Green Bank Observer – Vol III, Issue 1

Director’s News

As the calendar year closes and I look back on the year, three exciting new initiatives at Green Bank really catch my attention. LASSI, a new project funded through the NSF MSIP program, will place a terrestrial laser scanner on the GBT to provide near-real time surface corrections. By project completion in 2022, LASSI will allow for high frequency operations during the daytime, and increase the available high frequency hours on the GBT by 1,000. We are also well into the design phase of a new wideband receiver for the GBT. Funded by the Gordon and Betty Moore Foundation, the 0.6 – 2.8 GHz system will double the sensitivity of the GBT for most pulsar timing experiments and will provide wide spectral coverage for other scientific pursuits. Finally, the kick-off meeting for the new First2 STEM Student Success Alliance launched just last week. This alliance, funded by the NSF INCLUDES initiative and led by Green Bank, is comprised of many different organizations across the state of West Virginia and is focused on attracting and retaining rural, first generation students attending West Virginia colleges and universities.

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Green Bank Observer – Vol II, Issue 3

News from the Director

The students and interns have gone home, the cafeteria staff all got to take last weekend off, and last night the temperature here dropped into the 40s (Fahrenheit). Green Bank’s summer is coming to an end. The summer itself was busy in a wonderful way – we had 10 summer students taking part in our REU, PING, and internship programs and an additional 36 other summer staff who worked on everything from painting the GBT to site maintenance and providing tours, food, and rooms to all the visitors on site. We were excited to welcome back the Governor’s STEM Institute to the site this year, as well as holding another PING camp for rising 9th graders, a digital signal processing workshop for high school teachers, Chautauqua Short Courses, Earth-Space science training for West Virginia teachers, StarQuest, SARA, Star Parties, and much more, all activities that kept the staff busy and gave many different groups of students, teachers, and the general public the opportunity to learn more about STEM, astronomy, and exciting new discoveries than they would through just a normal half day visit.

But with summer over we can now start looking forward to the fall and the increase in GBT observing time that comes with the end of summer maintenance and the increase in the number of beautiful, clear nights for high frequency observing. This fall we will be holding another observer training workshop as well as a workshop aimed toward people either planning on in the middle of large surveys on the GBT, looking for ways to optimize the science from these surveys. We are also in the planning stages for a couple of new instruments on the GBT which will increase the telescope’s scientific output at a variety of frequencies, and we will announce those plans as soon as they are fully in place.

Karen O’Neil
Director, Green Bank Observatory

Science News

Even Phenomenally Dense Neutron Stars Fall like a Feather

Harnessing the exquisite sensitivity of the National Science Foundation’s Green Bank Telescope (GBT), astronomers have given one of Einstein’s predictions on gravity its most stringent test yet. By precisely tracking the meanderings of three stars in a single system – two white dwarf stars and one ultra-dense neutron star – the researchers determined that even phenomenally compact neutron stars “fall” in the same manner as their less-dense counterparts, an aspect of nature called the “Strong Equivalence Principle.”

Einstein’s understanding of gravity, as outlined in his general theory of relativity, predicts that all objects fall at the same rate, regardless of their mass or composition. This theory has passed test after test here on Earth, but does it still hold true for some of the most massive and dense objects in the known universe, an aspect of nature known as the Strong Equivalence Principle? An international team of astronomers has given this lingering question its most stringent test ever. Their findings, published in the journal Nature, show that Einstein’s insights into gravity still hold sway, even in one of the most extreme scenarios the Universe can offer.

Read more …

Observatories Team Up to Reveal Rare Double Asteroid

New observations by three of the world‘s largest radio telescopes have revealed that an asteroid discovered last year is actually two objects, each about 3,000 feet (900 meters) in size, orbiting each other.

Near-Earth asteroid 2017 YE5 was discovered with observations provided by the Morocco Oukaimeden Sky Survey on Dec. 21, 2017, but no details about the asteroid’s physical properties were known until the end of June. This is only the fourth “equal mass” binary near-Earth asteroid ever detected, consisting of two objects nearly identical in size, orbiting each other. The new observations provide the most detailed images ever obtained of this type of binary asteroid.

