Galaxy History how we got here Galaxy History

Galaxy History – how we got here

Galaxy History – how we got here • Stars evolve, therefore so do galaxies • We parts of a rich history – they grow, starburst, acquire gas, lose gas, change chemistry, shut down starbirth, interact with central black holes • Contemporary hints – the galactic fossil record • Cosmic time machine – we can see their past! • We must be wide-ranging in space and energy • Tools: Hubble, Chandra, Spitzer, GALEX, ground -based telescopes – and brains

Stars have life cycles…

…so galaxies do too. Some clues are found in the contemporary fossil record.

…so galaxies do too. Some clues are found in the contemporary fossil record. Elliptical galaxy: only old stars, no cold gas to make more

…so galaxies do too. Some clues are found in the contemporary fossil record. Elliptical galaxy: only old stars, no cold gas to make more Spiral galaxy: all ages present, stars still formed in gas -rich disk

Waiting for the light – the Universe is a one-way time machine 2. 6 seconds round trip

8 minutes 75 minutes

4. 3 years 15, 000 years

60 million years 2 billion years

Galaxy collisions, mergers, and starbursts

Abell 2125 -C 153 A galaxy loses its gas

Across the spectrum - now Far. IR Mid. IR near. IR opt UV far. UV X-ray gamma GALEX Spitzer WMAP INTEGRAL FUSE Hubble Akari Chandra

A panchromatic view spiral galaxy M 81 ROSAT GALEX Kitt Peak Spitzer VLA

+ + San Pedro Martir 115° 27´ 49 W 31° 02´ 39 N 2, 830 m ++ + +

A sky survey for the new millennium • • • Potentially 4000+ objects per exposure Uniquely wide field for 6. 5 -meter telescope Uniquely wide slice of spectrum at once Add time dimension to Sloan survey galaxies Study internal galaxy structure UA involvement in project planning – at the table pending fundraising!

Even very distant galaxies can often be mapped from the ground Kitt Peak/Hubble, optical NASA IR telescope, IR

N=270

Galaxy history • Downsizing (I love the crash of a theory…) • Central black holes are ubiquitous and may regulate surrounding starbirth • Large galaxies grow at the expense of dwarfs • Galaxies have long interacted with their surroundings – gas, other galaxies…

Looking forward to looking back • • Chemistry of young galaxies How did these enormous black holes grow? What were the first stars like? Why do some galaxies shut down star formation, and others host massive rapid bursts?