Prototype Faraday Rotation Measure Catalogs from the Polarisation Sky Survey of the Universe’s Magnetism (POSSUM) Pilot Observations
The Polarisation Sky Survey of the Universe’s Magnetism (POSSUM) will conduct a sensitive ∼1 GHz radio polarization survey covering 20,000 deg ^2 of the southern sky with the Australian Square Kilometre Array Pathfinder. In anticipation of the full survey, we analyze pilot observations of low-band (...
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| Format: | Article |
| Language: | English |
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IOP Publishing
2024-01-01
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| Series: | The Astronomical Journal |
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| Online Access: | https://doi.org/10.3847/1538-3881/ad2fc8 |
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| author | S. Vanderwoude J. L. West B. M. Gaensler L. Rudnick C. L. Van Eck A. J. M. Thomson H. Andernach C. S. Anderson E. Carretti G. H. Heald J. P. Leahy N. M. McClure-Griffiths S. P. O’Sullivan M. Tahani A. G. Willis |
| author_facet | S. Vanderwoude J. L. West B. M. Gaensler L. Rudnick C. L. Van Eck A. J. M. Thomson H. Andernach C. S. Anderson E. Carretti G. H. Heald J. P. Leahy N. M. McClure-Griffiths S. P. O’Sullivan M. Tahani A. G. Willis |
| author_sort | S. Vanderwoude |
| collection | DOAJ |
| description | The Polarisation Sky Survey of the Universe’s Magnetism (POSSUM) will conduct a sensitive ∼1 GHz radio polarization survey covering 20,000 deg ^2 of the southern sky with the Australian Square Kilometre Array Pathfinder. In anticipation of the full survey, we analyze pilot observations of low-band (800–1087 MHz), mid-band (1316–1439 MHz), and combined-band observations for an extragalactic field and a Galactic plane field (low-band only). Using the POSSUM processing pipeline, we produce prototype rotation measure (RM) catalogs that are filtered to construct prototype RM grids. We assess typical RM grid densities and RM uncertainties and their dependence on frequency, bandwidth, and Galactic latitude. We present a median filter method for separating foreground diffuse emission from background components and find that after application of the filter, 99.5% of the measured RMs of simulated sources are within 3 σ of their true RM, with a typical loss of polarized intensity of 5% ± 5%. We find RM grid densities of 35.1, 30.6, 37.2, and 13.5 RMs per square degree and median uncertainties on RM measurements of 1.55, 12.82, 1.06, and 1.89 rad m ^−2 for the median-filtered low-band, mid-band, combined-band, and Galactic observations, respectively. We estimate that the full POSSUM survey will produce an RM catalog of ∼775,000 RMs with median-filtered low-band observations and ∼877,000 RMs with median-filtered combined-band observations. We construct a structure function from the Galactic RM catalog, which shows a break at 0.°7, corresponding to a physical scale of 12–24 pc for the nearest spiral arm. |
| first_indexed | 2024-04-24T07:50:32Z |
| format | Article |
| id | doaj.art-d2e4de9e984646d9b93b25fd21d34f35 |
| institution | Directory Open Access Journal |
| issn | 1538-3881 |
| language | English |
| last_indexed | 2024-04-24T07:50:32Z |
| publishDate | 2024-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astronomical Journal |
| spelling | doaj.art-d2e4de9e984646d9b93b25fd21d34f352024-04-18T13:12:24ZengIOP PublishingThe Astronomical Journal1538-38812024-01-01167522610.3847/1538-3881/ad2fc8Prototype Faraday Rotation Measure Catalogs from the Polarisation Sky Survey of the Universe’s Magnetism (POSSUM) Pilot ObservationsS. Vanderwoude0https://orcid.org/0009-0004-7773-1618J. L. West1https://orcid.org/0000-0001-7722-8458B. M. Gaensler2https://orcid.org/0000-0002-3382-9558L. Rudnick3https://orcid.org/0000-0001-5636-7213C. L. Van Eck4https://orcid.org/0000-0002-7641-9946A. J. M. Thomson5https://orcid.org/0000-0001-9472-041XH. Andernach6https://orcid.org/0000-0003-4873-1681C. S. Anderson7https://orcid.org/0000-0002-6243-7879E. Carretti8https://orcid.org/0000-0002-3973-8403G. H. Heald9https://orcid.org/0000-0002-2155-6054J. P. Leahy10https://orcid.org/0000-0003-2514-9592N. M. McClure-Griffiths11https://orcid.org/0000-0003-2730-957XS. P. O’Sullivan12https://orcid.org/0000-0002-3968-3051M. Tahani13https://orcid.org/0000-0001-8749-1436A. G. Willis14https://orcid.org/0000-0002-2173-6151David A. Dunlap Department of Astronomy and Astrophysics, University of Toronto , Toronto, ON M5S 3H4, Canada ; vanderwoude@astro.utoronto.ca; Dunlap Institute for Astronomy and Astrophysics, University of Toronto , Toronto, ON M5S 3H4, CanadaDunlap Institute for Astronomy and Astrophysics, University of Toronto , Toronto, ON M5S 3H4, Canada; Dominion Radio Astrophysical Observatory , Herzberg Astronomy and Astrophysics, National Research Council Canada, P.O. Box 248, Penticton, BC V2A 6J9, CanadaDavid A. Dunlap