The Global Magneto-ionic Medium Survey: A Faraday Depth Survey of the Northern Sky Covering 1280–1750 MHz

Journal Article · Thu Jul 01 04:00:00 EDT 2021 · The Astronomical Journal (Online)

DOI:https://doi.org/10.3847/1538-3881/ABF7C1· OSTI ID:23159285

Wolleben, M.; Landecker, T. L.; Douglas, K. A.; Gray, A. D.; Ordog, A.; Hill, A. S.; Kothes, R. ^[1]; Dickey, J. M. ^[2]; Carretti, E. ^[3]; Brown, J. C. ^[4]; Gaensler, B. M.; West, J. L. ^[5]; Han, J. L. ^[6]; Haverkorn, M. ^[7]; Leahy, J. P. ^[8]; McClure-Griffiths, N.; McConnell, D. ^[9]; Reich, W. ^[10]; Taylor, A. R. ^[11]; Thomson, A. J. M., ^[12]

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1. National Research Council Canada, Herzberg Research Centre for Astronomy and Astrophysics, Dominion Radio Astrophysical Observatory, P.O. Box 248, Penticton, BC V2A 6J9 (Canada)
2. School of Natural Sciences, Private Bag 37, University of Tasmania, Hobart, Tasmania 7001 (Australia)
3. INAF—Istituto di Radioastronomia, via P. Gobetti 101, I-40129 Bologna (Italy)
4. Department of Physics and Astronomy, University of Calgary, 2500 University Drive, Calgary, AB T2N 1N4 (Canada)
5. Dunlap Institute for Astronomy and Astrophysics, University of Toronto, 50 St. George Street, TO M5S 3H4 (Canada)
6. National Astronomical Observatories, CAS, Jia-20 DaTun Road, Chaoyang District, Beijing 100101 (China)
7. Radboud University Nijmegen, P.O. Box 9010, 6500 GL Nijmegen (Netherlands)
8. Jodrell Bank Centre for Astrophysics, Department of Physics and Astronomy, The University of Manchester, Manchester M13 9PL (United Kingdom)
9. Research School of Astronomy and Astrophysics, Australian National University, Cotter Road, Weston Creek, ACT 2611 (Australia)
10. Max-Planck-Institut für Radioastronomie, D-53121 Bonn, Auf dem Hügel 69 (Germany)
11. Department of Astronomy, University of Cape Town, Rondenbosch 7701, Republic of South Africa (South Africa)
12. CSIRO Astronomy & Space Science, P.O. Box 1130, Bentley, WA 6102 (Australia)

The Galactic interstellar medium hosts a significant magnetic field, which can be probed through the synchrotron emission produced from its interaction with relativistic electrons. Linearly polarized synchrotron emission is generated throughout the Galaxy and, at longer wavelengths, modified along nearly every path by Faraday rotation in the intervening magneto-ionic medium. Full characterization of the polarized emission requires wideband observations with many frequency channels. We have surveyed polarized radio emission from the Northern sky over the range 1280–1750 MHz, with channel width 236.8 kHz, using the John A. Galt Telescope (diameter 25.6 m) at the Dominion Radio Astrophysical Observatory, as part of the Global Magneto-Ionic Medium Survey. The survey covered 72% of the sky, decl. −30° to +87° at all R.A. The intensity scale was absolutely calibrated, based on the flux density and spectral index of Cygnus A. Polarization angle was calibrated using the extended polarized emission of the Fan Region. Data are presented as brightness temperatures with angular resolution 40′. Sensitivity in Stokes Q and U is 45 mK rms in a 1.18 MHz band. We have applied rotation measure synthesis to the data to obtain a Faraday depth cube of resolution 150 rad m{sup −2} and sensitivity 3 mK rms of polarized intensity. Features in Faraday depth up to a width of 110 rad m{sup −2} are represented. The maximum detectable Faraday depth is ±2 × 10{sup 4} rad m{sup −2}. The survey data are available at the Canadian Astronomy Data Centre.

• OSTI ID: 23159285
• Journal Information: The Astronomical Journal (Online), Journal Name: The Astronomical Journal (Online) Journal Issue: 1 Vol. 162; ISSN 1538-3881
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
79 ASTRONOMY AND ASTROPHYSICS
ASTRONOMY
ASTROPHYSICS
BRIGHTNESS
ELECTRONS
FARADAY EFFECT
FLUX DENSITY
GALAXIES
KHZ RANGE
MAGNETIC FIELDS
MHZ RANGE
POLARIZATION
RESOLUTION
ROTATION
SENSITIVITY
SYNCHROTRONS
TELESCOPES
WAVELENGTHS