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 3 rd Subaru Int. Conf. GALACTIC ARCHAEOLOGY Shuzenji, Japan Nov. 3, 2011

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. 2

The Simulations 3 X. Zhao & GJM, PRD (2011) CMB  LSS  Local Group

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

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

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

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

Local Group Galaxies 1 distance diameter luminosity type _____________________________________________ 2Milky Way - 100,000 14,000 spiral 3Sagittarius 78,000 15, elliptical 4 LMC 160,000 30,000 2,000 irregular 5SMC 190,000 20, irregular 6 Ursa Minor 225,000 1, elliptical 7 Draco 248, elliptical 8Sculptor 250,000 1, elliptical 9Carina 280, elliptical 10 Sextans 290,000 1, elliptical 11Fornax 430,000 3, elliptical 12 Leo II 750, elliptical 13 Leo I 880,000 1, elliptical 14Phoenix 1,270,000 1, irregular 15 NGC6822 1,750,000 8, irregular 16 And II 1,910,000 2,000 5 elliptical 17 NGC147 1,920,000 10, elliptical 18 NGC185 2,000,000 6, elliptical 19Andromeda 2,500, ,000 40,000 spiral 20 M32 2,500,000 5, elliptical 21NGC205 2,500,000 10, elliptical 22M33 2,500,000 40,000 4,000 spiral 23 IC1613 2,500,000 12, irregular 24 LGS 3 2,500,000 1, irregular 8 distance diameter luminosity type _____________________________________________ 25And I 2,570,000 2,000 5 elliptical 26 And III 2,570,000 3,000 1 elliptical 27 EGB ,600,000 1, elliptical 28 Tucana 2,900, elliptical 29WLM 3,000,000 7, irregular 30 SagDIG 3,700,000 5,000 2 irregular 31 IC10 4,000,000 6,000 1,000 irregular 32 Pegasus 5,800,000 7, irregular ___________________________________________________________ distance and diameter are in light-years luminosity is in millions of Suns

Local Group Simulations 9 Dark Matter

Galaxies form in Dark Matter Potentials 10

11 Galaxies

Disk Galaxies 12

A Milky Way Like Galaxy 13

14 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

Simulation Comoving Velocity Flow 15 Zhao & Mathews (2011)

Is there evidence for aligned flow in the Local Group? 16

High Velocity Clouds 17 B. Wakker et al. (1999)

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

19

20 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