1. Constraints on Secular Evolution from Star Clusters in Spirals and Lenticulars Jean P. Brodie UCO/Lick Observatory University of California Santa Cruz S tudy of A strophysics of G lobular clusters in E xtragalactic S ystems P. Barmby (CfA), M. Beasley (UCSC), K. Bekki (UNSW), J. Cenarro (UCSC/ U Madrid), L. Chomiuk (UCSC), D. Forbes (Swinburne), J. Huchra (CfA), S. Larsen (ESO), M. Pierce (Swinburne), R. Peterson (UCSC), R. Proctor (Swinburne), J. Howell (UCSC), L. Spitler (UCSC), J. Strader (UCSC)

2. Overview Galaxy Formation Background: Globular clusters and their relevance to galaxy formation Global properties of GC systems in early and late-type galaxies Bimodal color distributions and implications for GC/galaxy formation Constraints on secular evolution from GC ages, metallicities, specific frequencies and correlations with host galaxy properties Lenticular Galaxies Faint Fuzzies: discovery and characteristics Ideas on formation Signposts for secular evolution?

3. What are Globular Clusters? SSPs – single age and metallicity 10 5 – 10 6 M sun All galaxies M V <–15 have at least one GC ~150 in MW ~400 in M31 > 10,000 in some ellipticals S N  N GC  10 0.4(M v +15), 2 – 3  greater in E’s M 13

4. Associated with galaxies of all morphological types Constrain theories of galaxy formation and evolution When and how? Differences Constraining galaxy formation

5. Good tracers of star formation histories of galaxies Massive star clusters form during all major star formation events (Schweizer 2001) #of young clusters scales with amount of gas involved in interaction (Kissler-Patig et al 1998) Cluster formation efficiency depends on SFR in spirals (Larsen & Richtler 2000) NGC 6946 Larsen et al 2001

6. Bimodal Color Distributions V-I = 0.95 1.15[Fe/H] = -1.5 -0.5 Bimodal color distributions  globular cluster sub-populations Color differences are due to age differences and /or metallicity differences  Multiple epochs and/or mechanisms of formation

7. GC/Galaxy Formation Models 1. Formation of ellipticals/GCs in mergers (Schweizer 1987, Ashman & Zepf 1992) 2. In situ/multi-phase collapse (Forbes, Brodie & Grillmair 1997) 3. Accretion/stripping (Cote’ et al. 1998) 4. Hierarchical merging (Beasley et al. 2002) 2 & 4 require (temporary) truncation of GC formation at high redshift z

8. Model Predictions Key properties: Ages, metallicities, abundance ratios, kinematics, luminosity functions of red and blue sub-pops  Merger model  old population (~age of universe less ~1 Gyr) +young population with age of merger  Multi-phase  2 old populations one slightly (~2–4 Gyr) collapse younger than other  Accretion  blue and red clusters about the same age  Hierarchical  age substructure in red sub-pop + merging red globulars in low-luminosity field/group ellipticals ~ 2 Gyr younger than in bright cluster ellipticals

9. GC Ages Increasing evidence that both red and blue globular clusters are very old (>10 Gyr) Small percentage of red globular clusters may be young Ellipticals/Lenticulars: NGC 1399 (Kissler-Patig, Brodie, Schroder et al. 1998; Forbes et al 2001) M87 (Cohen, Blakeslee & Ryzhov 1998) NGC 4472 (Puzia et al 1998; Beasley et al. 2000) NGC 1023 (Larsen & Brodie 2002) NGC 524 (Beasley et al 2003) NGC 3610 (Strader, Brodie et al 2003, 2004) NGC 4365 (Larsen, Brodie et al 2003) NGC 1052 (Pierce et al 2004) NGC 7457 (Chomiuk, Strader & Brodie 2004) + PhD theses of T. Puzia and M. Hempel Spirals: M 31 (Barmby et al. 2000; Beasley, Brodie et al 2004) M 81 (Schroder, Brodie, Huchra et al. 2001) M 104 (Larsen, Brodie, Beasley et al 2002)

10. Constraint # 1 Old ages of both sub-populations Inconsistent with major merger picture Relevance to Secular Evolution? Read on!

