Astronomy Tea Talk

To sustain star formation and to match the chemical enrichment history of the local neighborhood, gas must be constantly fed into the disc of our very typical galaxy. I will argue that the gas overwhelmingly enters from the almost limitless supply of coronal gas at over a milion K. Why does this gas cool onto the disc several kpc from the centre and not onto the bulge and central black hole, where it's cooling time must be much shorter? Why doesn't X-ray emitting gas not form star-forming discs in groups and clusters of galaxies in close analogy to what's happening on a smaller scale in disc galaxies? I'll present a series of model calculations that together with observations of warm and cold gas around the Galaxy answer these questions and explain how star formation is currently sustained and why it will eventually peter out, causing the Galaxy to become red & dead.

Refreshments served at 4:00pm