ALMA Update
1 Recent news
1.1 Construction Progress
The big news for ALMA in May was the approval of NSF's request for
additional funding for ALMA by the National Science Board. This action
provided the
NSF Director with spending authority that covers the revised baseline
cost of ALMA as
approved by the ALMA Board. It was the first step to acquiring the needed
additional funds; discussions with the U.S. administration and congress
are yet to come. As you may recall from previous newsletters, ESO was
able to approve the additional funding required for ALMA in late 2005
and the need to secure additional funds from the U.S. side has been
a major preoccupation of the last six months.
In physical construction news,
the outside shell of the main building at the 5000 m high site has been
completed and the contract to finish the interior has been let.
The contract for construction of the
Operations Support Facility (OSF) at the 3300 m site, an ESO
responsibility, has been
approved by the ALMA Board at their June 2006 meeting. After a review
of the feasibility of building a separate power station for ALMA, it has
been decided to connect to the Chilean grid rather than construct
and operate a stand-alone facility. Successful fringing tests using
the intermediate frequency (IF) downconverters were carried out in the
lab in Socorro, New Mexico, in which the IF output from two warm multiplier
assemblies were passed through the
backend analog and digital subsystems to the correlator where
cross-correlation power spectrum and phase plots were run.
Figure 1: the completed shell of the main building for the
Array Operations Center
for ALMA at the high site (5000 m elevation)
Dr. Paola Andreani has recently been selected to be the Manager of
the European ALMA Regional Center (ARC) for ESO. Her counterpart on the
North American side is Dr. John Hibbard of NRAO. Dr. Chris Carilli was
recently selected to head the North American ALMA Science Center
(NAASC) in Charlottesville, ( http://www.cv.nrao.edu/naasc/
) which includes the North American ARC and which will be responsible
for user support for the North American community
and other aspects of ALMA operations. A major task for the North American
community is securing the money for ALMA operations, which will ramp
up over the next few years in preparation for Early Science observations
in 2010.
We took advantage of the recent AAS meeting in Calgary to have
a meeting between U.S. and Canadian scientists involved in ALMA operations
planning to begin to define what role Canada will play in the operations
era. We will be having a series of telecons and an additional face-to-face
meeting over the summer to work out the details before the U.S. operations
plan is submitted to the NSF in the early fall of this year.
1.2 ALMA Science Meetings
The second world-wide
meeting on "Science with the Atacama Large Millimeter Array" will be
held in Madrid, Spain, on 13-16 November 2006. Registration for this
meeting is open until July 1, 2006 and is limited to 250 people.
The conference will cover a wide range of topics, which will
include the main scientific drivers of ALMA: the formation and evolution
of galaxies, the physics and chemistry of the interstellar medium, and the
processes of star and planet formation. The web page
for the conference, including the preliminary scientific program
and registration information, is available at http://www.oan.es/alma2006/
.
Students and postdocs will be interested to know that HIA will be
hosting a summer school on Submillimetre Observing Techniques,
which will include talks on observing with ALMA, from 14-17 August
2006 in Victoria. Registration for this meeting is open until June 30, 2006,
and information about the school can be found at http://hia-iha.nrc-cnrc.gc.ca/astroschool/
.
Chris Wilson presented an overview of the ALMA project and the types of
science it will do at the CASCA meeting in Calgary. In case anyone missed
the talk (it was moved from the second day to the first day to accommodate the
late arrival of Jim Stone, who was the first speaker), the talk will be
available on the Canadian ALMA web site at http://www.almatelescope.ca/
.
There was also a
special session on ALMA at the AAS meeting in Calgary,
with science talks on star formation by Doug
Johnstone (HIA), nearby galaxies by Jean Turner (UCLA), and high
redshift galaxies by Andrew Blain (Caltech).
2 ALMA Science Advisory Committee
The ASAC met 28-29 January, 2006, at the University of Maryland.
The ASAC had three charges for that meeting: to review the
progress in the science software development for ALMA; to review the
plans and progress toward the scientific integration of the Atacama
Compact Array into the baseline ALMA project; and to review the
existing analysis on the imaging performance of the hybrid ALMA
array and advise the project on whether additional work needs to
be done in this area.