11. Color-Magnitude Diagrams Average blue peak color (V–I) o =0.95  0.02 Average red peak color (V–I) o =1.18  0.04 [Fe/H]= – 1.4, –0.6 (Kissler-Patig, Brodie, Schroder et al. 1998 AJ)

12. Milky Way Peaks at [Fe/H] ~ – 1.5 and – 0.6 (Zinn 1985) MW GCs are all old

13. Sombrero Peaks at (V–I) 0 =0.96 and 1.21 Larsen, Forbes & Brodie (MNRAS 2001) Follow-up spectroscopy at Keck indicates vast majority of GCs (both red and blue) are old (~13 Gyr) Larsen, Brodie, Forbes (2002)

14. GCs and Galaxy Assembly Colors of both reds and blues correlate with galaxy mass (M V and  ) and color Blue relation difficult to explain under accretion/major merger scenarios Constraints on Hierarchical Merging Paradigm from ages of GCs in dwarfs (~12 Gyr) Brodie 2001; Larsen, Brodie et al 2001; Strader, Brodie & Forbes 2004

15. Work in progress…….. Even more highly significant with as proxy for mass !  (km/s) V-I

16. . Metal-rich GCs in spirals and ellipticals have the same origin — they formed along with the bulge stars Spirals fit the trend Brodie & Huchra 1991; Forbes, Brodie & Grillmair 1997; Forbes, Larsen & Brodie 2001; Larsen, Brodie, Huchra et al 2001 Red GC relation has same slope as galaxy color relation  Red GCs and galaxy stars formed in the same star formation event

17. Constraints # 2 Similarities between peak colors in spirals and ellipticals Hints at universal GC formation processes Slope of red GC color vs galaxy mass relation is same as galaxy color vs galaxy mass relation (true for spirals and ellipticals) Red GC formation is linked to formation of bulge

18. Bulge GCs Forbes, Brodie & Larsen ApJL (2001) of metal-rich GCs scales with the bulge Number of metal-rich GCs scales with the bulge

19. Numbers/Specific Frequency  The fraction of red GCs in ellipticals is about 0.5  The bulge S N for field ellipticals is ~1  Spirals and field ellipticals have a similar number of metal-rich GCs per unit (bulge) starlight  Metal-rich GCs in spirals are associated with bulge not disk  # bulge (red/MR) GCs scales with bulge luminosity  # red GCs/unit bulge light = bulge S N ~1  The total S N for field ellipticals is 1  3 (Harris 1991)

20. Specific Frequency SNSN B/T 0.5 2.0 1.0 0.80.2 S N (total) constant at ~0.55 for spirals with B/T≤0.3 (Sb and later) Constant number of GCs formed in late-type spirals Universal old halo population S N (total) ~ 2 for “field” Es If higher S N for Es due to “extra” GCs formed with bulge, expect S N to scale with B/T from ~0.55±0.25 at B/T=0 to ~1.9±0.5 at B/T=1 Goudfrooij et al 2003 Chandar et al 2004  3957 M51

21. Exceptions  Secular Evolution? NGC 3628: Interacting HI tidal plume + bridge connection with NGC 3627 – extra GCs formed in interaction? NGC 7814: Best evidence? Least luminous sample galaxy (5 x less than NGC 4594). Satellite-to-main galaxy mass ratios of 10% more common for low mass galaxies (Goudfrooij et al 2003) M 51: Does it have a bulge? Interacting with NGC 5195 Too few “bulge” (MR) GCs? (uncertain estimate) 16 vs 98 (bulge/disk deconvolution) or 16 vs 45 (  – BH mass) (Chandar et al 2004)

22. Constraints #3 Number of metal-rich GCs scales with the bulge luminosity Specific frequency as function of B/T broadly consistent with universal halo (blue) GC population + “extra” (red) GC population formed with bulge

