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Upcoming Events

NRAO Community Day at UMBC
Jun 13 - 14, 2019 | Baltimore, MD

CASCA 2019
Jun 17 - 20, 2019 | Montréal, Québec

Radio/mm Astrophysical Frontiers in the Next Decade
Jun 25 - 27, 2019 | Charlottesville, VA

7th VLA Data Reduction Workshop
Oct 7 - 18, 2019 | Socorro, NM

ALMA2019: Science Results and Cross-Facility Synergies
Oct 14 - 18, 2019 | Cagliari, Sardinia, Italy

Semester 2019B Proposal Outcomes

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The NRAO has completed the Semester 2019B proposal review and time allocation process for the Very Large Array (VLA) and the Very Long Baseline Array (VLBA).

For the VLA a single configuration (the D array) will be available in the 19B semester and 124 new proposals were received by the 1 February 2019 submission deadline including one large and sixteen time critical (triggered) proposals. The oversubscription rate (by proposal number) was 2.5 and the proposal pressure (hours requested over hours available) was 2.1, both of which are similar to recent semesters.

For the VLBA 27 new proposals were submitted, including two large proposals and one triggered proposal. The oversubscription rate was 2.1 and the proposal pressure was 2.3, both of which are similar to recent semesters.

There was significant demand for the time made available on space observatories through inter-observatory agreements, and fourteen proposals requesting time on HST, Swift or Chandra (together with AUI/NRAO telescope time) were submitted.

The proposals were reviewed for scientific merit by nine Science Review Panels (SRPs) and for technical feasibility by NRAO staff. These reviews were completed in February – March 2019 and then considered by the Time Allocation Committee (TAC) at a face-to-face meeting on 24-25 April 2019 in Green Bank, West Virginia. The TAC – comprising the 9 SRP chairs – was charged with recommending a science program for Semester 2019B to the Observatory Director. The recommended program was reviewed and approved on 8 May 2019.

Proposals submitted to the GBO were assessed through the same process. Fifty eight proposals for the GBT were received for the 19B Semester, including one large and four triggered proposals. The oversubscription rate is 2.5 and the proposal pressure is 2.2. For information on proposals for GBT observations see the GBO website.

A disposition letter was sent to the Principal Investigator and Co-Investigators of each proposal on 16 May 2019 and a TAC report containing information for proposers and observers, including statistics and telescope pressure plots, was released the same day. The approved science program for the VLA and the VLBA has been posted to the NRAO science website. The authors, title, abstract, and scheduled hours for each approved proposal can be accessed from the Proposal Finder Tool.

The Student Observing Support program continues to be available for NRAO observing programs and we encourage Principal Investigators of highly ranked VLA and VLBA proposals to consider applying for support.

The NRAO welcomes community feedback on the proposal review and time allocation process. Please provide such feedback via the Proposal Review department of the NRAO Helpdesk.

Announcement of Opportunity – Extra-Large Proposals

NRAO and GBO will consider submissions of Extra-Large observing proposals (X-proposals for short) at the upcoming 1 August proposal submission deadline. This opportunity is open for observers seeking to use the VLA, VLBA and / or GBT. Extra-Large proposals will be defined as those requesting a total of more than 1000 hours of telescope time and / or extending over four or more observing semesters. Note that the earliest that successful Extra-Large projects could be scheduled is the start of Semester 2020B in August 2020. The opportunity to submit Extra-Large proposals will likely not be repeated for at least three years.

Regular and Large proposals continue to be encouraged for Semesters 2020A and beyond. At least 50% of open skies science time on each of the VLA, VLBA and GBT will continue to be made available for Regular and Large proposals from Semester 2020B. (The maximum amount of time that can be requested through a Large proposal will be capped at 1000 hours starting from Semester 2020B.)

To be accepted, Extra-Large proposals will be expected to demonstrate outstanding science impact, a high level of scientific and technical readiness, and excellent legacy science value (potential to generate high science impact from community use of archival data and data products.)

