ALMA Update

1 Recent News

On 31 May 2010, a fifth ALMA antenna arrived at the 5000 m elevation Array Operations Site (AOS) and was placed on one of the pads that are slated for use eventually with the Atacama Compact Array (ACA) 12 m antennas. ALMA astronomers and engineers were quickly succesful in linking all five antennas together for use in commissioning. Having ten baselines available gives a marked improvement in ALMA's current imaging capabilities. (On a personal note, my entire thesis consisted of data with no more than 9 baselines!)

Figure 1: View of five antennas at the ALMA high site in June 2010. Image credit: ALMA (ESO / NAOJ / NRAO) photo by Nick Whyborn, 3 June 2010.

By the start of Early Science observations in about a year from now, there will be sixteen antennas providing a total of 120 baselines. The Early Science ALMA array will give astronomers unprecedented sensitivity and precision with which to explore the southern sky.

The first call for ALMA observing proposals is expected in Q1 2011. Early Science with ALMA is expected to include at least 16 antennas, 4 receiver bands, baselines to 250 m, and single field interferometry. A goal is to offer baselines to 1 km and single dish mapping of extended objects in continuum and spectral line modes. While Early Science will coexist with array commissioning and construction, a portion of the available time will be allocated for science observations. Stay tuned!

2 Construction Progress

There has been a lot of progress on the various ALMA sites over the last 3 months. In March, two of the first three ALMA antennas were moved to pads located within the cluster of pads that is designated for the ACA. This was the first change of configuration for the fledgling array and allows access to much shorter ( ~ 30 m) baselines which give better stability for many commissioning tests. A fourth antennas was transported to the high site in April and a fifth at the end of May.

With shorter baselines as well as cooler autumn temperatures reducing the effect of turbulence from the lower atmosphere, a key commissioning goal has been to measure the antennas surface performance using holography on astronomical sources. Initial tests show that the telescopes are performing as predicted by models based on measurements from the Operations Support Facility (OSF), which is a warmer and lower elevation location.

The integration of the third quadrant of the 64-station correlator continues at the AOS Technical Building nearby the array. Tests of the ACA correlator from NAOJ are also proceeding.

New antennas and electronics continue to be accepted, integrated, and tested at the OSF. Front ends continue to be delivered from the North American, European, and East Asian Front End Integration Centers, including the first Front End to contain receiver cartridges for 6 different frequency bands.

Antenna assembly continues at the contractor's camps, with over 15 antennas in various stages of construction. In addition, several antennas are fully constructed and are undergoing holography, pointing, and other tests. A highlight in March was the sucessful integration of the backup structure onto the mount structure for one of the European Alcatel (AEM) antennas. The dish structures for two of the AEM antennas, complete with all their reflector panels, were mounted onto the pedestal and cabin structures in April.

2.1 Personnel news

In April, Mark McKinnon became ALMA North American Project Manager. He will continue to work closely with Adrian Russell until Adrian's departure to ESO this summer. Richard Prestage, Head of the Division of Technical Services (DTS) at the Joint ALMA Observatory in Chile, has announced that he will be returning to NRAO.

In July, Rick Murowinski and his family will return to Victoria. As the ALMA Project Engineer since May 2004, Rick has made deep, lasting contributions to the construction of this global astronomical facility. We are grateful to Rick for all his hard work on ALMA and welcome him and his family back to Canada.

As Chair of the ALMA Budget Committee, Jim Hesser was involved in extensive discussions prior to the April Board meeting regarding the Project's efforts towards improved understanding of operations and associated budgetary issues, as required by the Board and Project for Revision E of the ALMA Operations Plan (the currently approved ALMA AOP is Version D). For Version E the partnership will be clarifying policies and approach to development of future ALMA capabilities (e.g., new receivers, VLBI capability). Both the operations budget and AOP revision efforts are ongoing. Jim is also participating as Board representative in the selection process for a vacancy among the ALMA Key (senior) Staff.

