ALMA Update

1  Recent news

1.1  First Antennas Accepted

On 19 December 2009, the first 12 m antenna was handed over to the ALMA project. This antenna was one of four built by Mitsubishi Electric Corporation for the National Astronomical Observatory of Japan. Accepting an antenna from the vendor is a major milestone in the ALMA project. Interested readers can find more information in the NRAO press release at http://www.nrao.edu/pr/2008/alma/firstantenna.shtml

On 6 February 2009, a second production antenna from a different vendor was conditionally accepted by the ALMA project. This antenna was designed and built by the Vertex division of General Dynamics Corp. under contract with the Associated Universities, Inc. It will be equipped with the Front End recently delivered from the East Asian Front End Integration Center in Taiwan. After the next two antennas are accepted, the plan is to push one antenna through the test procedures each month. The NRAO ALMA Project Director, Adrian Russell, reports that General Dynamics is on track to complete delivery of their 25 antennas within days of the original schedule.

On 22 January 2009 scientists and engineers at the OSF achieved astronomical validation of an ALMA continuum system. The Moon was detected in three of the four bands available in the Front End, at 3 mm, 1.3 mm, and 1 mm (100 GHz, 240 GHz and 310 GHz). The sky from this low altitude site (2900m) did not cooperate with an attempt to observe at 0.44 mm (675 GHz) though signal throughput was attempted by detecting the antenna shutter. The newly accepted ALMA antenna was used with the first receiver assembly from the Front End Integration Center assembled at the NRAO Technology Center in Charlottesville, and a Back End assembled at the Socorro, NM Array Operations Center.

 

 
Figure 1: The first ALMA production antenna (constructed by Mitsubishi) being used to validate the ALMA system by observing the moon. Image from NRAO enews website (Feb 2009)
  

1.2  Other Construction Progress

To date, over 50 foundations have received structural concrete at the Array Operations Site (AOS) at 5000 m altitude. The first quadrant of the ALMA correlator continues to run in the Technical Building at the AOS. The 1-msec continuum integration mode was successfully tested recently and support of 2-, 4-, and 8-msec integrations is in development.

With 13 antennas in various stages of construction at the Operations Support Facility (OSF) at 3000 m, things are getting a little crowded! On 20 November 2008, Lore, one of the mammoth antenna transporters, moved the assembled Vertex antenna No 4 from the Site Erection Facility building to an antenna foundation above the Operations Support Facility to await further tests. Vertex No 2 completed installation of new linear sensor devices and alignment/tuning of sensors is in process. Photogrammetry is now complete for Vertex No 6. The pedestal and Backup Structure (BUS) for Vertex No 7 have been mated and panel installation in progress. The pedestal and BUS for Vertex No 9 have arrived and are awaiting a free antenna foundation to begin assembly.

The second engineering model Front End, this one from the East Asian Front End Integration Center (EA FEIC), achieved provisional acceptance site (PAS) on 17 December 2008. On the software side, CASA patch 2.3.1 has been released. Approximately 200 new users have registered and downloaded CASA since its public release in July 2008.

If my quarterly ALMA updates are not frequent enough for you, a good source for monthly updates on the ALMA project is the new electronic NRAO newsletter http://www.nrao.edu/news/newsletters/

And don't forget the new ALMA observatory web site http://www.almaobservatory.org/ which contains wide range of information about the observatory, including details about science and technology, infrastructure, geographical location, etc.

 

Figure 2: The first production antenna from Vertex is carried into the testing area of the OSF by one of the two ALMA antenna transporters on 6 Feb 2009. Image from NRAO enews website (Feb 2009)

 

2  ALMA Meetings

2.1  Preparing for ALMA: from Science to Observations

Are you curious about ALMA? Think ALMA will help your science? Concerned that you haven't used radio/submm or interferometric telescopes before? And how DO those interferometers work anyway? McMaster University will be hosting a hands-on workshop for Canadian faculty, postdocs and students interested in learning about how to use ALMA. The workshop will run from 1-3 June 2009, immediately following the CASCA annual meeting in Toronto.
In less than 2 years, early science will begin with ALMA and Canadian astronomers will have access to the entire North American pool of observing time ( 34%). In order to take advantage of this unprecedented access to this premiere facility, it is imperative that Canadian astronomers begin to familiarize themselves with how ALMA will observe and how to propose for time. The goal of this 3-day workshop is to educate astronomers from all backgrounds about radio astronomy and interferometry, the ALMA Observing Tool, the ALMA Simulator, the ALMA data reduction software (CASA), and other ALMA tools.
Participants will be able to take their science idea from concept through simulation and proposal design and process a supplied real or simulated data set using CASA. Participants will carry out this work on their own portable computers with the help of CASA and radio astronomy experts.
Although the workshop will provide a sufficient introduction to interferometry concepts, its primary aim is to introduce the community to the ALMA specific tools. It is meant to complement, rather than replace, the focused NRAO Interferometry summer school. Confirmed speakers for the meeting include Crystal Brogan (NRAO), Claire Chandler (NRAO), Sean Dougherty (NRC/HIA), James Di Francesco (NRC/HIA), Remy Indebetouw (NRAO), George Moellenbrock (NRAO), Tony Remijian (NRAO), Gerald Schieven (NRC/HIA), David Wilner (Harvard-Smithsonian CfA), and Chris Wilson (McMaster).
A maximum of 50 participants will be registered. Registration is now open and will close 30 April 2009. A registration fee of $50 is payable in advance More information and registration forms can be found at http://www.almatelescope.ca/Workshop
The first 20 graduate students at Canadian institutions to register will receive travel support toward accommodations and meal expenses during the workshop. See web site for more information.

