ALMA Update

1  Recent news

1.1  Construction Progress

February 23, 2008 marked the fifth anniversary of the signing of the Agreement concerning the Joint Construction and Operation of the Atacama Large Millimeter Array (ALMA). The sixth year now entered will be the last year before commissioning observations will begin. In December, 2007, the U. S. Congress enacted the FY2008 budget, which provided funding for the seventh year of ALMA construction at the level requested by the National Science Foundation. In early February, the President requested funding for FY2009, the eighth year of this eleven year project.
At the Array Operations Site (AOS, 16570ft altitude), the grading of the central cluster area should be completed in May. Work on antenna foundations continues. Work on the transporter hangar should be completed soon.
The ALMA transporters are continuing toward acceptance expected later in the month. Tuning of the two transporters on the OSF-AOS road is taking place; they are routinely moving up and down with dummy antenna load. Provisional acceptance on site of Front End # 1 is expected shortly.
At the Operations Support Facility (OSF, 9600ft altitude), provisional acceptance for the ALMA Camp Extension was given 21 April, finishing this project. Vertex Antenna # 1 informal pointing tests are continuing nightly with AIV support. Installation of the Holography receiver on this antenna has been postponed until repairs to the damaged quadripod structure are completed. Formal acceptance of this antenna has slowed owing to equipment failures. Vertex antennas # 2 and # 3 underwent photogrammetry 14-22 May. Vertex antenna # 4 panels are being installed along with other work. Vertex antenna # 5 pedestal and BUS are en route to Chile. Melco Antenna # 1 holography measurements were finished and the holography receiver and the minirack were successfully uninstalled by Assembly, Integration and Verification (AIV) crew. Melco # 3 continues antenna driving tests; Melco # 4 continues photogrammetry and panel adjustment. The surface accuracy of the first ACA 12-m antenna already achieved less than 13 microns rms.
At the ALMA Test Facility (ATF, VLA site), the first interferometric pointing results by TelCal were demonstrated. Interferometric phase calibrations and pointing calibration with TelCal reduction and QuickLook display is now working. On 17 May, a critical brake failure on the AEC antenna halted operations for some time. Scheduling Blocks created using the ALMA Observing Tool (OT) are being observed routinely at the ATF, using the Interactive mode of the Operator Master Client (OMC). The ATF will remain in operation until September 1, 2008 and is being used primarily to test ALMA software.
The second quadrant of the correlator is completely assembled except for the data port interface installation; handover to the Computing team for systems verification will be in about 1 month. At the North American Front End Integration Center (NA FEIC), a nearly complete second ALMA front end is mounted on the tilt table in the environmental chamber, with a third front end partially assembled on the second tilt table. All Tunable Filter Board (TFB) cards to complete the 3rd quadrant of the correlator have been functionally tested in Bordeaux.
In Europe, the assembly and integration of the steel structure for the first AEM antenna is continuing. Acceptance of the first antenna now expected around April 2009. The CFRP cabin for the AEM antenna suffered damage to two backup structure (BUS) interface flanges during transport and needs repair at manufacturer in France. Elements of the amplitude calibration device, calibration wheels and two hot loads have been received by ESO and the integration of the first prototype is progressing well.
In Japan, assembly of the first Band 4 (2mm) cartridge has been started. In Taiwan, testing of a Band 7 (.85 mm) cartridge and Band 9 (.65mm) cartridge has been completed at the East Asian Front End Integration Center (EA FEIC).
This report covers the period Feb 25 to May 19, 2008 and is condensed from Al Wootten's bi-weekly calendars, which are available at 
http://www.cv.nrao.edu/~awootten/mmaimcal/ALMACalendars.html

1.2  Personnel news

The ALMA Board was pleased to announce that Dr. Tetsuo Hasegawa would take up the position of Interim ALMA Project Manager at the Joint ALMA Office in Santiago effective 1 May 2008. Dr. Hasegawa is a world expert in millimeter astronomy, with excellent scientific and instrumental credentials. He has been the Project Director and Project Manager for the Japanese contribution to ALMA and has substantial experience in coordinating large international projects.
The search committees for a new Director and a new Project Manager have been working hard over the last three months. Both committees expect to interview possible candidates during the next month and to forward a recommended short list to the ALMA Board shortly thereafter.
Richard Prestage, Assistant Director for Green Bank Operations, has accepted an appointment as Head of Technical Services at the Joint ALMA Observatory. He plans to start his new duties in early May in Santiago.

