Origin and Evolution of Structure and Streaming Flows in the Local Group
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Transcript of Origin and Evolution of Structure and Streaming Flows in the Local Group
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Origin and Evolution of Structure and Streaming Flows in the Local Group
Grant J. MathewsCenter for Astrophysics/JINA
University of Notre Dame
X. ZhaoDepartment of Astronomy &
AstrophysicsPenn State University
3rd Subaru Int. Conf.GALACTIC ARCHAEOLOGYShuzenji, JapanNov. 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.
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The Simulations
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X. Zhao & GJM, PRD (2011)
http://www.nd.edu/~xzhao/
CMB LSS Local Group
Initial conditions
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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
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Large Scale Structure Simulation
Local Group
no
GADGETSPH Hydro
yes
GravityN-body
Heating/Cooling
Star Formation
Stellar Wind
Mass ejectionNucleosnthesisHeating
6X. Zhao & GJM (2011)
Begin with LSS
Large Scale Structure Simulations
X. Zhao & GJM (2011)
Scan for Poor Clusters
Local Group Galaxies1 distance diameter luminosity type
_____________________________________________ 2 Milky Way - 100,000 14,000 spiral 3 Sagittarius 78,000 15,000 30 elliptical 4 LMC 160,000 30,000 2,000 irregular 5 SMC 190,000 20,000 250 irregular 6 Ursa Minor 225,000 1,000 0.3 elliptical 7 Draco 248,000 500 0.3 elliptical 8 Sculptor 250,000 1,000 1.5 elliptical 9 Carina 280,000 500 0.4 elliptical 10 Sextans 290,000 1,000 0.8 elliptical 11 Fornax 430,000 3,000 20 elliptical 12 Leo II 750,000 500 1 elliptical 13 Leo I 880,000 1,000 10 elliptical 14 Phoenix 1,270,000 1,000 0.8 irregular 15 NGC6822 1,750,000 8,000 300 irregular 16 And II 1,910,000 2,000 5 elliptical 17 NGC147 1,920,000 10,000 80 elliptical 18 NGC185 2,000,000 6,000 110 elliptical 19 Andromeda 2,500,000 150,000 40,000 spiral 20 M32 2,500,000 5,000 300 elliptical 21 NGC205 2,500,000 10,000 250 elliptical 22 M33 2,500,000 40,000 4,000 spiral 23 IC1613 2,500,000 12,000 80 irregular 24 LGS 3 2,500,000 1,000 0.6 irregular
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• distance diameter luminosity type _____________________________________________
25 And I 2,570,000 2,000 5 elliptical 26 And III 2,570,000 3,000 1 elliptical 27 EGB0427+63 2,600,000 1,000 0.8 elliptical 28 Tucana 2,900,000 500 0.6 elliptical 29 WLM 3,000,000 7,000 30 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 7,000 50 irregular
___________________________________________________________ distance and diameter are in light-years luminosity is in millions of Suns
Local Group Simulations
9Dark Matter
Galaxies form in Dark Matter Potentials
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Galaxies
A Milky Way Like Galaxy
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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
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• Is there evidence for aligned flow in the Local Group?
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High Velocity Clouds
17B. Wakker et al. (1999)
Observed Local Group Radial motion
18-1.5 Mpc +1.5 Mpc0.0
Need to analyze extended Local Group
Redshift distributionGoslowski et al 2006
19http://www.astro.utu.fi/EG/ELG/
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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