The capabilities available for Extra-Large Proposals will be restricted to a subset of general observing capabilities – Shared Risk Observing and Resident Shared Risk Observing capabilities will not be available for Extra-Large proposals, and high-frequency bands (12 GHz and above) are likely to be excluded or severely restricted for all three telescopes because of scheduling difficulty and the limited available time with suitable observing conditions. Specific capabilities that will not be available for Extra-Large proposals are:

  • For the VLA – pulsar modes, phased array, subarrays, mixed 3/8-bit samplers, moving sources (including Solar and planetary observing), and On-The-Fly mosaicking; in addition, observing time at 12 GHz and above will be restricted according to the expected availability of suitable observing conditions;
  • For the VLBA – moving sources and 3mm observing; in addition, observing time in the 2cm, 1cm, and 7mm bands will be restricted according to expected availability of suitable observing conditions;
  • For the GBT – monitoring and fixed time observations, observations with any weather restrictions (typically above 8 GHz).

Extra-Large Proposals requiring fixed observing dates will not be supported for any telescope. Additional band, configuration, response time and cadence restrictions may also apply for each telescope. The definitive list of capabilities excluded from Extra-Large proposals will be provided in the Call for Proposals that will be released on 2 July 2019.

The scientific review process for Extra-Large proposals will be different from the normal NRAO Science Review Panel (SRP) / Time Allocation Committee process. The Science Review Panels will assess the scientific potential of each Extra-Large proposal in their science area, providing comments and a coarse grading. A new X-Proposal Science Assessment Committee (XSAC) appointed by the NRAO and GBO Directors will assess the Extra-Large proposals for their scientific merit and likely legacy science value, taking into account the initial assessments from the SRPs. Observatory staff will assess each proposal for technical readiness, and the final selection of proposals will involve a face to face scientific, technical and operations readiness review in Spring 2020.

Preference will be given to proposals which demonstrate substantial engagement with astronomers at U.S. institutions. Preference may be given to proposals with lower requirements for observatory support, and lower operational impact. The progress of Extra-Large projects that are accepted will be monitored through NRAO Program Management Department processes.

The announcement of successful Extra-Large proposals is anticipated to occur in July 2020. The deadline for submissions will be 1 August 2019, the same as for Semester 2020A regular and large proposals.

Submission of Extra-Large proposals will be via the usual NRAO Proposal Submission Tool (PST) with the same 10-page limit for the Scientific Justification. Extra-Large proposals will be required to also submit (or provide a link to) additional material addressing the following issues:

  • The data management and delivery plan, including computing resource requirements;
  • A set of major project milestones and schedule;
  • The team resources (including plans for resident scientists at the Observatory).

Proposers are also encouraged to address the following:

  • The demonstrated feasibility of the project;
  • Any special requirements (such as scheduling, calibration, scanning, data processing);
  • Engagement of U.S. astronomical community;
  • For the GBT, an observing plan.

The ability of the proposing team to execute the data management plan, as well as the feasibility for NRAO to accommodate any requests made of it in the data management plan, will be evaluated as part of the review process

Information that assists Observatory staff to assess likely operational and NRAO/GBO support implications will be welcomed as part of the additional material. This will be the focus of the final face to face technical and operations readiness reviews with the highest ranked proposal teams.

More details will be provided in the formal call for proposals on 2 July at Please direct any questions regarding X-proposals to the “VLA/GBT/VLBA Proposing” department of the NRAO Helpdesk.

VLBA Commissioning Complete to Double Data Rate

Over the past year, Mark6 recording units have been deployed to all Very Long Baseline Array (VLBA) antennas. The Mark6 recorder, designed by Haystack Observatory and Conduant Corporation, offers a number of advantages over the Mark5 series of recorders. The most important and user-visible feature is support for higher data rates. The Mark5C, when used in "single-bank" mode, reliably supports data rates as high as 2048 Mbps, which is the VLBA's current sustainable rate. This corresponds to 256 MHz of bandwidth when observing with both polarizations. The Mark6 units, fed by the existing VLBA data acquisition system, will support science observing at 4096 Mbps or 512 MHz of dual-polarization bandwidth.

Please watch for the announced availability of this capability in the upcoming Call for Proposals. Standard observing setups for continuum observing will be made available at that time.

The Mark6 units (left) and Mark5 units (right) feeding the VLBA correlator in Socorro, NM. Unlike the Mark5 units, each Mark6 can play back data from multiple modules at the same time. In the VLBA's deployment, the first and third racks host "system chassis" containing a high-end computer motherboard and Infiniband networks. The second and fourth racks host "expansion chassis", which simply host additional modules. In the current configuration, the VLBA has the capacity to simultaneously correlate from 24 Mark6 modules and 9 Mark5 modules.

