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Minutes of the talk on:
      Galactic ALFA Surveys: What might Happen in a Week

Chris Salter (NAIC)

GALFA is really a consortium of 3 separate sub-consortia centered around different science topics: Galactic HI, Continuum and Recombination lines.

So far, interest in GALFA has been expressed through web-sign up by 56 individuals. This include 26 post-upgrade users and 30 potential new users. The breakdown includes: 33 US vs 23 non-US. 36 staff/faculty, 14 postdocs and 6 grad students.

The GALFA workshop will be held next week. There will be 29 participants (18 post-upgrade users, 11 potential new users), very heavily US-based.

Potential key projects

A number of different projects are being discussed by the GALFA group, including:

Of course, part of the idea would be to piggyback these surveys where possible. Note that the time to do the whole Arecibo sky would be 1000 hours. At the same time, you could make an L-band map of SNR in OTF mode, basketweaving scans in RA and in Dec (the HI map would require more time than the continuum data).

A map made with the current system was presented showing the distribution of HI coincident with continuum emission. A total power continuum map from Jan 03 data by Giovanelli et al is confusion-limited with all the strong NVSS sources clearly visible in the map.


Riccardo What about accelerations and decelerations? What does that do to pointing, etc?
Chris It could be taken out in software.
Eli B. In the map you showed, how fast were you scanning there?
Chris I'm not sure.
Riccardo Given the current spectrometer plans, a survey for extragalactic HI might be limited to 2 km/s resolution. Would such a survey be at all useful for galactic purposes or is it passe?
Mary P. The HIPASS 26 km/s resolution was still very useful for the study of HVCs.
DJ P. Naomi McClure-Griffiths' southern survey has a resolution of about 1 km/s.
Judith I. The Canadian galactic plane survey has a resolution of 0.86 km/s.
Paulo Since GALFA is a very disparate set of small projects, would it make more sense to have many small groups?
Riccardo Let me ask again: would a survey with a 3 arcmin beam and 2.5 km/s survey be useful or not at all interesting? I understand it would not be ideal.
Chris It would certainly be of use to some people but not to all.
Judith There are of course the other surveys: the VLA galactic survey, the Canadian survey and the southern survey. What is missing, that Arecibo could contribute, is the low order spacings.
Chris Arecibo can fill in what VLA is missing right up to B array.
Lister Why not just record voltages and dump them onto disk?
Mary In the galactic plane, you want the high resolution, but when you start covering the whole sky, lower resolution is probably ok for most purposes.

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Next: Survey Simulations Up: Minutes of the 1st Previous: RFI at Arecibo

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Last modified: Thu Apr 17 18:09:17 EDT 2003