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Parkes HI Surveys

Parkes HI Surveys. HIPASS An extragalactic survey reprocessed for Galactic science Magellanic System Stream, SMC, LMC Galactic HI SGPS Some issues for GALFA speed, tertiary skirt, deconvolution.

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Parkes HI Surveys

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  1. Parkes HI Surveys • HIPASS • An extragalactic survey reprocessed for Galactic science • Magellanic System • Stream, SMC, LMC • Galactic HI • SGPS • Some issues for GALFA • speed, tertiary skirt, deconvolution Lister Staveley-Smith – GALFA March 21, 2003

  2. HIPASS parametersBarnes et al (2001), Ryan-Weber et al. (2002), Zwaan et al (2003), Koribalski et al. (2003), Meyer et al. (in prep) • Decl. range -90o<<+25o • 5000 hrs with Parkes telescope, 13-beam receiver • 14.3’ beam (15.5’ when gridded) • 18-26 km/s velocity resolution • -1200 to 12,700 km/s • HI mass limit 106 D2Mpc M (3-) • Column density limit ~1018 cm-2 (3-) • 7000 galaxies

  3. Non-extragalactic HIPASS • High-velocity clouds (Putman et al. 2002) • MINMED5 reprocessing of raw HIPASS data |v|<500 km/s • 1956 HVCs, including 179 CHVCs • Talk by Mary Putman • Magellanic System (Putman et al. 2003) • Orbital history of Clouds, tidal stripping rate of SMC/Bridge • Mass spectrum of clumps, Galactic tidal & ram-pressure forces • Leading Arm • Talks by Putman, Brüns, Stanimirović HIPASS HVC catalog Lister Staveley-Smith – GALFA March 21, 2003 LMC, SMC and Magellanic Stream

  4. The Magellanic System • LMC (Staveley-Smith et al. 2003) , SMC (Stanimirović et al. 1999), Magellanic Bridge (Muller et al. 2003), Magellanic Stream (Brüns 2002). • Typical observing parameters: • 8 MHz/2048 channels (0.8 km/s) • 7 inner beams only (maintain coma to <–17dB and beam ellipticity to <0.03) • “On-the-fly” mapping @ 60”/sec • Mapping rate 35 deg2/hr (64 mK, 1.8x1017cm-2 sensitivity) • “In-band” frequency-switching at 0.2 Hz • Data dumping at 0.2 Hz • Nyquist-sampling of sky Lister Staveley-Smith – GALFA March 21, 2003

  5. Parkes LMC survey resultsStaveley-Smith et al. 2003 • Tidal tails found – due to influence of Galaxy and SMC. • Tidal mass outflow rate  most MACHO microlensing events are self-lensing. • Possible signature of diffuse Galactic halo gas. • No ionisation truncation edge. • HI mass 50% greater than previously measured! • No intergalactic HVC’s found (HD269546 IVC belongs to LMC). • With ATCA survey, gives spatial scales 15pc – 10kpc. Lister Staveley-Smith – GALFA March 21, 2003

  6. Southern Galactic Plane Survey (McClure-Griffiths et al. 2002) • 358o< l < 253o • -10o< b <10o • 1.0 km/s resolution • 1419/1422.125 MHz freq.switch • AIPS++ Gridzilla • ATCA data for |b|<1.5o. (resolution 15’  3’). • e.g. GSH 277+00+36 at d ~ 6.5 kpc, diameter~600 pc Lister Staveley-Smith – GALFA March 21, 2003

  7. SGPS L-V diagram at 3’ resolutionhttp://www.astro.umn.edu/naomi/sgps.html Lister Staveley-Smith – GALFA March 21, 2003

  8. Issues for GALFA – I. speed •  Point-source speed: sensitivity #beams beam area •  Extended-source speed: •  Max area coverage (Nyquist sampling): • 17deg2/hr at max ZA drive rate (2.4’/sec) Lister Staveley-Smith – GALFA March 21, 2003

  9. Issues for GALFA – II. Tertiary Skirt • Tertiary skirt will reduce Tsys at low frequencies (=high-z) by locating far-sidelobes on cold sky. • But it will complicate spillover pattern! Tertiary skirt Lister Staveley-Smith – GALFA March 21, 2003

  10. Issues for GALFA – III. deconvolution Complicated by a PSF which varies with time, frequency, position and beam number. Cortes-Medellin (2002) Lister Staveley-Smith – GALFA March 21, 2003

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