A Pioneering Experiment Combining Single-antenna and Aperture-synthesis Data to Measure Faraday Rotation with GMIMS and the CGPS
Structures in the magnetoionic medium exist across a wide range of angular sizes owing to large-scale magnetic fields coherent over the Galactic spiral arms combined with small-scale fluctuations in the magnetic field and electron density resulting from energy injection processes such as supernovae....
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| Format: | Article |
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IOP Publishing
2025-01-01
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| Series: | The Astronomical Journal |
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| Online Access: | https://doi.org/10.3847/1538-3881/adc929 |
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| author | Anna Ordog Jo-Anne C. Brown T. L. Landecker Alex S. Hill Roland Kothes Jennifer L. West John M. Dickey Marijke Haverkorn Ettore Carretti Alec J. M. Thomson Andrea Bracco D. A. Del Rizzo Ryan R. Ransom Robert I. Reid |
| author_facet | Anna Ordog Jo-Anne C. Brown T. L. Landecker Alex S. Hill Roland Kothes Jennifer L. West John M. Dickey Marijke Haverkorn Ettore Carretti Alec J. M. Thomson Andrea Bracco D. A. Del Rizzo Ryan R. Ransom Robert I. Reid |
| author_sort | Anna Ordog |
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| description | Structures in the magnetoionic medium exist across a wide range of angular sizes owing to large-scale magnetic fields coherent over the Galactic spiral arms combined with small-scale fluctuations in the magnetic field and electron density resulting from energy injection processes such as supernovae. For the first time, we produce diffuse Galactic synchrotron emission Faraday rotation maps covering all spatial scales down to ${3}^{{\prime} }$ resolution for magnetic field studies. These maps complement total and polarized intensity maps combining single-antenna and interferometric data that have been produced, such as the Canadian Galactic Plane Survey (CGPS). Combined maps have sensitivity to large scales from the single-antenna component and angular resolution from the interferometric component. We combine Global Magneto-Ionic Medium Survey High-Band North single-antenna and CGPS aperture-synthesis polarization data after spatial filtering, producing Stokes Q and U maps for the four CGPS frequency channels. We calculate rotation measures (RMs) for all pixels using a linear fit to polarization angle versus wavelength squared. Smooth polarized emission regions require the large-scale sensitivity of the single antenna to illuminate the Faraday rotation, while aperture synthesis reveals small-scale RM variability. While these maps show magnetic field structures on the full range of spatial scales they probe, the RM values should be interpreted with caution, as the narrow λ ^2 coverage limits sensitivity to Faraday complexity. Despite this limitation of the CGPS 35 MHz bandwidth, we demonstrate that useful Faraday rotation information can be obtained from the combined data set, highlighting the important synergy between future broadband interferometric and single-antenna polarization surveys. |
| format | Article |
| id | doaj-art-2661d74c1bd94faa87a77f3b60dac5b3 |
| institution | Kabale University |
| issn | 1538-3881 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astronomical Journal |
| spelling | doaj-art-2661d74c1bd94faa87a77f3b60dac5b32025-08-20T03:49:32ZengIOP PublishingThe Astronomical Journal1538-38812025-01-01169631210.3847/1538-3881/adc929A Pioneering Experiment Combining Single-antenna and Aperture-synthesis Data to Measure Faraday Rotation with GMIMS and the CGPSAnna Ordog0https://orcid.org/0000-0002-2465-8937Jo-Anne C. Brown1https://orcid.org/0000-0003-4781-5701T. L. Landecker2https://orcid.org/0000-0003-1455-2546Alex S. Hill3https://orcid.org/0000-0001-7301-5666Roland Kothes4https://orcid.org/0000-0001-5953-0100Jennifer L. West5https://orcid.org/0000-0001-7722-8458John M. Dickey6https://orcid.org/0000-0002-6300-7459Marijke Haverkorn7https://orcid.org/0000-0002-5288-312XEttore Carretti8https://orcid.org/0000-0002-3973-8403Alec J. M. Thomson9https://orcid.org/0000-0001-9472-041XAndrea Bracco10https://orcid.org/0000-0003-0932-3140D. A. Del Rizzo11Ryan R. Ransom12https://orcid.org/0000-0003-2469-1611Robert I. Reid13https://orcid.org/0000-0003-2391-8650Department of Computer Science, Math, Physics, & Statistics, University of British Columbia , Okanagan Campus, Kelowna, BC V1V 1V7, Canada ; anna.ordog@ubc.ca; Dominion Radio Astrophysical Observatory , Herzberg Research Centre for Astronomy and Astrophysics, National Research Council Canada, PO Box 248, Penticton, BC V2A 6J9, Canada; Department of Physics and Astronomy, University of Calgary , 2500 University Drive NW, Calgary, Alberta, T2N 1N4, CanadaDepartment of Physics and Astronomy, University of Calgary , 2500 University Drive NW, Calgary, Alberta, T2N 1N4, CanadaDominion Radio Astrophysical Observatory , Herzberg Research Centre for Astronomy and Astrophysics, National Research Council Canada, PO Box 248, Penticton, BC V2A 6J9, CanadaDepartment of Computer Science, Math, Physics, & Statistics, University of British Columbia , Okanagan