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the faint end …. …. in neutral gas “luminous” Radio spectroscopy 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) MHI /L Log MHI Mpg M81, CVn, NGC 1023 Groups 18 0.4 15 3 0.4 1.3 6.8 6.6 7.9 7.8 7.7 8.1 -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 (Schneider etal 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 Integral HI mass content: (1990) 7.0x107 Mo Mpc-3 (HIMF faint end slope: a = -1.28 ) Parkes HIPASS results (2003): Integral HI mass content: 6.1x107 Mo Mpc-3 ( faint end slope: a = -1.3 ) … 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 diffuse clouds in LG … optically ?thin at the Lyman limit How sensitive & Milky Way halo exercise in observational techniques … rfi, passband calibration, … good match to long maintenance periods HI Park proposers… • • • • Briggs Barnes de Blok Freeman • • • • • Gibson Korbalski Reynolds Staveley-Smith Zwaan Progess: 25 days observations – John Reynolds extragalactic preview – Jackie Cooper MOTIVE ? QSO absorption line interception cross sections DLA Z=3 Ly break galaxy CIV MgII/ Lyman limit (CII, FeII, SiII, …) HI Column density distribution function Petijean etal 1993 -10 Number of interceptions in range: N to N+dN f(N) dN -15 Log f(NHI) tLL > 1 Lya forest IGM -20 12 14 /unit Z DLA CIV Log NHI 18 20 22 HI Map of M81 Group Yun, Ho & Lo 1994 M82 M81 NGC 3077 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 Feed orientation for drift scans 1x 4x 3x Path of Survey Strip: Galactic Coords Dcloud >1 kpc Limits at 250on kpc tiny masses …intoSculptor… fill beam 3x104 dMpc2 solar masses 05:56 FORNAX Dec –32d53’ R.A. 2200 km/s 0 03:34 22:55 Dec –32d53’ R.A. 2200 km/s 0 20:36 Sculptor (Putman et al) 01:14 SCULPTOR Dec –32d53’ R.A. 2200 km/s 0 22:55 Magellanic Stream (Putman et al) DEEP Centaurus Survey (Disney et al) 01:14 Dec –32d53’ R.A. 2200 km/s 0 22:55 Conclusions: (no I.G. HI clouds…) Large mass halos Star 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 … faint end still not known… ATA… SKA Sun up ! Velocity 1100 0 -500 RA Velocity 1100 0 -500 RA 2800 Velocity One Day – One Beam 0 -500 Right Ascension 1100 km/s Velocity Galactic Plane crossing: L ~ 250o 0 -500 RA Velocity 1100 0 -500 RA Velocity 1100 0 -500 RA