Properties of the Molecular Clouds in NGC 205

Abstract

The nearby dwarf elliptical galaxy NGC 205 offers a unique opportunity for high resolution studies of the interstellar medium in an elliptical galaxy. This paper investigates the distribution of molecular gas, molecular line ratios, and the relationships between atomic gas, molecular gas, and dust in NGC 205. The line ratios 12CO(2-1)/(1-0) and 12CO(1-0)/13CO(1-0) in one of the molecular clouds in NGC 205 are consistent with the ratios found in other elliptical galaxies and in Galactic giant molecular clouds; they suggest that the CO in this cloud is probably subthermally excited. Atomic gas, molecular gas, and dust are very closely associated on scales of 100 pc; the atomic gas can be understood as photodissociated envelopes around the molecular clouds. The atomic column densities in this galaxy are quite low (10^20 cm^-2) because the interstellar UV field is relatively low. The total gas-to-dust column density ratios are consistent with Galactic gas-to-dust ratios. In short, the molecular gas in NGC 205 seems to have very similar properties to the familiar molecular clouds in our own Galaxy, except for the low atomic column densities.

To appear in AJ (November 2000?). 32 pages including 8 figures

References in corpus (3)

• Far Infrared and Submillimeter Emission from Galactic and Extragalactic Photo-Dissociation Regions
• Multiple Scattering in Clumpy Media. II. Galactic Environments
• The star formation history of the Local Group dwarf elliptical galaxy NGC 185: II. Gradients in the stellar population

Cited by in corpus (6)

• Giant Molecular Clouds in M64
• Molecular Gas in Elliptical Galaxies: Distribution and Kinematics
• Mapping and Mass Measurement of the Cold Dust in NGC 205 with Spitzer
• Radio Continuum and Star Formation in CO-rich Early Type Galaxies
• Properties of a Molecular Cloud in NGC 185
• Impact of UV Radiation from Giant Spirals on the Evolution of Dwarf Galaxies