Here are the spectral channels/bandwidth values for the prototype LTA. The minimum integration time is 16 ms for cross-corretations & 1 ms for auto-correlations (i.e., there is no time/spectral channel trade off as in earlier designs)

Mode Spectral Baseband Baseband

Channels Bandwidth Bandwidth

not oversampled oversampled

0 512 2 GHz 1 GHz

1 1024 1 GHz 500 MHz

2 2048 500 MHz 250 MHz

3 4096 250 MHz 125 MHz

4 8192 125 MHz 62.5 MHz

5 16384 62.5 MHz na --------

Configurations - Min

Comments on MMA Memo No. 274.

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MAC Meeting - Wootten

So here is a possible agenda for the 9 October meeting.

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ALMA Science Advisory Committee

9 October 1999

Agenda

Omni Shoreham Hotel

0900 Committee Caucus

Overview of the Project at Midcourse -- R. Brown

Antenna Procurement Contract -- P. Napier, Anderson(?)

Other Technical Reports

Report on LO PDR -- as appropriate

ALMA Frequncy Bands -- Wootten

Science updated -- Wootten

Blueprint for the Joint ALMA Project D&D Phase -- R. Kurz, R. Brown

Definition and Formation of Joint ALMA Science Advisory Committee -- Wootten, Churchwell,

Guilloteau, Menten

Committee Caucus -- Churchwell, Menten

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Stephane proposed a similar set of goals:

" US-Europe Meeting goals

- Setup a proposal for the joint ALMA SAC (format, suggested names perhaps in a restricted session)

- Discuss timeline differences between Europe and US

- Discuss the 35 GHz band issue

- Discuss the longest baseline issue

- Present and discuss the draft Work Plan which we must have prepared for that date (I'll send you soon a preliminary draft)

- Discuss our position vis-a-vis the Japanese proposals

- Any items you wish

- Any other business

Since most of the scientific topics will have been covered before, I believe we should stick to practical problems."

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ALMA Science Meeting

I will update everyone on the status of this event.

Registered: 169 (-2 cancellations)

Paid: 115

Banquet: 109

Posters: 52 abstracts received; 72 including intendees. Kate has posted these to the WWW. I will order posterboards enough for 72 posters.

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PR -- Wootten

Geoff Blake wrote: Lee Mundy has made a nice image of what ALMA might see in a YSO accretion disk. I think it is quite pretty, and there are lots of features in the image: 1) A central hole 3 AU in radius. 2) A roughly 2AU wide cleared ring centered 7 AU with soft edges -- Lee used a Gaussian in absorption. 3) A protoplanet overdensity at 9 AU with a Gaussian FWHM of 2 AU and a factor of 9 overdensity. The wings are created by a second Gaussian component which is elongated along the orbital path. 4) A protoplanet overdensity at 22 AU with a Gaussian FMWH of 1.5 AU and a factor of 6 overdensity 5) A protoplanet overdensity at 37 AU with a Gaussian FWHM of 3 AU and a factor of 4 overdensity 6) The word ALMA written in the lower part of the disk with an overdensity of a factor of 2 on the underlying disk The leters are 12 pixels wide and 100 pixels high -- that is roughly 4 AU by 35 AU. 7) The word ALMA written in the upper part of the disk with an underdensity of 20 percent. Each of the protoplanets also has an underdensity of 10 percent in a ring at the same orbital radius. The ALMA letters are in there as a gauge of image fidelity. In the ALMA simulated observations, the beam for 10 km baselines at 230 GHz is around 20 milli-arcseconds which is 2.8 AU at Taurus (the pixel size in the model is about 0.35 AU). There is no phase noise in the simulated image, but there is gaussian noise at the level appropriate for the stated ALMA sensitivities. The image really drives home what ALMA can do in planet forming environments. I think we are also going to try and add an envelope to this for very deeply embedded systems, and Michiel Hogerheijde is going to run a 2D Monte Carlo simulation for spectral line work.

I spoke with Lee about what went into this. He randomly placed 50 antennas on a 10km ring and let the array observe the source on the right for 6 hours. This array does not sample the uv plane too well, he found. He added data from a 3km array, with 50 randomly placed antennas spaced greater than 100 nanosec or so. This gave the needed short spacings. We plan on using this image in the display for the ALMA meeting. Lee can prvide the FITS file if needed.

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Number of Subarrays

What science will be lost if we have three or fewer subarrays? --------

Total Power Mapping --'Holdaway Holdover' Memo - Butler

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Action Items 30 August 99

DECISION: Configurations--where are we?

DECISION: Is a nutating secondary necessary?

DECISION: What is the effect of 1/f noise in the HEMT amplifiers of SIS receivers upon our ability to combine total power and interferometric images into a faithful representation of the sky?

MEETINGS: MAC meeting 15 September 1999 at noon. Next ImCal meeting 13 September 1999. ------

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Travel

If your travel isn't on here you have not sent me a travel authorization.

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A. Wootten:

J. Mangum:

M. Yun:

B. Butler:

S. Radford: