# Presentation: 003386

## The colour-magnitude relation in galaxy clusters 

**from z~0.8 to z=0**

**Gabriella De Lucia**
**Max-Planck Institut für Astrophysik**

## The CMR - some facts

- _The CMR - some facts_

## The CMR - the conjectures #1

- _The CMR - the conjectures #1_

## The CMR - the conjectures #2

- _The CMR - the conjectures #2_

## A truncation in the CMR in high redshift clusters

## The Eso Distant Cluster Survey

-      **Completed – White et al. 2005**
-   near-IR photometry from NTT (20 nights)
-      **Completed - Aragon-Salamanca et al. in preparation**
-   multi-object spectroscopy with FORS2 on VLT (25 nights)
-      **Completed - Halliday+ 2006; Milvang-Jensen+ in prep**
-   80 orbits of HST to image 10 high-z clusters!!!
-     **Completed - Desai et al. in preparation**
-   WFI  R (120m), V, I (60m)
-     **Completed**

- A detailed follow-up of 20 clusters from LCDCS (Gonzalez et al. 2001)
**10 clusters at z ******** 0.5 and 10 clusters at z ******** 0.8**

- _The __**E**__so __**Dis**__tant __**C**__luster __**S**__urvey_

## Some EDisCS clusters

**White et al. 2005**

- _Some __**EDisCS **__clusters_

## Some EDisCS CMRs

**De Lucia et al. 2006, astro-ph/0610373**

## The CMR - passive evolution

- _The CMR - passive evolution_

- redshift

- zero-point

**De Lucia et al. 2006, astro-ph/0610373**

- The location of the CMR requires high redshifts of formation (z~3) and the slope is consistent with a correlation betweel luminosity and metal content

## The build-up of the CMR #1

- # of galaxies

- z = 0.45

- z = 0.57

- z = 0.75

- # of galaxies

- MI(obs)

- MI(obs)

- MV(rest)

- MV(rest)

- MV(rest)

- _The build-up of the CMR #1_

**De Lucia et al. 2006, astro-ph/0610373**

- l/f = 0.48 +/- 0.08
- l/f = 0.53 +/- 0.09

-  0.71 +/- 0.10
-  0.86 +/- 0.13

-  0.89 +/- 0.14
-  0.95 +/- 0.14

## The build-up of the CMR #2

- redshift

- nlum/nfaint

- _The build-up of the CMR #2_

**De Lucia et al. 2006, astro-ph/0610373**

- the blue galaxies observed in distant galaxy clusters provide the logical progenitors of faint red galaxies at z=0

## The build-up of the CMR #3

**De Lucia et al. 2006, astro-ph/0610373**

- # of galaxies

- # of galaxies

- MV(rest)

- MI(obs)

- sigma < 600 km/s

- sigma > 600 km/s

## The build-up of the CMR #4

**De Lucia et al. 2006, astro-ph/0610373**

- nlum/nfaint

- redshift

- sigma > 600 km/s

- sigma < 600 km/s

## The build-up of the CMR #4

**De Lucia et al. 2006, astro-ph/0610373**

- redshift

- redshift

- nlum/nfaint

## Semi-analytic 

**models**

## galaxy formation

**galaxy formation**

*Cooling  *                           (metallicity,structure, conductivity)

*Star formation* (threshold, efficiency, initial mass function)

*Dust **   *          (formation, distribution, heating and cooling)

*Galaxy interactions* (morphological transformations, induced star formation)

*Winds*                    (IGM heating,        IGM enrichment)

*Stellar evolution*    (spectro-photometric evolution, yields,feedback)

*AGN *
- (BH growth, feedback)

## The SAM - the hybrid models

- _The SAM - the hybrid models_

## The SAM - the hybrid models

- _The SAM - the hybrid models_

## The SAMs - the (simplified) physics

***star formation***

***recycling***

**Hot Gas**

**Cold Gas**

**Ejected Gas**

**Stars**

***re-incorporation***

- De Lucia, Kauffmann & White, 2004

- _The SAMs - the (simplified) physics_

## The build-up of the CMR in SAMs

- The evolution of the CM relation in SAM models

- Coma

- Single burst zf=3

- Exp. tau = 1

- _The build-up of the CMR in SAMs_

**De Lucia et al. in preparation**

- U-V

- U-V

- U-V

- U-V

- U-V

- MV

- MV

- MV

- MV

- MV

## The build-up of the CMR in SAMs

- Very little build-up of the red-sequence!

**De Lucia et al. in preparation**

- _The build-up of the CMR in SAMs_

- V-I

- V-I

- V-I

- V-I

- nlum/nfaint

- MV

- MI

- MI

- MI

- MI

- redshift

- l/f = 0.31
- z = 0.0

- l/f = 0.37
- z = 0.32

- l/f = 0.38
- z = 0.41

- l/f = 0.45
- z = 0.62

- l/f = 0.47
- z = 0.76

- U-V

## u - r

- Quantitatively the CM bimodality is not well reproduced

- _The colour-magnitude bimodality_

- Mr = -22.75

- Mr = -21.25

- Mr = -19.75

- Mr = -18.25

**Baldry et al. 2004**

**in preparation**

- fraction

- fraction

## The D4000 distribution

- _The D4000 distribution_

- fraction

- fraction

- D4000

- D4000

- D4000

- Same problems in the D4000 distribution

**in preparation**

## The star formation history

- Lookback time (Gyr)

- _The star formation history_

- Most massive elliptical galaxies also the shortest formation timescales

**De Lucia et al. 2006**

## The star formation history

**De Lucia et al. 2006**

- _The star formation history_

## Formation and assembly

- _Formation and assembly_

- 50 % stars formed

- 80 %

- Fraction of galaxies

- redshift

**De Lucia et al. 2006**

## Formation and assembly of BCGs

- ”Assembly vs formation”
- history

- 125 BCGs selected
- @z=0

- _Formation and assembly of BCGs_

## The ellipticals progenitors number

- Mstar [M h-1]

- Effective # of progenitors

- Neff = 1/2 Mfinal/<Mform>

- No  disk instability

- Disk instability

- In the monolithic
- approximation: Neff=1

- _The ellipticals progenitors number_

**De Lucia et al. 2006**

## The age and metallicity dependence

- _The age and metallicity dependence_

- B - V

- Log[Mstar]

- z=0.00

- z=0.00

- Zstar/Z

- Age (Gyr)

**De Lucia et al. in preparation**

## Conclusions

-  Indication for a truncation of the colour-magnitude
-     relation at high redshift
-  Dependence on environment not clear
-  SAMs do reproduce “qualitatively” the observed
-     down-sizing
-   A clear difference between “assembly” and
-     “formation” time
-  SAMs do not reproduce “quantitatively” the colour
-     bimodality