1. The High Redshift Universe Next Door
Josh Simon
Carnegie Observatories

2. Things I Work On Galaxy kinematics Dark matter
Milky Way satellites and streams
HII regions/chemical evolution
Dwarf galaxies
Supernovae
Metal-poor stars

3. Pop Quiz, Hotshot Is your primary research (a) observational
(b) theoretical
(c) don’t know
If you answered (b) or (c), please skip to the last question

4. Pop Quiz, Hotshot 2. At what wavelengths do you observe? (a) gamma-ray
(b) X-ray
(c) UV
(d) optical
(e) IR
(f) radio

5. Pop Quiz, Hotshot 3. Are the objects you observe
(a) pretty close (solar system)
(b) far away (Galactic)
(c) really far away (extragalactic)
(d) really, really far away (cosmological) .

6. Pop Quiz, Hotshot 4. What is your favorite color? (a) Red. (b) Orange.
(c) Green.
(d) Blue. No, yellow!

7. Outline I. Formation histories of Local Group dwarfs
a) What were the properties of the first stars and galaxies?
b) What role did the dwarfs play in the buildup of the Milky Way halo?
c) What distinguishes dwarfs from globular clusters?
II. Kinematics of dwarf galaxies
a) What is their dark matter content?
b) What is the nature of dark matter?

8. A Whole New Local Group 2011: 27 (!) Milky Way satellite galaxies
New dwarfs up to 600 times fainter than any previously known galaxies
(Willman et al., Zucker et al., Belokurov et al.)
globular clusters
tidal stream
new dwarf
Belokurov et al. (2006a)

9. Why Study Nearby Galaxies?
Oesch et al. (2009)
Belokurov et al. (2006b)

10. Why Study Nearby Galaxies?
Oesch et al. (2009)
Belokurov et al. (2006b)
1/r2 at z=7: 2  10-59
1/r2 at 100 kpc: 1  10-47

11. Spectroscopic Surveys of Dwarfs
Metallicity distribution functions
Dwarf galaxy evolution and the formation of the halo
Chemical abundance patterns as a function of metallicity
Search for the most metal-poor stars
Nucleosynthesis and chemical evolution in the early universe

12. Spectroscopic Surveys of Dwarfs
Gas outflow (and infall) needed to explain MDFs
MDFs depend on luminosity
Kirby et al. (2011)

13. Luminosity-Metallicity Relation
Faint dwarfs ≠ tidally-stripped bright dwarfs
Stars know what luminosity system they live in
Progress needed: How do we match these dwarfs to subhalos in simulations?
Kirby et al. (2011)

14. Universal Early Chemical Evolution?
[Mg/Fe]
[Ti/Fe]
[Ca/Fe]
[Cr/Fe]
MV = -20.5
MV = -11.1
MV = -6.6
MV = -6.3
MV = -5.7
MV = -3.9
MV = -3.8 .
Collaboration opportunity: Compare abundance patterns to high-z Ly-a systems?
Frebel et al. (2010)
Simon et al. (2010)

15. Search for the First Stars in Dwarfs

16. 2000 Stars in Sculptor

17. 2000 Stars in Sculptor [Fe/H] ~ -3.1 [Fe/H] = -3.8 [Fe/H] ~ -3.8
A star?
M dwarf?

18. The Nature of Dark Matter
The missing satellite problem ?
Belokurov et al. (2006a)
Springel et al. (2001)
Progress needed:
(1) More/deeper searches for dwarfs
(2) Larger spectroscopic surveys of kinematics
(3) Understanding observation-simulation comparison

19. The Nature of Dark Matter
Indirect detection of dark matter
Fermi Space Telescope
Ursa Minor
Segue 1
Strigari et al. (2008)
Martinez et al. (2009)
Simon et al. (2010)

20. The Nature of Dark Matter
The density profiles of dark matter halos
cusp/core 1 2
Radial velocities only
Strigari et al. (2007)
d(r2) dr
Jeans equation: r =
—  r
— 2(r)r2
GM(r)

21. The Nature of Dark Matter
The density profiles of dark matter halos
cusp/core 1 2
GMT/TMT proper motions
Radial velocities only
Strigari et al. (2007)
d(r2) dr
Jeans equation: r =
—  r
GM(r)
— 2(r)r2

22. Other Projects How are heavy elements distributed through galaxies?
What are the progenitors of Type Ia SNe?
What is the effect of a low-metallicity environment on star formation and gas tracers?

23. Opportunities for Collaboration
Observational: stellar kinematics of Local Group dwarfs
Theoretical: understanding the matching between real dwarfs and simulated subhalos
Theoretical: predictions for observable effects of dark subhalos on tidal streams

24. New Opportunity for Students

25. Summary Local Group dwarfs are unique laboratories for
Dark matter - missing satellites, indirect detection, dark matter density profiles
Early galaxy formation – first stars, chemical evolution
Come talk to me about:
Comparisons between observations and N-body simulations
Spectroscopic surveys in the Local Group
Observational tests of dark matter models
Predicted properties of first stars and SNe