Regarding the science software development,
the ASAC noted the continued progress by the
software development teams. The fact that
the major redevelopment of AIPS++ (to be renamed CASA)
required for ALMA data reduction remains to
be completed means that there continues to be a risk
on the development path. In addition to the technical work
remaining to be done, there is some concern that scientists
(both expert and novice users) may be hesitant to adopt the
new software given the history of the development of AIPS++.
The ASAC recommended that the ALMA software team develop a
plan to encourage adoption of the software as the system becomes
available to science users.
The ASAC also recommended that the ALMA project be 100% committed to sole
use of the ALMA science software during the commissioning period and
noted that it
is essential that the computing resources are available to support this use.
Regarding the scientific integration of the Atacama Compact Array (ACA),
the ASAC noted that there has been substantial
progress in the integration of the ACA into the baseline ALMA project. The
work on calibration has revealed the need for additional
clarification in the calibration
requirements, specifically in the area
of the cross-calibration accuracy between the ACA and
the 12m array. The ASAC report proposes
precise definitions for this requirement and three
other calibration requirements that are already in use for ALMA but
are not always clearly defined.
The addition of the ACA increases
the number of observing modes and the ASAC recommended that
the project carry out a detailed study of both the
calibration and the scheduling impact of these new modes.
Finally, the ASAC noted that the Design Reference Science
Plan does not include projects using receiver bands 4 (125-163 GHz or
1.8-2.4 mm) or Band 8 (385-500 GHz or 0.6-0.8 mm), or
detailed information for the use of the ACA, and recommended that
the DRSP be updated to include this missing information.
Regarding the polarization and mosaicing performance of ALMA,
the ASAC believes that having two designs for
the 12m antennas should not preclude any of the Level 1 science
goals for ALMA, including imaging fidelity and wide-field polarization,
as long as tight control of key antenna specifications is maintained.
The ASAC
recommended that the Antenna or System Engineering IPT use EM
modeling to estimate the beam and its sidelobes and that these
results be compared to the results from holographic data and
fed into further work by the Science IPT on mosaic
image fidelity and wide-field polarization imaging.
On other issues, the ASAC feels that ALMA outreach and public relations need a higher profile with better
coordination between the different groups involved. The ASAC recommended
that a fully-integrated and properly resourced IPT be formed to
ensure that ALMA has a single public face that reflects the
scientific excitement and technological excellence of the project.
The full ASAC report is available at
http://www.alma.nrao.edu/committees/ASAC/asacreport_2006jan.pdf
John Richer (Cambridge) is the new chair of the ASAC and
Lee Mundy (Maryland) is the
new vice-chair.
The next ASAC meeting will be held September 16-17, 2006 in Florence, Italy,
where the ASAC will review the revised Commissioning and Science Verification
Plan, the revised Calibration Plan, and the existing work on developing
complete descriptions of the ALMA observing modes.
3 ALMA Developments in Canada
3.1 Band 3 Receiver Development
The Band 3 Receiver Development continues to keep pace with the ALMA project.
Over
the past three months the team has completed the testing of the first Band 3
pre-production cartridge, including the phase stability measurement. The
cartridge passed its testing with flying colours and has met or exceeded all
of
the ALMA requirements. The team also prepared for and passed the Test
Readiness
Review which examined the acceptance test plan of the Band 3 cartridge
to ensure that the performance characteristics can be verified. The review
panel consisted of the Front End IPT leader and deputy-leader, Front End
IPT systems
engineer, and the project managers of the North American and European Front
End Integration Centers.
The
review panel was satisfied with the proposed acceptance test plan prepared
by
the Band 3 team. Congratulations to all.
An important milestone in
mixer testing at HIA has been passed with the completion of the automated
mixer test set. This automation enables the team to perform noise
temperature
measurements of the double sideband (DSB) and sideband separating (2SB)
mixers
without any operator intervention. The automation substantially reduces the
manpower required for the mixer testing operation and increases the
accuracy and
repeatability of the measurements.
