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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 for each survey that was sensitive to M HI. -. -. -. Volume (Mpc 3 ). -. -.
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Upper limits to space density of intergalactic HI Clouds # Clouds /Mpc3 /decade MHI
Volume for each survey that was sensitive to MHI - - - Volume (Mpc3) - - MHI
Upper limits to space density of intergalactic HI Clouds # Clouds /Mpc3 /decade HI in Galaxies MHI
Upper limits to space density of intergalactic HI Clouds # Clouds /Mpc3 /decade MHI
Lo & Sargent (1979) M81, CVn, NGC 1023 Groups MHI /L 18 0.4 15 3 0.4 1.3 Log MHI 6.8 6.6 7.9 7.8 7.7 8.1 Mpg -8.7 -12.3 -11.5 -13.1 -15.2 –15.5
… the writing is on the wall… (… and in the literature…)
more HI in M96 than the Ring (Schneideretal 1989)
Giovanelli, Haynes, Chengalur “Virgo HI Cloud”
HI Mass Function: (dashed curve) Felton 1985, Luminosity Function F-T for MHI/L(L)
HI Content according to galaxy mass
(1990) Parkes HIPASS results (2003): Integral HI mass content: 6.1x107 Mo Mpc-3 ( faint end slope: a = -1.3 ) Integral HI mass content: 7.0x107 Mo Mpc-3 (HIMF faint end slope: a = -1.28 )
… 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 diffuse clouds in LG & Milky Way halo How sensitive ? … optically thin at the Lyman limit Goals:ultra sensitive to low column densities exercise in observational techniques … rfi, passband calibration, … good match to long maintenance periods
Briggs Barnes de Blok Freeman Gibson Korbalski Reynolds Staveley-Smith Zwaan HI Park proposers… Progess: 25 days observations – John Reynolds extragalactic preview – Jackie Cooper
DLA CIV MgII/ Lyman limit (CII, FeII, SiII, …) MOTIVE ? QSO absorption line interception cross sections Z=3 Ly break galaxy
HI Column density distribution function Number of interceptions in range: N to N+dN f(N) dN /unit Z tLL > 1 Lya forest IGM DLA CIV Petijean etal 1993 -10 -15 Log f(NHI) -20 12 14 18 20 22 Log NHI
M82 M81 NGC 3077 HI Map of M81 Group Yun, Ho & Lo 1994
NGC 3344
HIPARK Goal… Sensitivity: to achieve 6s < 3 x 1017 cm-2 need ~ 6 hours of integration per beam Drift scan: 15’ beam transits in ~ 1 minute a ~360 transits
Multibeam!!! Barnes et al
1x 4x 3x Feed orientation for drift scans
Path of Survey Strip: Galactic Coords Dcloud >1 kpc at 250 kpc … to fill beam Limits on tiny masses in Sculptor… 3x104 dMpc2 solar masses
05:56 FORNAX Dec –32d53’ R.A. 03:34 2200 km/s 0
22:55 Dec –32d53’ R.A. 20:36 2200 km/s 0
Sculptor (Putman et al)
01:14 SCULPTOR Dec –32d53’ R.A. 22:55 2200 km/s 0
Magellanic Stream (Putman et al)
DEEP Centaurus Survey (Disney et al)
01:14 Dec –32d53’ R.A. 22:55 2200 km/s 0
Large mass halosStar Formation Galaxies Early Low mass halos Star Formation ISM Lost Late Low mass halos never capture gas, (No Star Formation) No Intergalactic Neutral Hydrogen Clouds at Z=0 Conclusions: (no I.G. HI clouds…) … faint end still not known… ATA… SKA
Velocity Sun up ! 1100 0 -500 RA
Velocity 1100 0 -500 RA
Velocity One Day – One Beam 2800 0 -500 Right Ascension
Galactic Plane crossing: L ~ 250o Velocity 1100 km/s 0 -500 RA
Velocity 1100 0 -500 RA
Velocity 1100 0 -500 RA