Probing the curvature and dark energy

1. Probing the curvature and dark energy Gong, Yungui 龚云贵 Chongqing University of Posts and Telecommunications 重庆邮电学院 “宇宙暗物质和暗能量”研讨会，2005年7月8日

2. Dark Energy Introduction • Current Status of Parameterizations • One-parameter Parameterization • Conclusion

3. Why Dark Energy?

4. Model independent method • Taylor expansion of Hubble parameter, M. Visser, CQG 21 (2004) 2603 • Prameterizations of energy density: 2nd Order Polynomial, U. Alam etal. MNRAS 354 (2004) 275 • Negative Power Polynomial, U. Alam etal. MNRAS 354 (2004) 275

5. Common Parameterization of WQ • Constant equation of state w • Linear equation of state w=w0+w1z • Stable Parameterizations • Wetterich Parameterization • Parameterization H.K. Jassal, MNRAS 356(2005) L11

6. Fitting Results Y. Gong, astro-ph/0405446 , Class. Quantum Grav. 22 (2005) 2121 • Taylor expansion of Hubble parameter

13. Supernova Fit to dark energy

14. One parameter Parameterization Y. Gong and Y.Z. Zhang, astro-ph/0502262

19. Results

20. Summary

22. Thanks!