%0 Generic %1 Khochfar2011 %A Khochfar, Sadegh %A Emsellem, Eric %A Serra, Paolo %A Bois, Maxime %A Alatalo, Katherine %A Bacon, Roland %A Blitz, Leo %A Bournaud, Frederic %A Bureau, Martin %A Cappellari, Michele %A Davies, Roger L. %A Davis, Timothy A. %A de Zeeuw, P. T. %A Duc, Pierre-Alain %A Krajnovic, Davor %A Kuntschner, Harald %A Lablanche, Pierre-Yves %A McDermid, Richard M. %A Morganti, Raffaella %A Naab, Thorsten %A Oosterloo, Tom %A Sarzi, Marc %A Scott, Nicholas %A Weijmans, Anne-Marie %A Young, Lisa M. %D 2011 %K early fast mergers rotators slow type %T The ATLAS3D Project-- VIII: Modelling the Formation and Evolution of Fast and Slow Rotator Early-Type Galaxies within $Łambda$CDM %U http://arxiv.org/abs/1107.5059 %X We propose a simple model for the origin of fast and slow rotator early-type galaxies (ETG) within the hierarchical $Łambda$CDM scenario, that is based on the assumption that the mass fraction of stellar discs in ETGs is a proxy for the specific angular momentum expressed via $łambda_R$. Within our model we reproduce the fraction of fast and slow rotators as a function of magnitude in the survey, assuming that fast rotating ETGs have at least 10% of their total stellar mass in a disc component. In agreement with observations we find that slow rotators are predominantly galaxies with $ M_* > 10^10.5$ M$_ødot$ contributing $20%$ to the overall ETG population. We show in detail that the growth histories of fast and slow rotators are different, supporting the classification of ETGs into these two categories. Slow rotators accrete between $50% -90%$ of their stellar mass from satellites and their most massive progenitors have on average up to 3 major mergers during their evolution. Fast rotators in contrast, accrete less than 50% and have on average less than one major merger in their past. We find that the underlying physical reason for the different growth histories is the slowing down and ultimately complete shut-down of gas cooling in massive galaxies. Once cooling and associated star formation in disc stops, galaxies grow via infall from satellites. Frequent minor mergers thereby, destroy existing stellar discs via violent relaxation and also tend to lower the specific angular momentum of the main stellar body, lowering $łambda_R$ into the slow rotator regime. Abridged...

@misc{Khochfar2011, abstract = { We propose a simple model for the origin of fast and slow rotator early-type galaxies (ETG) within the hierarchical $\Lambda$CDM scenario, that is based on the assumption that the mass fraction of stellar discs in ETGs is a proxy for the specific angular momentum expressed via $\lambda_R$. Within our model we reproduce the fraction of fast and slow rotators as a function of magnitude in the \atl survey, assuming that fast rotating ETGs have at least 10% of their total stellar mass in a disc component. In agreement with \atl observations we find that slow rotators are predominantly galaxies with $ M_* > 10^{10.5}$ M$_{\odot}$ contributing $\sim 20%$ to the overall ETG population. We show in detail that the growth histories of fast and slow rotators are different, supporting the classification of ETGs into these two categories. Slow rotators accrete between $\sim 50% -90%$ of their stellar mass from satellites and their most massive progenitors have on average up to 3 major mergers during their evolution. Fast rotators in contrast, accrete less than 50% and have on average less than one major merger in their past. We find that the underlying physical reason for the different growth histories is the slowing down and ultimately complete shut-down of gas cooling in massive galaxies. Once cooling and associated star formation in disc stops, galaxies grow via infall from satellites. Frequent minor mergers thereby, destroy existing stellar discs via violent relaxation and also tend to lower the specific angular momentum of the main stellar body, lowering $\lambda_R$ into the slow rotator regime. Abridged... }, added-at = {2011-07-27T17:49:24.000+0200}, author = {Khochfar, Sadegh and Emsellem, Eric and Serra, Paolo and Bois, Maxime and Alatalo, Katherine and Bacon, Roland and Blitz, Leo and Bournaud, Frederic and Bureau, Martin and Cappellari, Michele and Davies, Roger L. and Davis, Timothy A. and de Zeeuw, P. T. and Duc, Pierre-Alain and Krajnovic, Davor and Kuntschner, Harald and Lablanche, Pierre-Yves and McDermid, Richard M. and Morganti, Raffaella and Naab, Thorsten and Oosterloo, Tom and Sarzi, Marc and Scott, Nicholas and Weijmans, Anne-Marie and Young, Lisa M.}, biburl = {https://www.bibsonomy.org/bibtex/2da26a4e094581e4db18f949b9f20c09b/miki}, description = {[1107.5059] The ATLAS3D Project-- VIII: Modelling the Formation and Evolution of Fast and Slow Rotator Early-Type Galaxies within $\Lambda$CDM}, interhash = {f2544b0702bdbc969329fb3c8513875c}, intrahash = {da26a4e094581e4db18f949b9f20c09b}, keywords = {early fast mergers rotators slow type}, note = {cite arxiv:1107.5059Comment: Accepted for publication in MNRAS}, timestamp = {2011-07-27T17:49:24.000+0200}, title = {The ATLAS3D Project-- VIII: Modelling the Formation and Evolution of Fast and Slow Rotator Early-Type Galaxies within $\Lambda$CDM}, url = {http://arxiv.org/abs/1107.5059}, year = 2011 }