1. Galaxy Clusters & Large Scale Structure Ay 16, April 3, 2008 Coma Cluster =A1656

2. Galaxies Are Not Randomly Distributed in Space Fundamental discovery (and debate) in the 20th century is that Galaxies cluster. On small scales: Binaries ~100 kpc intermediate scales: Groups ~1 Mpc larger scales: Clusters few Mpc even larger scales: Superclusters 10’s Mpc largest seen: Voids + Cosmic Web ~50 Mpc

3. M51 = Whirlpool = NGC 5194+95 NOAO

5. Seyfert’s Sextet

6. Stefan’s Quintet

7. Abell 1689

8. Coma Cluster

9. Coma in X-rays

10. Mass Estimators: M V = M P = Σ R i (V i -V G ) 2 with f PM =10.2 and γ = 1.5 (Heisler, Tremaine & Bahcall 1985, ApJ 298, 8) 3 π Σ σ P 2 R P 2 G f PM π G (N – γ)

12. Hydrostatic Equilibrium Abell 2142 in X-rays CXO

13. Gravitational Lensing

14. Cluster Mass Estimates Now three techniques agree fairly well for the same clusters -- Galaxy Dynamics, Gas Hydrostatic Equilibrium + Gravitational Lensing masses give a mean M/L of around 300 in blue light (solar units) and 100 in infrared light. This is important for cosmology as it implies (1) that there’s lots of Dark Matter on large scales, and (2) that  matter is ~ 0.25.

15. Perseus Cluster Shocks in the hot Gas (Fabian+)

16. Abell 2597 shocks and bubbles

17. Large Scale Structure The study of the galaxy distribution on large scales started out with maps.

18. Election ’06 Congressional Districts

19. Its all in the display: Election ’04 By County R/B By County color range By state scaled by population

20. Messier’s map: What do you see?

21. W. Herschel

22. New General Catalogue + Index Catalogues

23. Fritz Zwicky et al. CGCG

24. Zwicky’s Catalog

25. Early “Modern” Views Hubble: The Large Scale is “Sensibly Uniform,” one cluster per 50 square degrees. “General Field of galaxies, isolated groups and clusters. versus Zwicky “Clusters are Common” “cluster cells separated by saddles or minima... and … not … flatlands”

26. Statistics of Clustering Many different “statistical” measures. Peebles and Totsuji & Kihara introduced the correlation function -- a measure of the excess probability of finding a galaxy near another galaxy --- in the early 1970’s.

27. Correlation Functions 2D Angular Correlation Function dP = N [1 + w(  )] d  where N = surface density of galaxies  = angular separation and  = solid angle (area of sky)

29. 3D Spatial Correlation Function dP = n [ 1 +  (r) ] dV where n is now the volume density dV is the volume element and r is some measure of separation e.g. s = [d  2 + ((v 1 - v 2 )/H) 2 ] 1/2

30. Hubble ’ s Discovery of Expansion

32. Redshift Surveys 3747 +/- 20 CfA Survey

33. 3D Maps of the Local Universe Not much progress until the mid 1970’s! Catalogs existed from Photographic Surveys- 2D only (Zwicky++; Vorontosov-Velyaminov++) In 1972 the largest “complete” galaxy redshift sample had only ~250 galaxies Key was innovations in detector technology: computers + digital detectors sensitive radio receivers

34. Larson wasn’t quite right…

35. The Little Telescope that could. Tillinghast 1.5-m

36. The Z Machine Davis, Tonry, Latham & Huchra Based on a concept by Shectman & Gunn

38. Spectral features in galaxies

40. CfA2 Slice

41. 1985 CfA 2 deLapparent, Geller & Huchra

42. CfA2 1995

44. 6dF Fiber Positioner, SRC Schmidt, Coonabarabran

45. K S < 11.25 We are here Great Wall Pisces- Perseus LSC

47. M. Westover

48. Magenta V < 1000 km/s Blue 1000 < V < 2000 km/s Green 2000 < V < 3000 km/s

49. Red 3000 < v < 4000 Blue 4000< v < 5000 Green 5000 < v < 6000 Red 3000 < v < 4000

50. Red 6000 < v < 7000 Blue 7000 < v < 8000 Green 8000 < v < 9000

51. Red 9000 < v < 11000 Blue 11000 < v < 13000 Green 13000 < v < 15000

52. SCDM LCDM Virgo Consortium: testing cosmological models with LSS. Obs vs Simulations

53. Red = DM from Grav lensing Blue = Hot x-ray gas

54. Next Steps: o Distances via TF, d_n-sigma, SN, etc. 4000 galaxies inside 15000 km/s with HI and 2MASS photometry (e.g. see the Cornell group’s work) o Redshifts to K=12.25, ~100,000 galaxies all sky (6dF in the south, ??? in the north) o Hollywood (movies!)

55. Remember, This Is A Sphere!

56. Going Deeper: Wide Field Telescopes The MMT

57. Hectospec Positioner on MMT Dan Fabricant et al.

58. Hectospec Positioner on MMT 300 Fibers covering a 1 degree field of view D. Fabricant

59. Large Synoptic Survey Telescope