Green Bank Observer – Summer 2019

From the Director

Summer is upon us again here in Green Bank, bringing with it summer staff and all the fun educational camps and workshops here at the Observatory. We are also in the midst of several new upgrades for the GBT which will continue over the next few years and which will increase the GBT’s availability for high frequency science, provide a new wideband feed optimized for pulsar science, and test innovative techniques for RFI detection and excision. Like everyone in the community, we have also spent time thinking about the next decade of astronomical science and the Observatory’s place within those scientific goals.

We also have a couple of workshops coming up – one focusing on astrobiology (“Moonshots and Earthshots in the Search for Life Beyond Earth, Barry Blumberg Memorial Workshop”) and the other looking at recent advances in studies of the Warm Ionized Medium.

I hope that your summer is as exciting and busy as ours, but that you also left room in your summer plans to submit to the upcoming 2020A GBT proposal call and the NEW Extra-Large Proposal Call, both of which are due August 1.

Have a great end of your summer!
Karen O’Neil
Director, Green Bank Observatory

GBO Call for Proposals: 2020A Semester & NEW Extra-Large Proposal Call

The GBO invites scientists to participate in the 2020A Semester Call for Proposals for the Green Bank Telescope (GBT).  The entire proposal call can be found here.

Please note that there are new limits on the sizes of regular and large proposals, as outlined in the details of the weather, hours, and time span categories.

The opportunity to apply for Extra-Large observing proposals is open for observers seeking to use the GBT, VLA and/or VLBA. Extra-Large proposals are defined as those requesting a total of more than 1000 hours of telescope time and/or extending over four or more observing semesters. This call will likely not be repeated for at least three years. The earliest that successful Extra-Large projects could be scheduled is the start of Semester 2020B in August 2020. A joint proposal with external facilities (e.g., HST) may be included in an Extra-Large proposal, but the total time available for the external facility is limited. Application guidelines and restrictions.

The submission deadline for ALL Semester 2020A proposals is Thursday, 1 August 2019, at 17:00 EDT (21:00 UTC).

LASSI: Ever Closer to Improved High Frequency Daytime Observations

Image of GBT with laser scanning device
The Green Bank Telescope will use a laser scanning system to measure and adjust its surface precisely. Image : GBO/AUI

Work is progressing on the Laser Antenna Surface Scanning Instrument (LASSI) a metrology system that will allow for real time adjustments to the collecting surface of the GBT. This will improve current calibrating techniques that are more time consuming, and ineffective for high frequency daytime observations that are impacted by thermal gradients.

Measurement of the GBT surface in real time will allow operation at the highest frequencies night or day, extending the available telescope time at 3mm wavelength, and increasing the observing efficiency for all projects that operate above 25 GHz. 

This project takes advantage of the GBT active surface and large collecting area, consisting of 2008 panels, which makes it the largest telescope in the world operating at mm wavelengths.

This project is funded through the NSF MSIP program.

GBO Deploys VEGAS Pulsar Modes

The VErsatile GBT Astronomical Spectrometer (VEGAS) is GBO’s primary backend, used with essentially all receivers and for all types of observing, including continuum, spectral line, pulsar and Break Through Listen (BTL). VEGAS went into initial shared risk observing in March 2014 for spectral line modes.

A VEGAS prototype was built originally by the CICADA collaboration (NRAO Green Bank and the Center for Astronomy Signal Processing and Electronics Research (CASPER) at the University of California, Berkeley), and funded by a National Science Foundation Advanced Technologies and Instrumentation (NSF-ATI) program (Award Number: 1006509, PI: Dan Werthimer). The VEGAS prototype saw first light December 2011 and was designed to harness the power of the then new K-band Focal Plane Array by providing digital spectroscopy on up to eight dual-polarization inputs, each with a total bandwidth of up to 1.25 GHz. The instrument was designed with CASPER ROACH II FPGA boards feeding a cluster of GPU-enabled computers.

Starting in 2017 GBO renewed efforts to complete pulsar modes and to refactor code to improve reliability and performance.  The first round of pulsar modes were released in February 2018, and this spring the latest version of VEGAS was released that supports all envisioned spectral line and pulsar modes.  VEGAS will fully replace the Green Bank Ultimate Pulsar Processing Instrument (GUPPI) after a period of parallel operations, on target for May 2020.

