# Presentation: 470566

## The Warm/Hot Universe

**Summary**
**Neta A. Bahcall**
**Princeton University**

- The Hot Universe: Clusters
- Powerful tool for Cosmology
- Powerful tool for Tracing Large Scale Structure
- Growth of structure
- ICM physics; heating, cooling, non-thermal, soft & hard excess, AGN, metalicities;  Evolution of the ICM
- The Warm Universe:  IGM
- Where are the other baryons?
- Tracing the IGM and Large-scale Structure
- Cosmology; comparison with simulations
- Test MOND

##  Clusters:  Powerful Tool for Cosmology

- Cluster Mass (Temp) Function and its Evolution
-              Ωm    Ω    (need accurate Mcl)
- Baryon (Gas) Fraction and its Evolution
-             Ωm   Ω     (understand ICM evolution)
- Baryon Acoustic Oscillations using Clusters
-            Ωm    Ω    (‘Standard Ruler’)
- Cluster Shape   ******    **    Ωm    
- M/L Function        Ωm

##  Cluster Abundance and Evolution

***  **Powerful method to determine  **********m**** **, **********8  ******, ******w***
***       ************8 ****=  Amplitude of mass fluctuations     *
*** ******n******cl ******(z~0)**** ********** **** ****8**** ******m**0.6****  ******~ ****0.35   **(MF Shape **** ****8**)*
*** ******n******cl ******(hi z)****  **** ****  ****Breaks degeneracy *
*  ****  **********m******=0.2+-0.05  ****and**** ************8******=0.9+-0.1***
*Need accurate Mass calibration for precision cosmology*
**
*********8****** ****(galaxies)(obs) ****~ ****0.9*
*If ****Mass ~ Light**** (on large scale) **** **********8****(m)****~ ****0.9*

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

_*** ***_

*Fit: ****m**=0.2*
*      ****8**=0.9*

## Ωm -    (Clusters MF) (Bahcall, Dong etal ‘03)

## Cluster Abundance Evolution  8 (Bahcall & Bode ‘03)

- 8

## Cosmological Constraints (Bahcall & Bode)(from Low and Hi redshift cluster abundance)

***Hi z***

***Low z***

*************** ******- ************m***

## Evolution of Cluster XLF  (Mantz etal 08)

## Dark Energy Task Force ‘07  

- _Stage II (current) error-bars_

- _Stage III (next)_

- _W vs DE_

- Clusters

- Pess.

- Optim.

## Dark Energy Task Force:  Stage-3 Comparison

- BAO

- CL

- SN

- WL

- ALL

## Dark Energy Task Force: Stage-4 Comparison (Space)

- BAO

- CL

- SN

- WL

- SN+WL

- SN+wL+BAO

## DETF: Compare All (Stage 4: space+ground)

## 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 -- heating, cooling, non-thermal, merging...)
- Need accurate and reliable Mass calibration
-     (accurate comparisons of lensing, X-ray, SZ, Opt, and sims.)
- Clusters:  Important method when combined with SN or BAO (which measure only d(z)), in order to test both D.E. and GR  (CL and WL measure both d(z) and gravitational growth)

*** ************b******/************m****** = 0.18 +- 0.02   ****h=0.7*
***                                  ****(Clusters; CMB)*
*** ************b ******= 0.042 +- 0.004  ****(BBN; CMB)*
***    ************  ************m****** = 0.24 +- 0.04***

*********m ******from Baryon Fraction***

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

*** ****m **= 0.24*

## Evolution of Cluster Gas Fraction(Allen et al 07)

## Cosmology:  Evolution of Gas Fraction(Allen 07)

## Comlogical constraints from Gas Fraction(Allen etal 07)

## Baryon Acoustic Oscillations: SDSS(Eisensteain etal 05)

## BAO: Cluster Correlation Function (Bahcall and Soneira 1983)

## BAO: Cluster Correlation Function (Bahcall and Soneira 1983)

## Shape and Alignment of Clusters

-  The Shape of Clusters
-  Alignment of Cluster Pairs
-  Evolution of Shape & Alignment
-  New Tool in Cosmology:
-            ***Cluster Ellipticity***

## Evolution of Cluster Ellipticity<E> versus Redshift and Mass (Hopkins, Bahcall, etal ’05)

- <E>

- Redshift

- 0

- 1

- 2

- 3

- 0.3

- 0.4

- 0.5

- 0.6

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

## Clusters Shape and Alignment

- Clusters are *Triaxial*
-        >  More so at earlier times
*<E**cl**> ~ 0.3  **to ** 0.5*   (z ~ 0 to 3)
-  (ellipticity causes selection bias: opt, lensing, X-ray; need to account for it)
- Strong Cluster *Alignment to** ~100 Mpc*
- Alignment and Ellipticity *increase with z*
*** **  **New Tool* *in* *Cosmology:*
*                 **<E**cl**>  ****  ****8**   ****m    **w*

## Clusters: Tool for LSS, Structure Formation and Evolution, ICM physics and evolution

- Large Scale Structure (CF, Pk, SCs)
- Evolution of baryon fraction; gas vs. gal
- ICM Physics; Cooling, heating, AGNs, non-thermal,
-     merging and shocks, winds, metalicities, evolution
- Substructure; merging clusters; high-velocity mergers (e.g., Bullet Cluster)
- Soft - hard excess emission in clusters
- Ellipticity and alignment of clusters vs. z

## The Warm Universe (105-107)

- Where are ~50% of the baryons?
- Define ‘WHIM’ better (e.g. diffuse and bound/groups?) how best look for it -- use different methods, emission, absorption, targeted SCs, ...;  Are most in Groups?
- Tracing the IGM, SCs/filaments, galactic halos
- Evolution of the warm IGM and its LSS; Physics of the Warm IGM
- Cosmology: comparison with LCDM

## Superclusters:  Filaments or Pancakes?(Wray, Bahcall, Bode, etal ‘06)

- 1D - Filaments

- 3D - Spherical

- Triaxial

- 2D - Pancakes

- a2/a1

- a3/a2

- 0

- 1

- 0.6

- 0

- 1

## Summary

- The Hot Universe: Clusters
- Powerful tool for Cosmology  (Ωm  Ω    )
- Need accurate Mass calibration and baryon/ICM physics and evolution!
- Powerful tool for Tracing Large Scale Structure (Pk, SCs, BAO)
- Structure Formation and Growth; ICM physics & Evolution
- The Warm Universe:  IGM
- Where are all the baryons? Use variety methods to search
- Tracing the IGM and Large-scale Structure; Physics of WHIM
- Cosmology: compare with expectations
- Test MOND

## The End

-  Many thanks to Frits, Richard Lieu and all the organizers of this fruitful and enjoyable meeting!
- Good Luck and good progress in the
- Warm-Hot Universe

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

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

## Cluster M/L : SDSS

- Ω m= 0.2

## Dark Energy Task Force: BAO

## DETF