The Astrophysical Journal (Jan 2024)
Faraday Tomography with CHIME: The “Tadpole” Feature G137+7
- Nasser Mohammed,
- Anna Ordog,
- Rebecca A. Booth,
- Andrea Bracco,
- Jo-Anne C. Brown,
- Ettore Carretti,
- John M. Dickey,
- Simon Foreman,
- Mark Halpern,
- Marijke Haverkorn,
- Alex S. Hill,
- Gary Hinshaw,
- Joseph W. Kania,
- Roland Kothes,
- T. L. Landecker,
- Joshua MacEachern,
- Kiyoshi W. Masui,
- Aimee Menard,
- Ryan R. Ransom,
- Wolfgang Reich,
- Patricia Reich,
- J. Richard Shaw,
- Seth R. Siegel,
- Mehrnoosh Tahani,
- Alec J. M. Thomson,
- Tristan Pinsonneault-Marotte,
- Haochen Wang,
- Jennifer L. West,
- Maik Wolleben,
- Dallas Wulf,
- CHIME and GMIMS Collaborations
Affiliations
- Nasser Mohammed
- ORCiD
- Department of Computer Science, Math, Physics, & Statistics, University of British Columbia , Okanagan Campus, Kelowna, BC V1V 1V7, Canada ; [email protected]; Dominion Radio Astrophysical Observatory, Herzberg Research Centre for Astronomy and Astrophysics, National Research Council Canada , PO Box 248, Penticton, BC V2A 6J9, Canada ; [email protected]
- Anna Ordog
- ORCiD
- Department of Computer Science, Math, Physics, & Statistics, University of British Columbia , Okanagan Campus, Kelowna, BC V1V 1V7, Canada ; [email protected]; Dominion Radio Astrophysical Observatory, Herzberg Research Centre for Astronomy and Astrophysics, National Research Council Canada , PO Box 248, Penticton, BC V2A 6J9, Canada ; [email protected]
- Rebecca A. Booth
- ORCiD
- Department of Physics and Astronomy, University of Calgary , 2500 University Drive NW, Calgary, Alberta, T2N 1N4, Canada
- Andrea Bracco
- ORCiD
- INAF—Osservatorio Astrofisico di Arcetri , Largo E. Fermi 5, 50125 Firenze, Italy; Laboratoire de Physique de l’Ecole Normale Supérieure, ENS, Université PSL , CNRS, Sorbonne Université, Université de Paris, F-75005 Paris, France
- Jo-Anne C. Brown
- ORCiD
- Department of Physics and Astronomy, University of Calgary , 2500 University Drive NW, Calgary, Alberta, T2N 1N4, Canada
- Ettore Carretti
- ORCiD
- INAF-Istituto di Radioastronomia , Via Gobetti 101, 40129 Bologna, Italy
- John M. Dickey
- ORCiD
- School of Natural Sciences, University of Tasmania , Hobart, Tas 7000 Australia
- Simon Foreman
- ORCiD
- Department of Physics, Arizona State University , Tempe, AZ 85287, USA
- Mark Halpern
- ORCiD
- Department of Physics and Astronomy, University of British Columbia , 6224 Agricultural Road, Vancouver, BC V6T 1Z1, Canada
- Marijke Haverkorn
- ORCiD
- Department of Astrophysics/IMAPP, Radboud University , PO Box 9010, 6500 GL Nijmegen, The Netherlands
- Alex S. Hill
- ORCiD
- Department of Computer Science, Math, Physics, & Statistics, University of British Columbia , Okanagan Campus, Kelowna, BC V1V 1V7, Canada ; [email protected]; Dominion Radio Astrophysical Observatory, Herzberg Research Centre for Astronomy and Astrophysics, National Research Council Canada , PO Box 248, Penticton, BC V2A 6J9, Canada ; [email protected]
- Gary Hinshaw
- ORCiD
- UBC Vancouver Department of Physics and Astronomy , 6224 Agricultural Rd, Vancouver BC V6T 1Z1, Canada
- Joseph W. Kania
- ORCiD
- Department of Physics and Astronomy, West Virginia University , P.O. Box 6315, Morgantown, WV 26506, USA; Center for Gravitational Waves and Cosmology, West Virginia University , Chestnut Ridge Research Building, Morgantown, WV 26505, USA
- Roland Kothes
- ORCiD
- Dominion Radio Astrophysical Observatory, Herzberg Research Centre for Astronomy and Astrophysics, National Research Council Canada , PO Box 248, Penticton, BC V2A 6J9, Canada ; [email protected]
- T. L. Landecker
- ORCiD
- Dominion Radio Astrophysical Observatory, Herzberg Research Centre for Astronomy and Astrophysics, National Research Council Canada , PO Box 248, Penticton, BC V2A 6J9, Canada ; [email protected]
- Joshua MacEachern
- ORCiD
- Department of Physics and Astronomy, University of British Columbia , 6224 Agricultural Road, Vancouver, BC V6T 1Z1, Canada
- Kiyoshi W. Masui
- ORCiD
- MIT Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, MA 02139, USA; Department of Physics, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, MA 02139, USA
- Aimee Menard
- ORCiD
