Molecular gas and star formation in local early-type galaxies
Bureau, M.; Davis, T.A.; Cappellari, M.; Davies, R.L.; Scott, N.; Alatalo, K.; Blitz, L.; Crocker, A.F.; Young, L.M.; Combes, F.; Bois, M.; Emsellem, E.; Lablanche, P.-Y.; Bournaud, F.; De Zeeuw, P.T.; Krajnović, D.; Kuntschner, H.; Duc, P.-A.; Khochfar, S.; McDermid, R.M.; Morganti, R.; Oosterloo, T.; Serra, P.; Naab, T.; Sarzi, M.; Weijmans, A.
Citation: Bureau , M , Davis , T A , Cappellari , M , Davies , R L , Scott , N , Alatalo , K , Blitz , L , Crocker , A F , Young , L M , Combes , F , Bois , M , Emsellem , E , Lablanche , P-Y , Bournaud , F , De Zeeuw , P T , Krajnović , D , Kuntschner , H , Duc , P-A , Khochfar , S , McDermid , R M , Morganti , R , Oosterloo , T , Serra , P , Naab , T , Sarzi , M & Weijmans , A 2010 , ' Molecular gas and star formation in local early-type galaxies ' Proceedings of the International Astronomical Union , vol 6 , pp. 55-58 .
The molecular gas content of local early-type galaxies is constrained and discussed in relation to their evolution. First, as part of the ATLAS 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.
Tracing the Ancestry of Galaxies (on the land of our ancestors) Proceedings IAU Symposium No. 277, 2010 C. Carignan, F. Combes & K.C. Freeman, eds.