Campus, Kelowna, BC V1V 1V7, Canada ; anna.ordog@ubc.ca; Dominion Radio Astrophysical Observatory , Herzberg Research Centre for Astronomy and Astrophysics, National Research Council Canada, PO Box 248, Penticton, BC V2A 6J9, CanadaDominion Radio Astrophysical Observatory , Herzberg Research Centre for Astronomy and Astrophysics, National Research Council Canada, PO Box 248, Penticton, BC V2A 6J9, CanadaDominion Radio Astrophysical Observatory , Herzberg Research Centre for Astronomy and Astrophysics, National Research Council Canada, PO Box 248, Penticton, BC V2A 6J9, CanadaSchool of Natural Sciences, University of Tasmania , Hobart, Tas 7000, AustraliaDepartment of Astrophysics/IMAPP, Radboud University , PO Box 9010, 6500 GL Nijmegen, The NetherlandsINAF-Istituto di Radioastronomia , Via Gobetti 101, 40129 Bologna, ItalyATNF , CSIRO Space & Astronomy, Bentley, WA, AustraliaINAF Osservatorio Astrofisico di Arcetri , Largo E. Fermi 5, 50125 Firenze, Italy; Laboratoire de Physique de l'École Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université de Paris , F-75005 Paris, FranceDominion Radio Astrophysical Observatory , Herzberg Research Centre for Astronomy and Astrophysics, National Research Council Canada, PO Box 248, Penticton, BC V2A 6J9, CanadaDominion Radio Astrophysical Observatory , Herzberg Research Centre for Astronomy and Astrophysics, National Research Council Canada, PO Box 248, Penticton, BC V2A 6J9, Canada; Department of Physics and Astronomy , Okanagan College, Kelowna, BC V1Y 4X8, CanadaDepartments of Radiology and Information Technology , Mayo Clinic, 200 1st. St. SW, Rochester, MN 55905, USAStructures in the magnetoionic medium exist across a wide range of angular sizes owing to large-scale magnetic fields coherent over the Galactic spiral arms combined with small-scale fluctuations in the magnetic field and electron density resulting from energy injection processes such as supernovae. For the first time, we produce diffuse Galactic synchrotron emission Faraday rotation maps covering all spatial scales down to ${3}^{{\prime} }$ resolution for magnetic field studies. These maps complement total and polarized intensity maps combining single-antenna and interferometric data that have been produced, such as the Canadian Galactic Plane Survey (CGPS). Combined maps have sensitivity to large scales from the single-antenna component and angular resolution from the interferometric component. We combine Global Magneto-Ionic Medium Survey High-Band North single-antenna and CGPS aperture-synthesis polarization data after spatial filtering, producing Stokes Q and U maps for the four CGPS frequency channels. We calculate rotation measures (RMs) for all pixels using a linear fit to polarization angle versus wavelength squared. Smooth polarized emission regions require the large-scale sensitivity of the single antenna to illuminate the Faraday rotation, while aperture synthesis reveals small-scale RM variability. While these maps show magnetic field structures on the full range of spatial scales they probe, the RM values should be interpreted with caution, as the narrow λ ^2 coverage limits sensitivity to Faraday complexity. Despite this limitation of the CGPS 35 MHz bandwidth, we demonstrate that useful Faraday rotation information can be obtained from the combined data set, highlighting the important synergy between future broadband interferometric and single-antenna polarization surveys.https://doi.org/10.3847/1538-3881/adc929Milky Way magnetic fieldsGalaxy magnetic fieldsMilky Way diskInterstellar magnetic fieldsRadio telescopesRadio observatories |
| spellingShingle | Anna Ordog Jo-Anne C. Brown T. L. Landecker Alex S. Hill Roland Kothes Jennifer L. West John M. Dickey Marijke Haverkorn Ettore Carretti Alec J. M. Thomson Andrea Bracco D. A. Del Rizzo Ryan R. Ransom Robert I. Reid A Pioneering Experiment Combining Single-antenna and Aperture-synthesis Data to Measure Faraday Rotation with GMIMS and the CGPS The Astronomical Journal Milky Way magnetic fields Galaxy magnetic fields Milky Way disk Interstellar magnetic fields Radio telescopes Radio observatories |
| title | A Pioneering Experiment Combining Single-antenna and Aperture-synthesis Data to Measure Faraday Rotation with GMIMS and the CGPS |
| title_full | A Pioneering Experiment Combining Single-antenna and Aperture-synthesis Data to Measure Faraday Rotation with GMIMS and the CGPS |
| title_fullStr | A Pioneering Experiment Combining Single-antenna and Aperture-synthesis Data to Measure Faraday Rotation with GMIMS and the CGPS |
| title_full_unstemmed | A Pioneering Experiment Combining Single-antenna and Aperture-synthesis Data to Measure Faraday Rotation with GMIMS and the CGPS |
| title_short | A Pioneering Experiment Combining Single-antenna and Aperture-synthesis Data to Measure Faraday Rotation with GMIMS and the CGPS |
| title_sort | pioneering experiment combining single antenna and aperture synthesis data to measure faraday rotation with gmims and the cgps |
| topic | Milky Way magnetic fields Galaxy magnetic fields Milky Way disk Interstellar magnetic fields Radio telescopes Radio observatories |
| url | https://doi.org/10.3847/1538-3881/adc929 |
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