1. Young bulges and old ellipticals
Daniel Thomas
University of Oxford
Formation epochs of elliptical galaxies
SF-AGN connection
Stellar populations in spiral bulges
Age of the MW Bulge

2. Old ellipticals - old plots
Worthey et al 1992
Absorption-line indices
Bender et al 1992
Fundamental Plane
Bower et al 1992
Colour-magnitude relation
Kodama et al 1998
Colour-magnitude at z>0
Bender et al 1996
Mgb- at z>0
Renzini 2006

3. Epochs of early-type galaxy formation
Kauffmann & Charlot 1998
Thomas, Maraston, Bender, Mendes de Oliveira 2005

4. Galaxy formation caught in the act
sub-mm sources
Smail et al 2002; Swinbank et al 2004
z~2–6
Massive objects
~ 1011 M
High star formation rates
~ 1000 M/yr
Bertoldi et al 2003

5. Ellipticals in the SDSS
Sample of 30,000 morphologically selected ellipticals
Kevin Schawinsky (Oxford)
Sugata Kaviraj (Oxford)
Claudia Maraston (Oxford)
Marc Sarzi (Hertfordshire)
Seok-Joo Joo (Oxford, Yonsei)
Sukyoung Yi (Yonsei)

6. AGN feedback at work

7. What about bulges?

8. Bulges - Imaging Recent star formation in later-type bulges?
Bulges in later type spirals have steeper
color gradients and are younger
(optical/NIR color maps; Balcells & Peletier
1994; Peletier et al 1999; Carollo et al 2001)
Recent star formation in later-type bulges?
Fingerprints of secular evolution?

9. Ellis, Abraham, Dickinson 2001
Blue bulges at high z
Ellis, Abraham, Dickinson 2001

10. The Bulge of the Milky Way
Zoccali et al 2003

11. Sample of spiral bulges
Proctor & Sansom (2002)
 32 objects (11 Es, 6 S0s, 16 bulges)
 Exposure ~ 1h per object on 4m
 Edge-on, minor axis
 Galaxy type from S0 – Sbc
 Wavelength range 4000 ≤  ≤ 5500 Å
 Ages and Mg/Fe ratios of bulges
lower than ellipticals
Maraston et al (2003)
 Milky Way bulge (integrated light in Baade’s window)
 Lick absorption line indices

12. Deriving stellar population parameters
SSP models: TMB03, TMK04

13. Comparison bulges and ellipticals
Thomas & Davies 2006

14. Rejuvenation of bulges
Thomas & Davies 2006

15. A spectrum of the Bulge
Maraston et al 2003

16. The Milky Way Bulge
Thomas & Davies 2006

17. The Milky Way Bulge
SSP models: TMB03, TMK04

18. The Milky Way Bulge
Thomas & Davies 2006

19. The Milky Way Bulge: really old?
Maraston 2004
Zoccali et al 2003

20. Summary Ellipticals follow anti-hierarchical pattern
Spiral bulges follow anti-hierarchical pattern
The Milky Way Bulge is young (rejuvenated)
‘Downsizing’, ‘The hierarchy is broken’
Interplay SF-AGN observed in SDSS
Rejuvenation at redshifts z < 0.5
Same stellar populations like ellipticals
Disc influence negligible down to Sbc

21. Optical vs near UV
Passive
Star forming

22. Anti-hierarchical AGN’s
De Lucia et al 2005
Thomas et al 2005
Hasinger, Takamitsu, Schmidt 2005