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2019 Jansky Lectureship Awarded to Caltech Professor

Dr. Anneila Sargent

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Associated Universities, Inc. (AUI), and the National Radio Astronomy Observatory (NRAO) have awarded the 2019 Karl G. Jansky Lectureship to Dr. Anneila Sargent, Ira S. Bowen Professor of Astronomy, Emeritus, at the California Institute of Technology (Caltech). The Jansky Lectureship is an honor established by the trustees of AUI to recognize outstanding contributions to the advancement of radio astronomy.

Professor Sargent is being honored for her pioneering, and continuing, studies of young stars and the dusty disks that surround them -- disks from which planets form. In addition, she has been a leader in the astronomical community, serving on important boards and committees and in offices for scientific organizations, while also helping shape the careers of younger astronomers and standing out as an inspiring role model for female scientists.

A member of the U.S. National Science Board and a Fellow of the American Academy of Arts and Sciences, Sargent is a past president of the American Astronomical Society. She chaired the NASA Space Science Advisory Committee and the U.S. National Research Council Board of Physics and Astronomy, and served on the U.K. Science and Technology Facilities Council.

A native of Scotland, Sargent earned her B.Sc. at the University of Edinburgh and her Ph.D. from Caltech, where she has spent her career. She was Caltech's Vice President for Student Affairs from 2007 to 2015.

She has led in the development of important radio observatories, serving as director of Caltech's Owens Valley Radio Observatory, and as founding director of the Combined Array for Millimeter-wave Astronomy, the U.S. precursor to the international Atacama Large Millimeter/submillimeter Array (ALMA). She served on the ALMA board for a decade and chaired it twice.

As Jansky Lecturer, Sargent will give lectures at NRAO facilities in Charlottesville, Virginia, and Socorro, New Mexico. These lectures are open to the public.

First awarded in 1966, the Jansky Lectureship is named in honor of the man who, in 1932, first detected radio waves from a cosmic source. Karl Jansky's discovery of radio waves from the central region of the Milky Way started the science of radio astronomy.

Past recipients of the Jansky award include seven Nobel laureates (Drs. Subrahmanyan Chandrasekhar, Edward Purcell, Charles Townes, Arno Penzias, Robert Wilson, William Fowler, and Joseph Taylor) as well as Jocelyn Bell-Burnell, discoverer of the first pulsar, and Vera Rubin, discoverer of dark matter in galaxies.

Starlink & Constellations of Communication Satellites

Recent news reports of planned constellations of communication satellites, including the SpaceX Starlink proposal, have pointed out the potential impacts these systems may have on radio astronomy. For decades, the NRAO and the Green Bank Observatory (GBO), in cooperation with the National Science Foundation (NSF), have worked to ensure that innovations in communications can advance while still preserving our ability to explore the Universe from Earth and conduct essential fundamental research through radio astronomy.

Most recently, the NRAO and GBO have been working directly with SpaceX to jointly analyze and minimize any potential impacts from their proposed Starlink system. These discussions have been fruitful and are providing valuable guidelines that could be considered by other such systems as well. To date, SpaceX has demonstrated their respect for our concerns and their support for astronomy. This includes an agreed-upon protocol to monitor impacts and address issues to NRAO's current and future cutting-edge research facilities. We continue to monitor, analyze, and discuss the evolving parameters of the SpaceX system. Among the many proposals under consideration are defining exclusions zones and other mitigations around the NSF's current radio astronomy facilities and the planned future antenna locations for the next generation Very Large Array. We also are working with our international partners, including the Square Kilometre Array, to present their concerns as well.

The United States continues to be a world leader in radio astronomy research and engineering innovations. With the explosion of wireless technologies and the growing potential to lease portions of the electromagnetic spectrum for commercial purposes, it is essential that we safeguard our ability to perform basic research. Ground-based astronomy, whether optical or radio, has benefits that cannot be matched by even the most advanced space-based observatories. The recent imaging of a supermassive black hole is just one example of how ground-based radio astronomy facilities provide powerful and unique capabilities.

