Magnetic Field Vector Structure of NGC6946
We studied large-scale magnetic field reversals of a galaxy based on a magnetic vector map of NGC6946. The magnetic vector map was constructed based on the polarization maps in the C and X bands after the determination of the geometrical orientation of a disk with the use of an infrared image and th...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2019-05-01
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| Series: | Galaxies |
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| Online Access: | https://www.mdpi.com/2075-4434/7/2/59 |
| _version_ | 1819028488436318208 |
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| author | Kohei Kurahara Hiroyuki Nakanishi |
| author_facet | Kohei Kurahara Hiroyuki Nakanishi |
| author_sort | Kohei Kurahara |
| collection | DOAJ |
| description | We studied large-scale magnetic field reversals of a galaxy based on a magnetic vector map of NGC6946. The magnetic vector map was constructed based on the polarization maps in the C and X bands after the determination of the geometrical orientation of a disk with the use of an infrared image and the velocity field, according to the trailing spiral arm assumption. We examined the azimuthal variation of the magnetic vector and found that the magnetic pitch angle changes continually as a function of the azimuthal angle in the inter-arm region. However, the direction of the magnetic field had <inline-formula> <math display="inline"> <semantics> <msup> <mn>180</mn> <mo>∘</mo> </msup> </semantics> </math> </inline-formula> jumps at the azimuthal angles of <inline-formula> <math display="inline"> <semantics> <mrow> <msup> <mn>20</mn> <mo>∘</mo> </msup> <mo>,</mo> <msup> <mn>110</mn> <mo>∘</mo> </msup> <mo>,</mo> <msup> <mn>140</mn> <mo>∘</mo> </msup> <mo>,</mo> <msup> <mn>220</mn> <mo>∘</mo> </msup> <mo>,</mo> <msup> <mn>280</mn> <mo>∘</mo> </msup> </mrow> </semantics> </math> </inline-formula>, and <inline-formula> <math display="inline"> <semantics> <msup> <mn>330</mn> <mo>∘</mo> </msup> </semantics> </math> </inline-formula>. These reversals seem to be related to the spiral arms since the locations of the jumps are coincident with those of the spiral arms. These six reversals of the magnetic field were seen only in the inner region of NGC6946 whereas four reversals can be identified in the outer region. |
| first_indexed | 2024-12-21T05:59:10Z |
| format | Article |
| id | doaj.art-08c15eff9b274227b68723d437820f2f |
| institution | Directory Open Access Journal |
| issn | 2075-4434 |
| language | English |
| last_indexed | 2024-12-21T05:59:10Z |
| publishDate | 2019-05-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Galaxies |
| spelling | doaj.art-08c15eff9b274227b68723d437820f2f2022-12-21T19:13:48ZengMDPI AGGalaxies2075-44342019-05-01725910.3390/galaxies7020059galaxies7020059Magnetic Field Vector Structure of NGC6946Kohei Kurahara0Hiroyuki Nakanishi1Graduate School of Science and Engineering, Kagoshima University, 1-21-35 Korimoto, Kagoshima 890-0065, JapanGraduate School of Science and Engineering, Kagoshima University, 1-21-35 Korimoto, Kagoshima 890-0065, JapanWe studied large-scale magnetic field reversals of a galaxy based on a magnetic vector map of NGC6946. The magnetic vector map was constructed based on the polarization maps in the C and X bands after the determination of the geometrical orientation of a disk with the use of an infrared image and the velocity field, according to the trailing spiral arm assumption. We examined the azimuthal variation of the magnetic vector and found that the magnetic pitch angle changes continually as a function of the azimuthal angle in the inter-arm region. However, the direction of the magnetic field had <inline-formula> <math display="inline"> <semantics> <msup> <mn>180</mn> <mo>∘</mo> </msup> </semantics> </math> </inline-formula> jumps at the azimuthal angles of <inline-formula> <math display="inline"> <semantics> <mrow> <msup> <mn>20</mn> <mo>∘</mo> </msup> <mo>,</mo> <msup> <mn>110</mn> <mo>∘</mo> </msup> <mo>,</mo> <msup> <mn>140</mn> <mo>∘</mo> </msup> <mo>,</mo> <msup> <mn>220</mn> <mo>∘</mo> </msup> <mo>,</mo> <msup> <mn>280</mn> <mo>∘</mo> </msup> </mrow> </semantics> </math> </inline-formula>, and <inline-formula> <math display="inline"> <semantics> <msup> <mn>330</mn> <mo>∘</mo> </msup> </semantics> </math> </inline-formula>. These reversals seem to be related to the spiral arms since the locations of the jumps are coincident with those of the spiral arms. These six reversals of the magnetic field were seen only in the inner region of NGC6946 whereas four reversals can be identified in the outer region.https://www.mdpi.com/2075-4434/7/2/59galaxies: magnetic fieldsspiralmethods: observational |
| spellingShingle | Kohei Kurahara Hiroyuki Nakanishi Magnetic Field Vector Structure of NGC6946 Galaxies galaxies: magnetic fields spiral methods: observational |
| title | Magnetic Field Vector Structure of NGC6946 |
| title_full | Magnetic Field Vector Structure of NGC6946 |
| title_fullStr | Magnetic Field Vector Structure of NGC6946 |
| title_full_unstemmed | Magnetic Field Vector Structure of NGC6946 |
| title_short | Magnetic Field Vector Structure of NGC6946 |
| title_sort | magnetic field vector structure of ngc6946 |
| topic | galaxies: magnetic fields spiral methods: observational |
| url | https://www.mdpi.com/2075-4434/7/2/59 |
| work_keys_str_mv | AT koheikurahara magneticfieldvectorstructureofngc6946 AT hiroyukinakanishi magneticfieldvectorstructureofngc6946 |