Molecular Gas and Star Formation in Local Early-type Galaxies

Journal article

The molecular gas content of local early-type galaxies is constrained and discussed in relation to their evolution. First, as part of the ATLAS 3D survey, we present the first complete, large (260 objects), volume-limited single-dish survey of CO in normal local early-type galaxies. We find a surprisingly high detection rate of 22%, independent of luminosity and at best weakly dependent on environment. Second, the extent of the molecular gas is constrained with CO synthesis imaging, and a variety of morphologies is revealed. The kinematics of the molecular gas and stars are often misaligned, implying an external gas origin in over a third of the systems, although this behaviour is drastically diffferent between field and cluster environments. Third, many objects appear to be in the process of forming regular kpc-size decoupled disks, and a star formation sequence can be sketched by piecing together multi-wavelength information on the molecular gas, current star formation, and young stars. Last, early-type galaxies do not seem to systematically obey all our usual prejudices regarding star formation, following the standard Schmidt-Kennicutt law but not the far infrared-radio correlation. This may suggest a greater diversity in star formation processes than observed in disk galaxies. Using multiple molecular tracers, we are thus starting to probe the physical conditions of the cold gas in early-types. © Copyright International Astronomical Union 2011.

Authors: Bureau, M; Davis, T; Alatalo, K; Crocker, A; Blitz, L

• Publication status: Published
• Journal: TRACING THE ANCESTRY OF GALAXIES (ON THE LAND OF OUR ANCESTORS)
• Volume: 6
• Issue: 277
• Pages: 55-58
• Publication date: 2011-01-01
• DOI: 10.1017/S1743921311022459
• EISSN: 1743-9221
• ISSN: 1743-9213
• Language: English
• Keywords: ISM: molecules; galaxies: evolution; galaxies: elliptical and lenticular; ISM: kinematics and dynamics; cD; galaxies: ISM; galaxies: kinematics and dynamics; ISM: evolution