- Department of Computer Science, Math, Physics, & Statistics, University of British Columbia , Okanagan Campus, Kelowna, BC V1V 1V7, Canada ; [email protected]; Dominion Radio Astrophysical Observatory, Herzberg Research Centre for Astronomy and Astrophysics, National Research Council Canada , PO Box 248, Penticton, BC V2A 6J9, Canada ; [email protected]
- Ryan R. Ransom
- ORCiD
- Dominion Radio Astrophysical Observatory, Herzberg Research Centre for Astronomy and Astrophysics, National Research Council Canada , PO Box 248, Penticton, BC V2A 6J9, Canada ; [email protected]; Department of Physics and Astronomy, Okanagan College , Kelowna, BC V1Y 4X8, Canada
- Wolfgang Reich
- ORCiD
- Max-Planck-Institut für Radioastronomie , Auf dem Hügel 69, 53121 Bonn, Germany
- Patricia Reich
- ORCiD
- Max-Planck-Institut für Radioastronomie , Auf dem Hügel 69, 53121 Bonn, Germany
- J. Richard Shaw
- ORCiD
- Department of Physics and Astronomy, University of British Columbia , 6224 Agricultural Road, Vancouver, BC V6T 1Z1, Canada
- Seth R. Siegel
- ORCiD
- Perimeter Institute for Theoretical Physics , 31 Caroline Street N, Waterloo, ON N25 2YL, Canada; Department of Physics, McGill University , 3600 rue University, Montréal, QC H3A 2T8, Canada; Trottier Space Institute, McGill University , 3550 rue University, Montréal, QC H3A 2A7, Canada
- Mehrnoosh Tahani
- ORCiD
- Banting and KIPAC Fellowships: Kavli Institute for Particle Astrophysics & Cosmology (KIPAC), Stanford University , Stanford, CA 94305, USA
- Alec J. M. Thomson
- ORCiD
- ATNF, CSIRO Space & Astronomy , Bentley, WA, Australia
- Tristan Pinsonneault-Marotte
- ORCiD
- Department of Physics and Astronomy, University of British Columbia , 6224 Agricultural Road, Vancouver, BC V6T 1Z1, Canada
- Haochen Wang
- ORCiD
- MIT Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, MA 02139, USA; Department of Physics, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, MA 02139, USA
- Jennifer L. West
- ORCiD
- Dominion Radio Astrophysical Observatory, Herzberg Research Centre for Astronomy and Astrophysics, National Research Council Canada , PO Box 248, Penticton, BC V2A 6J9, Canada ; [email protected]
- Maik Wolleben
- ORCiD
- Skaha Remote Sensing Ltd. , 3165 Juniper Drive, Naramata, BC V0H 1N0, Canada
- Dallas Wulf
- ORCiD
- Department of Physics, McGill University , 3600 rue University, Montréal, QC H3A 2T8, Canada; Trottier Space Institute, McGill University , 3550 rue University, Montréal, QC H3A 2A7, Canada
- CHIME and GMIMS Collaborations
- DOI
- https://doi.org/10.3847/1538-4357/ad5099
- Journal volume & issue
-
Vol. 971,
no. 1
p. 100
Abstract
A direct consequence of Faraday rotation is that the polarized radio sky does not resemble the total intensity sky at long wavelengths. We analyze G137+7, which is undetectable in total intensity but appears as a depolarization feature. We use the first polarization maps from the Canadian Hydrogen Intensity Mapping Experiment. Our 400–729 MHz bandwidth and angular resolution, $17^{\prime} $ – $30^{\prime} $ , allow us to use Faraday synthesis to analyze the polarization structure. In polarized intensity and polarization angle maps, we find a tail extending 10° from the head and designate the combined object, the tadpole . Similar polarization angles, distinct from the background, indicate that the head and tail are physically associated. The head appears as a depolarized ring in single channels, but wideband observations show that it is a Faraday rotation feature. Our investigations of H i and H α find no connections to the tadpole. The tail suggests motion of either the gas or an ionizing star through the interstellar medium; the B2(e) star HD 20336 is a candidate. While the head features a coherent, ∼ −8 rad m ^−2 Faraday depth, Faraday synthesis also identifies multiple components in both the head and tail. We verify the locations of the components in the spectra using QU fitting. Our results show that approximately octave-bandwidth Faraday rotation observations at ∼600 MHz are sensitive to low-density ionized or partially ionized gas, which is undetectable in other tracers.
Keywords
- Interstellar medium
- Interstellar magnetic fields
- Stellar-interstellar interactions
- Radio astronomy
- Interstellar dust
- Interstellar clouds
