A map of diffuse radio emission at 182 MHz to enhance epoch of reionization observations in the Southern hemisphere
Abstract
We present a broad-band map of polarized diffuse emission at 167–198 MHz developed from data from the Murchison Widefield Array (MWA). The map is designed to improve visibility simulation and precision calibration for 21 cm Epoch of Reionization (EoR) experiments. It covers a large swath – 11 000 sq. deg. – of the Southern hemisphere sky in all four Stokes parameters and captures emission on angular scales of 1–9°. The band-averaged diffuse structure is pre-dominantly unpolarized but has significant linearly polarized structure near RA = 0 h. We evaluate the accuracy of the map by combining it with the GLEAM catalogue and simulating an observation from the MWA, demonstrating that the accuracy of the short baselines (6.1–50 wavelengths) now approaches the accuracy of the longer baselines typically used for EoR calibration. We discuss how to use the map for visibility simulation for a variety of interferometric arrays. The map has potential to improve calibration accuracy for experiments such as the Hydrogen Epoch of Reionization Array and the forthcoming Square Kilometre Array as well as the MWA.
Additional Information
© 2021 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 2021 No v ember 6. Received 2021 November 2; in original form 2021 April 26. Published: 12 November 2021. We thank James Aguirre, George Heald, Zachary Martinot, and Michael Wilensky for discussions that directly contributed to this work. This work was directly supported by National Science Foundation grants AST-1613855, 1506024, 1643011, and 1835421. NB and CL are supported by the Australian Research Council Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D), through project number CE170100013. This scientific work makes use of the Murchison Radio-astronomy Observatory, operated by the Commonwealth Scientific and Industrial Research Organisation. We acknowledge the Wajarri Yamatji people as the traditional owners of the observatory site. Support for the operation of the MWA is provided by the Australian Government (NCRIS), under a contract to Curtin University administered by Astronomy Australia Limited. We acknowledge the Pawsey Supercomputing Centre which is supported by the Western Australian and Australian Governments. Data Availability: The data products underlying this article are available in its online supplementary material. For ease of access, we provide the polarized diffuse maps in two file formats: a FITS format and a SKYH5 format. The SKYH5 file is compatible with PYRADIOSKY,7 a Python utility for reading and writing sky model data and interfacing with simulation packages. The raw data underlying this article were accessed from the MWA All-Sky Virtual Observatory (ASVO)8 and are publicly available. For instructions on accessing the raw data files from the MWA ASVO, please contact the corresponding author.Attached Files
Published - stab3276.pdf
Accepted Version - 2107.11487.pdf
Submitted - 2107.11487v1.pdf
Supplemental Material - stab3276_supplemental_file.zip
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Additional details
- Eprint ID
- 112534
- Resolver ID
- CaltechAUTHORS:20211217-233158343
- AST-1613855
- NSF
- AST-1506024
- NSF
- AST-1643011
- NSF
- AST-1835421
- NSF
- CE170100013
- Australian Research Council
- Commonwealth Scientific and Research Organization (CSIRO)
- Created
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2021-12-20Created from EPrint's datestamp field
- Updated
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2022-07-25Created from EPrint's last_modified field