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Zheng , Yi 郑逸 Shanghai Astronomical Observatory P . Zhang, J. Pan, and Y. Zheng , 1207.2722.

Peculiar velocity decomposition, redshift distortion and velocity reconstruction in redshift surveys. Zheng , Yi 郑逸 Shanghai Astronomical Observatory P . Zhang, J. Pan, and Y. Zheng , 1207.2722. Y. Zheng , P. Zhang et al. (2012), in preparation. Outline .

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Zheng , Yi 郑逸 Shanghai Astronomical Observatory P . Zhang, J. Pan, and Y. Zheng , 1207.2722.

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  1. Peculiar velocity decomposition, redshift distortion and velocity reconstruction in redshift surveys Zheng, Yi 郑逸 Shanghai Astronomical Observatory P. Zhang, J. Pan, and Y. Zheng, 1207.2722. Y. Zheng, P. Zhang et al. (2012), in preparation.

  2. Outline • I. Introduction. (Why RSD interesting?) • II. Velocity decomposition. (What do decomposed velocity components look like?) • III. RSD modeling and velocity reconstruction. • IV. Discussions and conclusions

  3. Introduction The redshift position s: Reid et al. 2012 5-10% O(1%) Observationally: A. J. S. Hamilton, astro-ph/9708102 Theoretically: Nonlinear mapping Nonlinear evolution Bias modelling Euclid, BigBOSSet all: Torre & Guzzo, 1202.5559

  4. RSD modeling I Dark matter and LCDM cosmology The redshift position s: From mass conservation: The redshift space power spectrum:

  5. Velocity decomposition correlated with irrotational component uncorrelated with rotational component Background from Wang et al. 2012

  6. Simulation: 1200 Mpc/h & 100 Mpc/h, 1024^3 Nearest Particle method Velocity power spectrum Definition:

  7. Velocity correlation function Definition: O(1 Mpc/h) O(10 Mpc/h)

  8. A new RSD formulae 1.Underestimation of by 3. Physical FOG: CL, dispersion, NG 2.Determined by W(k)!

  9. Window function I underestimation

  10. Window function II Do fitting using region

  11. 3D velocity reconstruction 1. The 1stMethod: 2. The 2nd Method: By tuning such that is isotropic at large scales, we could obtain the correct and hence the correct field. Application example: k-SZ tomography (Ho et al. 0903.2845, Shao et al. 1004.1301) Velocity field Momentum field k-SZ effect Missing baryons CMB

  12. Conclusions and discussions • Conclusions: • a velocity decomposition method  a new RSD model lower systematic error. • a simple fitting formula for • 2 new methods for 3D velocity reconstruction in light of RSD information. • Future work: • More simulation calculations to impove RSD model and test its accuracy, halo, galaxy.... • Velocity reconstruction methods need more theoretical and numerical considerations.

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