ALMA previous meeting     next meeting

Contact Information

* 2009-10-21 14:30 UT
Note UT time unchanged. Summer time ends in Europe 25 Oct and in US 1 Nov. * Note: C. Wilson points out line noise may be muted by pressing *6 which works thru the call center.
* Duration: 1 hr
* USA Toll Free Number: 877-874-1919
* Toll Number: +1-203-320-9891
* Passcode: 185064
* Leader: Hills, Wootten, Testi, Morita
* Attendees:

Topics

1 Old Business The enhanced Agenda from last meeting is available. Science IPT notes from last month's telecon are not available.

Two Antennas at the  at AOS TB

DV01 and PM03 have been placed near each other at the AOS in preparation for interferometry, on stations 96 and 109. On Friday 16 October 2009, Joe McMullin reported:
  • 1330 Antenna arrived at station A109 at the AOS
  • 1355 Antenna put down on pad
  • 1500 Antenna moved via control cabinet on platform
  • The next few days will finalize the connectivity, test the computing hardware monitoring and control and begin observations.

See other images and animations. See other images.

  1. New Business--Project news/updates.(Hills, Peck)
    1. R. Hills
      1. ASAC met at ESO, Garching, on 13th and 14th Oct. In addition to the usual reviews of project status, discussion of technical issues with implications for performance, (see edm_links, the committee discussed the planning leading to Early Science including the ARCs and the software, especially the observing tool. The reviews of the Commissioning Plans and of Operational Planning were summarized and there was discussion of aspects of the Proposal Review Process and of the Science Requirements.
      2. A proposed requirement for software "latency" - the overhead time due to software has been drafted and sent to CIPT. Software Latency Requirements (pdf)
      3. Testing activities at the OSF have continued but at a lower pace due to the antenna moves to the high site. This provides an opportunity to get reports written up.
      4. The report from the Commissioning and Science Verification Plan Review took place at the OSF on September 2nd and 3rd, chaired by Bob Wilson with other panel members were Nario Kuno, Peter Schilke and Melvyn Wright, has been received.
      5. A review of the Science Operations took place in Santiago 29-30 Sept.
      6. Antennas: Elements of more than 16 antennas from all vendors are at the OSF--necessary for early science (but not sufficient). Next antenna acceptance DV05 shortly. First ACA 7m antenna has embarked upon the high seas from Japan.
    2. Employment
      • JAO positions Commissioning Scientists. Search status: Offers made--Two additional commissioning scientist posts have been filled - Lance Simms and Eric Villard will be joining the team early next year.
      • ESO ALMA Fellows position open
      • ALMA, NAASC positions, more to be advertised.
      • NAOJ
    3. ALMA Science IPT wiki page
    4. Astronomer Outreach: JAO ALMA Webpages. JAONews. ESO Newsletter No 16 NRAO eNews ALMA News. NAOJ News. NRAO ALMA Calendar
    5. Current ALMA System Block Diagram Vers P.
  2. Directories

Science IPT Group Activity Reports

Please include your Group Activity Report here (How to Enter Your Report), or email it to AlWootten

Project Scientists

  1. Change Requests. A significant change request was discussed last meeting: Band 6 CRE. This relates to the Band 6 performance and in particular requests that the range of IF frequencies over which the performance is assured be limited to 6 to 10GHz instead of the original range of 4.5 to 10GHz. The instantaneous bandwidth was always limited to 4GHz so the main effect is to reduce flexibility in making simultaneous observations of two or more lines. In particular it will no longer be possible to observe 12CO J = 2-1 and 13CO J = 2-1 at the same time. Note that these two lines may be observed simultaneously in the J=3-2 line, but not in J=1-0 owing to the interplay between the line separation and the IF choices ALMA has made. We requested a reconsideration of this in particular to assure performance over 5 to 10 GHz but with a relaxation of the gain slope specification. Al reports that. "Tests were made of mixer-preamp performance using the older version of the bonded interface, with the result that the noise temperature in the 4-6 GHz IF range is improved, but gain slope using the present warm IF amplifiers (which have equalizers optimized for 6-10 GHz performance) is an issue." REH received the following from John Effland:
    • Between 5 and 10 GHz IF, for 2 GHz bandwidth, gain slope of 5 dB from 6-10 GHz and 6 dB from 5-6 GHz (as per Richard Hill's recommendation).
    • Between 5 and 10 GHz, for 5 GHz bandwidth, gain slope of 7 dB
    • Get MTS LO fixed to eliminate noise spike - will assume 20% of mixers fail new 5-10 GHz specs.
    • CRE should include changing top level science specs, FE, and Band 6 specs.
    • Old (IN1A) Design:
      • No time at the present for additional experiments. Wait a few months and review production schedule.
      • Write up and submit to Science IPT benefits of using IN1A .
  2. Configuration change. The location of the northernmost pad has been under discussion, see Maps of North Arm (pdf). Sawada-san has checked on the effect of pad relocation (pdf). This main effect is to make the beam somewhat elliptical with the extension N-S. Does anyone see a strong objection? Otherwise we will go ahead with this.

