Proper Motions of Water Masers in W49 N Measured by KaVA
We report the proper motions of 22 GHz water masers toward W49 N that were observed by the KVN and VERA Array (KaVA) during 2017 February–May. We found 263, 268, and 310 features in three successive epochs; they were distributed in a region of size 4 × 4 arcsec ^2 . The strongest flux density was in...
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| Format: | Article |
| Language: | English |
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IOP Publishing
2023-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/aca6f1 |
| _version_ | 1797702085771264000 |
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| author | Kitiyanee Asanok Malcolm D. Gray Tomoya Hirota Koichiro Sugiyama Montree Phetra Busaba H. Kramer Tie Liu Kee-Tae Kim Bannawit Pimpanuwat |
| author_facet | Kitiyanee Asanok Malcolm D. Gray Tomoya Hirota Koichiro Sugiyama Montree Phetra Busaba H. Kramer Tie Liu Kee-Tae Kim Bannawit Pimpanuwat |
| author_sort | Kitiyanee Asanok |
| collection | DOAJ |
| description | We report the proper motions of 22 GHz water masers toward W49 N that were observed by the KVN and VERA Array (KaVA) during 2017 February–May. We found 263, 268, and 310 features in three successive epochs; they were distributed in a region of size 4 × 4 arcsec ^2 . The strongest flux density was in the third epoch, and its averaged value was 18,090 Jy at V _LSR +0.47 km s ^−1 . For 102 H _2 O maser features, proper motion was detected across all three epochs. The average proper motions in R.A. and decl. offset were −0.352 and +0.890 mas yr ^−1 , respectively. The morphology of the distribution of the H _2 O maser features was found to be a bipolar outflow structure with an inclination angle of 37° ± 13° to the line of sight, and the features were expanding from a well-defined outflow center. A model of the source combining expansion and rotation yielded a distance to W49 of 11.12 ± 0.96 kpc that is consistent with the results from trigonometric parallax. A redshifted lobe was situated in the northeast direction and a blueshifted lobe in the southwest direction. We also discussed the location of the powerful flaring H _2 O maser feature at V _LSR = + 6 km s ^−1 and its possible mechanisms on the basis of spatial structures for the maser feature in VLBI maps observed with the KaVA, timed just before and during the rebrightening phase. |
| first_indexed | 2024-03-12T04:45:05Z |
| format | Article |
| id | doaj.art-805facc803044a999ed0853d6ff988f1 |
| institution | Directory Open Access Journal |
| issn | 1538-4357 |
| language | English |
| last_indexed | 2024-03-12T04:45:05Z |
| publishDate | 2023-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj.art-805facc803044a999ed0853d6ff988f12023-09-03T09:29:25ZengIOP PublishingThe Astrophysical Journal1538-43572023-01-0194327910.3847/1538-4357/aca6f1Proper Motions of Water Masers in W49 N Measured by KaVAKitiyanee Asanok0https://orcid.org/0000-0002-4125-0941Malcolm D. Gray1https://orcid.org/0000-0002-2094-846XTomoya Hirota2https://orcid.org/0000-0003-1659-095XKoichiro Sugiyama3https://orcid.org/0000-0002-6033-5000Montree Phetra4Busaba H. Kramer5https://orcid.org/0000-0001-8168-5141Tie Liu6https://orcid.org/0000-0002-5286-2564Kee-Tae Kim7https://orcid.org/0000-0003-2412-7092Bannawit Pimpanuwat8https://orcid.org/0000-0001-8782-0754National Astronomical Research Institute of Thailand , 260 Moo 4, Tambol Donkaew, Amphur Maerim, Chiang Mai, 50180, Thailand ; kitiyanee@narit.or.thNational Astronomical Research Institute of Thailand , 260 Moo 4, Tambol Donkaew, Amphur Maerim, Chiang Mai, 50180, Thailand ; kitiyanee@narit.or.th; The University of Manchester , Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, Alan Turing