fundação de Amparo à Pesquisa do Estado de Sao Paulo (FAPESP)
- 2015/19936-1
- Created
-
2019-11-18Created from EPrint's datestamp field
- Updated
-
2022-02-12Created from EPrint's last_modified field
- Caltech groups
- Astronomy Department