(BojanNikolic-- I'm not sure it is fair to consider the fitted Gaussian main beam in this case. This assumes that the observer is interested in a wide range of angular scales, but obviously in O28 they are likely to be interested in the finest scales.

Maybe the way to tackle this would be to compare the difference in the fitted main beams between say O25 and O28-original and the difference in O25 to O28-new. This would show how if (and how much) on losses with this change, compared with just discarding some of the most extended configurations.

Also, since I assume the big area of concern here is the loss of resolution, it would be good to also plot the beam maps in the report much enlarged (e.g. 0.03x0.03 arcsecs total map size), so that one can see the change in the main beam and innermost sidelobes. )

As a partial response here (pdf) is the u-v coverage for a snapshot observation of a source at the zenith, with some statistics.

Jeff Mangum -- Calibration

  • Temporary weather stations installated on roof of AOS TB. Some adjustments, calibrations will be done on them.
  • ATCA survey of calibrators at 20 and 95 GHz to be included in OT list.

Bojan Nikolic/John Richer -- WVRs

  • The first (quite short) test of the Water Vapour Radiometer phase correction technique at the OSF was carried out on the night 4th October. The preliminary results look encouraging. Plots are shown in attached document OSFFirstResults.pdf

Lars-Ake Nyman -- eSSR

  • ALMA SciOps Implementation Plan Review was held at SCO 2009 September 29-30, 2009.

Testi, Klaassen-- Design Reference Science Plan

  • DRSP updates have been completed

Wootten -- Site Characterization

Remijan, Markwick -- Splatalogue

Science Corner:

arXiv:0910.1609 Title: The Science Case for Building a Band 1 Receiver for ALMA Authors: D. Johnstone, J. Di Francesco, B. Matthews, N. Bartel, S. Casassus, S. Chitsazzadeh, G. Duchene, A. Hales, M. Houde, P. M. Koch, R. Kothes, S-P. Lai, G. Moriarty-Schieven, D. Scott, H. Shang, S. Takakuwa, J. Wagg, A. Wootten

Calendar

1 Next meeting is on Nov 18th (14:30 UT). Dec16th for the following month.

Events of Interest

(see also Al's ALMA Biweekly Calendar)

2009
 
 
 
 
 
 
Day
Date
Time
Event
location
details
 
 
Oct 21
 
Sci IPT
telecon
 
 
 
Nov 16
 
ALMA AAER
 
 
 
Nov 18
 
Sci IPT
telecon
 
 

Upcoming Meetings

From circumstellar disks to planetary systems Nov 3-6 Garching

Astrobiology Science Conference 2010 April 26-29, 2010 League City, Texas

Recent Meetings (presentations online)

Science at Q Band Sep 14-15, Manchester

Mass Assembly and Star Formation History of Galaxies Sep 21-24, Charlottesville, Virginia

To the Edge of the Universe: 30 years of IRAM Sep 28-30, Grenoble

Data Needs For ALMA. Oct 5-7 Koln Germany

-- AlWootten - 2009-10-20
Topic attachments
I AttachmentSorted ascending Action Size Date Who Comment
Effect_of_pad_relocation.pdfpdf Effect_of_pad_relocation.pdf manage 2 MB 2009-10-21 - 08:23 RichardHills  
Maps_North_Arm.pdfpdf Maps_North_Arm.pdf manage 259 K 2009-10-21 - 08:37 RichardHills  
OSFFirstResults.pdfpdf OSFFirstResults.pdf manage 118 K 2009-10-21 - 05:29 BojanNikolic Plots of the WVR phase correction experiment
Outer_Pad_Mods.pdfpdf Outer_Pad_Mods.pdf manage 50 K 2009-10-21 - 10:19 RichardHills  
Software_Latency_Requirements.pdfpdf Software_Latency_Requirements.pdf manage 20 K 2009-10-21 - 07:14 RichardHills  
Topic revision: r12 - 2010-08-02, ToddHunter
This site is powered by FoswikiCopyright © by the contributing authors. All material on this collaboration platform is the property of the contributing authors.
Ideas, requests, problems regarding NRAO Public Wiki? Send feedback