Galaxy Tutorial

Page
2

Sun may have shifted ~2kpc

N-body simulation

Slide 14

Pollution

Pollution proceeds fastest near Galactic centre

Older stars have fewer heavy elements

Radial migration leads to big spread in [Fe/H] at given age

Slide 15

Velocity space from Hipparcos

Distribution of stars lumpy in velocity space

Pointer to the Galactic bar and spiral structure

Slide 16

Stars trapped by the bar

Slide 17

Interstellar Gas

Systematic effect: circular streaming

Slide 18

CO

HI

Slide 19

The Galactic Bar

Gas towards the GC moving away at ~150km/s

Slide 20

Expected if Galaxy barred

to Sun

Slide 21

If we could look down

Slide 22

Near IR Photometry

Galaxy brighter on left of GC

Slide 23

Individual objects (eg HB stars) also brighter on left

Slide 24

The Galactic Centre

Slide 25

Sgr A and Filaments

Slide 26

Inclined Nuclear Disk

Slide 27

The Black Hole

Weak radio source Sgr A* marks spot

Orbiting stars reveal its force-field

Slide 28

Globular Clusters

M3

100 000 stars

Slide 29

Halo & Disk Clusters

Disk

Halo

Slide 30

Disk clusters more metal-rich

Also a population of field stars traced by blue horizontal branch stars & RR Lyrae stars

many from destroyed globular clusters

Slide 31

Stellar halo (SDSS)