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박창범 ( 고등과학원 ) & 김주한 ( 경희대학교 ), J. R. Gott (Princeton, USA), J. Dubinski (CITA, Canada)

Cosmological N-Body Simulation of Cosmic Structure Formation. 한국계산과학공학회 창립학술대회 2009. 9. 12. 박창범 ( 고등과학원 ) & 김주한 ( 경희대학교 ), J. R. Gott (Princeton, USA), J. Dubinski (CITA, Canada). Simulation of Cosmic Structure Formation 1. Purpose of cosmological simulations 2. Structure

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박창범 ( 고등과학원 ) & 김주한 ( 경희대학교 ), J. R. Gott (Princeton, USA), J. Dubinski (CITA, Canada)

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  1. Cosmological N-Body Simulation of Cosmic Structure Formation 한국계산과학공학회 창립학술대회 2009. 9. 12 박창범 (고등과학원) & 김주한(경희대학교), J. R. Gott (Princeton, USA), J. Dubinski (CITA, Canada)

  2. Simulation of Cosmic Structure Formation 1. Purpose of cosmological simulations 2. Structure 3. Requirements 4. Recent achievement

  3. History of the Universe

  4. 우주 조망도관측 가능한 시공간 대폭발 특이면 빛 분리면 암흑시대 재이온화시기 high-z시대 현재

  5. Comparison between simulated universes with the real universe Cosmological model Initial linear density fluctuation Non-linear gravitational evolution Galaxy biasing Redshift space distortion Past light cone effects Survey characteristics The real universe Observed sample of galaxies Simulated sample of 'galaxies' Statistical test of adopted models Calibration of systematic effects Prediction of new phenomena

  6. Simulation of Cosmic Structure Formation 1. Purpose 2. Structure of cosmological simulations 3. Requirements 4. Recent achievements

  7. Execution of Cosmological Simulations 0-1. Simulation code N-body gravity code: PM, P3M, Tree, PM-Tree codes Hydro code: 1. particle - SPH 2. mesh (AMR) - ENZO, FLASH 0-2. Dynamic ranges Mass range: simulation particle, collapsed object, total # of particles Spatial range: simulation box size, force resolution

  8. Structure of Cosmological Simulations 1. Initial conditions Cosmological model: power spectrum, high-order correlations Generation of initial conditions on a simulation mesh 2. Evolution & Intermediate analyses Snapshot, past-light cone, collapsed object data at predetermined epochs 3. Post analyses Merger tree construction Assignment of physical values to collapsed objects Comparison with observations

  9. Growth of Structures from initial Density Fluctuations 11.8b 13.7b tb=0 7.7b

  10. Simulation of Cosmic Structure Formation 1. Purpose 2. Structure 3. Requirements of cosmological simulations 4. Recent achievements

  11. Requirements for cosmological simulations * Galaxy, a city of stars, is the building block of the universe ** Force resolution 10 times higher than the mean particle separation assumed

  12. Simulation of Cosmic Structure Formation 1. Purpose 2. Structure 3. Requirements 4. Recent achievements

  13. Major simulations of the KIAS astrophysical simulation group : LCDM model, PMTree N-body code, galaxy ~ cosmological scale * Horizon Run ** Horizon Run-II, a trillion particle simulation

  14. (김주한 & 박창범 2004) Simulation of bright galaxies and large-scale structure --> SDSS Main galaxy survey

  15. SDSS Main Universe seen along the past light cone Inflation Deceleration (Matter Dominated) Reionization Epoch Decoupling Epoch Dark Ages Acceleration (Dark Energy Dominated) Here Now Structure Formation & Evolution The First Objects HI + g + He p + e- + g + He T H E H O R I Z O N R U N Kim, Park, Gott & Dubinski (2009) http://astro.kias.re.kr/Horizon_Run

  16. (김주한, 박창범, Gott & Dubinski 2009) Simulation of very bright galaxies and large-scale structure; the 1st simulation out to the horizon --> SDSS-III Luminous Red Galaxy survey

  17. Horizon Run-II Evolution of the number of simulation particles Horizon Run Millennium Run

  18. Evolution of the spatial dynamic range box size Horizon Run-II Horizon Run resolution scale Millennium Run

  19. Comparison between simulated universes with the real universe Cosmological model Initial linear density fluctuation Non-linear gravitational evolution Galaxy biasing Redshift space distortion Past light cone effects Survey characteristics The real universe Observed sample of galaxies Simulated sample of 'galaxies' Statistical test of adopted models Calibration of systematic effects Prediction of new phenomena

  20. A tour of the real universe : SDSS galaxies KSG-VAGC DR7 sample

  21. Final SDSS DR7 Main Galaxy Sample (2008) [Choi et al. 2009]

  22. The Cosmic Runner (Park et al. 2005) The Sloan Great Wall (Gott et al. 2005) The CfA Great Wall (Geller and Huchra 1989)

  23. CfA1986 SDSS2006

  24. Voids (blue - 7% low), filaments/clusters (red - 7% high) => Sponge !! (Gott et al. 2008) SDSS2006

  25. A mock survey of massive halos out to z=0.6 simulating the SDSS-III Luminosity Red Galaxy Survey that will finish in 2014. [the Horizon Run (Kim et al. 2009)]

  26. Summary 1. The cosmological N-body gravity simulation is limited by memory, and hydrodynamics simulation is limited by both memory and speed. 2. In the near future a trillion particle N-body gravity simulation will be made for the first time. 3. The low-resolution cosmological simulation is now reaching the horizon scale. 4. The high-R cosmological simulations are increasing the box size, and the low-R simulations are increasing the force resolution toward smaller scales. 5. Cosmological simulations are indispensable for understanding the observed universe, guiding new surveys, and predicting new scientific findings.

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