1. Summary Neta A. Bahcall Princeton University
The Warm/Hot Universe
Summary
Neta A. Bahcall
Princeton University

2. The Hot Universe: Clusters
Powerful tool for Cosmology
Powerful tool for Tracing Large Scale Structure
Structure Formation; ICM, gas, baryons, & Evolution
The Warm Universe: IGM, Clusters/Groups
Where are all the baryons?
Tracing the IGM and Large-scale Structure
Cosmology
Soft excess in Clusters; Groups
Test MOND

3. Clusters: Powerful Tool for Cosmology
Cluster Mass (Temp) Function and its Evolution
  Ωm Ω 
Baryon (Gas) Fraction and its Evolution
 Ωm Ω 
Baryon Acoustic Oscillations using Clusters
 Ωm Ω  (‘Standard Ruler’)
M/L Function  Ωm
Cluster Shape   Ωm 

4. Cluster Abundance and Evolution
 Powerful method to determine m , 8 , w
8 = Amplitude of mass fluctuations
ncl (z~0)  8 m0.6 ~ 0.35
ncl (hi z)  Breaks degeneracy
 m= and 8=
Need accurate Mass calibration for precision cosmology

8 (galaxies)(obs) ~ 0.9
If Mass ~ Light (on large scale)  8(m)~ 0.9

5. Mass-Function SDSS Clusters (Bahcall, Dong, et al ‘02) Best-fit MF: m=0.2 and 8=0.9

6. Ωm -  (Clusters MF)

7. Cluster Abundance Evolution  8 (Bahcall & Bode)

8. Cosmological Constraints (Bahcall & Bode) (from Low and Hi redshift cluster abundance)
Low z
Hi z

9. Evolution of Cluster XLF (Mantz etal 08)

10. Dark Energy Task Force ‘07
Clusters
Stage II (current) error-bars
W vs DE
Stage III (next)
Pess.
Optim.

11. Dark Energy Task Force: Stage-3 Comparison
ALL CL SN WL
BAO

12. Dark Energy Task Force: Stage-4 Comparison (Space)WL SN
SN+wL+BAO
SN+WL
BAO CL

13. Cluster Method: DETF Strong statistical benefits
Largest systematic errors (vs. SN, BAO, WL?)
Need to control systematics due to non-linear astrophysical processes (baryon physics; baryon evolution; ICM; etc)
Need accurate and reliable Mass calibration
(accurate comparisons of lensing, X-ray, SZ, Opt)
Clusters: Important method when combined with SN or BAO (which measure only d(z)), in order to test both DE and GR (CL measure both d(z) and gravitational growth)

14. m from Baryon Fraction
b/m = h=0.7
(Clusters; CMB)
b = (BBN; CMB)
 m =

15. Baryon Fraction vs. Scale ( 0.18) (Bahcall & Martin ‘07)

16. Evolution of Cluster Gas Fraction (Allen et al 07)

17. Cosmology: Evolution of Gas Fraction (Allen 07)

18. Comlogical constraints from Gas Fraction (Allen etal 07)

19. Baryon Acoustic Oscillations: SDSS (Eisensteain etal 05)

20. BAO: Cluster Correlation Function (Bahcall and Soneira 1983)

21. BAO: Cluster Correlation Function (Bahcall and Soneira 1983)

22. Mass-to-Light Function (Bahcall, Lubin & Dorman ‘95; Bahcall and Fan ‘98)

23. Cluster M/L Function from SDSS (Sheldon et al 07)

24. Cluster M/L : SDSS
Ω m= 0.2

25. Shape and Alignment of Clusters
 The Shape of Clusters
 Alignment of Cluster Pairs
 Evolution of Shape & Alignment
 New Tool in Cosmology:
 Cluster Ellipticity
 Superclusters: Filaments or Pancakes?

26. Evolution of Cluster Ellipticity <E> versus Redshift and Mass (Hopkins, Bahcall, etal ’05)
0.6
<E>
0.5
0.4
0.3 1 2 3
Redshift

27. Cluster Ellipticity   (Ho, Bahcall, Bode ‘06)

28. Clusters Shape and Alignment
Clusters are Triaxial
> More so at earlier times
<Ecl> ~ 0.3 to (z ~ 0 to 3)
Strong Cluster Alignment to ~100 Mpc
Alignment and Ellipticity increase with z
 New Tool in Cosmology:
<Ecl>  8 m w

29. Clusters: Tool for LSS, Structure Formation and Evolution, ICM, baryons
Large Scale Structure (CF, Pk, SCs)
Evolution of baryon fraction; gas vs. gal
Baryon Fraction vs. Mass or T
( heating, cooling, winds)
ICM Physics; Cooling, heating, AGNs, non-thermal
Soft excess emission in clusters
Substructure; merging clusters; high-velocity mergers (e.g., Bullet Cluster)
Ellipticity and alignment of clusters vs. z

30. The Warm Universe Where are all the baryons? Tracing the IGM
Tracing the Large-scale structure, SCs
Evolution of the warm IGM and its LSS
Groups of galaxies; Mass-Function
Cosmology: comparison with LCDM
Other…

31. Superclusters: Filaments or Pancakes? (Wray, Bahcall, Bode, etal ‘06)1
1D - Filaments
3D - Spherical
a3/a2
Triaxial
2D - Pancakes
a2/a1 1
0.6

32. Summary The Hot Universe: Clusters
Powerful tool for Cosmology (Ωm Ω  )
Need accurate Mass calibration and baryon evolution!
Powerful tool for Tracing Large Scale Structure
Structure Formation; ICM, gas, baryons, & Evolution
The Warm Universe: IGM, Clusters/Groups
Where are all the baryons?
Tracing the IGM and Large-scale Structure
Cosmology
Soft excess in Clusters; Groups
Test MOND

34. Dark Energy Task Force: BAO

35. DETF