Beyond the ALMA project, the Band 3 team has been drumming up business for
its innovative technology. A license agreement was signed with Nanowave
Technologies Inc of Toronto to manufacture and market the HIA 4-8 GHz
cryogenic
amplifiers for other commercial applications. HIA received a modest amount
of
royalty payment after the signing of the license agreement. Two customized
units
were sold to CEA Saclay, a French physics research laboratory in Paris, to
measure shot noise levels of materials at cryogenic temperature. As well,
Dr Bernard Placais and Dr. Christian Glattie from the Ecole Normale
Superieure
in Paris have expressed a keen interest to use the HIA amplifiers to study
the
DC and RF characteristics of single-walled carbon nanotubes. The Band 3
team is
in the process of formulating the technical requirements of a new
generation
of cryogenic amplifiers to operate up to the 30-40 GHz range.
For more information on the ALMA Band 3 Receiver Project contact Keith
Yeung (Project Manager, keith.yeung@nrc-cnrc.gc.ca), Stephane
Claude (Project Engineer, stephane.claude@nrc-cnrc.gc.ca), or Doug
Johnstone (Project Scientist, doug.johnstone@nrc-cnrc.gc.ca).
3.2 Software
Software work for the ALMA Offline system and the ALMA Common Software
system is continuing in Calgary and at DRAO. Raymond Rusk continues to work
on the porting of the
AIPS++ application libraries for the reduction and analysis of
radio astronomy data into the new CASA framework. In the new
framework, the libraries are accessible through a direct Python binding
as well as an ALMA Common Software (ACS) Corba binding. He has
completed porting the Calibrater tool for synthesis calibration and is in
the final testing stage of porting the Measures tool, which is
used for handling units, quantities, and reference frames including
coordinate and time conversions. He is also working on the
Coordsys tool, which is used for creation and manipulation of
coordinate systems, and the Image tool, which is used for accessing and
analyzing images. Work on these modules should be complete by
mid-September.
Since the previous report, Dr. Gary Li, who has worked on the ALMA
offline software for the past two years at the University of Calgary,
returned to his roots in the geophysics community.
Gary was a valued member of the Off-line
team and we wish him well in his new position.
Shannon Jaeger, Gary Li's replacement, joined the offline team just in
time to attend the ALMA Offline Developer's meeting which was held in
Calgary from June 1-6, 2006.
Shannon will be spending a couple of
weeks in Socorro during July to come up to speed on CASA development.
She is currently working on the migration of the Functionals tool
to the new framework.
The ALMA Offline Developer's meeting was held at the CASCA/AAS
conference hotel June 1-6, 2006. This meeting
allowed the offline developers to mix and
become acquainted with some members of the Canadian astronomical
community. It also provided an excellent environment in which the
team could rapidly debate some key implementation details necessary for
the first release of CASA planned for later this year. A follow-up
meeting to be held in conjunction with the Tuscon ADASS meeting is
planned for this fall.
David Fugate, an ALMA Common Software worker located at the University of
Calgary, has accepted a position at Microsoft to begin in early August.
David's expertise from four years of developing ACS software, both with NRAO
in Socorro and at the University of Calgary, will be difficult to replace.
We wish him the best of luck as he returns to the United States with his new
Canadian bride.
Chris Wilson was heavily
involved in the second user test of the ALMA Pipeline which
began in early March and ran for a month. Brenda Matthews
from HIA and John Hibbard and Ed Fomalont from NRAO were the other
astronomers involved in this test.
The test focused on flagging and calibration of single field
interferometric data. Because no real or simulated ALMA data are available
yet, the test used data from the VLA and the Plateau de Bure interferometer.
The test was quite successful, with the testers
who had participated in the previous year's test noting that there had
been a lot of progress in the pipeline algorithms. The next user test
is planned for late fall and will include full end-to-end processing
of the data for the science target for the first time.
HIA hosted a successful ALMA Archive team meeting in Tofino from May 12-13,
2006, with 6 of the 8 members in attendance. Technical issues and
the distribution, coordination, and scheduling of tasks were the focus
of the meeting. Norman
Hill continues to attend the weekly ALMA Archive team teleconferences.
Delays in hiring continue to prevent the CADC from making its full
contribution to the ALMA Archive development; once the position is filled,
work will begin on the design and implementation of the Request
Handling component of the Archive system.
Chris Wilson wilson@physics.mcmaster.ca
Canadian ALMA Project Scientist
(with input from Séverin Gaudet, Doug Johnstone, and Raymond Rusk)
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On 20 Jun 2006, 17:07.