Building, M139PL, UKMizusawa VLBI Observatory, National Astronomical Observatory of Japan , Osawa 2-21-1, Mitaka-shi, Tokyo, 181-8588, Japan; Department of Astronomical Sciences, SOKENDAI (The Graduate University for Advanced Studies) , Osawa 2-21-1, Mitaka-shi, Tokyo, 181-8588, JapanNational Astronomical Research Institute of Thailand , 260 Moo 4, Tambol Donkaew, Amphur Maerim, Chiang Mai, 50180, Thailand ; kitiyanee@narit.or.thGraduate School, Department of Physics and Material Science, Faculty of Science, Chiang Mai University , Chiang Mai, 50200, ThailandNational Astronomical Research Institute of Thailand , 260 Moo 4, Tambol Donkaew, Amphur Maerim, Chiang Mai, 50180, Thailand ; kitiyanee@narit.or.th; Max-Planck-Institut für Radioastronomie , Auf dem Hügel 69, Bonn, D-53121, GermanyShanghai Astronomical Observatory, Chinese Academy of Sciences , 80 Nandan Road, Shanghai, 200030, People's Republic of China; Korea Astronomy and Space Science Institute , 776 Daedeokdae-ro, Yuseong-gu, Daejeon, 34055, Republic of KoreaKorea Astronomy and Space Science Institute , 776 Daedeokdae-ro, Yuseong-gu, Daejeon, 34055, Republic of KoreaThe University of Manchester , Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, Alan Turing Building, M139PL, UKWe report the proper motions of 22 GHz water masers toward W49 N that were observed by the KVN and VERA Array (KaVA) during 2017 February–May. We found 263, 268, and 310 features in three successive epochs; they were distributed in a region of size 4 × 4 arcsec ^2 . The strongest flux density was in the third epoch, and its averaged value was 18,090 Jy at V _LSR +0.47 km s ^−1 . For 102 H _2 O maser features, proper motion was detected across all three epochs. The average proper motions in R.A. and decl. offset were −0.352 and +0.890 mas yr ^−1 , respectively. The morphology of the distribution of the H _2 O maser features was found to be a bipolar outflow structure with an inclination angle of 37° ± 13° to the line of sight, and the features were expanding from a well-defined outflow center. A model of the source combining expansion and rotation yielded a distance to W49 of 11.12 ± 0.96 kpc that is consistent with the results from trigonometric parallax. A redshifted lobe was situated in the northeast direction and a blueshifted lobe in the southwest direction. We also discussed the location of the powerful flaring H _2 O maser feature at V _LSR = + 6 km s ^−1 and its possible mechanisms on the basis of spatial structures for the maser feature in VLBI maps observed with the KaVA, timed just before and during the rebrightening phase.https://doi.org/10.3847/1538-4357/aca6f1Astrophysical masersWater masersStar formationInterstellar mediumInterstellar moleculesStellar jets |
| spellingShingle | Kitiyanee Asanok Malcolm D. Gray Tomoya Hirota Koichiro Sugiyama Montree Phetra Busaba H. Kramer Tie Liu Kee-Tae Kim Bannawit Pimpanuwat Proper Motions of Water Masers in W49 N Measured by KaVA The Astrophysical Journal Astrophysical masers Water masers Star formation Interstellar medium Interstellar molecules Stellar jets |
| title | Proper Motions of Water Masers in W49 N Measured by KaVA |
| title_full | Proper Motions of Water Masers in W49 N Measured by KaVA |
| title_fullStr | Proper Motions of Water Masers in W49 N Measured by KaVA |
| title_full_unstemmed | Proper Motions of Water Masers in W49 N Measured by KaVA |
| title_short | Proper Motions of Water Masers in W49 N Measured by KaVA |
| title_sort | proper motions of water masers in w49 n measured by kava |
| topic | Astrophysical masers Water masers Star formation Interstellar medium Interstellar molecules Stellar jets |
| url | https://doi.org/10.3847/1538-4357/aca6f1 |
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