{"title":"利用野边山 45 米望远镜通过氨线测绘(KAGONMA)进行鹿儿岛星系天体巡天:发现大犬座恒星形成区的等秒尺度CO耗竭","authors":"Yushi Hirata, Takeru Murase, Junya Nishi, Yoshito Shimajiri, Toshihiro Omodaka, Makoto Nakano, Kazuyoshi Sunada, Takumi Ito, Toshihiro Handa","doi":"10.1093/pasj/psad080","DOIUrl":null,"url":null,"abstract":"In observational studies of infrared dark clouds, the number of detections of CO freeze-out on to dust grains (CO depletion) at the pc scale is extremely limited, and the conditions for its occurrence are, therefore, still unknown. We report a new object where pc-scale CO depletion is expected. As part of the Kagoshima Galactic Object survey with Nobeyama 45 m telescope by Mapping in Ammonia lines (KAGONMA), we have made mapping observations of NH3 inversion transition lines towards the star-forming region associated with Canis Major OB1, including IRAS 07077−1026, IRAS 07081−1028, and PGCC G224.28−0.82. By comparing the spatial distributions of NH3 (1,1) and C18O (J = 1–0), an intensity anti-correlation was found in IRAS 07077−1026 and IRAS 07081−1028 on the ∼1 pc scale. Furthermore, we obtained a lower abundance of C18O at least in IRAS 07077−1026 than in the other parts of the star-forming region. After examining high-density gas dissipation, photodissociation, and CO depletion, we concluded that the intensity anti-correlation in IRAS 07077−1026 is due to CO depletion. On the other hand, in the vicinity of the center of PGCC G224.28−0.82, the emission line intensities of both NH3 (1,1) and C18O (J = 1–0) were strongly detected, although the gas temperature and density were similar to IRAS 07077−1026. This indicates that there are situations where C18O (J = 1–0) cannot trace dense gas on the pc scale and implies that the conditional differences in which C18O (J = 1–0) can and cannot trace dense gas are unclear.","PeriodicalId":20733,"journal":{"name":"Publications of the Astronomical Society of Japan","volume":null,"pages":null},"PeriodicalIF":2.2000,"publicationDate":"2023-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"KAgoshima Galactic Object survey with Nobeyama 45 m telescope by Mapping in Ammonia lines (KAGONMA): Discovery of parsec-scale CO depletion in the Canis Major star-forming region\",\"authors\":\"Yushi Hirata, Takeru Murase, Junya Nishi, Yoshito Shimajiri, Toshihiro Omodaka, Makoto Nakano, Kazuyoshi Sunada, Takumi Ito, Toshihiro Handa\",\"doi\":\"10.1093/pasj/psad080\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"In observational studies of infrared dark clouds, the number of detections of CO freeze-out on to dust grains (CO depletion) at the pc scale is extremely limited, and the conditions for its occurrence are, therefore, still unknown. We report a new object where pc-scale CO depletion is expected. As part of the Kagoshima Galactic Object survey with Nobeyama 45 m telescope by Mapping in Ammonia lines (KAGONMA), we have made mapping observations of NH3 inversion transition lines towards the star-forming region associated with Canis Major OB1, including IRAS 07077−1026, IRAS 07081−1028, and PGCC G224.28−0.82. By comparing the spatial distributions of NH3 (1,1) and C18O (J = 1–0), an intensity anti-correlation was found in IRAS 07077−1026 and IRAS 07081−1028 on the ∼1 pc scale. Furthermore, we obtained a lower abundance of C18O at least in IRAS 07077−1026 than in the other parts of the star-forming region. After examining high-density gas dissipation, photodissociation, and CO depletion, we concluded that the intensity anti-correlation in IRAS 07077−1026 is due to CO depletion. On the other hand, in the vicinity of the center of PGCC G224.28−0.82, the emission line intensities of both NH3 (1,1) and C18O (J = 1–0) were strongly detected, although the gas temperature and density were similar to IRAS 07077−1026. This indicates that there are situations where C18O (J = 1–0) cannot trace dense gas on the pc scale and implies that the conditional differences in which C18O (J = 1–0) can and cannot trace dense gas are unclear.\",\"PeriodicalId\":20733,\"journal\":{\"name\":\"Publications of the Astronomical Society of Japan\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":2.2000,\"publicationDate\":\"2023-12-07\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Publications of the Astronomical Society of Japan\",\"FirstCategoryId\":\"101\",\"ListUrlMain\":\"https://doi.org/10.1093/pasj/psad080\",\"RegionNum\":4,\"RegionCategory\":\"物理与天体物理\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"ASTRONOMY & ASTROPHYSICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Publications of the Astronomical Society of Japan","FirstCategoryId":"101","ListUrlMain":"https://doi.org/10.1093/pasj/psad080","RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ASTRONOMY & ASTROPHYSICS","Score":null,"Total":0}
KAgoshima Galactic Object survey with Nobeyama 45 m telescope by Mapping in Ammonia lines (KAGONMA): Discovery of parsec-scale CO depletion in the Canis Major star-forming region
In observational studies of infrared dark clouds, the number of detections of CO freeze-out on to dust grains (CO depletion) at the pc scale is extremely limited, and the conditions for its occurrence are, therefore, still unknown. We report a new object where pc-scale CO depletion is expected. As part of the Kagoshima Galactic Object survey with Nobeyama 45 m telescope by Mapping in Ammonia lines (KAGONMA), we have made mapping observations of NH3 inversion transition lines towards the star-forming region associated with Canis Major OB1, including IRAS 07077−1026, IRAS 07081−1028, and PGCC G224.28−0.82. By comparing the spatial distributions of NH3 (1,1) and C18O (J = 1–0), an intensity anti-correlation was found in IRAS 07077−1026 and IRAS 07081−1028 on the ∼1 pc scale. Furthermore, we obtained a lower abundance of C18O at least in IRAS 07077−1026 than in the other parts of the star-forming region. After examining high-density gas dissipation, photodissociation, and CO depletion, we concluded that the intensity anti-correlation in IRAS 07077−1026 is due to CO depletion. On the other hand, in the vicinity of the center of PGCC G224.28−0.82, the emission line intensities of both NH3 (1,1) and C18O (J = 1–0) were strongly detected, although the gas temperature and density were similar to IRAS 07077−1026. This indicates that there are situations where C18O (J = 1–0) cannot trace dense gas on the pc scale and implies that the conditional differences in which C18O (J = 1–0) can and cannot trace dense gas are unclear.
期刊介绍:
Publications of the Astronomical Society of Japan (PASJ) publishes the results of original research in all aspects of astronomy, astrophysics, and fields closely related to them.