2  ALMA Meetings

2.1  ALMA Science Advisory Committee (ASAC)

Doug Johnstone continues to play an active role in the ALMA Science Advisory Committee (ASAC). In late January, the ASAC met face to face in Chile to discuss charges from the ALMA Board on ALMA software, the ALMA calibration plan, and the ALMA Development Plan. During the trip, they were able to visit both the OSF, where five antennas were in various states of completion, and the AOS at over 5000 metres, where the first antenna pads were being poured.
The ASAC was generally pleased with the ongoing software progress although as yet the software is not ready for Early Science. As well, the calibration plan seems in very good shape and the project is well served by the addition of a full-time Project Scientist (Richard Hills) and Assistant Project Scientist (Alison Peck). The long term ALMA Development Plan, however, has required further consultation with the Board and will continue to be dealt with during the next few months. It is likely the first step in this process will involve a careful examination of the scientific drivers for ALMA beyond its present instrument complement. This is likely to be undertaken, at least at the beginning, by a small team of astronomers with broad perspectives and expertise at multiple wavelengths who will work with the community. Stay tuned and please feel free to pass along to members of the CASAC or ASAC any specific thoughts you might have for future science and instrument complements for ALMA.
Although the ASAC report from the January meeting was been presented to the Board at their meeting in April, the full report is not yet available on the public ALMA web site. The next ASAC meeting will be held in late September, 2008, in Charlottesville, Virginia.

2.2  Upcoming Science Meetings

The North American ALMA Science Center will host its third annual science workshop in Charlottesville, Virginia September 25-27, 2008. The subject of this year's workshop is "The Birth and Feedback of Massive Stars, Within and Beyond the Galaxy", a timely theme, given the ability of ALMA's frequency coverage, sensitivity, and resolution to bridge the gap between Galactic and low-redshift extragalactic studies of star formation and feedback. More details about the program and logistics can be found at the workshop website 
http://www.cv.nrao.edu/naasc/massive08/  
ESO recently held a workshop on "Gas and Stars in Galaxies: A Multi-Wavelength 3D Perspective" June 10-13, 2008 in Garching, Germany 
http://www.eso.org/gal3D2008
This conference brought together the optical/near-IR and submillimetre/radio communities working on 3-dimensional extragalactic data. The talks from the conference will be made available on the conference web site.

3  ALMA Developments in Canada

3.1  Band 3 Receiver Development

The Band 3 Receiver Development Team has completed assembly and testing of the original eight pre-production receivers and is now moving forward with the production run of 65 additional cartridges. In all five cartridges have been sent to Front End Assembly locations in North America, Europe and Asia. An additional four cartridges have been fully tested, and three more are completely or partially assembled.
The process of outsourcing to industry the procurement, component testing, and assembly of the receivers is underway and should be finalized soon.  Already the mixer assembly and cryogenic amplifier assembly and qualification are taking place outside HIA.  The final testing of the completed receivers will continue to be performed by the Band 3 Development Team at HIA.
Another milestone for the ALMA Project was realized this spring when the first Front End, including a Band 3 receiver, was delivered to Chile where it is now undergoing testing. 