Department of Astronomy and Astrophysics, University of Toronto , Toronto, ON M5S 3H4, Canada ; vanderwoude@astro.utoronto.ca; Dunlap Institute for Astronomy and Astrophysics, University of Toronto , Toronto, ON M5S 3H4, CanadaMinnesota Institute for Astrophysics, University of Minnesota , Minneapolis, MN, USADunlap Institute for Astronomy and Astrophysics, University of Toronto , Toronto, ON M5S 3H4, Canada; Research School of Astronomy & Astrophysics, The Australian National University , Canberra, ACT 2611, AustraliaATNF , CSIRO Space & Astronomy, P.O. Box 1130, Bentley, WA 6102, AustraliaThüringer Landessternwarte, Sternwarte 5, D-07778 Tautenburg, GermanyResearch School of Astronomy & Astrophysics, The Australian National University , Canberra, ACT 2611, AustraliaINAF, Istituto di Radioastronomia , Via Gobetti 101, 40129 Bologna, ItalyATNF , CSIRO Space & Astronomy, P.O. Box 1130, Bentley, WA 6102, AustraliaJodrell Bank Centre for Astrophysics, Department of Physics & Astronomy, The University of Manchester , Oxford Road, Manchester M13 9PL, UKResearch School of Astronomy & Astrophysics, The Australian National University , Canberra, ACT 2611, AustraliaDepartamento de Física de la Tierra y Astrofísica & IPARCOS-UCM, Universidad Complutense de Madrid , 28040 Madrid, SpainBanting and KIPAC Fellowships: Kavli Institute for Particle Astrophysics & Cosmology (KIPAC), Stanford University , Stanford, CA 94305, USADominion Radio Astrophysical Observatory , Herzberg Astronomy and Astrophysics, National Research Council Canada, P.O. Box 248, Penticton, BC V2A 6J9, CanadaThe Polarisation Sky Survey of the Universe’s Magnetism (POSSUM) will conduct a sensitive ∼1 GHz radio polarization survey covering 20,000 deg ^2 of the southern sky with the Australian Square Kilometre Array Pathfinder. In anticipation of the full survey, we analyze pilot observations of low-band (800–1087 MHz), mid-band (1316–1439 MHz), and combined-band observations for an extragalactic field and a Galactic plane field (low-band only). Using the POSSUM processing pipeline, we produce prototype rotation measure (RM) catalogs that are filtered to construct prototype RM grids. We assess typical RM grid densities and RM uncertainties and their dependence on frequency, bandwidth, and Galactic latitude. We present a median filter method for separating foreground diffuse emission from background components and find that after application of the filter, 99.5% of the measured RMs of simulated sources are within 3 σ of their true RM, with a typical loss of polarized intensity of 5% ± 5%. We find RM grid densities of 35.1, 30.6, 37.2, and 13.5 RMs per square degree and median uncertainties on RM measurements of 1.55, 12.82, 1.06, and 1.89 rad m ^−2 for the median-filtered low-band, mid-band, combined-band, and Galactic observations, respectively. We estimate that the full POSSUM survey will produce an RM catalog of ∼775,000 RMs with median-filtered low-band observations and ∼877,000 RMs with median-filtered combined-band observations. We construct a structure function from the Galactic RM catalog, which shows a break at 0.°7, corresponding to a physical scale of 12–24 pc for the nearest spiral arm.https://doi.org/10.3847/1538-3881/ad2fc8Sky surveysCatalogsSpectropolarimetryPolarimetryAstrophysical magnetismGalaxy magnetic fields |
| spellingShingle | S. Vanderwoude J. L. West B. M. Gaensler L. Rudnick C. L. Van Eck A. J. M. Thomson H. Andernach C. S. Anderson E. Carretti G. H. Heald J. P. Leahy N. M. McClure-Griffiths S. P. O’Sullivan M. Tahani A. G. Willis Prototype Faraday Rotation Measure Catalogs from the Polarisation Sky Survey of the Universe’s Magnetism (POSSUM) Pilot Observations The Astronomical Journal Sky surveys Catalogs Spectropolarimetry Polarimetry Astrophysical magnetism Galaxy magnetic fields |
| title | Prototype Faraday Rotation Measure Catalogs from the Polarisation Sky Survey of the Universe’s Magnetism (POSSUM) Pilot Observations |
| title_full | Prototype Faraday Rotation Measure Catalogs from the Polarisation Sky Survey of the Universe’s Magnetism (POSSUM) Pilot Observations |
| title_fullStr | Prototype Faraday Rotation Measure Catalogs from the Polarisation Sky Survey of the Universe’s Magnetism (POSSUM) Pilot Observations |
| title_full_unstemmed | Prototype Faraday Rotation Measure Catalogs from the Polarisation Sky Survey of the Universe’s Magnetism (POSSUM) Pilot Observations |
| title_short | Prototype Faraday Rotation Measure Catalogs from the Polarisation Sky Survey of the Universe’s Magnetism (POSSUM) Pilot Observations |
| title_sort | prototype faraday rotation measure catalogs from the polarisation sky survey of the universe s magnetism possum pilot observations |
| topic | Sky surveys Catalogs Spectropolarimetry Polarimetry Astrophysical magnetism Galaxy magnetic fields |
| url | https://doi.org/10.3847/1538-3881/ad2fc8 |
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