(Proposal ID) S15A-107

(PI) Ferre-Mateu, Anna

(Proposal Title)
 The IMF of nearby relic massive galaxy candidates

(Abstract)
There is a growing body of publications that support a non-universal, bottom-
heavy, Initial Mass Function (IMF) in massive early-type galaxies (ETGs) from 
different techniques. The IMF slope is found to vary with galaxy mass, as 
traced by the velocity dispersion. Recently a step further was achieved in the 
field as we found that, unlike in a low-mass ETG, the IMF varies radially in 
at least two massive slow-rotators. However, we found a flat, bottom-heavy, 
IMF gradient in a massive relic galaxy candidate that rotates fast. Therefore 
the IMF is a local, rather than global, galaxy property, which might not be 
necessarily linked to other stellar population properties. We aim at obtaining 
very deep long-slit spectra with FOCAS with R~1000, for 4 nearby such relic 
galaxy candidates, showing a very strong decay of the velocity dispersion with 
radius, to study their optical and near-IR IMF-sensitive features as a 
function of galacto-centric distances. We will use state-of-the-art stellar 
population models with varying IMF and abundance ratios to derive any radial 
IMF dependence, out to 1 Re. The local variations of the IMF and other 
relevant stellar population and dynamical parameters will allow us to 
constrain the leading property shaping such local IMF variations.