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The C-Band All-Sky Survey: total intensity point-source detection over the northern sky

Grumitt, R. D. P. and Taylor, Angela C. and Jew, Luke and Jones, Michael E. and Dickinson, C. and Barr, A. and Cepeda-Arroita, R. and Chiang, H. C. and Harper, S. E. and Heilgendorff, H. M. and Jonas, J. L. and Leahy, J. P. and Leech, J. and Pearson, T. J. and Peel, M. W. and Readhead, A. C. S. and Sievers, J. (2020) The C-Band All-Sky Survey: total intensity point-source detection over the northern sky. Monthly Notices of the Royal Astronomical Society, 496 (2). pp. 1941-1958. ISSN 0035-8711. https://resolver.caltech.edu/CaltechAUTHORS:20200903-132014697

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Abstract

We present a point-source detection algorithm that employs the second-order Spherical Mexican Hat wavelet filter (SMHW2), and use it on C-Band All-Sky Survey (C-BASS) northern intensity data to produce a catalogue of point sources. This catalogue allows us to cross-check the C-BASS flux-density scale against existing source surveys, and provides the basis for a source mask that will be used in subsequent C-BASS and cosmic microwave background (CMB) analyses. The SMHW2 allows us to filter the entire sky at once, avoiding complications from edge effects arising when filtering small sky patches. The algorithm is validated against a set of Monte Carlo simulations, consisting of diffuse emission, instrumental noise, and various point-source populations. The simulated source populations are successfully recovered. The SMHW2 detection algorithm is used to produce a 4.76GHz northern sky source catalogue in total intensity, containing 1784 sources and covering declinations δ ≥ −10°. The C-BASS catalogue is matched with the Green Bank 6 cm (GB6) and Parkes-MIT-NRAO (PMN) catalogues over their areas of common sky coverage. From this we estimate the 90 per cent completeness level to be approximately 610mJy⁠, with a corresponding reliability of 98 per cent, when masking the brightest 30 per cent of the diffuse emission in the C-BASS northern sky map. We find the C-BASS and GB6 flux-density scales to be consistent with one another to within approximately 4 per cent.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1093/mnras/staa1572DOIArticle
https://arxiv.org/abs/1910.08583arXivDiscussion Paper
ORCID:
AuthorORCID
Grumitt, R. D. P.0000-0001-9578-6111
Jew, Luke0000-0002-1831-4898
Jones, Michael E.0000-0003-3564-6680
Dickinson, C.0000-0002-0045-442X
Cepeda-Arroita, R.0000-0002-9043-2645
Pearson, T. J.0000-0001-5213-6231
Peel, M. W.0000-0003-3412-2586
Readhead, A. C. S.0000-0001-9152-961X
Sievers, J.0000-0001-6903-5074
Alternate Title:The C-Band All-Sky Survey (C-BASS): Total intensity point-source detection over the northern sky
Additional Information:© 2020 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 2020 May 29. Received 2020 May 28; in original form 2019 October 18. Published: 05 June 2020. 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, UKZN and the South African Radio Observatory in South Africa, and the King Abdulaziz City for Science and Technology (KACST) 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, STFC, 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. CD and SH acknowledge support from an STFC Consolidated grant no. (ST/P000649/1). CD acknowledges support from an ERC Starting (Consolidator) grant no. (307209). MWP acknowledges funding from a FAPESP Young Investigator fellowship, grant no. 2015/19936-1. We make use of the PYTHON MATPLOTLIB (Hunter 2007), NUMPY (Oliphant 2006), SCIPY (Jones et al. 2001), HEALPY (Górski et al. 2005; Zonca et al. 2019), ASTROPY (Astropy Collaboration et al. 2013, 2018), OPENCV (Kaehler & Bradski 2016), PYMC3 (Salvatier et al. 2016), and THEANO (Al-Rfou et al. 2016) packages.
Group:Astronomy Department
Funders:
Funding AgencyGrant Number
NSFAST-0607857
NSFAST-1010024
NSFAST-1212217
NSFAST-1616227
NASANNX15AF06G
University of OxfordUNSPECIFIED
Royal SocietyUNSPECIFIED
Science and Technology Facilities Council (STFC)ST/P000649/1
South African Radio Astronomy Observatory (SARAO)UNSPECIFIED
National Research Foundation (South Africa)UNSPECIFIED
Department of Science and Technology (South Africa)UNSPECIFIED
European Research Council (ERC)307209
Fundação de Amparo à Pesquisa do Estado de Sao Paulo (FAPESP)2015/19936-1
Subject Keywords:catalogues – surveys – methods: data analysis – cosmic background radiation – radio continuum: general – cosmology: observations
Issue or Number:2
Record Number:CaltechAUTHORS:20200903-132014697
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20200903-132014697
Official Citation:R D P Grumitt, Angela C Taylor, Luke Jew, Michael E Jones, C Dickinson, A Barr, R Cepeda-Arroita, H C Chiang, S E Harper, H M Heilgendorff, J L Jonas, J P Leahy, J Leech, T J Pearson, M W Peel, A C S Readhead, J Sievers, The C-Band All-Sky Survey: total intensity point-source detection over the northern sky, Monthly Notices of the Royal Astronomical Society, Volume 496, Issue 2, August 2020, Pages 1941–1958, https://doi.org/10.1093/mnras/staa1572
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:105245
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:08 Sep 2020 17:09
Last Modified:08 Sep 2020 17:09

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