The NRAO looks forward to future discussions and is confident that the needs of both the research and communications communities can be met and preserved.

ALMA Program News

Pablo Carrillo

AN ALMA antenna is moved to its extended configuration location by an ALMA transporter.

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Cycle 6 Science Observing
The ALMA antennas have been deployed to their most extensive C43-10 configuration (16.2 km maximum baseline; approximate diameter of Washington D.C. beltway.). Atacama Compact Array observations continue, and 12-m Array observing has resumed in the long baseline configurations. The array will gradually move to shorter baselines over the next few months.

Cycle 7 Call for Proposals
Cycle 7 proposals have been distributed to the reviewers, who will meet in Atlanta, Georgia 16-21 June 2019. Results are expected at the end of July. The Call for Cycle 7 proposals closed with a total of 1785 submitted proposals, a 3% decrease from the 1838 proposals submitted in Cycle 6. In Cycle 7, there were 9123 registered ALMA users, compared to 8811 for Cycle 6, and 8082 for Cycle 5. The total time requested for the 12-m Array is just short of 19,338 hours, 360 hours less than in Cycle 6. This is an oversubscription factor of 4.5X above the 4300 available hours. For the 7-m and Total Power arrays, the total time requested is 9019 hours and 6938 hours, respectively, slightly lower than in Cycle 6. The median amount of 12-m Array time being requested per proposal is 8.9 hours, similar compared to earlier cycles. Detailed statistics for the Cycle 7 Call for Proposals are available at the ALMA Science Portal.

Fourth ALMA Science Conference
The ALMA partnership is organizing the Fourth ALMA Science Conference in Cagliari (Sardinia, Italy) on 14-18 October 2019. The full breadth of ALMA science will be discussed, with special emphasis on results from the first rounds of ALMA Large Programs, ALMA's high resolution and high frequency capabilities, the new Solar and VLBI modes, as well as the synergy between ALMA and other observatories. As in previous editions of the conference series, we expect to discuss the scientific priorities for the implementation of the ALMA Development Roadmap.

Abstract submission for the conference closed on 15 May 2019. Response was gratifying, exceeding the capacity of the venue. As a result, registration has closed, and prospective participants may register on a waiting list basis only. Participant selection is under way; those wishing to attend should postpone further planning until informed of the outcome of the selection process in the second half of June.

Whispers Special Session
Call for oral contributions and posters (deadline: 28 June 2019)
Massive data processing and analysis in radioastronomy: Amsterdam, 26 September 2019

Datasets produced by the current and future generations of radio telescopes are becoming extremely large, due to the increase in sensitivity, instantaneous bandpass per pixel, and the number of pixels per receiver. This main instruments in the (sub)millimeter through the centimeter domain, such as ALMA and the Jansky Very Large Array, now routinely process several tens of GHz with spectral resolutions of the order of 100 kHz, implying the measurement of about 500,000 frequencies simultaneously. Instruments planned for the relatively near-term future, such as a next generation Very Large Array and Square Kilometre Array, will drive yet another revolution in data rate.

Data processing and analysis of these large volumes requires the development of innovative methods based on the most recent advances in signal processing. A proposed one-day session during the Workshop on Hyperspectral Image and Signal Processing: Evolutions in Remote Sensing (Whispers) Workshop in Amsterdam aims at presenting the challenges encountered by the radio-astronomy community and the on-going activities that are designed to solve them.

ngVLA Project News

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Now that the Astro2020 Decadal Survey process is underway, the next generation Very Large Array (ngVLA) Project Office is continuing to work on producing materials for submission to the Survey.  The most immediate submission will be our Activity, Project, and Statement of the Profession Consideration (APC) White Paper, due 10 July, and our full project submission (ngVLA Reference Design) expected to be due later in the Fall.  The ngVLA Reference Design is the technical complement to our Science Book, and includes ~ 54 documents (~1500 pages) describing the end-to-end system design with a full bottoms-up supported costing estimate.  All materials submitted to Astro2020 will include a critical review by members of the astronomical community.

A number of key scientific documents included in the Reference Design, such as the ngVLA Science Requirements and Operations Concept, have recently been released by the Project Office and can be found on the ngVLA website.  These documents, as well as all of the compelling science white papers submitted to Astro2020, will be discussed at our Radio/Millimeter Astrophysical Frontiers in the Next Decade meeting later this month (25 – 27 June) in Charlottesville. I look forward to seeing many of you there!