2.2  Upcoming ALMA Science Meetings

The next NRAO workshop is still in the planning stages, but will focus on the assembly, gas content, and star formation history of galaxies. The workshop will be held 21-24 September 2009 in Charlottesville, Virginia.
Outside North America, ESO is hosting a workshop on "ALMA and ELTs: A Deeper, Finer View of the Universe" from March 24-27, 2009. This workshop aims to explore the scientific synergies between ALMA and the planned very large optical/infrared telescopes. In Taiwan, the Academica Sinica is hosting a conference on "Millimeter and Submillimeter Astronomy at High Angular Resolution" from June 8-12, 2009.

2.3  ALMA Science Advisory Committee (ASAC)

Doug Johnstone (HIA) represented Canada at the ASAC face-to-face meeting, which took place in late January 2009 at the Operation Support Facility (OSF) part way up to the ALMA high site so that committee members could tour the ongoing construction, assembly, and integration of the array intertwined with the gathering. The ASAC arrived just after the first Vertex antenna had been conditionally accepted by the ALMA project and the site was busy with activity as the antenna was put through its commissioning tests.
The ASAC discussions covered a wide variety of issues including consideration of the new project schedule (which still indicates a call for Early Science in mid-2010), the status of the ALMA software, and the progress of system integration and commissioning.  A large amount of time was devoted to the issue of Early Science readiness, including the minimum status of the array that must be reached before Early Science can begin (at least sixteen antennas) and the process by which proposals will be accepted. As might be expected, the issue of proposal selection and time allocation remains a complex topic within the international ALMA project.  The ASAC also continued its discussions around the need for an ALMA Development Fund and the type of projects that might be considered.  With the US Decadal Report underway in our neighbour to the south, this is a very timely and hot topic!
Doug Johnstone adds "On a personal note, I was astounded by the progress at the ALMA site over the year since the ASAC last visited. I believe that this can be significantly credited to the strong and dynamic team the project has put together, including Canadians Rick Murowinski and Lewis Knee. I suspect the next year will be even more productive as two-element, and hopefully three-element, interferometric observations begin."

3  ALMA Developments in Canada

3.1  Band 3 Receiver Development

The Band 3 production scheduling review was held at HIA on Jan 27-28, 2009. A proposed production plan was presented to Adrian Russell, the North American ALMA Project Manager, and Philip Puxley, the NSF representative on the ALMA board. The reviewers were very impressed with the progress of work at HIA and with the level of industrial collaboration involved. With the help of an excellent SIS wafer from the University of Virginia last year, we are able to double the yield estimate of the Band 3 mixer production. Consequently, we were able to move the delivery date of the last cartridge up by more than half a year to November 2011. In order to deliver Band 3 cartridges at this accelerated schedule, ALMA management has given us the assurance that we will receive the incoming parts from ALMA at the same rate as well.
The manufacturing readiness review (MRR) of the Band 3 cartridge was held on 12 February 2009 at HIA. The review committee was satisfied with the technical performance of the 13 finished Band 3 cartridges and the proposed production plan. Mike Rodriguez, the chairman of the review committee, has given the approval for the production of the remaining 60 Band 3 cartridges to be delivered to the ALMA project by the fall of 2011.

3.2  Software

On 6 February 2009, the final version of the ALMA Request Handler, developed by the CADC, was delivered to the ALMA Archive group at ESO. The Request Handler provides both a graphical user interface and a programmatic interface to the Archive system to allow users to access data stored in the archives and/or to initiate processing to generate data for retrieval. It supports access to public data by any user, and access to proprietary data limited to authorized users. It also supports synchronous and asynchronous (staged) data access.
At Calgary, Shannon Jaeger's responsibilities continue to be the image analysis portion of the CASA software package. This portion of the software includes statistics, convolution and deconvolution, probing for information, and in general manipulating CASA images. Most of her work centers around building the user-friendly Python interface to the existing infrastructure; image smoothing will be in the next release of CASA. She has also been working with image region support which affects not only the Python interface but the image viewer as well. The hope is to be able to read/write regions to several file formats and have the viewer display them.
At McMaster, Chris Wilson has begun a second round of regression tests for the ALMA Pipeline subsystem. These tests focus on reducing single field interferometric data and are a follow-up to a first round of regression tests held last summer. So far she has been able to look at two of the ten data sets, one from the VLA and one from the Plateau de Bure interferometer, that were used to develop the pipeline script. She finds the web-based user interface easy to use, although (as usual) inspecting the hundreds of plots of the various reduction stages becomes tedious after a while. Ultimately the pipeline will present a more condensed overview for the general user, but during development it is important that the testers be able to inspect all the stages in detail. (Chris has been known to joke to family and friends that pipeline testing is the world's most boring video game.)
Chris Wilson wilson@physics.mcmaster.ca
Canadian ALMA Project Scientist
(with input from Shannon Jaeger, Doug Johnstone, and Gerald Schieven, as well as material from Al Wootten)


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On 19 Mar 2009, 19:01.