An inventory of the stellar initial mass function in early-type galaxies

Understand

Given a flurry of recent claims for systematic variations in the stellar initial mass function (IMF), we carry out the first inventory of the observational evidence using different approaches.

• This includes literature results, as well as our own new findings from combined stellar-populations synthesis (SPS) and Jeans dynamical analyses of data on $\sim$~4500 early-type galaxies (ETGs) from the SPIDER project.
• We focus on the mass-to-light ratio mismatch relative to the Milky Way IMF, \dimf, correlated against the central stellar velocity dispersion, \sigs.
• We find a strong correlation between \dimf\ and \sigs, for a wide set of dark matter (DM) model profiles.