Read more …

eXtra Large Proposal Reminder

The Green Bank Observatory (GBO),  Long Baseline Observatory (LBO), and National Radio Astronomy Observatory (NRAO), invite submission of brief Expressions of Interest (EoIs) in Principal Investigator-led “eXtra Large Proposals” (X-Proposals) for the Green Bank Telescope, Very Long Baseline Array, and Very Large Array (VLA) requiring 1000 hours or more of telescope time, and running over multiple semesters (and possibly multiple VLA configurations).

Responses will be used to gauge the level of community interest in such proposals, and their scientific potential. GBO, LBO and NRAO will seek advice from their advisory committees and the joint Time Allocation Committee on the EoIs submitted. It is important to note that the observatories may not proceed to a Call for X-Proposals if, for example, there is judged to be insufficient community interest, scientific merit, or differentiation from Large Proposals.

Expressions of Interest can be submitted using the web form at:

http://go.nrao.edu/xproposals

The deadline for submissions is 31 August 2018.

Proposal Call Results

A total of 97 proposals requesting NSF funded “open skies” time were submitted to the Green Bank Observatory’s Robert C. Byrd Green Bank Telescope (GBT)  for semester 18B.  Proposals are reviewed on a competitive basis with a panel review system (see Proposal Review System).  Below are the statistics by proposal count and hours.  The oversubscription is the ratio of the number of submitted proposals to the number of approved proposals.  The pressure is the ratio of the requested time to the available time in hours.  Here we only include proposals submitted for the 18B semester that have been reviewed by the Green Bank Observatory Telescope Allocation Committee (TAC).

A description of the 18B proposals accepted can be found at 2018B Science Program.

Recent GBO Publications

From time to time, we update our list of publications on the GBO Web site. Here are a few listed alphabetically below:

Anderson, L.D. et al. 2018 ApJS, 234, 33.
“A Green Bank Telescope Survey of Large Galactic HII Regions”

Andrews, J.J. et al. 2018 RNAAS, 2, 60.
“A Serendipitous Pulsar Discovery in a Search for a Companion to a Low-mass White Dwarf”

Archibald, A.M. et al. 2018 Nature, 559, 73.
“Universality of free fall from the orbital motion of a pulsar in a stellar triple system”

Arzoumanian, Z. et al. 2018 ApJ, 859, 47.
“The NANOGrav 11-year Data Set: Pulsar-timing Constraints On The Stochastic Gravitational-wave Background”

Bhattacharyya, B.; 2018 MNRAS, 477, 4090.
“A Long-term study of three rotating radio transients”

Bietenholz, M.F. et al. 2018 MNRAS, 475, 1756. SN 2014C:
“VLBI images of a supernova interacting with a circumstellar shell”

Burkhardt, A.M. et al. 2018 MNRAS, 474, 5068.
“Detection of HC$_5$N and HC$_7$N Isotopologues in TMC-1 with the Green Bank Telescope”

A complete list may be found on our Publications Page.

Optimizing Science from Green Bank Telescope Surveys

Since its commissioning, the Green Bank Telescope (GBT) has been used for a number of surveys that have produced unique data of lasting value. Recent GBT surveys are measuring star-forming molecular clouds in the Gould Belt, searching for new chemical species in Taurus, determining the HI properties of galaxies in the local Universe, determining the distribution of dense gas in galaxies and hot gas in galaxy clusters, searching for H2O megamasers in nuclear disks, and searching for new pulsars toward the north celestial pole.

The Green Bank Observatory (GBO) is interested in assisting its users who perform surveys. The assistance could take many forms: hosting a survey website; arranging team meetings; training student observers; organizing the observing; curating the final data products. To explore the ways that the GBO might assist survey science there will be a workshop “Optimizing Science from Green Bank Telescope Surveys” at the Green Bank Observatory on November 13-14, 2018. The goal of the workshop will be to develop practical policies for GBO support of survey science, but there will also be time set aside for survey team meetings, discussion with GBO staff on technical issues, or any other activity that might benefit current and future GBT surveys.