NSF Award Will Create New Technology & Train First-Generation College Students

Luke Hawkins and Satori Chin inspect a circuit board
GBO Engineer Luke Hawkins and Allegheny College computer science major Satori Chin inspect a circuit board to be used in the NSF grant award project. (NSF/AUI/GBO)

GBO has been awarded a grant award from the National Science Foundation. The project, “New Wide-band Digital Technology and Interference Excision for Radio Astronomy,” is under the direction of GBO scientist Ryan S. Lynch. New research will develop cutting-edge technologies to enable ultra-wide bandwidth (UWB) radio astronomy and innovative detection and excision of radio frequency interference (RFI).  This will lay the foundation for the next generation of end-to-end digital signal processing systems (DSP) and spectrometers that can effectively share the radio spectrum with the growing number of commercial, private, and governmental users.  GBO will integrate new analog to digital converters (ADCs) and field programmable gate arrays (FPGAs), develop firmware for interfacing these technologies with peripheral systems, and determine optimal methods for handling very high data rates.  GBO will also create a standard procedure for testing and validating RFI excision algorithms that will build confidence in their use among scientists.  This project will include a two-week undergraduate internship program aimed at first-generation college students and a summer research experience for an additional student.

The scientific and educational components of this project will impact an extremely large and diverse community. The results of GBO’s work will be shared to enable similar advances at other US and world observatories.  The internship program will leverage GBO’s membership in the NSF-INCLUDES for first-generation students and provide mentoring opportunities to additional undergraduates. 

The NSF award begins July 15, 2019 and ends June 30, 2021.

Moonshots and Earthshots in the Search for Life Beyond Earth, Barry Blumberg Memorial Workshop

July 20-23, GBO will host fifty specialists from diverse fields to discuss progress and challenges in astrobiology that we expect over the next decade (the Earthshots) and future plans that might require several decades work and possibly major technical or intellectual advances (the Moonshots).

Topics will include

  • History and status of the search for technosignatures
  • Radio emission from planets
  • Chemical complexity in the interstellar medium
  • Habitable planets in the Milky Way
  • The structure and chemistry of planet-forming disks
  • Precursors for biotic chemistry in the Solar System
  • Searches for life in the Solar System
  • Ethics and philosophy of the search for extraterrestrial life
  • Exoplanet biosignatures
  • Technical developments: telescopes & spacecraft & …

Talks will be shared via webcast and links to videos Schedules and more information can be found here.

This program is supported by a grant from Unither Bioelectronique, in honor of Dr Barry Blumberg, the late Chairman of its corporate parent’s Scientific Advisory Board.

Astro2020 Decadal Survey & White Papers Summary

A detailed breakdown of the approximately 600 white papers submitted shows that over 80 are relevant for GBT science, 38 of which explicitly requested the GBT, with an additional 25 requesting capabilities that the GBT can provide. GBO scientific staff worked with members of the community on the next round of white papers for the July deadline, discussing these projects and the state of the profession.

Topics for submission include:

  • A case for a fully funded GBT
  • The “advanced GBT”, discussing several potential upgrades
  • New instrumentation including ARGUS+, a K-band focal plane array, and a Ka-band radar system
  • The role of observatories like GBO in professional training
  • A paper highlighting our education, public outreach, and broader impacts

Dosvedanya and Farewell, RadioAstron

On May 30, 2019, the Russian RadioAstron satellite — the farthest element of an Earth-to-space radio-telescope system — ended its service. During its mission, RadioAstron helped to capture some of astronomy’s highest-resolution images and studied the extreme physics of astronomical objects by working with telescopes around the world, including the GBT.

Launched in July 2011, RadioAstron used the 140 Foot (43 Meter) Telescope at GBO as one of only two sites to download data for the Russian-made satellite.

RadioAstron excited the international scientific community for the unique science it enabled. Its high resolution was achieved through a technique known as “Very Long Baseline Interferometry,” which linked various radio antennas on Earth with the orbiting RadioAstron satellite to create a single virtual telescope that extended into space.  

RadioAstron’s achievements included observing a black hole jet in the center of the giant galaxy NGC 1275 (also known as radio source Perseus A, or 3C 84) revealing the jet structure 10 times closer to the black hole than previously known; the discovery of the smallest Galactic water maser sources ever observed, some as small as the Sun; and the detection of low frequency interference fringes on long baselines, giving a new understanding of the ionized interstellar medium.

The RadioAstron project was led by the Astro Space Center of the Lebedev Physical Institute of the Russian Academy of Sciences and the Lavochkin Scientific and Production Association under a contract with the Russian Federal Space Agency, in collaboration with partner organizations in Russia and other countries.

Fall Workshop: Warm Ionized Medium (WIM) In Galaxies

Join us at GBO October 6-9, 2019 for a workshop on the Warm Ionized Medium (WIM) in Galaxies. A similar meeting was held twenty years ago in Green Bank in September 1999. A summary of that meeting can be found in PASP:

The warm ionized medium, also called diffuse ionized gas, is a major component of the Galactic interstellar medium and is clearly important in other galaxies as well. In the twenty years since our previous workshop, understanding on the ionization, heating, cooling and overall dynamics of this gas has remained challenging. With several new Galactic surveys, the wealth of extragalactic data, and the advances in theoretical and computational models in the past few decades a workshop to reevaluate our understanding of the warm ionized medium is timely.

