Magnetised HI superbubbles in the Small Magellanic Cloud revealed by the POSSUM pilot survey
Fuente:
arXiv
Saved in:
| Main Authors: | , , , , , , , , , , , , , , , |
|---|---|
| Format: | Preprint |
| Published: |
2024
|
| Subjects: | |
| Online Access: | |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1866913519643918336 |
|---|---|
| author | Jung, Seoyoung Lyla Seta, A. Price, J. M. McClure-Griffiths, N. M. Livingston, J. D. Gaensler, B. M. Ma, Y. K. Tahani, M. Anderson, C. S. Federrath, C. Van Eck, C. L. Leahy, D. O'Sullivan, S. P. West, J. Heald, G. Akahori, T. |
| author_facet | Jung, Seoyoung Lyla Seta, A. Price, J. M. McClure-Griffiths, N. M. Livingston, J. D. Gaensler, B. M. Ma, Y. K. Tahani, M. Anderson, C. S. Federrath, C. Van Eck, C. L. Leahy, D. O'Sullivan, S. P. West, J. Heald, G. Akahori, T. |
| contents | Neutral hydrogen (HI) bubbles and shells are common in the interstellar medium (ISM). Studying their properties provides insight into the characteristics of the local ISM as well as the galaxy in which the bubbles reside. We report the detection of magnetic fields associated with superbubbles in the nearby irregular galaxy, the Small Magellanic Cloud (SMC). Using the Polarisation Sky Survey of the Universe's Magnetism (POSSUM) pilot survey, we obtain a high-density grid ($\approx 25 \,\rm sources\,deg^{-2}$) of Faraday rotation measure (RM) from polarized sources behind the SMC. This provides a sufficiently large number of RM measurements to study the magnetic properties of three of the largest HI shells previously identified in the SMC. The RM profiles as a function of distance from the shell centre show characteristic patterns at angular scales comparable to the shell size. We demonstrate that this can be explained by magneto-hydrodynamic simulation models of bubbles expanding in magnetised environments. From the observations, we estimate the line-of-sight magnetic field strength at the edges of the shells is enhanced by $\sim1\,\rm μG$ with respect to their centres. This is an order of magnitude larger than the field strength in the ambient medium ($\sim 0.1\,\rm μG$) estimated based on the expansion velocity of the shells. This paper highlights the power of densely mapped RM grids in studying the magnetic properties of galactic substructures beyond the Milky Way. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2409_17666 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Magnetised HI superbubbles in the Small Magellanic Cloud revealed by the POSSUM pilot survey Jung, Seoyoung Lyla Seta, A. Price, J. M. McClure-Griffiths, N. M. Livingston, J. D. Gaensler, B. M. Ma, Y. K. Tahani, M. Anderson, C. S. Federrath, C. Van Eck, C. L. Leahy, D. O'Sullivan, S. P. West, J. Heald, G. Akahori, T. Astrophysics of Galaxies Neutral hydrogen (HI) bubbles and shells are common in the interstellar medium (ISM). Studying their properties provides insight into the characteristics of the local ISM as well as the galaxy in which the bubbles reside. We report the detection of magnetic fields associated with superbubbles in the nearby irregular galaxy, the Small Magellanic Cloud (SMC). Using the Polarisation Sky Survey of the Universe's Magnetism (POSSUM) pilot survey, we obtain a high-density grid ($\approx 25 \,\rm sources\,deg^{-2}$) of Faraday rotation measure (RM) from polarized sources behind the SMC. This provides a sufficiently large number of RM measurements to study the magnetic properties of three of the largest HI shells previously identified in the SMC. The RM profiles as a function of distance from the shell centre show characteristic patterns at angular scales comparable to the shell size. We demonstrate that this can be explained by magneto-hydrodynamic simulation models of bubbles expanding in magnetised environments. From the observations, we estimate the line-of-sight magnetic field strength at the edges of the shells is enhanced by $\sim1\,\rm μG$ with respect to their centres. This is an order of magnitude larger than the field strength in the ambient medium ($\sim 0.1\,\rm μG$) estimated based on the expansion velocity of the shells. This paper highlights the power of densely mapped RM grids in studying the magnetic properties of galactic substructures beyond the Milky Way. |
| title | Magnetised HI superbubbles in the Small Magellanic Cloud revealed by the POSSUM pilot survey |
| topic | Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2409.17666 |