the faint end …. …. in neutral gas

“luminous”

Radio spectroscopy

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

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

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

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

Lo & Sargent (1979) M81, CVn, NGC 1023 Groups Log M HI M pg –15.5 M HI /L

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

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

Giovanelli, Haynes, Chengalur “Virgo HI Cloud”

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

HI Content according to galaxy mass

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

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

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

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

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

HI Column density distribution function Petijean etal 1993 Log f (N HI ) 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

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

NGC 3344

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

Barnes et al Multibeam !!!

1x1x 4x4x 3x3x Feed orientation for drift scans

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

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

20:36 22:55 R.A km/s0 Dec –32d53’

Sculptor (Putman et al)

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

Magellanic Stream (Putman et al)

DEEP Centaurus Survey (Disney et al)

22:55 01:14 R.A km/s0 Dec –32d53’

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…)

RA Velocity Sun up !

RA Velocity

Right Ascension Velocity One Day – One Beam

RA Velocity km/s Galactic Plane crossing: L ~ 250 o

RA Velocity

RA Velocity