This workshop is intended for scientists and students who are involved with current or past GBT surveys, or who are planning future GBT surveys.

Logistics at the GBO limit the workshop to about 40 participants. There will be no registration fee, and all on-site expenses, include lodging and meals, will be covered by the GBO.

Workshop information page

Summer Students Wrap Up Their Work

Green Bank Observatory recently bid a fond farewell to our 2018 class of undergraduate summer students. Eight students, three from the Research Experience for Undergraduate program, four from the Physicists Inspiring the Next Generation program, and one from GBO’s research assistant program, spent the summer living and working at the observatory. Their projects focused on pulsars and fast radio bursts, Galactic and Local Group HI, the conditions for water on Mars, new instrumentation for the GBT, and RFI mitigation. Our students were active members of the observatory community, participating in numerous education and outreach programs and local community events, in addition to their research projects. We look forward to seeing many of them at upcoming professional meetings – including the 2019 Winter AAS meeting, and as observers at the GBT – and wish them success in their future endeavors.

All undergraduate and graduate students are encouraged to apply for the 2019 GBO/NRAO summer student programs. We’ll have an informational table at the 2019 Winter AAS undergraduate student reception and throughout the AAS meeting in the main exhibit hall.  Information about 2019 research opportunities will be available in December. The application deadline for the 2019 summer student programs will be Feb 1, 2019. Please visit our summer student program page for additional information on GBO and NRAO student programs.

YY1_20FITS
Quick look display of a galactic center map from a 10 minute observation.

Twenty Meter Telescope Available for
Undergraduate Student Educational Use

The Green Bank Observatory is pleased to make the 20 Meter Telescope available for observational projects as part of college and university astronomy courses.

The 20 Meter Telescope was built in Green Bank by RSI, and funded by the US Naval Observatory (USNO) to be part of their Earth orientation observing program, and was operated by USNO from 1995-2000. In 2012, the 20 Meter was refurbished, and joined the Skynet Robotic Telescope Network project operated by the University of North Carolina, Chapel Hill.

The NRAO 20-meter telescope is the only radio telescope in the network, providing a unique capability to include radio astronomy as a lab component in university/college astronomy courses. Much of today’s professional astronomical research is multi-wavelength, with scientists using combinations of radio, optical, infrared, or other telescopes to gain a complete picture of the objects they study. The 20 Meter Telescope gives students the same ability and provides them with a better understanding of modern research.

Two receivers formerly used on the 140-foot telescope were revived and adapted for use on the 20 Meter, providing receivers sensitive to 1.3-1.8 GHz, and 8-10 GHz. The 1.3-1.8 GHz receiver is usually on the telescope providing access to studies of neutral hydrogen emission, OH emission as well as continuum observations to a declination limit of  about -45 degrees.

Telescope time may be purchased for both educational and research activities. The highly competitive educational rate requires the observations to be used for student training and education as the primary activity. Professors and teachers interested in learning more about educational observing projects can contact Sue Ann Heatherly at sheather–at–nrao.edu. For detailed information regarding the 20 Meter capabilities visit [www.gb.nrao.edu/20m], or contact Frank Ghigo, 20 Meter Scientist, at fghigo–at–nrao.edu.

Events/Workshops

Family Day and Open House – September 9, 1 – 5 P.M.

