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arXiv · 1102.1922

Molecular Gas and Star Formation in Local Early-Type Galaxies

M. Bureau·T. A. Davis·K. Alatalo·A. F. Crocker·L. Blitz·L. M. Young·F. Combes·M. Bois·F. Bournaud·M. Cappellari·R. L. Davies·P. T. de Zeeuw·P. -A. Duc·E. Emsellem·S. Khochfar·D. Krajnovic·H. Kuntschner·P. -Y. Lablanche·R. M. McDermid·R. Morganti·T. Naab·T. Oosterloo·M. Sarzi·N. Scott·P. Serra·A. Weijmans
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Abstract

The molecular gas content of local early-type galaxies is constrained and discussed in relation to their evolution. First, as part of the Atlas3D 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.

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M. Bureau, T. A. Davis, K. Alatalo, A. F. Crocker, L. Blitz, L. M. Young, F. Combes, M. Bois, F. Bournaud, M. Cappellari, R. L. Davies, P. T. de Zeeuw, P. -A. Duc, E. Emsellem, S. Khochfar, D. Krajnovic, H. Kuntschner, P. -Y. Lablanche, R. M. McDermid, R. Morganti, T. Naab, T. Oosterloo, M. Sarzi, N. Scott, P. Serra, A. Weijmans. 2011-02-09. Molecular Gas and Star Formation in Local Early-Type Galaxies. https://doi.org/10.1017/s1743921311022459

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