1. The evolution of (the number density of) morphologically-selected early-type galaxies C. Scarlata - Motivation - Non-parametric morphological analysis - Sample selection - Number density evolution of M.S.E.T. galaxies - Conclusions & Future

2. For each galaxy we measured: Gini coefficient M 20 Concentration Asymmetry How to combine this information? INITIAL SAMPLE: ~ 60,000 galaxies with I AB < 24, detected on the ACS images

3. PC i are linear combinations of the C,A,G, (and M20) Parameter space is reduced to 2 dimensions PC1 = 0.91 C - 0.28 A + 0.84 G PC2 = 0.05 C - 0.94 A + 0.34 G Principal components analysis

4. Meaning of the Principal Components (BRIGHT CONTROL SAMPLE, 14000 GALAXIES with I AB < 22.5) Morphological EARLY-TYPE (Sersic n>2.5, Mark’s analysis ) -2 2 PC1 0 4 -2 PC2 4 A>0.3

5. THIS TALK: PC2 1.5 “SYMMETRIC”, “EARLY-TYPE” GALAXIES Morphological EARLY-TYPE (Sersic n>2.5, Mark’s analysis ) -2 2 PC1 0 4 -2 PC2 4 1.5 1.2 8038 PC1,PC2-selected GALAXIES with I AB <24

6. PC1-PC2 selected sample  >0.7 FURTHER CUT TO SAMPLE, WHICH LEAVES: 7835 PC1,PC2-SELECTED GALAXIES WITH  <0.7

7. Galaxies in shaded area cannot “passively” evolve onto the z=0 Kormendy relation of massive galaxies FURTHER CUT TO SAMPLE Kormendy relation Solid line: (Joergensen et al. 1995)

8. FINAL SAMPLE: 6751 MORPHOLOGICALLY-SELECTED, EARLY-TYPE galaxies down to I AB of 24.

9. Evolution of the number density of morphologically- & Kormendy-selected early-type galaxies

10. Evolution of the number density of morphologically- & Kormendy-selected early-type galaxies NUMBER DENSITY OF MORPHOLOGICALLY- & KORMENDY-SELECTED EARLY-TYPE GALAXIES: - CONSTANT OUT TO z~0.9 - SHARP DROP (~x3) BEYOND!

11. Luminosity function (1/V max )

12. Conclusions 1.Non parametric morphological analysis robust down to I<24 2.PCA reduces the parameter space 3.PC-selected sample of early-type galaxies down to I AB =24 4.Decrease of factor ~3 of the number density of “early-type” galaxies between z~0.9 and z~1.2 In progress -USE PCA ANALYSIS TO IDENTIFY GALAXY POPULATIONS - STUDY EVOLUTION OF STRUCTURE, CLUSTERING PROPERTIES, HALO-OCCUPATION-STATISTIC OF DIFFERENT POPULATIONS (see Porciani’s talk) -EVOLUTION = f(ENVIRONMENT)