3 ALMA Meetings

3.1 Upcoming ALMA Science Meetings

ESO will host a workshop on "The impact of Herschel Surveys on ALMA Early Science" 17-19 November 2010 in Garching, Germany. The registration deadline is 30 July 2010. The workshop is designed to explore the powerful combination between Herschel and ALMA, taking advantage of the Herschel's first results to best exploit the ALMA Early Science call for proposals expected towards the end of 2010. ESO hopes also to foster collaborations among Herschel users and between the Herschel and ALMA communities. The conference web site is

http://www.eso.org/sci/meetings/almaherschel2010/index.html

NRAO together with HIA will host the next NAASC conference on "ALMA: Extending the Limits of Astrophysical Spectroscopy", a 3 day workshop to be held in Victoria, BC, 15-17 January 2011. ALMA will make unique contributions to our understanding of the universe by allowing astronomers to probe physical and chemical environments, kinematics and dynamics in diverse objects from our own solar system to high-redshift galaxies. Please see the announcement in this issue of e-CASS, or visit

http://almatelescope.ca/Spectroscopy2011/

Pre-registration will begin July 1, and registration will be limited.

3.2 Early Science workshops in Canada

Want to get a head start on proposing to ALMA during the Early Science phase (deadline expected Q1 2011)? Members of the Millimetre Astronomy Group at HIA are willing to travel to your area to conduct mini-workshops on the use of the ALMA proposal tool and software, and/or give related science seminars. Please consult with Gerald Schieven (Gerald.Schieven(at)nrc-cnrc.gc.ca) if you'd be interested in hosting a mini-workshop in your area this fall or winter.

3.3 Previous Science Meetings

A special information session on ALMA was held at the 2010 CASCA Annual Meeting at Saint Mary's University in Halifax. This session focused on informing the community about Early Science opportunities with ALMA. Under the current construction plan, the first call for proposals for Early Science is expected to be issued in Q1 2011. The workshop included a discussion of the expected capabilities of ALMA during Early Science and the software tools that are available to prepare for and analyze ALMA data. There was also a more detailed demo of the Phase I proposal tool immediately after the end of the the CASCA meeting on Friday afternoon. The presentations from the information session will be posted on the Canadian ALMA web site

http://almatelescope.ca/

A special session on "Preparing for ALMA" was also held at the American Astronomical Society meeting on 24 May 2010. The special session included an introduction to the major tools that users will to prepare their observations and analyze their data, including the ALMA Observing Tool (OT) for proposal preparation and submission, the Common Astronomy Software Applications (CASA) package that will be used to reduce ALMA science data and includes an "observing simulator" task, and Splatalogue, an on-line VO-queriable spectral line database. The five presentations from the AAS meeting are available at

http://science.nrao.edu/events/preparingforalma.shtml#talks

4 ALMA Science Advisory Committee (ASAC)

The ASAC met most recently in Japan March 9-10. While the main topic of the meeting was ALMA Early Science, the ASAC also considered specific charges from the board.relating the the ALMA Proposal Review Process, possible ways to restore an acceptable level of contingency in the budget, the ALMA development fund, and revisions to the ALMA Scientific Requirements and Specifications. Here I give a brief summary of those aspects of the report which relate most to Early Science. For anyone interested in more details, the most recent ASAC report is available at

https://safe.nrao.edu/wiki/pub/ALMA/AlmaSac/ASAC_report_09Mar10_submit.pdf

The ASAC was charged with continuing to monitor the readiness of the ALMA software system. The committee noted important recent progress in the development of the Observing Tool (OT), but are concerned that the OT remains on the critical path for the ALMA project. The committee endorsed the current plan for a general community release by the third quarter of 2010, well in advance of the call for Early Science proposals. Regarding the other critical user tool, the CASA data redution package, the ASAC was very positive on the developments within CASA and the pace at which it was progressing. One issue that was raised was to what extent individual ALMA users will be able to (re)process ALMA data on their home institute's computer facilities.

