NRAO eNews

Volume 4, Issue 6  •  June 14, 2011

Upcoming Events

ALMA Cycle 0 Early Science Proposal Submission Deadline
Jun 30, 2011, 15h UT / 11h EDT / 8h PDT

SKA 2011
Jul 4 - 8, 2011 | Banff, Alberta Canada

Sixth NAIC/NRAO School on Single Dish Radio Astronomy
Jul 10 - 16, 2011 | Green Bank, WV

New Assistant Director for EVLA, VLBA, and NM Ops Appointed

Fred K.Y. Lo and Phil Jewell

It is our pleasure to announce the appointment of Dale Frail as Assistant Director (AD) for the Expanded Very Large Array (EVLA) and the Very Long Baseline Array (VLBA), and Site Director for New Mexico Operations (NM Ops), effective 1 August 2011. 

This appointment is the result of a very comprehensive open search.  Dale stood out as the candidate who will provide the best scientific leadership for the EVLA and the VLBA, and who will reach out effectively to the broad astronomy community. This is essential for NM Ops as the EVLA and the ALMA enter full science operations, and for the future success of the NRAO in the long term.

Dale arrived at NRAO in late 1989 as a Jansky postdoc and joined the scientific staff in 1993 where he served in various roles throughout the Observatory. Dale served as the Head of the Division of Science and Academic Affairs from 2006 until 2009. In this key NRAO position, Dale provided leadership and management oversight for our entire scientific staff and their research.  He led the hiring of new scientific staff and the annual review of the research and associated professional activities for all scientific staff.  Dale also managed the NRAO Postdoctoral and Jansky Fellowship programs, the Jansky Lectureship, and the NRAO colloquium series.

As Site Director for NM Ops, Dale will provide leadership and set science-driven operational priorities for the EVLA and the VLBA. He will be responsible for optimizing the scientific impact of these major NRAO research facilities, including enhancements for the EVLA and VLBA.  Dale will lead and provide management oversight for all NM Ops activities, including the scientific, technical, and operational activities of the EVLA and VLBA, the Domenici Science Operations Center, the EVLA construction project, as well as all ALMA activities and NRAO development projects in Socorro.  Dale will serve on the NRAO senior management team and be a key participant in policy and implementation decisions regarding Observatory-wide initiatives. He will also actively participate in the semi-annual Director’s Review, where the final decisions regarding EVLA, VLBA, and Green Bank Telescope observing time assignments are made.  

Please join us in welcoming Dale into this important NRAO role.  Claire Chandler will continue to serve as Interim AD until Dale takes over in August.  We thank Claire for her excellent service in this capacity.

This Month @ the NAASC

ALMA Proposal Submission Open & Science Verification Data Available

The ALMA Science Archive at the Joint ALMA Observatory (JAO) is now open for the submission of Cycle 0 Early Science observing proposals until the submission deadline at 15h UT/11h EDT/08h PDT on Thursday, June 30, 2011.

Proposers are reminded that all proposals must be submitted to the Science Archive using the ALMA Observing Tool, and that all PIs and co-Is must be registered at the ALMA Science Portal.

Additional information regarding ALMA Early Science proposals, the Observing Tool, and the proposal submission process is available via the ALMA Science Portal.

The first 2 ALMA Science Verification datasets are also now available:

(1) The protoplanetary disk source TW Hya at Band 7 (0.87 mm), with high spectral resolution; and

(2) The galaxy merger NGC 3256 at Band 3 (3 mm), with low spectral resolution.

These datasets demonstrate the very early capabilities of ALMA. They were observed before 10 ALMA antennas were available and while many of the subsystems were still being tested, so they should not be construed to represent the data quality for Early Science. These datasets are provided now to enable the user community to become acquainted with the ALMA data structure, observing strategies, and data reduction techniques.

Additional information regarding the Science Verification Data is available via the "ALMA Data" tab at the ALMA Science Portal.