High-Resolution Radio Interferometry in Space: 2nd International Meeting

Following the spectacular images from the Event Horizon Telescope and the successful Space Very Long Baseline Interferometry (VLBI) missions – the Highly Advanced Laboratory for Communications and Astronomy (HALCA) and RadioAstron – there is growing interest in the next set of Space VLBI technical concepts, including next-generation constellations and millimeter-wavelength systems. This meeting is a second in a series of international meetings, the first of which was held at Noordwijk in 2018. The focus of this second meeting is to review black hole and other Space VLBI science cases, and begin to assess the maturity of the relevant technologies and needed technology developments and roadmaps.

The tentative dates for this second international meeting are 27-29 January 2020 at the NRAO headquarters in Charlottesville, Virginia. Please save these dates and stay tuned for additional information in eNews and at the NRAO science website.

SADC: Delivering High-Speed Data With Minimal Power

Laboratory test setup for SADC and integrated receiver developments, including cryogenic front-end, warm electronics modules, 10 km fiber-optic link, and backend signal processing.

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Almost a decade ago [1], researchers at the NRAO Central Development Lab (CDL) conceived of a method for capturing and delivering digital imaging data over great distances by optical fiber using a factor of ten less power than is consumed by conventional systems. The technique, which leverages the natural, statistical properties of noise-laden data, is implemented in two parts: a digitizer for capturing and transmitting the data, known as the Serial Analog-to-Digital Converter (SADC), and a patented deserialization algorithm [2]–[3] which parses the information at a data processing center potentially many kilometers away. This concept is now a key component of the next generation Very Large Array (ngVLA) Reference Design, as well as a candidate for commercial applications in markets that are sensitive to size, weight, power, and cost, such as wearable technologies, automotive radar, and the Internet of Things (IoT).

The CDL engineers pursuing this line of development achieved a significant milestone this month by successfully streaming live data from a radio-astronomy front-end to a Field Programmable Gate Array processor through 10 km of fiber on a spool (see Figure). The data stream comprised four synchronous channels or lanes, essentially corresponding to upper- and lower-sidebands from two polarization inputs, each running at 8 Gigabits per second (Gbps), for a total throughput of 32 Gbps.

While this milestone was achieved using off-the-shelf hardware programmed to mimic the intended operation of the SADC, a separate application-specific integrated circuit (ASIC) chip has already been developed to perform the same function with an order of magnitude less power and smaller footprint. Test and demonstration boards that utilize this new chip are currently in progress.

Alongside the chip development, the CDL continues to make improvements in the associated deserialization and data processing algorithms, and prototyping the integrated warm-electronics modules needed for the ngVLA. The ultimate goal is to achieve a data rate of 56 Gbps per lane on at least four light wavelengths (about 200 Gbps aggregate per fiber) with a range of 40 km from a front-end receiver module no bigger than a cell phone.


  1. M. Morgan and J. Fisher, Word-boundary Detection in a Serialized, Gaussian-distributed, White-noise Data Stream, Electronics Division Technical Note #213, October 2009.
  2. M. Morgan and J. Fisher, Statistical Word Boundary Detection in Serialized Data Streams, U.S. Patent No. 8,688,617, April 1, 2014. People's Republic Of China Patent No. 201180046318.8, February 5, 2017.
  3. M. Morgan, J. Fisher, and J. Castro, Unformatted Digital Fiber-optic Data Transmission for Radio Astronomy Front Ends, Publications Of The Astronomical Society Of The Pacific, 125, 695-704, June 2013.

From the Archives

From the Archives

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About this month's photo: A replica of Karl Jansky's original antenna at Bell Laboratories, used in Jansky's detection of radio waves from the center of the Milky Way which was announced in a front-page article in the New York Times on 5 May 1933, was built at Bell Laboratories for installation at the entrance to the Green Bank site. The reconstruction in Green Bank was completed 55 years ago, in June 1964. In this spring 1995 photo, David Jansky (left), Karl Jansky's son, and Grote Reber (right), confer in front of the replica. Photo by Ken Kellermann.

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.

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