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Lister Staveley-Smith – GALFA March 21, 20031 Parkes HI Surveys  HIPASS –An extragalactic survey reprocessed for Galactic science  Magellanic System.

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Presentation on theme: "Lister Staveley-Smith – GALFA March 21, 20031 Parkes HI Surveys  HIPASS –An extragalactic survey reprocessed for Galactic science  Magellanic System."— Presentation transcript:

1 Lister Staveley-Smith – GALFA March 21, 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

2 HIPASS parameters Barnes et al (2001), Ryan-Weber et al. (2002), Zwaan et al (2003), Koribalski et al. (2003), Meyer et al. (in prep)  Decl. range -90 o <  <+25 o  5000 hrs with Parkes telescope, 13-beam receiver  14.3’ beam (15.5’ when gridded)  km/s velocity resolution  to 12,700 km/s  HI mass limit 10 6 D 2 Mpc M  (3-  )  Column density limit ~10 18 cm -2 (3-  )  7000 galaxies

3 Lister Staveley-Smith – GALFA March 21, 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 LMC, SMC and Magellanic Stream HIPASS HVC catalog

4 Lister Staveley-Smith – GALFA March 21, 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” 60”/sec –Mapping rate 35 deg 2 /hr (64 mK, 1.8x10 17 cm -2 sensitivity) –“In-band” frequency-switching at 0.2 Hz –Data dumping at 0.2 Hz –Nyquist-sampling of sky

5 Lister Staveley-Smith – GALFA March 21, Parkes LMC survey results Staveley-Smith et al  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 (HD IVC belongs to LMC).  With ATCA survey, gives spatial scales 15pc – 10kpc.

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

7 Lister Staveley-Smith – GALFA March 21, SGPS L-V diagram at 3’ resolution

8 Lister Staveley-Smith – GALFA March 21, Issues for GALFA – I. speed  Point-source speed: sensitivity#beamsbeam area   Extended-source speed:  Max area coverage (Nyquist sampling): – 17deg 2 /hr at max ZA drive rate (2.4’/sec)

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

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


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