1. QSO host galaxy properties from GEMS and COSMOS from z=0 to 3
Knud Jahnke
Max Planck Institute for Astronomy, Heidelberg
Sebastián F. Sánchez (CAHA)
Lutz Wisotzki (AIP)
+the GEMS team
Eva Schinnerer (MPIA)
Vernesa Smolcic (MPIA)
Chris Impey (U Arizona)
Jared Gabor (U Arizona)
+the COSMOS team(s)

2. Goals: state & evolution of QSO host galaxies
role in general galaxy formation
GEMS: 80 broad line QSOs z<3)
optically selected (COMBO17)
photo-z‘s (COMBO17)
ACS imaging F606W (=V), F850LP (=z)
COSMOS: 120 broad line QSOs (25 March 06)
optically selected (SDSS & SDSS+MMT)
radio selected (VLA-COSMOS)
spectro-z‘s (IMACS, zCOSMOS, SDSS)
ACS imaging F814W (=i)

3. Broad-line AGN sample: redshift distribution (z<3)
COSMOS
120 QSOs
55 QSOs
GEMS

4. 2“
F606W
(GEMS)
500 stars
4500 stars
F814W
(COSMOS)
F850LP
(GEMS)

5. „Resolved“ point sources: stars minus PSF
10% of objects
Frequency
>4% of residual flux
Normalized subtraction residual

6. 0.3–0.7
0.9–1.0
1.0–1.15
1.15–1.3
1.3–1.5
1.5–1.6
1.6–1.8
1.8–1.9
1.9–2.1
2.1–2.9
z =
COSMOS ACS F814W 4“

7. z=0.65
z=1.53
z=2.16
z=2.24

8. Resolved QSOs: QSO minus PSF
>4% of residual flux
Frequency
Normalized subtraction residual

9. 0.3–0.7
0.9–1.0
1.0–1.15
1.15–1.3
1.3–1.5
1.5–1.6
1.6–1.8
1.8–1.9
1.9–2.1
2.1–2.9
z =

10. Current status & knowledge
COSMOS: ~50 resolved type 1 QSO hosts
GEMS: ~45 resolved (with optical colour)
Sanchez et al. 2004
Jahnke et al. 2004
Jahnke et al. (in prep)
Others: Kukula/Dunlop et al., Hutchings et al., Falomo et al., Kuhlbrodt et al. (at high z, 1–10 objects each)

11. GEMS & ground based colours
B&C03 (solar)
disk dominated
bulge dominated
undecided

12. GEMS z=0.7 Kormendy relation

13. COSMOS: host galaxy luminosities

14. COSMOS+GEMS: homogeneous inactive comparison samples
z=0.6
z=1.0

15. COSMOS+GEMS combined
Radio detected

16. Results
BL QSO host galaxies span colour range from reddish to blue  contribution of young stars
Bulge-dominated and elliptical hosts can be substantially bluer than inactive counterparts
Confirmed for z=0 to 1.1 (SDSS+HES+GEMS)
Merger/distortion fraction seems increased (to be tested!)
Moderate to substantial SF at z~2, similar to LBGs
Radio selected QSO are more luminous than optically selected

17. Diagnostic power
Differential host galaxy evolution compared to inactive galaxies
Influence of interaction on QSO activity (from merger fraction)
Test unified model for AGN from radio loud—quiet & type 1—type 2 comparison (luminosities, morphology)
QSO host galaxy parent population
With 2nd COSMOS HST band: spectrum of interaction strength triggering AGN activity (7/120 QSOs with NICMOS data)

18. TBD Full sample definition and selection description Time variable PSF
2d modelling + peak subtraction
Morphology analysis (Galfit et al.), direct comparison to inactive sample
Analysis of radio properties