Topics to be discussed:

  1. The WIM in our Galaxy
  2. The WIM in other galaxies
  3. Optical/UV observations of the WIM
    a. H-alpha surveys
    b. He I, [NII], [SII], etc.
  4. Radio and sub-mm observations of the WIM
    a. Pulsar and FRB observations
    b. Radio recombination lines
    c. Radio polarimetry
  5. Infrared observations of the WIM
    a. Fine-structure transitions ([CII], [NII], etc.)
  6. Theory and simulations
    a. Ionization of the WIM
    b. Distribution and dynamics of the WIM
    c. Heating of the WIM
  7. Relationship to other ISM components
  8. Future WIM surveys

In the tradition of past Green Bank Workshops the total number of participants will be limited (50 people) which allows for candid discussions. The workshop will be held from the evening of Sunday, October 6 through the afternoon of Wednesday, October 9. Only a limited number of talks will be given which will allow ample time for discussion. Talks given will focus on new results and general reviews.

Registration is open through August 1.

For all details and to register visit the event page.

Meet our Summer Students

summer students

Pictured above from left to right

David Magda is a rising senior at David and Elkin College studying computer science. David is working with Dane Sizemore on development of pyCLEO as part of the REU program.

Kennedy Sleet is a rising sophomore at Baylor University studying astrophysics. Kennedy is working with Laura Jensen on systems engineering modeling for a GBO data center as part of the PING program.

Vayl Sorenson is a rising junior at the University of Vermont studying physics, astronomy, and math. Vayl is working with Sue Ann Heatherly on developing new projects for the 20-m telescope as part of the PING program.

Riley Dunnagan is a rising junior at Rose-Hulman Institute of Technology studying physics, astronomy, and mathematics. Riley is working with Natalie Butterfield analyzing ALMA observations of the Galactic center as part of the REU program. Dave Frayer will also be helping with the project.

Max Hawkins is a sophomore at the University of Alabama studying electrical engineering and math. Max is working with Ryan Lynch and Luke Hawkins on RFI mitigation techniques as an undergraduate intern.

Isiah Holt is a rising senior at Penn State University studying astronomy and physics. Isiah is working with Andrew Seymour on searches for fast radio bursts as part of the PING program. Ryan Lynch will also be helping with the project.

Alyssa Bulatek is a rising senior at Macalaster College studying physics and applied mathematics. Alyssa is working with Steve White on the design and testing of the ultrawideband receiver as part of the REU program.


Nicholas Miklave is a rising senior at Stony Brook University studying physics, astronomy, and mathematics. Nicholas is working with Tapasi Ghosh and Chris Salter on searching for transient radio sources in the GALFACTS survey as part of the REU program.

Evan Smith is a grad student at West Virginia University (and a former Green Bank tour guide and research assistant — welcome back Evan!). Even is working with DJ Pisano at WVU on a variety of projects, including RFI mitigation, and he’ll be continuing that work with Luke Hawkins and Ryan Lynch this summer as a graduate intern.

Education & Public Outreach

Summer is a busy season for education at GBO! Host to numerous camps, workshops, and student visits including:

PING students taking a break while on a hike. (NSF/AUI/GBO)

Star Quest 2019

Star Quest, an annual star party hosted at GBO by the Central Appalachian Astronomy Club, was held June 26-29th and welcomed hundreds of observers and campers with their optical telescopes onsite. Participants of all ages enjoyed a variety of workshops, talks, and activities. This year’s theme focused on the 50th anniversary of the Apollo landing, along with a wide range of topics from astrophotography to asteroids. For more information on future Star Quest programs, follow Star Quest and the Central Appalachian Astronomy Club through their websites and Facebook.

Star Quest participants set up an optical telescope for a night-sky viewing. (NSF/AUI/GBO)

Visit Us & Upcoming Events

Visit GBO 7 days a week during our summer schedule

Science Center& Gift Shop open 8:30 a.m. – 7 p.m., Starlight Café, 11 a.m. – 7 p.m.

Guided Tours on the hour, 9 a.m. – 6 p.m., no advanced registration required (ticket fee applies)

SETI Tours, select Fridays, see schedule for descriptions, dates, & reservations

High Tech Tours, select Thursdays, see schedule for descriptions, dates, & reservations

Scout Weekends, select weekends for Girl Scouts and Boy Scouts, see schedule for descriptions, dates, & reservations

Field Trips

Outreach, bring the Green Bank Observatory to YOU!

Take a tour of the Green Bank Observatory on one of our air-conditioned buses. (NSF/AUI/GBO)

Job Openings

Want to work with us? Keep an eye on the jobs page at our website.

Current Openings

Electronics Engineer II

Operations Specialist I (Telescope Operator)

GBO staff in front of the Jansky Building (NSF/AUI/GBO)