ALMA Update

1  Recent news

There have been a lot of major events occurring in the ALMA project in the last three months. One major piece of good news was the signing of the European contract for their share of the 12 m antennas for ALMA. The contract with Alcatel Alenia Space, EIE, MT Aerospace Consortium was signed on December 6, 2005 by the European Southern Observatory (ESO). The procurement contract is to supply 25 antennas, with an option to supply up to 32 antennas. Both the European and North American contracts for the 12 m ALMA antennas have now been signed; the first antenna should arrive in Chile in about 18 months!
The major focus of activity in the international ALMA project this year has been the rebaselining of the project to bring it up to date since the last definition of its schedule and budget in October 2002. I'm happy to be able to report that this activity is now complete. A list of possible changes to the baseline ALMA project was sent to the ALMA Board for consideration at their November, 2005 meeting in Santiago. Changes which would have had an impact on ALMA's scientific capabilities were also sent to the ASAC for review and formed a major focus of the ASAC in the preparation leading up to their October, 2005 meeting. Among the many possible changes to the baseline project that were identified, only one change was accepted by the Board that will have a significant scientific impact, namely a reduction in the number of 12 m antennas in the main ALMA array from 64 to 50 antennas. While the goal is still to build 64 antennas for ALMA, the high cost of antennas in the final bids left the Board with very few options.
A high-level international review of the scope, schedule, and budget of the proposed 50-antenna ALMA was held October 13-16, 2005 in Germany. The committee chaired by Steve Beckwith and co-chaired by Thijs de Graauw produced a thoughtful report for the ALMA Board. Since ALMA's technical specifications established about 5 years ago were exceptionally ambitious, it is testimony to the hard work of the international teams that the committee found that "ALMA's technical readiness level is high. There is little risk that the project will be delayed because of technical issues." In their generally positive report, they further concluded that the scientific capability of ALMA remains compelling and provided constructive suggestions for bringing ALMA's construction phase to successful conclusion within the increased budget identified during rebaselining. The Board began implementing their recommendations during the November meeting.
One aspect of the ALMA project that could not be considered at the cost review in October was the impact of having two different vendors for the baseline project's 12 m antennas. As a result, the project will hold a "delta" cost review in late January to assess the impact of two different antenna vendors on the cost and schedule for ALMA. This review will be carried out by a subset of the panel that participated in the October cost review. There will also be an unassociated review of the North American project management, also in late January.

 

In other ALMA news, two major design reviews for the Japanese contribution to ALMA, of the 12 m antennas and the Atacama Compact Array System, were held in Japan in November. Preparations are continuing for optical pointing tests using the prototype antennas at the ALMA Test Facility at the VLA site. With Spring weather, construction began at the end of October for the ALMA Operations Site technical building. Trustees from Associated Universities, Inc. (AUI), which operates NRAO for the NSF, visited the ALMA high site on October 29, 2005. Jim Hesser and Lewis Knee from HIA were part of the group. During their visit, the AOS was blessed by local religious leaders during a special ceremony involving a blend of readings of Biblical scriptures and ceremonies traditional to the native Atacameo peoples.
 
Figure 1: Jim Hesser and Lewis Knee (clutching their green oxygen cannisters) at the ALMA high site October 29, 2005.

 

In science news, plans are well underway for the second world-wide meeting on "Science with the Atacama Large Millimeter Array" to be held in Madrid, Spain, on 13-16 November, 2006. This international ALMA conference is envisioned as a way for the astronomers interested on ALMA, not necessarily radio astronomers, to exchange views, to plan preparatory observations for the scientific exploitation of the interferometer, and to obtain the information needed to orient their scientific work to the best possible use of ALMA. The conference will cover a wide range of topics, which will include the main scientific drivers of ALMA: the formation and evolution of galaxies, the physics and chemistry of the interstellar medium, and the processes of star and planet formation. The web page for the conference is available at 
http://www.oan.es/alma2006/