3.2  Software

The end of February marked an important event in that Canada completed delivery of all the FTE-years of software development time specified in the original agreement between NRC and NSF. There has been a discussion about the way ahead between the Radio Astronomy Group at the University of Calgary and HIA. We expect software work in Canada to continue over at least the next 18 months
During the period from mid-December 2007 until mid-March 2008 when CASA Beta Patch 1 was released, Raymond Rusk's focus switched from image analysis to data processing in the uv-plane. He implemented Hanning smoothing of uv-spectral data and an AIPS UVSUB-like task. He also worked on regression testing including a mosaicing regression test based on an NGC 1333 dataset, and he resolved numerous bugs, many of which were related to FITS image headers. During the period from mid-March to the CASA Beta Patch 2 in June, 2008, Raymond worked on the CASA User Reference Manual and performed bug fixes.
Shannon Jaeger has added a tasking layer to the image tools, which include the tasks imhead, imcontsub, immoments, imregrid, imstat and imfit. She is currently improving these tasks and adding others such as imregion, immath, and imregrid. The task development environment is evolving, and considerable interaction with end-users is involved in design of the task interface. Shannon spent a week in Charlottesville discussing these issues with Crystal Brogan and others. She has also helped out in several areas with the plotxy tool, one of her former responsibilities, now reassigned to a developer in Socorro.
At the end of February, both Raymond and Shannon attended a four day CASA developer's meeting hosted by NRAO at the VLA in New Mexico. The subject of discussion was the current status and development of the offline software during the next year. With all developers present, group consensus on many issues was possible making consistency in the software more likely, especially in the area of user interfaces. In May, Raymond presented a poster at CASCA 2008 in Victoria summarizing working done in Canada on ALMA software from 2002-2008.
As previously reported, the first phase of the ALMA Request Handler was completed in March 2008 and has now been delivered to the ALMA Archive Group. Norman Hill attended the ALMA Archive Group meeting in Garching Germany April 7-9, 2008. As part of this meeting, installation of the Request Handler on the ALMA Archive Group systems in Germany was started. Completion of the installation is pending availability of effort from the Archive Group in Germany.
Dustin Jenkins and Adrian Damian are nearing completion of the second phase of the Request Handler development. The new functionality to process data before delivery to users, and to allow data to be delivered to users on physical media, is completed and is ready for external review by the ALMA Archive Group. This second phase of the Request Handler is expected to be delivered to the ALMA Archive Group in June.
The fifth user test of the ALMA Pipeline was completed February 15 and the final report has been submitted. This was the first test to involve automatic processing of the single dish data that is expected from the 12 m antennas in the ACA.
The pipeline development team held a face-to-face meeting in Socorro in April, 2008; Chris Wilson attended for two of the three days. One of the main topics of the meeting was the priorities for development for both the single dish and the interferometric pipelines, as well as plans for regression tests on both pipelines and a sixth user test (this time of the interferometric pipeline) to be held early in 2009.

3.3  ALMA Test Facility

This spring, Doug Johnstone, James Di Francesco, and Henry Matthews undertook visits to the ALMA Test Facility (ATF) at the VLA site of the NRAO near Socorro, New Mexico.  Ostensibly these visits were to test the hardware and software which will be used by ALMA in Chile by undertaking observations with the prototype telescopes. During Doug's visit, however, he often found himself being used to help test systems under supervision by the ALMA Project Scientist Richard Hills.
During Doug's trip there was some time for science observations too. Since Orion had already been viewed, and the Galactic Plane high mass sources were not yet visible, they observed the evolved star IRC 10216, a star which is losing its exterior back into the interstellar medium. Prior observations have shown that this source has a very bright and fast moving shell, observable with the CS molecule. 

After much frustration with a blown fuse, they managed to find an hour or so to set-up and run the observing scripts (actual time observing the sky was only about 30 minutes).  The accompanying two very rough and dirty figures show the raw results of the observations.  While there is nothing new in these observations, they do show that the ALMA interferometry works, and perhaps more importantly, that the data can be reduced using the CASA software.

Figure 1: An overview of the observed data (Calibrator and Source): (Top panel) The signal phase as a function of time (averaged over all channels). You can clearly see the times where we observed the calibrator. For most of the run the phase seems to stay quite stable which is a testament to the reasonable weather during the observations. (Middle Panel) The amplitude of the signal averaged over all channels. The calibrator amplitude stays quite stable which again tells us that the system is running very well. (Bottom Panel) The amplitude versus frequency channel for the source. The very strong blip seen in the centre of the graph is the CS line. We haven't  yet determined what the other strong spikes are due to.
Figure 2: A blown up version of the bottom panel of the previous figure, showing the intricate structure of the CS line. The double horn appearance is due to the fact that the bright emitting shell around the star is expanding both toward (blueshifted) and away (redshifted) from us.

 

Chris Wilson wilson@physics.mcmaster.ca
Canadian ALMA Project Scientist
(with input from Severin Gaudet, Doug Johnstone, and Raymond Rusk, as well as material from Al Wootten)


File translated from TEX by TTH, version 3.81.
On 18 Jun 2008, 10:29.