 

Spotlight on NAASC Services: Computing & Data Processing

The data challenge posed by ALMA is one of the most severe in current astronomy. The size of the raw data is predicted to grow by ~200 Terabytes per year. Unlike most astronomy facilities with this order of data volume, which tend to take uniform survey datasets, ALMA data is taken in a traditional, proposal driven manner, in a wide variety of user-specified modes. Only the EVLA archive will rival it in both size and complexity for the forseeable future. In addition, ALMA will be the first and only interferometric telescope with a pipeline capable of dealing with a wide range of observational setups.

Although the main ALMA pipeline will be run in Santiago, the nature of interferometric data, and the many modes in which ALMA can operate means that multiple reprocessings of these data are to be expected. For North American users, these reprocessings will use the pipeline installation at the NAASC.

The Data Services Group (DSG) coordinates the processing, archiving and distribution of ALMA data at the NAASC, and is also responsible for the development and maintenance of tools for proposal preparation, data processing and data analysis that are produced in North America, but are not part of the main ALMA project. These tools supplement the ALMA project software development effort, and currently consist of Splatalogue and the Simdata task (within CASA). Eventually, the DSG will also direct the effort within North America to produce tools to analyze the large data cubes ALMA will produce. The DSG also coordinates the deployment of the NAASC instance of the ALMA User Portal, and the provision of the ALMA helpdesk to the ALMA project. The DSG coordinates with the NRAO Computing and Information Services (CIS) division to ensure the provision of the hardware necessary to undertake the data transfer, processing and storage tasks, and to ensure that software environments are set up correctly to allow the pipeline and associated software to function efficiently.

The NAASC will host a full copy of the ALMA archive, both to provide convenient local access to ALMA data, and to provide a backup copy to the main archive in Santiago (along with copies at the ALMA regional centers in Europe and Japan). Data storage will be through the Next Generation Archive System (NGAS), developed by the European Southern Observatory as part of their contribution to the ALMA project. The NGAS nodes will be linked to a fast Lustre file system that will act as a staging area for the data processing cluster. The details of the processing cluster are yet to be defined, but it is expected to be a near-clone of the main pipeline processing cluster in Santiago, with up to 64 processing nodes. There is a large overlap with the archiving, data processing and software interests within NRAO Observatory Science Operations. The NAASC DSG will be working with colleagues at the other NRAO sites to identify areas of common interest, and will also work closely with the Virtual Observatory (VO), its US incarnation, the Virtual Astronomical Observatory, and the ALMA archive development group to ensure the transparent integration of ALMA data into the VO.

NAASC Data Services is currently a small group, consisting of 1.5 staff (Mark Lacy and Remy Indebetouw) and two postdocs (Robin Pulliam and Amy Kimball) with Mike Hatz and Dan Klopp matrixed in from CIS. Data Services is expected to grow as the emphasis of the NAASC shifts from face-to-face user support during ALMA Early Science to supporting users remotely after the pipeline is fully operational.

 

The Canadian Contingent of the NAASC: Resources for ALMA Users at NRC-HIA

Brenda Matthews

Within the NAASC are members who are proud to contribute ALMA support from foreign shores. These members are located in Victoria, Canada at the National Research Council of Canada’s Herzberg Institute of Astrophysics (NRC-HIA). The scientific expertise of the NAASC members at NRC-HIA is strongly focused on star formation and circumstellar disks through Group Leader Gerald Schieven, and members James Di Francesco, Doug Johnstone and Brenda Matthews. There is a high level of interferometry experience within NRC-HIA as well.

ALMA users will interact with the NAASC members at NRC-HIA as they would any other member of the NAASC. The comprehensive ALMA Primer created at the NRC-HIA has received wide electronic and hardcopy distribution, and has proven quite popular. The latest version of the ALMA Primer incorporates contributions from the North American, European, and East Asian ALMA Regional Centers. The NAASC team at the NRC-HIA has also facilitated the ALMA Tutorials for Early Science in Canada, events that are analogous to the Community Days organized in the US.

