Magnetic Fields in the Southern Coalsack and Beyond
Starlight polarimetry, when combined with accurate distance measurements, allows for exploration of the three-dimensional structure of local magnetic fields in great detail. We present optical polarimetric observations of stars in and close to the Southern Coalsack, taken from the Interstellar Polar...
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| Format: | Article |
| Language: | English |
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IOP Publishing
2024-01-01
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| Series: | The Astronomical Journal |
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| Online Access: | https://doi.org/10.3847/1538-3881/ad2e08 |
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| author | M. J. F. Versteeg Y. Angarita A. M. Magalhães M. Haverkorn C. V. Rodrigues R. Santos-Lima Koji S. Kawabata |
| author_facet | M. J. F. Versteeg Y. Angarita A. M. Magalhães M. Haverkorn C. V. Rodrigues R. Santos-Lima Koji S. Kawabata |
| author_sort | M. J. F. Versteeg |
| collection | DOAJ |
| description | Starlight polarimetry, when combined with accurate distance measurements, allows for exploration of the three-dimensional structure of local magnetic fields in great detail. We present optical polarimetric observations of stars in and close to the Southern Coalsack, taken from the Interstellar Polarization Survey. Located in five fields of view approximately 0.°3 × 0.°3 in size, these data represent the highest density of optical polarimetric observations in the Southern Coalsack to date. Using these data, combined with accurate distances and extinctions based on Gaia data, we are able to characterize the magnetic field of the Coalsack and disentangle contributions to the polarization caused by the Southern Coalsack and a background structure. For the Southern Coalsack, we find an average magnetic field orientation of θ ∼ 75° with respect to the Galactic north pole and an average plane-of-sky magnetic field strength of approximately B _POS = 10 μ G, using the Davis–Chandrasekhar–Fermi method. These values are in agreement with some earlier estimates of the Coalsack’s magnetic field. In order to study the distant structure, we introduce a simple method to separate and isolate the polarization of distant stars from foreground contribution. For the distant structure, which we estimate to be located at a distance of approximately 1.3–1.5 kpc, we find an average magnetic field orientation of θ ∼ 100° and estimate a field strength of B _POS ∼ 10 μ G, although this will remain highly uncertain until the precise nature of the distant structure can be uncovered. |
| first_indexed | 2024-04-24T19:14:12Z |
| format | Article |
| id | doaj.art-8341e0283ff94c3fa895e187fbd0e7b1 |
| institution | Directory Open Access Journal |
| issn | 1538-3881 |
| language | English |
| last_indexed | 2024-04-24T19:14:12Z |
| publishDate | 2024-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astronomical Journal |
| spelling | doaj.art-8341e0283ff94c3fa895e187fbd0e7b12024-03-26T08:17:06ZengIOP PublishingThe Astronomical Journal1538-38812024-01-01167417710.3847/1538-3881/ad2e08Magnetic Fields in the Southern Coalsack and BeyondM. J. F. Versteeg0https://orcid.org/0000-0003-0400-8846Y. Angarita1https://orcid.org/0000-0001-5016-5645A. M. Magalhães2https://orcid.org/0000-0002-1580-0583M. Haverkorn3https://orcid.org/0000-0002-5288-312XC. V. Rodrigues4https://orcid.org/0000-0002-9459-043XR. Santos-Lima5https://orcid.org/0000-0001-6880-4468Koji S. Kawabata6https://orcid.org/0000-0001-6099-9539Department of Astrophysics/IMAPP, Radboud University , P.O. Box 9010, 6500 GL Nijmegen, The NetherlandsDepartment of Astrophysics/IMAPP, Radboud University , P.O. Box 9010, 6500 GL Nijmegen, The NetherlandsDepto. de Astronomia, IAG, Universidade de São Paulo , BrazilDepartment of Astrophysics/IMAPP, Radboud University , P.O. Box 9010, 6500 GL Nijmegen, The NetherlandsDivisão de Astrofísica, Instituto Nacional de Pesquisas Espaciais (INPE/MCTI) , Av. dos Astronautas, 1758, São José dos Campos, SP, BrazilDepto. de Astronomia, IAG, Universidade de São Paulo , BrazilHiroshima Astrophysical Science Center, Hiroshima University , Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8526, JapanStarlight polarimetry, when combined with accurate distance measurements, allows for exploration of the three-dimensional structure of local magnetic fields in great detail. We present optical polarimetric observations of stars in and close to the Southern Coalsack, taken from the Interstellar Polarization Survey. Located in five fields of view approximately 0.°3 × 0.°3 in size, these data represent the highest density of optical polarimetric observations in the Southern Coalsack to date. Using these data, combined with accurate distances and extinctions based on Gaia data, we are able to characterize the magnetic field of the Coalsack and disentangle contributions to the polarization caused by the Southern Coalsack and a background structure. For the Southern Coalsack, we find an average magnetic field orientation of θ ∼ 75° with respect to the Galactic north pole and an average plane-of-sky magnetic field strength of approximately B _POS = 10 μ G, using the Davis–Chandrasekhar–Fermi method. These values are in agreement with some earlier estimates of the Coalsack’s magnetic field. In order to study the distant structure, we introduce a simple method to separate and isolate the polarization of distant stars from foreground contribution. For the distant structure, which we estimate to be located at a distance of approximately 1.3–1.5 kpc, we find an average magnetic field orientation of θ ∼ 100° and estimate a field strength of B _POS ∼ 10 μ G, although this will remain highly uncertain until the precise nature of the distant structure can be uncovered.https://doi.org/10.3847/1538-3881/ad2e08Interstellar magnetic fieldsInterstellar mediumDark interstellar cloudsPolarimetryStarlight polarizationMilky Way magnetic fields |
| spellingShingle | M. J. F. Versteeg Y. Angarita A. M. Magalhães M. Haverkorn C. V. Rodrigues R. Santos-Lima Koji S. Kawabata Magnetic Fields in the Southern Coalsack and Beyond The Astronomical Journal Interstellar magnetic fields Interstellar medium Dark interstellar clouds Polarimetry Starlight polarization Milky Way magnetic fields |
| title | Magnetic Fields in the Southern Coalsack and Beyond |
| title_full | Magnetic Fields in the Southern Coalsack and Beyond |
| title_fullStr | Magnetic Fields in the Southern Coalsack and Beyond |
| title_full_unstemmed | Magnetic Fields in the Southern Coalsack and Beyond |
| title_short | Magnetic Fields in the Southern Coalsack and Beyond |
| title_sort | magnetic fields in the southern coalsack and beyond |
| topic | Interstellar magnetic fields Interstellar medium Dark interstellar clouds Polarimetry Starlight polarization Milky Way magnetic fields |
| url | https://doi.org/10.3847/1538-3881/ad2e08 |
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