Star Formation in Cluster Cooling Flows

1. Star Formation in Cluster Cooling Flows Brian R. McNamara Ohio University Cooling Flows in Galaxies & Clusters of Galaxies, June 1, 03 Charlottesville, VA

3. Talk Outline • Optical-UV properties of starbursts • Difficulties estimating star formation rates & histories • Einstein/Rosat Era: -star formation & the cooling flow problem -star formation histories inconsistent with steady cooling • Chandra & XMM era: -star formation associated with coolest gas -cooling rates converging with star formation rates -feedback & reduced cooling

4. Acknowledgements Collaborators: M. Wise, C. Sarazin, L. Blanton, P. Nulsen, R. O’Connell, D. Rafferty, L. Birzan Rafferty M. Sharma, C. O’Dea, C. Carilli, S. Baum, L. David, J. Houck, & others Colleagues: C. Crawford, S. Allen, A. Fabian, N. Cardiel, W. Romanishin, L. Hansen, A. Edge, R. Johnstone, & others

5. Typical Surface Brightness Profiles Abell 1068 Normal Profile

7. cD Galaxy Optical Spectra Normal cD galaxies A1068 Starburst Crawford et al. 99 McNamara & O’Connell 89

9. Blue Color Correlates with Einstein/Rosat Cooling Rates Bluer . McNamara 97, 02 JFN 87, MO 89

10. Mass-to-light vs Age

11. Population Color vs Age Classical Cooling flow A1068 Redder

12. Star Formation Histories • Burst population: ages ~10 Myr or less • Continuous or extended star formation with ages ~100 Myr Inconsistent with long-lived, continuous star Formation in a classical cooling flow

13. Radio Triggered Burst Mode Theory De Young 95, Begelman & Cioffi 89 Abell 2597 Abell 1795 McNamara et al. 93, 96 Koekemoer et al. 99

14. Starburst Paradigm Gas accretion onto the nucleus Radio source turns on Radio source triggers or enhances starburst Repeats on several hundred Myr timescale

15. Triggering Physics Unclear Hydra A No shocks No in situ cooling A2052 McNamara et al. 00 Blanton et al. 02

16. Starburst in Abell 1068 SFR~70 Mo yr-1 LIR=1045.2 erg s-1 MH2=2x1010 Mo (Edge 01) Lrad=1039.8 erg s-1 LSN=1043.2 erg s-1 Lcool=1044.1 erg s-1 . M < 140 Mo yr-1 McNamara, Wise, Murray 03

17. Coolest gas associated with young stars Wise, McNamara, & Murray (2003) Abell 1068 z=0.13

18. Star Formation Peaks in Regions of Short Cooling Time Cooling time 95% of UV photons 5x108 yr Radius

19. Star Formation Associated with coolest gas Abell 1795 X-ray: Fabian et al. (2001) Nebular emission: Cowie et al. (1983) Star formation: McNamara et al. (1996)

20. Disk Star Formation in Hydra A disk I-band U-band

21. Disk embedded in gas with short cooling time Star Formation U-band + X-rays McNamara 95 McNamara et al. 00

22. Cooling vs Star Formation

23. Cooling vs Star Formation

24. Cooling vs Star Formation A1068 Hydra A A2597 A1795 A2052

25. Feedback

26. Classical Cooling Flow A1068

27. Summary Star Formation Histories • Burst mode of star formation t* ~ 107 yr • Continuous mode t* ~108 yr • Inconsistent with continuous accretion for >109 yr New Trends from Chandra/XMM • Star formation follows regions where tc < 5x108 yr • Star formation rates and cooling rates converging • Feedback important in some but not all cases!

28. The Future • Deep, high resolution X-ray spectroscopy • Sensitive, high resolution ultraviolet imaging • Infrared observations with SIRTF -understand the effects of Dust Restrictive limits on cooling & star formation • Understand the roll of feedback: -radio source, conduction, supernovae, etc.

29. THANK YOU! Local Organizing Committee Thank you Thomas!!!

30. Comparison of Cooling Flow and Non Cooling Flow Surface Brightness

31. P, T, ne gradients in Cooling Flows Abell 2597 Surface brightness density temperature pressure McNamara et al (2001)

32. Abundance Gradients Wise, McNamara, & Murray (2003)

33. Hydra A X-ray Cavities in Clusters • 25-35 kpc diameters • No shocks • PV=1.2 x 1059 erg • texp = 2-6 x 107 yr • Pgas ~ 5-10 x Prad McNamara et al. (2000) David et al. (2001) Nulsen et al. (2002)

34. Abell 2052 Blanton et al. (2001) • tcool > trad : nebular emission not cooling gas • Cool gas lifted by the radio source? Radio

35. Cool Gas Uplifted by Radio Sources Hydra A entropy R (kpc) David et al. (2001) Nulsen et al. (2002)

36. Ghost Cavities Abell 2597 z=0.08 McNamara et al. (2001)

37. Ghost Cavities: Radio Relics • Diameter ~ 18 kpc • Nuc distance ~ 30 kpc • trise ~ 50-100 Myr McNamara et al. (2001) Fabian et al. (2000) pV ~ 3 x 1058 erg Etot ~ 1061 erg

38. X-ray Cavities • Probe mechanical energy of radio jets • Deposit ~ 1061 erg into ICM • Direct heating not seen • Induce bulk motion; redistribute mass • May suppress cooling in some systems • Two surprises: cool rims; long lived

39. Conclusions & Discussion • Clusters show a great deal of structure and are not simple, isothermal spheres • Distant clusters: temperature function, mass function, assembly physics • Structure may be more dramatic in distant clusters probed by Con-X: QSOs, powerful radio galaxies, merging, star formation • Interpreting Con-X spectra will require careful modeling based on detailed physics learned from Chandra & XMM-Newton