Including the tutorial associated with the Victoria NAASC Conference on Spectroscopy in mid-January 2011, we will have facilitated 6 ALMA Tutorials across Canada before the 30 June 2011 Early Science deadline. North American ALMA users will also interact with NAASC members at NRC-HIA through the Helpdesk.

NRC-HIA will be an alternative location for assistance in reducing ALMA data, and will be particularly accessible to ALMA users on the west coast of North America.

New CASA Release (3.2.1) Available

The CASA Team

CASA, the Common Astronomy Software Applications (CASA) package is being developed by the NRAO, the European Southern Observatory, and the National Astronomical Observatory of Japan and is used for the offline reduction and analysis of both ALMA and EVLA data. CASA is fully scriptable. Full support is provided for ALMA, VLA, and EVLA formats, but almost any data that can be written in uvfits format can be imported and reduced in CASA (e.g.: CARMA, SMA, ATCA).

Linux and MacOS distributions of CASA 3.2.1 are now available from the CASA webpage:
http://casa.nrao.edu

Please follow the links to "Obtaining CASA".

New features in CASA 3.2.1 include:

* new task flagcmd allows flagging based on a string of flagging commands
* clean has more stokes options
* improvements in multi-scale multi-frequency imaging and deconvolution
* plotms has the option to iterate through the data (eg. by baseline or spw)
* uvcontsub2 offers polynomial fits to the data
* simdata includes ALMA early science Cycle 0 antenna configurations
* new interpolation method in cvel based on FFT shifts
* 'Perley-Butler 2010' is now the new default flux standard
* CASA can now handle data with (air) wavelength spectral axes
* support of multi-extension fits in the viewer
* speed improvement in single dish baseline fitting

For a full list of the CASA release 3.2.1 features, please see the release notes.

We encourage you to subscribe to either or both of the following subscription lists:

*Casa-announce*    for announcement of new releases, workshops, etc.;
please subscribe at http://listmgr.cv.nrao.edu/mailman/listinfo/casa-announce

*Casa-users*     for critical bugs and code updates;
please subscribe at http://listmgr.cv.nrao.edu/mailman/listinfo/casa-users

If you have any questions, please consult the NRAO helpdesk: http://help.nrao.edu

ALMA Construction Progress

Al Wootten

June 2011 saw fourteen antennas probing the clear austral winter skies at the 16,500 foot elevation ALMA Array Operations Site (AOS). In Figure-1 (left), taken early June, there are fourteen antennas. 

Sixteen antennas have passed through the four stages of AIV and nineteen have been accepted by ALMA.  Although not apparent in this image, the process of moving antennas from the Atacama Compact Array (ACA) foundations onto the compact configuration of the main array has begun, following acceptance of foundations in a nearby sector of the central cluster.  Commissioning and Science Verification activities continue, using this larger set of antenna stations, some of which will also be used for the Early Science arrays.

At the 2900m elevation Operations Support Facility (OSF) the 19th antenna began the AIV process.  Twenty ALMA front ends have passed preliminary on-site acceptance.  The OSF interferometer included one Melco 12m and one 7m antenna.  The first European antenna should obtain first celestial light early in June, having passed its pointing and surface setting tests.  During June, the 20th Vertex antenna is expected to leave the factory in Texas for delivery to Chile.

The NRAO and the Virtual Astronomical Observatory

Doug Tody, Brian Kent, Gareth Hunt

A primary goal of the US Virtual Astronomical Observatory (VAO) is to improve the facilities available to astronomers for research using data from US and international observatories, surveys, data centers and archives.  NRAO, like other US data providers, hopes to leverage VAO to improve access to and analysis of data from NRAO telescopes including ALMA.  The VAO will be an operational facility building upon the work done earlier by the US National Virtual Observatory (NVO) in concert with our international partners in the ongoing International Virtual Observatory Alliance (IVOA).

