1. 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

2. HI Park proposers… Briggs Barnes de Blok Freeman Gibson Korbalski Reynolds Staveley-Smith Zwaan HI Park progress ? Pilot sessions: June 2001, Dec 01/Jan 02 RIGHT NOW !!! maintenance period to overhaul Alt-drive using 16 MHz filters  3380 km/s @  v= 3km/s res

3. Quasar Absorption lines Lyman  forest DLA Metal lines Wavelength (Angstroms)

4. Quasar Absorption lines Lyman  forest DLA Metal lines LL

5. Quasar Absorption lines  thoroughly developed statistics !!! for metal lines…

6. C IV M gII / Lyman limit (CII, FeII, SiII, …) Relative interception cross sections … Z=3 Ly break galaxyDLA

7. 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 N HI = N H (n HI / n H ) Ionization fraction ~10 -3 ? Ly  forest IGM DLA C IV  LL > 1

10. This Week at Parkes

11. 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

12. Barnes et al Multibeam !!!

13. 1x1x 4x4x 3x3x Feed orientation for drift scans

14. 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

15. Magellanic Stream (Putman et al)

16. Sculptor (Putman et al)

17. Path of Survey Strip: Galactic Coords

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

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

20. RA Velocity -500 0 1100

21. RA Velocity -500 0 1100

22. RA Velocity -500 0 1100

23. RA Velocity -500 0 1100 Sun up !

25. T obs (f) = [ g 1 (f)T antenna (f) + T rec (f) ] g 2 (f) Receiver (Preamps etc) Spectrometer (Filters etc) T antenna (f) T receiver (f) (dominant noise) T obs (f) T ant (f) = [ T obs (f)/ g 2 (f) - T rec (f) ]/ g 1 (f) g 1 (f) g 2 (f) g3g3 Sun GALACTIC PLANE, g 4 Ground g 5

26. TIME (steps) Pilot run June 01: total power versus time Note erratic tot-pwr in Rx-5

27. passband calibrated continuum subtracted Dynamic Spectra: one receiver Frequency (64 MHz bandwidth) Time (vertical)

28. 1x1x 4x4x 3x3x Pilot Dec01/Jan02 8 MHz Bandwidth

29. DEEP Centaurus Survey (Disney et al)