IMF shape constraints from stellar populations and dynamics from CALIFA

M. Lyubenova et. al.In this paper, we describe how we use stellar dynamics information to constrain the shape of the stellar initial mass function (IMF) in a sample of 27 early-type galaxies from the CALIFA survey. We obtain dynamical and stellar mass-to-light ratios, ¿dyn and ¿*, over a homogenous aperture of 0.5 Re. We use the constraint ¿dyn¿¿* to test two IMF shapes within the framework of the extended MILES stellar population models. We rule out a single power-law IMF shape for 75 per cent of the galaxies in our sample. Conversely, we find that a double power-law IMF shape with a varying high-mass end slope is compatible (within 1¿) with 95 per cent of the galaxies. We also show that dynamical and stellar IMF mismatch factors give consistent results for the systematic variation of the IMF in these galaxies. © 2016, Published by Oxford University Press on behalf of the Royal Astronomical Society.This Paper is based on data obtained by the CALIFA survey, funded by the Spanish Ministry of Science under grant ICTS-2009-10, and the CAHA. IMN and JFB acknowledge funding from grant AYA2013-48226-C3-1-P from the Spanish Ministry of Economy and Competitiveness (MINECO) and, together with and GvdV, from the FP7 Marie Curie Actions via the ITN DAGAL (grant 289313). CJW acknowledges support through the Marie Curie Career Integration Grant 303912. Support for LG is provided by the Ministry of Economy, Development, and Tourism's Millennium Science Initiative through grant IC120009 awarded to The Millennium Institute of Astrophysics (MAS), and CONICYT through FONDECYT grant 3140566. RGD acknowledges support from AyA2014-57490-P. JMA acknowledges support from the ERC Starting Grant (SEDmorph; P.I. V. Wild).Peer Reviewe