After two years of preparations and delay the VAO finally got underway in mid-2010.  Work began in earnest in the fall of 2010, following the development of a program plan, with an inaugural VAO team meeting held at the NRAO Charlottesville headquarters in early October 2010.  Approximately 40 people from around the US attended.  As of this writing work is well underway at all VAO sites.  NRAO is one of nine core VAO member institutions contributing to VAO development.  VAO development and operations are jointly funded by NSF and NASA and managed by the VAO, LLC, which was created by AURA and AUI specifically for the purpose of managing the VAO.  The VAO, LLC offices are co-located with the AUI headquarters in Washington, DC.

Initial VAO work is focused around four year-1 VAO science initiatives: the VAO portal (main entryway to the VAO), a general large scale distributed cross match facility, SED construction and analysis, and time series analysis. Study initiatives for later work are also underway for data curation and preservation, large scale data mining, and integration of the desktop research environment both between (mostly legacy) applications on the desktop, and with VO services for remote access to data and computation

NRAO has a support role in all the year 1 VAO science initiatives, with most local work currently focused on development of international (IVOA) standards for science data access.  VAO development is based upon international VO standards hence ongoing development and evolution of these standards is required to support the VAO science initiatives and applications.  We are also leading a prototype effort to use IVOA data models for archive data discovery and access, as well as leading the study initiative for the desktop research environment integration initiative which is slated to go forward in year two.

These efforts are all of benefit to NRAO and the NRAO user community, e.g., for VO-enabled, NRAO-wide science archive data access including access to large radio data cubes, and integration of NRAO data analysis capabilities (e.g., CASA and pipeline processing) with the VO and VAO to help make research using NRAO and ALMA facilities more effective for the broader astronomical community.  In the near term an effort is underway to prototype a new interface for querying and accessing NRAO data using VO technology and software.  This effort is being coordinated with the VAO study initiative for archive data discovery and access mentioned above, hence can leverage VAO resources for much of the software development.  The NRAO archives in turn provide a valuable use case to help develop the VAO infrastructure and related VO standards.

Further information on VAO is available from http://www.usvao.org

VLBA Sensitivity Upgrade Status

Jon Romney, on behalf of the VLBA Sensitivity Upgrade team

The RDBE and Mark 5C units supporting the Very Long Baseline Array (VLBA) Sensitivity Upgrade's initial 2-Gbps recording rate (256 MHz per IF) were described comprehensively in the February 2011 eNews issue. Installation of this equipment at all ten VLBA stations, and at the Green Bank Telescope (GBT), was completed recently.  A test observation, including the initial operation at the GBT and two of the VLBA stations, demonstrated satisfactory performance at all 9 stations available in early May. This and other recent tests used the RDBE's polyphase filterbank (PFB) personality that was described in detail in the February issue, and will be available for the system's first use in observing semester 2011-B. Although the signal path is already performing well in tests, some control features and some auxiliary functions required for calibration are still being completed. A few additional details necessary for scheduling observations with the 2-Gbps system will be provided on the NRAO web site and communicated directly to proposers who have been awarded wideband observing time.

2011 Jansky Lectureship Awarded

Chris Carilli

The NRAO is pleased to announce that the 2011 Jansky Lecturer will be Prof. Sander Weinreb of Caltech/JPL.

Sandy's development of the first autocorrelation spectrometer and the detection of the first interstellar molecule at radio wavelengths revolutionized astronomy. He has been a leader in the technological development of cm and mm astronomy throughout his career, designing the electronics for the Very Large Array, and founding the NRAO electronics lab that has been the most productive and advanced radio astronomy electronics lab in the world.  At the Five College Radio Astronomy Observatory, Martin-Marietta, and Caltech, he has continued his leadership in technological innovation in radio astronomy, and has been the “guru” for several generations of students, with particular emphasis lately on pioneering work on MMICs. He has made seminal contributions to every low noise cryogenic receiver technology employed in radio astronomy, from parametric amplifiers to Superconductor-Insulator-Superconductor (SIS) mixers to field-effect transistor (FET) and High Electron Mobility Transistor (HEMT) amplifiers. He is currently Principle Scientist at NASA-Jet Propulsion Laboratory. As part of the Jansky award, Prof. Weinreb will be giving lectures at the NRAO sites on his work.

