Molecular Gas in NUclei of GAlaxies (NUGA): II. The Ringed LINER NGC7217
We present CO(1-0) and CO(2-1) maps of the LINER galaxy NGC 7217, obtained with the IRAM interferometer, at 2.4′′ x 1.9′′ and 1.2′′ x 0.8′′ resolution respectively. The nuclear ring (at r = 12′′ = 0.8 kpc) dominates the CO maps, and has a remarkable sharp surface density gradient at its inner edge....
| Autores: | , , , , , , , , , , |
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| Tipo de documento: | artigo |
| Estado: | Versão publicada |
| Data de publicação: | 2003 |
| País: | España |
| Recursos: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositório: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/6880 |
| Acesso em linha: | http://hdl.handle.net/10261/6880 |
| Access Level: | Acceso aberto |
| Palavra-chave: | Galaxies: general Galaxies: ISM Galaxies: active Galaxies: nuclei Galaxies: individual: NGC 7217 |
| Resumo: | We present CO(1-0) and CO(2-1) maps of the LINER galaxy NGC 7217, obtained with the IRAM interferometer, at 2.4′′ x 1.9′′ and 1.2′′ x 0.8′′ resolution respectively. The nuclear ring (at r = 12′′ = 0.8 kpc) dominates the CO maps, and has a remarkable sharp surface density gradient at its inner edge. The latter is the site of the stellar/Hα ring, while the CO emission ring extends farther or is broader (500-600 pc). This means that the star formation has been more intense toward the inner edge of the CO ring, in a thin layer, just at the location of the high gas density gradient. The CO(2-1)/CO(1-0) ratio is close to 1, typical of warm optically thick gas with high density. The overall morphology of the ring is quite circular, with no evidence of non-circular velocities. In the CO(2-1) map, a central concentration might be associated with the circumnuclear ionized gas detected inside r=3′′ and interpreted as a polar ring in the literature. The CO(2-1) emission inside 3′′ coincides with a spiral dust lane, clearly seen in the HST V - I color image. |
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