ALMA Update

1  Recent News

1.1  Earthquake in Chile

As you are no doubt aware, the major earthquake which struck Chile recently has had a devastating effect. Although initial word is that there have been no serious injuries to ALMA staff and their families, many have suffered property damage and everyone has been personally affected. The ALMA sites themselves in northern Chile were not affected by the earthquake and the offices in Santiago do not seem to have suffered major damage. Our thoughts are with our friends and colleagues in Chile.

1.2  Phase Closure Achieved

ALMA closed off 2009 by passing a key milestone of successfully linking three antennas at the 5000 m elevation Array Operations site (AOS).
The third antenna had arrived at the AOS on 20 November, and the next night saw the two-station interferometer at the AOS record fringes at a wavelength of 456 microns (658 GHz). Those observations of a water maser in the evolved star VY CMa on a 160 m baseline corresponded to a fringe spacing of 0.6 arcseconds and demonstrated the excellent performance of the instruments. Phase closure was the next major step and allows astronomers additional control over problems which can degrade the quality of an astronomical image, such as atmospheric turbulence or instrumental drifts. Using 3 antennas simultaneously allows astronomers to "close the loop" and cancel out many of these unwanted effects. The phase closure observations were made using the quasar 1924-292 which, unlike the majority of quasars, has bright emission in the millimetre and submillimetre wavelength range.

Phase closure is the first step on the path to the sensitive, precise, high-resolution imaging which will be an ALMA hallmark. Achieving phase closure also demonstrates the success of the full electronic and software system now being installed. It is also key step to the start of formal commissioning.

 

Figure 1: View of the three antennas at the ALMA high site that were used to achieve phase closure at the end of 2009. Figure copyright: ALMA (ESO/NAOJ/NRAO), W. Garnier (ALMA)

2  Construction Progress

ALMA Commissioning began 22 January 2010, exactly one year after first light on an ALMA antenna in Chile. The team has made good use of this year's unusually good "altiplanic winter" weather to work on commissioning correlator modes, water vapour radiometers, line length correctors, and other equipment that will be required for the first science observations. Much of the testing data is taken using "Schedule Blocks", which (as will sound familiar to JCMT and Gemini users) are small sets of observing commands generated by the ALMA Observing Tool (OT). This is the same software that ALMA PIs will use to submit proposals and generate Phase II observing instructions.
Two of the antennas at th AOS will soon be moved from their current locations (with baselines of about 200 m) to pads that will eventually hold the 7 m antennas of the Atacama Compact Array (ACA). The third antenna will remain about one km away so that tests on long baselines can continue as well. After about a month, the third antenna will also be moved to an ACA pad and all 3 antennas will be supplied with power from a central source.
There are currently a total of 24 antennas in various stages of construction in northern Chile. There are five East Asian 12 m antennas on site, two of which have been conditionally accepted by ALMA. In addition, the first of the 7 m antennas for the ACA has arrived and begun movement tests. There are 13 North American antennas on site: five have been conditionally accepted, one is in the final phases of acceptance testing, and the remaining 7 antennas are in various stages of assembly and integration. The first five European antennas have arrived at the OSF and are in various stages of construction. Two of the North American antennas and one of the East Asian antennas form the 3-element interferometer at the AOS. Two antennas are being used as a two element interferometer at the Operations Support Facility (OSF) at 2900 m elevation. This test interferometer allows ALMA staff to test new software, antennas and other equipment in parallel with the commissioning tasks being carried out at the AOS.
New Front Ends continue to arrive in tandem with the flow of new antennas. Receiver cartridges for Band 4 (2 mm) and Band 8 (600 mm) have been received from NAOJ in Japan and will soon be incorporated into dewars for shipment to Chile. One hundred sixty six of the 192 antenna pads at the AOS have passed preliminary acceptance. The pads in the ACA area will soon be available, which will allow interferometry on shorter baselines. A recent software upgrade at the AOS has brought many new capabilities on line, such as phase correction using the water vapour radiometers. The new software was used to observe the four Galilean satellites of Jupiter in a test of ephemeris capabilities. Interestingly, this observation with ALMA took place exactly four hundred years after Galileo's discovery of these moons of Jupiter.

2.1  Personnel news

Charles Cunningham from HIA is taking on the lead position with the North American Front End Integration Center. Nick Whyborn is the new ALMA System Integration Lead in Chile, taking over the position from Joe McMullin. Joe will be remaining in Chile for a period of overlap before returning to Socorro to work on the EVLA project
Adrian Russell, the North American ALMA Project Manager, will be leaving NRAO to take up a new position as Director of Programmes for the European Southern Observatory (ESO) in Garching, Germany on 1 July, 2010. While Adrian will definitely be missed, his new role will continue to benefit ALMA as well as strengthening the relationship between NRAO and ESO. Mark McKinnon, who is the current Project Manager for the EVLA, will be taking over the position of North American ALMA Project Manager.

