1. Determining cosmological parameters with current observational data
TPCSF
Li Hong

2. CMB 、LSS and SN The cosmological observations play
Recent years Cosmology became
more and more accurate
CMB 、LSS and SN
Complementary,
GRB and WL also make remarkable progress !
The cosmological observations play
a crucial role in understanding universe !

3. outline The global fitting analysis Constraints on EOS including GRBs
The constraints on cosmological parameters with the latest observational data
Constraints on EOS including GRBs
Simulations for LAMOST
Summary

4. Global fitting procedure
Parameterization of EOS:
Perturbation included
G.-B. Zhao, et al., PRD (2005)
Method : modified CosmoMC
Calculated at ShangHai Supercomputer Center (SSC)
Data : CMB+LSS+SNe
Cosmological parameters:
For simplicity,
usually consider flat Universe

5. Current constraint on the equation of state of dark energy
Quintessece
Quintom A
Quintom B
Phantom
WMAP5 result
E. Komatsu et al., arXiv:
Xia, Li, Zhao, Zhang, in preparation
Difference:
Data: SN (SNLS+ESSENCE+Riess et al.)
vs SN (307,Kowalski et al., arXiv: )
Method: WMAP distance prior vs Full CMB data.
However, results similar (Li et al., arXiv: )
Status:
1) Cosmological constant fits data well;
2) Dynamical model not ruled out;
3) Best fit value of equation of state:
slightly w across -1  Quintom model

6. Arxiv: 0805.1118, Accepted by APJ Lett.

8. For the published version :

10. Take into account the recent weak lensing data

15. Global analysis of the cosmological parameters including GRBs
Results from the global analysis with WMAP3+LSS+SNe(Riess 182 samples)+GRBs (Schaefer 69 sample)
New method for solution of the circulation problem

16. the 69 modulus published by Schaefer (in astro-ph/0612285)

17. Bias
with only GRB
Need
global analysis

18. Hong Li, M. su, Z.H. Fan, Z.G. Dai and X.Zhang, astro-ph/0612060,
Phys.Lett.B658:95-100,2008
WMAP3+LSS+SN
WMAP3+LSS+SN+GRB

19. The relevant papers on studies with GRBs:
E.L.Wright astro-ph/

20. F.Y. Wang, Z. G. Dai and Z. H. Zhu, astro-ph/0706.0938

21. Problems: The circulation problem :
Due to the lack of the low-redshift GRBs, the experiential correlation is obtained from the high-redshift GRBs with input cosmology !

22. What is the circulation problem?
Due to the lack of the low-redshift GRBs, the experiential correlations are obtained from the high-redshift GRBs with input cosmology which we intend to constrain, it lead to the circulation problem!
From the observation,
we can get: S_r, t_j, n, eta_r, E_peak
S_r is the fluence of the r-ray; t_j is the
Break time; n is the circumburst particle
Density; eta_r is the fraction of the kinetic
Energy that translate to the r-rays;
E_peak is the peak energy of the spectrum
With a fire ball GRB model:
Ghirlanda et al.

23. Input a cosmology
Usually
Get A & C

24. A new method for overcoming the circulation problem for GRBs in global analysis
Hong Li et al., APJ 680, 92 (2008)
Correlation as an example:
We take
We let A and C free:
We integrate them out in order to get the constraint on the cosmological parameter:
We can avoid the circulation problem !
And method can apply to the other correlations.

26. For flat universe !

27. With free !

28. For flat universe !

29. The constraints on A and C related with the correlation:
e., in the literature C is set to [0.89, 1.05]; A is set to 1.5
One can find that, this will lead to the bias to the final constraints on
The cosmological parameters!

30. Simulations for LAMOST
z~ 0.2
n~ galaxies
H.Feldman, et al. Astrophys.J. 426, 23 (1994)
Firstly we take the bias factor: b=1
Then we let b free, see the following

31. Simulated power spectrum
Fiducial model:

32. About other simulations
Planck: we assume the isotropic noise with variance and a symmetric gaussian beam of 7 arcminutes full-width half-maximum : A. Lewis, Phys.RevD71,083008(2005)
(See the paper by arXiv: , J.-Q. Xia, H. Li et al.)
SNLS: ~ 500 SN Ia

33. Constraint on cosmological parameters with LAMOST

34. Constraints on EoS of Dark Energy

35. Constraint on absolute neutrino mass

36. SUMMARY
Our results on determining EOS of DE with MCMC from WMAP+SDSS+SN(+GRBS) ;
Cosmological constant fits the current data well at 2 sigma;
Quintom is mildly favored ;
The Future observation like
Planck and LAMOST will
improve the constraints
H. Li, J.-Q. Xia, Zu-Hui Fan and X. Zhang, JCAP 10 (2008) 046

37. Thank You !