Detection of Molecular Clouds in the Interarm Region of Flocculent Galaxy NGC5055
Abstract
We present the results of high resolution 12CO (J=1-0) mapping observations towards the disk of the flocculent galaxy NGC5055 with the Nobeyama Millimeter Array, in order to study physical properties of molecular clouds in arm and interarm regions. The map obtained shows clumpy structures. Although these are mainly distributed along a spiral arm seen in near-infrared observations, some clouds are located far from the arm, namely in the interarm region. These clouds both in the arm and the interarm have typical size and mass of a few 100 pc and a few 106M⊙, respectively. These are corresponding to those of largest GMC in our Galaxy and slightly smaller than GMAs in the grand design spiral M51. We found no difference in the molecular clouds between the arm and the interarm, unlike M51. The lifetime of the interarm clouds indicates that they were formed in the interarm but not in the arm. This suggests that, in a flocculent galaxy such as NGC5055, cloud formation and ensuing star formation occur both in the arm and in the interarm. This is because local fluctuations can enhance the gas density, even in interarm regions, since the density wave is not strong in the flocculent galaxy NGC5055. This may control the optical morphology of spiral arms in spiral galaxies.
- Publication:
-
8th Asian-Pacific Regional Meeting, Volume II
- Pub Date:
- 2002
- Bibcode:
- 2002aprm.conf..221T