First awarded in 1966, the Karl G. Jansky Lectureship was established by the Trustees of Associated Universities, Inc. to recognize outstanding contributions to the advancement of radio astronomy. It is named in honor of Karl Jansky, who first detected radio waves from a cosmic source in 1932. You can find more information about the prize online.

First Light for the New GBT 4mm Receiver

David Frayer and the 4mm GBT Team

The National Radio Astronomy Observatory has constructed a dual-beam, dual-polarization receiver for the Green Bank Telescope to cover the low-frequency end of the 3mm atmospheric window from 68--92 GHz. The receiver was recently installed on the GBT to test the functionality of the system. On 3 May 2011, a successful first light spectrum of Orion-KL was obtained (Figure 1). Additional development and refinements are planned this summer, with the expectation of commissioning in the fall of 2011 and initial shared-risk science observations in early 2012. See http://www.gb.nrao.edu/4mm/ for more information.

Green Bank Telescope K-Band Receiver Retirement

Toney Minter

In late April 2011, the Green Bank Telescope (GBT) K-band receiver experienced a cryogenics failure.  As this receiver was slated to be replaced by the K-band Focal Plane Array (KFPA) in June 2011, we decided to retire the K-band receiver a few months early, after many years of service.

The K-band receiver was first used on the 140 Foot Telescope to help test the Monitor and Control software for the GBT while it was under construction.  Once on the GBT, the K-band receiver played an important role in showing that the GBT would work at higher frequencies.

The K-band receiver is responsible for detecting about 100 galaxies with H2O maser emission at 22 GHz, nearly 2/3 of the known population. The K-band receiver helped lay the ground work for being able to use the ammonia lines to determine the kinetic temperature in the disks of external galaxies, which led directly to the development of the KFPA.

All active K-band GBT proposals will be converted to using the KFPA by the fall of 2012.  Your project friends can be contacted regarding how to help you convert your observing to use the KFPA.

Recent Press Releases

Expanded VLA Flexing New Scientific Muscle
24 May 2011

A new and uniquely powerful tool for cutting-edge science is emerging on the crisp, high desert of western New Mexico. Outwardly, it looks much the same as the famed Very Large Array (VLA), a radio telescope that has spent more than three decades on the frontiers of astronomical research. The 27 white, 230-ton dish antennas still peer skyward, the 72 miles of railroad track still wait to transport the antennas across the arid plains, the familiar buildings remain, and crews still fan out across the desert to service the antennas. Functionally, however, everything has changed. The VLA has become the Expanded VLA (EVLA). Read more...

The Otherworldly Work of West Virginia's Green Bank Radio Telescope

At the National Radio Astronomy Observatory, situated in Green Bank West Virginia in the heart of the National Radio Quiet Zone, the Robert C. Byrd Green Bank Telescope detects faint radio signals from celestial bodies. Scientists study radio signals emitted from planets, stars (including our Sun), pulsars, nebulae, quasars, galaxies and black holes to better understand physical and chemical processes in the Universe. The data collected at this observatory, which is a facility of the National Science Foundation, supplement the information gained from optical telescopes like the Hubble Space Telescope and ground-based observatories. Read more...

Career Opportunities

From the Archives

Ellen Bouton

About this month's photograph: Very Large Array antennas outside the Antenna Assembly Building, April 1977.  NRAO staff quickly realized the vertical ladder from the ground to the base of the steps leading to the area above the azimuth bearing was extremely difficult, if not impossible, for engineers to ascend and descend while carrying tools and equipment.  A set of angled stairs was later installed on each antenna to replace the vertical ladders.

From the Archives is an ongoing series illustrating NRAO and U.S. radio astronomy history via images selected from our collections of individuals' and institutional papers. If readers have images they believe would be of interest to the Archives, please contact Ellen Bouton, ebouton@nrao.edu.