APEC Seminar (Astronomy - Particle Physics - Experimental Physics - Cosmology)

Speaker: Alessandro Sonnenfeld (Kavli IPMU)
Title: The Stellar IMF of Early-type Galaxies from Strong Gravitational Lensing
Date (JST): Tue, Oct 13, 2015, 12:00 - 13:00
Place: Seminar Room B
Abstract: In recent years a number of observational probes have pointed towards a non-universality of the stellar IMF, with the most massive galaxies having a heavier IMF compared to the Milky Way. The determination of the IMF in galaxies other than the Milky Way is however a very difficult task subject to many uncertainties, and it is therefore important to combine measurements from different techniques and in different samples of galaxies. Strong gravitational lensing allows for robust measurements of galaxy masses at cosmological distances. Combined with other probes, lensing can provide accurate measurements of the stellar IMF in the most massive early-type galaxies. I will show a detailed IMF measurement on a massive early-type galaxy at z=0.2, as well as an ensemble measurement of the IMF on a sample of 80 lenses out to z=0.8. These lensing measurements show that the IMF of the most massive galaxies is similar to a Salpeter IMF and confirm the trend of the IMF with galaxy mass detected with different probes.