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 foundin the contemporary fossil record.

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

Elliptical galaxy: only old stars, no cold gas to make more

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

Elliptical galaxy: only old stars, no cold gas to make more

Spiral galaxy: allages present, stars still formed in gas-rich disk

Waiting for the light – the Universe is a one-way time machine

2.6 secondsround trip

8 minutes

75 minutes

4.3 years

15,000 years

60 million years

2 billion years

Galaxy collisions, mergers, and starbursts

Abell 2125-C153 A galaxy loses its gas

Across the spectrum - now

FarIR MidIR nearIR opt UV farUV X-ray gamma

Spitzer

Hubble Chandra

GALEX

FUSE

INTEGRAL

WMAP

Akari

A panchromatic view -spiral galaxy M81

ROSATGALEXKitt PeakSpitzerVLA

San Pedro Martir115° 27´49 W 31° 02´39 N 2,830 m

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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?