1. the faint end …. …. in neutral gas

2. “luminous”

4. Radio spectroscopy

5. Upper limits to space density of intergalactic HI Clouds # Clouds /Mpc 3 /decade M HI

6. - - - - - Volume (Mpc 3 ) Volume for each survey that was sensitive to M HI M HI

7. Upper limits to space density of intergalactic HI Clouds # Clouds /Mpc 3 /decade M HI HI in Galaxies

8. Upper limits to space density of intergalactic HI Clouds # Clouds /Mpc 3 /decade M HI

9. Lo & Sargent (1979) M81, CVn, NGC 1023 Groups Log M HI 6.8 6.6 7.9 7.8 7.7 8.1 M pg -8.7 -12.3 -11.5 -13.1 -15.2 –15.5 M HI /L 18 0.4 15 3 0.4 1.3

11. … the writing is on the wall… (… and in the literature…)

12. more HI in M96 than the Ring (Schneider etal 1989)

13. Giovanelli, Haynes, Chengalur “Virgo HI Cloud”

14. HI Mass Function: (dashed curve) Felton 1985, Luminosity Function F-T for M HI /L ( L )

15. HI Content according to galaxy mass

16. Integral HI mass content: 7.0x10 7 M o Mpc -3 (HIMF faint end slope:  = -1.28 ) Integral HI mass content: 6.1x10 7 M o Mpc -3 ( faint end slope:  = -1.3 ) Parkes HIPASS results (2003): (1990)

17. … what else in the meanwhile… Relation of Galactic High Velocity Clouds to IGM… … HVCs mostly within 200 kpc (Zwaan 2000, thesis)

18. HIPark – a parked Parkes survey Goals: ultra sensitive to low column densities How sensitive ? … optically thin at the Lyman limit exercise in observational techniques … rfi, passband calibration, … good match to long maintenance periods diffuse clouds in LG & Milky Way halo

19. HI Park proposers… Briggs Barnes de Blok Freeman Gibson Korbalski Reynolds Staveley-Smith Zwaan Progess: 25 days observations – John Reynolds extragalactic preview – Jackie Cooper

20. C IV M gII / Lyman limit (CII, FeII, SiII, …) MOTIVE ? QSO absorption line interception cross sections Z=3 Ly break galaxyDLA

21. 12 14 18 20 22 HI Column density distribution function Petijean etal 1993 Log f (N HI ) -10 -15 -20 Log N HI Number of interceptions in range: N to N+dN f (N) dN /unit Z Ly  forest IGM DLA C IV  LL > 1

22. HI Map of M81 Group Yun, Ho & Lo 1994 M81 M82 NGC 3077

23. NGC 3344

24. HIPARK Goal … Sensitivity: to achieve 6  < 3 x 10 17 cm -2 need ~ 6 hours of integration per beam Drift scan: 15’ beam transits in ~ 1 minute  ~360 transits

25. Barnes et al Multibeam !!!

26. 1x1x 4x4x 3x3x Feed orientation for drift scans

27. Path of Survey Strip: Galactic Coords Limits on tiny masses in Sculptor… 3x10 4 d Mpc 2 solar masses D cloud >1 kpc at 250 kpc … to fill beam

28. 03:34 05:56 R.A. 2200 km/s0 FORNAX Dec –32d53’

29. 20:36 22:55 R.A. 2200 km/s0 Dec –32d53’

30. Sculptor (Putman et al)

31. 22:55 01:14 R.A. 2200 km/s0 SCULPTOR Dec –32d53’

32. Magellanic Stream (Putman et al)

33. DEEP Centaurus Survey (Disney et al)

34. 22:55 01:14 R.A. 2200 km/s0 Dec –32d53’

35. Conclusions: Early Low mass halos Star Formation ISM Lost Late Low mass halos never capture gas, (No Star Formation) Large mass halos Star Formation Galaxies No Intergalactic Neutral Hydrogen Clouds at Z=0 … faint end still not known… ATA… SKA (no I.G. HI clouds…)

36. RA Velocity -500 0 1100 Sun up !

37. RA Velocity -500 0 1100

38. Right Ascension Velocity 0 -500 2800 One Day – One Beam

39. RA Velocity -500 0 1100 km/s Galactic Plane crossing: L ~ 250 o

40. RA Velocity -500 0 1100

41. RA Velocity -500 0 1100