Astro Seminar: "Quenching and Bulge Growth Over Cosmic Time in Massive Galaxies"

Wed, 01/25/2017 - 14:00
Marc Huertas-Company (Paris Observatory)

The life of a galaxy is a balance between processes that trigger star formation by accelerating gas cooling and others which tend to prevent stars to form by expelling or heating gas.  Over the past years, the picture is emerging that, during most of its life, a galaxy seems to live a rather quiet life, gradually growing in stellar mass through the formation of new stars which are formed at a rate remarkably proportional to its stellar mass, This is interpreted as an indirect evidence that fuel in the form of cold gas is somehow continuously being fed into the galaxies to sustain star formation. Two major events, eventually related, can break this apparent equilibrium. An episode of high star formation activity (e.g starburst) can be triggered.  Or, suddenly something might happen that prevents the galaxy to continue forming new stars. Quenching is probably the most important event that a galaxy experiences during its life and a fundamental mechanism that helps understanding most of the properties of our surrounding Universe. There are a variety of different mechanisms entertained for the quenching process, e.g. feedback, interactions, halo driven shock heating, morphological quenching etc. Which one is dominantly driving galaxy evolution (if there is) or under which circumstances one or another process is triggered is still a mystery.

In my talk I will focus on the relation between structure and quenching in massive galaxies. By using advanced machine intelligence techniques, I will analyze the relation between quenching and bulge growth in massive galaxies from z~3. I will in fact show evidences of two distinct channels for the growth of bulges in the massive end of the present day Hubble sequence. I will also discuss challenges and solutions to estimate galaxy morphologies in future big-data surveys like EUCLID.

David Rittenhouse Laboratory, A4