ALMA Update

1  First antennas to the high site!

The ALMA project reached a major milestone on 23 September 2009, when the first of the 12 m antennas was transported to the Array Operations Site (AOS) at 5000 m altitude. The second ALMA antenna reached the high site on 16 October and by 21 October the pair of antennas had been used as an interferometer to detect fringes on an SiO maser in Orion in the 3 mm window (Band 3). Fringes were also soon achieved in the 1.3 mm (Band 6) and 850 micron (Band 7) windows. Detecting fringes with the antennas and the rest of the hardware and software constitutes a unique and important test of the system as a whole. Congratulations to everyone involved in this effort!

More details and press releases on the antenna transport (including a great 3-minute video) are available on the ALMA and NRAO web sites. A third antenna was transported to the high site in late November and the immediate goal of the project is to obtain phase closure with the three antenna system by the end of 2009. We expect more exciting announcements from ALMA early in the new year!
Figure 1: View of AOS interferometer taken from ALMA press release of 12 November 2009. Figure copyright: ALMA (ESO/NAOJ/NRAO), Alvaro Quintana and Jose Olivares (ALMA).

 

2  Other Construction Progress

At the AOS, concrete has now been poured for all of the 192 antenna pads that will be needed by ALMA. Work has now begun on buidling the access roads between the pads as well as constucting utilities (such as power and fiber optic cables). The second correlator of the ALMA correlator is now fully installed; ALMA's correlator is now equipped to handle up to 32 antennas.
At the Operations Support Facility (OSF), the third and fourth North American antennas have been accepted from the vendor (Vertex). Several European antennas (Alcatel) are currently undergoing receiver cabin tests. Recently, the parts for the first of the twelve 7 m antennas built by Mitsubishi have arrived and are waiting for construction to begin.

2.1  Canadians involved in ALMA

James di Francesco recently returned from three exciting weeks at the ALMA sites, where he was the first Canadian to provide operations support for the ALMA project in Chile. He writes
"Most of my time was spent at the OSF at 2900 m outside of San Pedro de Atacama in northern Chile. It was very thrilling to be at ALMA, and see an observatory come together for the first time. My work days were spent with the Assembly, Integration and Verification Team as they conducted numerous tests on the antennas delivered so far to the project by the vendors.

"At the time, two antennas had moved up to the AOS at 5050 m and three antennas were still at the OSF. The AOS pair were being used to conduct the first interferometric tests at the AOS, and I was there for the first fringes between these antennas at Band 7 (850 microns). Also, I used the AOS pair as two single-dish telescopes to test the large-scale mapping capabilities of the ALMA antennas. In addition, I developed pointing models for the three antennas at the OSF and significantly expanded the target list for further high frequency tests. (Thanks to my student, Shadi Chitsazzadeh, for providing me with a list of H2O masers at 658 GHz!) During my last few days, the AIV team obtained with the two AOS antennas first fringes at Band 9 (450 microns), the highest frequency band so far that ALMA can observe. Also, an OSF antennas was taken to the AOS by an ALMA antenna transporter, so that more extensive interferometric tests could begin with three antennas (and baselines).

Figure 2: James di Francesco at the ALMA Array Operations Center in November 2009.

"One of the most memorable experiences during my trip was my visit to the AOS itself. Given the high altitude of the AOS, most operations will occur from the OSF and access to the AOS is limited. (Indeed, for safety reasons, only individuals who have passed a high altitude physical are allowed to visit.) Fortunately, I was able to tag along with a group heading up one morning. The Chajnantor plateau is an eerie location that is still mostly empty, despite the construction progress of the last few years. It is extraordinarily quiet, though construction was proceeding near the location of our visit. Also, the air is very thin, and I had to monitor my blood oxygen levels and have an oxygen bottle on hand for safety's sake. On the Chajnantor plateau, I saw the two ALMA antennas up close, and toured the AOS building itself. I got to see up close the first of the four quadrants of the ALMA correlator, as well as the extensive laser synthesizer and digital transmission systems. In addition, numerous completed antenna pads were there, waiting for more ALMA antennas to be moved up in the coming months.
"The OSF itself is an impressive site, though önly" at 2900 m. It commands a spectacular view of the Atacama desert, where easily 100 km of salt flats, mountains, volcanoes and canyons can be seen in a glance. The OSF is a very busy site, since that's where a lot of the antenna assembly is occurring by the vendors. Indeed, it is like a global village with about 400 people from nearly 30 countries working there. Most people are working on the Chilean "turno" system, of eight 12-hour days in a row followed by six days off, so there were always people coming and going throughout a given week. (I was there for a double turno with a two day break in between.) Though I spent most of my time with the antennas and the AIV team, I did manage to meet many other passionate people working hard on this huge project.
"The coming months promise even more milestones for the ALMA project. As part of Canadian operations for ALMA, my HIA colleagues and I will return to Chile many times in the coming years as the project moves towards Early Science."

3  ALMA Meetings

3.1  Recent Science Meetings

The fourth North American ALMA Science Center (NAASC) conference, "Assembly, Gas Content, and Star Formation History of Galaxies", was held 21-24 September 2009 in Charlottesville, Virginia. The meeting was attended by approximately 170 astronomers, making it the largest NAASC ALMA conference to date, and the majority of the attendees were not traditional radio astronomers. The meeting started with a discussion of the fundamentals of star formation, such as the initial mass function and star formation laws. This introductory session was followed by presentations focusing on gas and star formation in galaxies ranging from normal galaxies to starbursts and AGN, both in our local neighbourhood and at cosmological distances. The effects of environment, mergers, and accretion on galaxy evolution was a focus of several talks, along with the effects of feedback from stars and AGN on the star formation process. Many of the conference presentations are available on the meeting's web site 
http://www.nrao.edu/meetings/galaxies09/

3.2  Upcoming ALMA Science Meetings

Based on the success of the McMaster workshop and the timeline for Early Science observations with ALMA, we plan to hold a special information session on ALMA at the 2010 CASCA Annual Meeting at Saint Mary's University in Halifax. This information session will likely occupy 1.5 hours within the normal schedule of the CASCA meeting and its primary purpose will be to inform 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 late in 2010. Stay tuned!

4  ASAC and ANASAC

Doug Johnstone continues to represent Canada on ALMA science advisory boards, both within North America (ANASAC) and internationally (ASAC). These committees continue to devote much of their efforts toward making sure that everyone is ready for ALMA Early Science. It has been an extremely exciting and productive year as all parts of the project begin to fuse together - hardware, software, human resources, etc. Nevertheless, significant challenges remain. Perhaps the three most important of these are (1) the demanding delivery and integration schedule (for which the Canadian Band 3 project has done an awesome job!), (2) the recruitment of scientific staff in Chile and at the ALMA Regional Centers (if you are interested or know someone who is, please contact us!), and (3) keeping within the construction budget. Looking beyond construction, it is already time to start contemplating the development of the next generation of ALMA instrumentation (see for example Band 1 write-ups in previous version sof this newsletter). Exciting times for ALMA, and its advisory committees, to be sure.

5  Further Information

I apologize if this report is somewhat less complete than usual, as I am writing it from the Herschel Space Observatory Data Processing Workshop and Initial Results conference in Madrid. 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 October 2009 contains a wealth of detail on the project, including a "day in the life" narrative and a historical overview of the ALMA antenna produrement.
Chris Wilson wilson@physics.mcmaster.ca
Canadian ALMA Project Scientist
(with input from James di Francesco, as well as material from Al Wootten and the NRAO and ALMA newsletters)


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On 21 Dec 2009, 09:19.