3  ALMA Meetings

3.1  Upcoming ALMA Science Meetings

The first call for ALMA observing proposals is expected in January 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.
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 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. The workshop will include 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. We also plan to present a more detailed demo of the Phase I proposal tool to anyone who is interested at the very end of the CASCA meeting on Friday afternoon. Please check the CASCA meeting schedule for further details.
Another special session, "Preparing for ALMA" will be held at the May meeting of the American Astronomical Society on Monday, 24 May from 6-8pm. This Special Session will describe this Early Science opportunity and the ALMA tools and support available through the North American ALMA Science Center (NAASC). The special session will include 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 next NAASC ALMA workshop, Ëxtending the Limits of Astrophysical Spectroscopy", is expected to be held in Victoria in mid-January 2011 after the Seattle AAS meeting. The workshop will focus on 1) The Atomic Universe: Atomic Spectra as Probes of Cool Gas; 2) The Molecular Cool Dense Universe: Star-forming Gas; 3) Isotopic Variety in Cool Gas; and 4) Our Molecular Origins: Prebiotic Molecules. An announcement should be sent out soon.

3.2  Previous Science Meetings

The ESO-MPE-MPA-USM Joint Workshop, "From circumstellar disks to planetary systems", was held November 3-6, 2009 in Garching, Germany. Many of the talks are available online in pdf format at the conference web site 
http://www.eso.org/sci/meetings/disks2009/index.html
People interested in ALMA science may also be interested in the presentations from the Herschel Initial Results, which was held in Madrid, Spain December 17-18, 2009. The presentations are available on-line at 
http://herschel.esac.esa.int/SDP_IR_wkshop.shtml

3.3  ALMA Science Advisory Committee (ASAC)

Doug Johnstone just returned from the ALMA Science Advisory Committee meeting in Tokyo, Japan. The main topic of the meeting was ALMA Early Science which is still on track, with an expected Call for Proposals by the end of the year. It is clear, however, that the schedule required for commissioning of the telescope is extremely tight and much work remains to be completed. The construction budget for ALMA appears to be in good shape, with appropriate contingency funds available. The Operations Budget, however, is still under significant stress, in part due to the surge in the cost of power and the Chilean currency.
The details of the Proposal Review Process for ALMA are not yet complete but it is likely that a single international review process, possibly including Chile, will be used to determine the highest ranking projects for the telescope. Canadians are considered part of the North American region when applying for time and thus we have unrestricted access to North American time.
Finally, commissioning of the telescope has delayed the launch of the first phase of the ALMA Development Plan by about six months. Nevertheless, a call for parties interested in designing and/or producing the next generation of ALMA instrumentation is expected sometime in the next year.

4   ALMA Developments in Canada

4.1  Band 3 Receivers and Development

Band 3 cartridges are continuing to be produced at a rapid pace. Including the five cartridges that are currently going through the preliminary acceptance review (PAI) process, we have completed 26 cartridges so far. An earlier problem of cracking mixer chips during assembly has been resolved. Finer 0.9 mil diameter ground wires are now used in the mixer assemblies, instead of the 1.0 mil wire. Production of the Band 3 cartridges resumed as of the beginning of 2010, with 14 cartridges delivered in the first two and a half months of 2010. In addition, the construction of a second cartridge test facility was completed on January 31, 2010. With two cartridge test sets in operations, we are in full production mode operating at a rate of 2.5 cartridges per month. The latest estimated completion date of the 73 Band 3 cartridges is March 1, 2012.

4.2  The ALMA Primer

The ÄLMA Primer", originally produced for the workshop at McMaster last June, has been revised and updated, and a pdf file is available at almatelescope.ca. A 36-page pamphlet was produced and about 250 copies were handed out at the AAS meeting in January. These will also be distributed at the upcoming CASCA AGM. This document has received interest and praise from other ALMA partners, and is now featured on the international ALMA website (almaobservatory.org) and on the NAASC website.

4.3  North American ALMA Science Center (NAASC)

HIA continues to work with the North American ALMA Science Center in Charlottesville, VA, as part of our in-kind contribution to ALMA operations in North America. For example, James di Francesco spent three weeks in Chile in November assisting with integration and testing of observatory systems (see previous newsletter). Discussions and negotiations are underway to define HIA's role during ALMA science operations, which are due to start next year.

4.4  Software

The first non-beta release of CASA, version 3.0.0, was released in January 2010. This software, along with example scripts and data sets, can be downloaded from the NRAO web site at 
http://my.nrao.edu
CASA supports direct import of data in ALMA, VLA, and EVLA formats, and almost any data set that can be written in uv-fits format can also be imported into CASA. Because the ALMA Pipeline will not be available during Early Science, astronomers will need to use CASA to reduce their first ALMA data.
The Pipeline team continues to prepare for the next User Test which will focus on improvements to the calibration algorithms for single field interferometry and also the first implementation of mosaics with interferometric data. This User Test is now anticipated to start in April.
The Canadian ALMA web site at almatelescope.ca has recently been revamped, and continues to be updated. Feedback would be greatly appreciated. At the request of the International ALMA Project office, HIA has just acquired öwnership" of other ALMA-related web domains, i.e. almaobservatory/alma-observatory/alma-telescope(.ca), which will eventually link either to almatelescope.ca or to almaobservatory.org.

5  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 January 2010 contains a wealth of detail on the project, including an in-depth discussion of the Atacama Compact Array and a detailed description of the recent work to achieve phase closure at the high site.
Chris Wilson wilson@physics.mcmaster.ca
Canadian ALMA Project Scientist
(with input from Gerald Schieven and Doug Johnstone, as well as material from Al Wootten and the NRAO and ALMA newsletters)


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On 25 Mar 2010, 22:07.