The ASAC was also charged with reviewing the plans to carry out the intial processing of Early Science data for delivery ot the user community. A particular point of interest is whether sufficient resources (especially staff) will be available. The observatory will have the responsibility to perform quality assurance up to the level of image fidelity checking, with a level close to what the pipeline will produce. The ASAC's major concern is that unanticipated issues with instrument performance, software glitches, or requests from Early Science PIs will require substantial trouble shooting. If the quality assurance process does not work as expected, this could require the investment of significant time and human resources. This will be a period of high pressure for the staff at the ALMA Regional Centers (ARCs) and they should be involved in the development of the procedures to maximize efficiency and communication during Early Science.

The ASAC report concludes that an Early Science call for proposals by the end of this year remains feasible, but notes that the schedule is exceptionally tight. The report emphasizes that the technical requirements for Early Science should not be compromised in order to meet this pre-determined deadline.

5 ALMA Developments in Canada

5.1 Band 3 Receivers and Development

Band 3 receiver construction is almost half way done. By 2010 June 4, HIA will have delivered a total of 32 cartridges to the three ALMA Front-End Integration Centers. We are definitely meeting the 2 cartridges per month production requirement, which will see the last band 3 cartridge (number 73) delivered by March 2012.

The HIA millimetre Instrumentation team is continuing progress in component R&D for the ALMA Band 1. A cryostat has been assembled in order to test key components such as Low Noise Amplifier (LNA), optics, mixer. The first LNA prototype was used in this test cryostat in order to start evaluating systems performance. More gain, better input match and lower noise is necessary to meet the stringent Band 1 specifications. A second LNA prototype is currently in the design phase. Also, in collaboration with Uvic, a mixer concept with two transistors has been proposed and a prototype is currently been designed. HIA Band 1 R&D work will be summarized in a paper at the SPIE 2010 in San Diego.

Collaboration with University of Chile and ASIAA in Taiwan is on going. Following the visit of Pablo Zorzi, PhD student of University of Chile, last September, the design work was summarized into a paper: P. Zorzi, D. Henke, S. Claude and P. Mena."Revisiting the ALMA Band 1 Optics Design", 21th Int'l Symp. on Space Terahertz Tech., Oxford, March 23-25, 2010.

5.2 Canadian ALMA email list

A new email mailing list has been created for Canadian astronomers interested in ALMA. This moderated list will periodically send out updates on ALMA's status, news of software releases, notices of upcoming ALMA science meetings and workshops, etc., which would be of interest to Canadian astronomers. Those who wish to be subscribe to the alma-users list are encouraged to visit the web page

http://lists.astrosci.ca/mailman/listinfo/alma-users

or send an email to Gerald.Schieven(at)nrc-cnrc.gc.ca.

5.3 Software

The sixth Pipeline User Test is in progress at the time of writing. With 9 testers evaluating 15 data sets, including interferometry mosaics, this is the most ambitious pipeline test to date. Several Canadians also participated in the recent Observing Tool user test which took place in May as part of the first ALMA integrated test of the software tools related to composing, submitting, and assessing proposals.

6 Further Information

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 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. From there, you can also check out and subscribe to the new ALMA electronic newsletter (go to Newsroom and click on Newsletter), which comes out every few months and contains longer articles on various aspects of ALMA as well as recent updates. A new ALMA newsletter in April 2010 contains a wealth of detail on the project, including an in-depth discussion of how ALMA will make images and a detailed description of the recent progress at the ALMA site.

Chris Wilson wilson@physics.mcmaster.ca

Canadian ALMA Project Scientist

(with input from Gerald Schieven, Stephane Claude, and Jim Hesser, as well as material from Al Wootten and the NRAO and ALMA newsletters)

File translated from T_EX by T_TH, version 3.40.
On 21 Jun 2010, 15:51.