2  ALMA Science Advisory Committee

The ASAC met October 1-2, 2005 in Santiago, Chile. The ASAC had four charges from the ALMA Board for this meeting: review the scientific impact of possible changes to the baseline ALMA coming from the rebaselining exercise; review the Scientific Specifications and Requirements document; continue their discussion from the previous two meetings on large projects, joint projects, and legacy projects; and discuss the scope and schedule of demonstration science with ALMA.
The rebaselining results were presented in the previous section. On the second charge, the ASAC recommended that the Board adopt the Science Requirements document after some clarifications, especially in the area of calibration and solar observations. The ASAC noted also that the document may require some revisions based on the outcome of the rebaselining process, e.g. changing the number of antennas from 64 to 50.
For the third charge, the ASAC reiterated their belief that a single international Program Review Committee (PRC) would best serve the ALMA project as well as minimizing several possible problems with joint programs and scientific duplication. Nevertheless, the ASAC report also describes a possible model based on regional PRCs and an International PRC that may minimize the adverse scientific effects of adopting a region-based review model. The ASAC also emphasized that they believe there is no need at this time to set up special procedures for large or legacy-type projects.
For the last charge, the ASAC proposed to split the concept of "demonstration science" into two different concepts: Science Verification and ALMA Public Images. Science Verification would be an end-to-end test of an ALMA mode using science projects proposed by external users. Science Verification is expected to start before Early Science and to continue, at a reducing pace, throughout the ALMA construction period. ALMA Public Images will be large-scale projects selected by the ALMA project, whose primary goal will be to demonstrate to the astronomy community and the wider public the value of ALMA. The first images are likely to be made for a very limited number of unique southern sources (e.g. objects like Eta Carinae and Centaurus A).
The ASAC report from the October 2005 meeting is available on the NRAO ALMA web site at 
http://www.alma.nrao.edu/committees/ASAC/
The next meeting of the ASAC is scheduled for January 28-29, 2006 in Los Angeles. We have three charges for that meeting: to review the progress in the science software development for ALMA; to review the plans and progress towards the scientific integration of the Atacama Compact Array into the baseline ALMA project; and to review the existing analysis on the imaging performance of the hybrid ALMA array and advise the project on whether additional work needs to be done in this area.

3  ALMA Developments in Canada

3.1  Band 3 Receiver Development

The Band 3 cartridge #2 is now being tested. So far, all tests performed have been satisfactory. The remaining tests are phase drift and gain saturation. The plan is to send this cartridge to NRAO early in the New Year, as the first delivered Band 3 cartridge. Cartridge #1 is awaiting the possibility of being upgraded with better mixers. Presently it has mixers from an early batch and the more recent mixers are of better quality. Assembly of cartridges #3 and #4 has begun, ensuring that there is much continuing work for the Band 3 team!
In order to demonstrate that our cartridge meets all requirements for mechanical integrity, we are subjecting a prototype engineering cartridge to shake and vibration tests, as well as testing all the thermal contacts.
The low-noise cryogenic IF amplifiers developed at HIA continue to attract attention from other receiver groups and low-temperature physics instrumentation groups. A research service agreement was put together in November between the CEA and HIA for the development of two ultra-high stability, low-noise amplifiers. CEA is the French Atomic Energy Commission and a world leader in atomic energy research. These amplifiers will be used by CEA physicists to study the characteristics of shot noise in GaAs materials at 4 K temperature. Christian Glattli, a nuclear physicist at CEA Saclay sent the following responses after the final test results of the amplifiers were delivered to CEA Saclay: "The specifications are incredibly good ! Far better than we expected. It is a real chance for us. 10% noise improvement means acquisition time reduced by one half in our detection system aimed to measure the fourth moment of the voltage fluctuations."
Finally, the Band 3 Critical Design Review is currently scheduled to take place in March 2006, although this is still be be confirmed.
For more information on the ALMA Band 3 Receiver Project contact Keith Yeung (Project Manager - keith.yeung@nrc-cnrc.gc.ca), Stephane Claude (Project Engineer - stephane.claude@nrc-cnrc.gc.ca), or Doug Johnstone (Project Scientist - doug.johnstone@nrc-cnrc.gc.ca).

3.2  Software

Software work for the ALMA Offline system and the ALMA Common Software system is continuing in Calgary and at DRAO. The ALMA Offline system (AIPS++) is currently in the midst of a major shift from glish to python-based scripting language and this is keeping everyone very busy. The first focus tests of the new python-based version will occur in January or February.
Chris Wilson attended the face-to-face meeting of the Science Software Requirements committee in Charlottesville in November. The Pipeline subsystem is gearing up for the next user test, which is currently anticipated to start in late January and will include outside testers from NRAO and HIA. This test will focus on flagging and calibration of single field interferometric data.
Chris Wilson wilson@physics.mcmaster.ca
Canadian ALMA Project Scientist
(with input from Doug Johnstone and Jim Hesser)


File translated from TEX by TTH, version 3.40.
On 20 Dec 2005, 08:15.