Origin and Evolution of Structure and Streaming Flows in the Local Group

1. Origin and Evolution of Structure and Streaming Flows in the Local Group Grant J. Mathews Center for Astrophysics/JINA University of Notre Dame X. Zhao Department of Astronomy & Astrophysics Penn State University 3rd Subaru Int. Conf. GALACTIC ARCHAEOLOGY Shuzenji, Japan Nov. 3, 2011

2. The Galaxy & the Local Group • The Galaxy did not form in isolation. • It is the product of the development of much larger structure. • It was formed in concert with the entire Local Group and was affected by dark matter, dark energy, mergers, star formation and nucleosynthesis processes, mass ejection, heating, and cooling occurring throughout a large volume.

3. The Simulations CMB  LSS  Local Group http://www.nd.edu/~xzhao/ X. Zhao & GJM, PRD (2011)

4. Initial conditions WMAP Cosmic Microwave Background Z ~ 1100 • CMBFAST • CMB power spectrum • Use power spectrum to generate a spectrum of random Gaussian fluctuations Z ~ 49

5. The Simulation GADGET SPH Hydro Large Scale Structure Simulation Gravity N-body no Stellar Wind Heating/Cooling Local Group yes Star Formation Mass ejection Nucleosnthesis Heating

6. Begin with LSS X. Zhao & GJM (2011)

7. Large Scale Structure Simulations Scan for Poor Clusters X. Zhao & GJM (2011)

8. Local Group Galaxies • distance diameter luminosity type _____________________________________________ • And I 2,570,000 2,000 5 elliptical • And III 2,570,000 3,000 1 elliptical • EGB0427+63 2,600,000 1,000 0.8 elliptical • Tucana 2,900,000 500 0.6 elliptical • WLM 3,000,000 7,000 30 irregular • SagDIG 3,700,000 5,000 2 irregular • IC10 4,000,000 6,000 1,000 irregular • Pegasus 5,800,000 7,000 50 irregular ___________________________________________________________ distance and diameter are in light-years luminosity is in millions of Suns • distance diameter luminosity type _____________________________________________ • Milky Way - 100,000 14,000 spiral • Sagittarius 78,000 15,000 30 elliptical • LMC 160,000 30,000 2,000 irregular • SMC 190,000 20,000 250 irregular • Ursa Minor 225,000 1,000 0.3 elliptical • Draco 248,000 500 0.3 elliptical • Sculptor 250,000 1,000 1.5 elliptical • Carina 280,000 500 0.4 elliptical • Sextans 290,000 1,000 0.8 elliptical • Fornax 430,000 3,000 20 elliptical • Leo II 750,000 500 1 elliptical • Leo I 880,000 1,000 10 elliptical • Phoenix 1,270,000 1,000 0.8 irregular • NGC6822 1,750,000 8,000 300 irregular • And II 1,910,000 2,000 5 elliptical • NGC147 1,920,000 10,000 80 elliptical • NGC185 2,000,000 6,000 110 elliptical • Andromeda 2,500,000 150,000 40,000 spiral • M32 2,500,000 5,000 300 elliptical • NGC205 2,500,000 10,000 250 elliptical • M33 2,500,000 40,000 4,000 spiral • IC1613 2,500,000 12,000 80 irregular • LGS 3 2,500,000 1,000 0.6 irregular

9. Local Group Simulations Dark Matter

10. Galaxies form in Dark Matter Potentials

11. Galaxies

12. A Milky Way Like Galaxy

13. Results of Simulations: • Significant star formation occurs far from the galaxy in protogalactic structures. • Dwarf Proto-galactic halos arrive in a stochastic stream flowing along dark-matter filaments. • The local-group like system shows an alignment defined by the directions of the streaming flows

14. Simulation Comoving Velocity Flow Zhao & Mathews (2011)

15. Is there evidence for aligned flow in the Local Group?

16. High Velocity Clouds B. Wakker et al. (1999)

17. Observed Local Group Radial motion Need to analyze extended Local Group Redshift distribution Goslowski et al 2006 +1.5 Mpc -1.5 Mpc 0.0

18. http://www.astro.utu.fi/EG/ELG/

19. Conclusions • Galaxies are not isolated objects but are the culmination of halo formation, mergers, star formation and nucleosynthesis in an extended connected environment. • Significant star formation and occurs far from the galaxy in aligned dwarf proto-galactic structures. • Dwarf Proto-galactic halos arrive in a stochastic stream flowing along dark-matter filaments. • There is marginal evidence for alignment and streaming motion in the Extended Local Group