CaltechAUTHORS
Published May 2023 | Version Published
Journal Article Open

H I filaments as potential compass needles? Comparing the magnetic field structure of the Small Magellanic Cloud to the orientation of GASKAP-HI filaments

Creators

  • 1. ROR icon Australian National University
  • 2. ROR icon Max Planck Institute for Radio Astronomy
  • 3. ROR icon Stanford University
  • 4. ROR icon Western Kentucky University
  • 5. ROR icon Keele University
  • 6. ROR icon Institute for Space Astrophysics and Planetology
  • 7. ROR icon Columbia University
  • 8. ROR icon University of Tasmania
  • 9. ROR icon Korea Astronomy and Space Science Institute
  • 10. ROR icon California Institute of Technology
  • 11. ROR icon Universidad de Guanajuato
  • 12. ROR icon Commonwealth Scientific and Industrial Research Organisation
  • 13. ROR icon Universidad Yachay Tech
  • 14. ROR icon Netherlands Institute for Radio Astronomy
  • 15. ROR icon University of Wisconsin–Madison

Abstract

High-spatial-resolution H i observations have led to the realization that the nearby (within few hundreds of parsecs) Galactic atomic filamentary structures are aligned with the ambient magnetic field. Enabled by the high-quality data from the Australian Square Kilometre Array Pathfinder (ASKAP) radio telescope for the Galactic ASKAP H i survey, we investigate the potential magnetic alignment of the ≳ 10 pc-scale H i filaments in the Small Magellanic Cloud (SMC). Using the Rolling Hough Transform technique that automatically identifies filamentary structures, combined with our newly devised ray-tracing algorithm that compares the H i and starlight polarization data, we find that the H i filaments in the north-eastern end of the SMC main body ('Bar' region) and the transition area between the main body and the tidal feature ('Wing' region) appear preferentially aligned with the magnetic field traced by starlight polarization. Meanwhile, the remaining SMC volume lacks starlight polarization data of sufficient quality to draw any conclusions. This suggests for the first time that filamentary H i structures can be magnetically aligned across a large spatial volume (≳ kpc) outside of the Milky Way. In addition, we generate maps of the preferred orientation of H i filaments throughout the entire SMC, revealing the highly complex gaseous structures of the galaxy likely shaped by a combination of the intrinsic internal gas dynamics, tidal interactions, and star-formation feedback processes. These maps can further be compared with future measurements of the magnetic structures in other regions of the SMC.

Additional Information

© 2023 The Author(s) Published by Oxford University Press on behalf of 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). We thank the anonymous referee for the comments, especially on the discussions on the statistical robustness of the bootstrapping procedures. We thank Christoph Federrath, Isabella Gerrard, Gilles Joncas, Marc-Antoine Miville-Deschênes, Snežana Stanimirović, and Josh Peek for the fruitful discussions on this work. We thank Rainer Beck for the careful reading of the manuscript and the thoughtful suggestions that have improved the presentation of this paper. YKM thanks Michael Kramer and Sui Ann Mao for their gracious extended host at the Max-Planck-Institut für Radioastronomie in Bonn, Germany. This research was partially funded by the Australian Government through the Australian Research Council. LU acknowledges support from the University of Guanajuato (Mexico) grant ID CIIC 164/2022. This scientific work uses data obtained from Inyarrimanha Ilgari Bundara/the Murchison Radio-astronomy Observatory. We acknowledge the Wajarri Yamaji people as the traditional owners and native title holders of the observatory site. The Australian SKA Pathfinder is part of the Australia Telescope National Facility which is managed by CSIRO. Operation of ASKAP is funded by the Australian Government with support from the National Collaborative Research Infrastructure Strategy. ASKAP uses the resources of the Pawsey Supercomputing Centre. Establishment of ASKAP, the Murchison Radio-astronomy Observatory, and the Pawsey Supercomputing Centre are initiatives of the Australian Government, with support from the Government of Western Australia and the Science and Industry Endowment Fund. The Parkes radio telescope is part of the Australia Telescope National Facility which is funded by the Australian Government for operation as a National Facility managed by CSIRO. We acknowledge the Wiradjuri people as the traditional owners of the observatory site. DATA AVAILABILITY. The GASKAP-H I Pilot Survey data are available on the CSIRO ASKAP Science Data Archive8 (CASDA). The auxiliary data products from this article will be shared on reasonable request to the corresponding author.

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Additional details

Additional titles

Alternative title
H I filaments as potential compass needles? Comparing the magnetic field structure of the Small Magellanic Cloud to the orientation of GASKAP-HI filaments

Identifiers

Eprint ID
120560
Resolver ID
CaltechAUTHORS:20230328-707475900.54

Funding

Australian Research Council
University of Guanajuato
CIIC 164/2022
Commonwealth Scientific and Research Organization (CSIRO)
Government of Western Australia
Science and Industry Endowment Fund

Dates

Created
2023-05-05
Created from EPrint's datestamp field
Updated
2023-05-05
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