23. Conclusions 1) Number of metal-rich GCs scales with the bulge luminosity 2) Chemical evidence also suggests that metal-rich GC formation closely linked to bulge formation 3) Metal-rich GCs are old 1),2) & 3) argue against secular evolution However, exceptions allow for bulge build-up by secular evolution  Galaxies of similar morphological type can have different formation histories

24. Lenticular Galaxies Faint Fuzzies Collaborators:Andi Burkert, Soeren Larsen Brodie & Larsen 2002 Larsen & Brodie 2000 HST program to study GCs in NGC 1023 (M B = –20) Nearby (10 Mpc) S0 galaxy  Faint end of GCLF

25. NGC 1023 GCLF Faint wing of NGC 1023 GCLF deviates significantly from Milky Way GCLF 3 rd population of clusters in addition to normal compact red and blue GC sub-populations

26. GC Selection Typical GC R eff =2–3 pc 29 objects in NGC 1023 with R eff >7 pc Almost all are red

27. Spatial Distribution Background cluster of galaxies ruled out Extended objects have annular distribution corresponding to galaxy isophotes

28. Color-Magnitude Diagram Extended red objects fainter than compact red clusters 23 < V < 24 M

29. Search for other Faint Fuzzies FFs detectable in 4 galaxies (3S0s, 1E) in HST WFPC2 archive Found in 2: N 1023, N 3384 (both SB0s in groups) Ruled out in 2: N 3115 (S01, isolated), N 3379 (E) ACS data……

30. Keck Spectroscopy NGC 1023 “master”spectrum FF1023 =–0.58±0.24 represents 133 hours of 10-m telescope time NGC 3384 - 30 hours FF3384 =–0.64±0.34 Brodie & Larsen AJ 2002

31. Velocities NGC 1023 =559 ± 64 km/s V gal =601 km/s NGC 3384 =768 ± 79 km/s V gal =704 km/s FFs are ~2 bulge R eff from center  disk not bulge objects

32. Ages FFs are mostly likely ~ 13 Gyr old and not younger than ~ 7–8 Gyr Stable against disruption

33. New Kind of Cluster? Milky WayNGC 1023 Globular Clusters Open clusters are smaller, younger and less massive No MW objects correspond in metallicity, luminosity and size

34. New Kind of Cluster? L vs Age L vs Size Milky Way Open Clusters Age > 1 Gyr Open clusters are smaller and less massive

35. Origins FFs have no analogs in MW or elsewhere in LG Found exclusively in lenticulars (so far) Is the mechanism responsible for the formation of FFs linked to the mechanism for forming lenticulars?

36. Distribution and Kinematics Distribution of V FF not same as galaxy rotation curve FFs located in a ring with radius ~1.5’ (4-5 kpc) and V rot 200 km/s Tidal radius 48 pc

37. Extended Cluster Formation 2. Resonance rings and secular evolution Simulations of Geyer & Burkert (2003, 2004) form bound clusters with sizes and masses of FFs in GMCs if star formation occurs with a density threshold Under what circumstances do these special star-forming conditions occur? 1. Galaxy-galaxy interations? e.g. Cartwheel 1

38. Faint Fuzzies Signposts for secular evolution ? NGC 1023 and NGC 3384 are barred NGC 3115 is not  B ~3.5 kpc in NGC 1023 (Debattista et al 2002) Bulge is red (old, MR) Kinematically and chemically decoupled nuclear disk (stars ~ 7 Gyr)

39. NGC 3081 M B =  20 early-type (S0/a, Sa) barred spiral (bulgeless) Inner ring encircles bar at ~5 kpc ~58 blue (young) clusters in ring with M V <  9 (V<23.6) Typical cluster effective radius ~11 pc ! Will these clusters survive? Is bar formation important in forming lenticular galaxies? Buta et al (2004)

40. Implications If FF formation is linked to bar formation in disk galaxies  Disks and bars were present in galaxies at high redshift (z >2)