GBT Remote Observer Training Workshop – September 17-18

2018 Jansky Lecture by Professor Roger D. Blandford – November 1, 7:00 P.M., in the Science Center Auditorium

Optimizing Science from Green Bank Telescope Surveys – November 13-14

The Observer: Volume II, Issue 2

Download a printable (PDF) version of The Observer

Director’s News

Spring is here in Green Bank, at least in theory (and if it would stop snowing that would be nice). This means we are now ramping up for our influx of summer staff and the many summer programs which we host on site. From workshops on single dish radio astronomy for undergraduate and graduate students, to REU and internship positions, summer camps for teachers and students, amateur astronomy gatherings, Pulsar Search Collaboratory meetings and training, and the annual Space Race Rumpus bike weekend, there is something for almost everyone going on here during the summer months. During this summer we are also spending time looking toward the future of the Observatory. As you will see in the ASTRO2020 article within this newsletter, we are actively soliciting input from the scientific community to help us shape our future and working with plan for what Green Bank Observatory should look like in 2020 and beyond.

Enjoy Your Spring!
Karen O’Neil
Director

News

Expression of Interest Invitation

Green Bank Observatory, LBO and NRAO invite submissions of brief Expressions of Interest (EoI) in PI-led “eXtra Large Proposals” (X-Proposals) for the GBT, VLBA and VLA requiring 1000 hours or more of telescope time, and running over multiple semesters (and possibly multiple VLA configurations).

X-Proposals are expected to be resourced by the proposing team. Projects should have extraordinary scientific merit and community legacy value, and will be expected to specify why the science goals cannot be achieved through the standard SRP/TAC process.

Responses will be used to gauge the level of community interest in such proposals, and their scientific potential. The observatories may not proceed to a Call for X-Proposals if, for example, there is judged to be insufficient community interest, scientific merit, or differentiation from Large Proposals.

The call for submission of EoIs is expected to be issued on June 1 with a deadline of July 11.

See the 2016 and 2017 NRAO User Committee reports for further background.

REU Students coming to Green Bank

Green Bank Observatory will be welcoming eight summer students in late May as part of the Research Experience for Undergraduates (REU) program and the Physicists Inspiring the Next Generation (PING) program. Students will be joining scientific and engineering staff for 10-12 week research projects and professional development activities. PING students will also spend one week mentoring middle school students participating in a science camp at the observatory. This core component of PING is designed to enhance the participation of underrepresented minorities in Science, Technology, Engineering, and Mathematics (STEM) fields. The Green Bank Observatory will also be welcoming a graduate intern working in the digital electronics group.

Astro2020 Update

The Green Bank Observatory kicked off plans for the Astro2020 Decadal Survey at the Winter AAS Meeting in Washington, DC. The effort started with the “Transformative Science for the Next Decade with the Green Bank Observatory” workshop in October 2017, which identified some key science drivers for the Observatory in the next decade. At the AAS meeting, Observatory science staff conducted an information-gathering session along with many of those very important booth and hallway conversations that spark new ideas. In January, we announced the Astro2020 activities for Green Bank with a letter from the Director to all who participated in the workshop and AAS activities to join the Observatory in crafting a series of science white papers in anticipation of a late 2018 call for papers. Science interests have been divided into seven scientific discussion categories and we are establishing teams for each category to identify key science cases and develop papers. The categories are:

  • Fundamental Physics (e.g. gravitational waves, general relativity, equivalence principle)
  • The transient sky (e.g. FRBs, SETI, Pulsars )
  • Stars & star formation (e.g. turbulence, magnetic fields, multi-scale molecular clouds, diffuse environments, ISM)
  • Galaxies & Galaxy Clusters (Milky Way and beyond) (e.g. cosmic web, HI extent of galaxies, galaxy structure, galaxy clusters)
  • Astrobiology & Astrochemistry (includes comets, SETI)
  • Planetary systems (e.g. sun, stars, asteroid, comets, exoplanets, planetary weather/atmosphere)
  • Cosmology & Large Scale Structure

Response has been excellent with more than 60 scientists and astronomy professionals signing up for one or more discussion groups. We encourage anyone with interest in future science at Green Bank to join the Astro2020 team. More information about the Astro2020 program and information for interested participants is available at on our ASTRO2020 page.

We hope to hear from you. We will keep you posted on the progress of the teams in upcoming newsletter articles.

Pulsar Watchers Close In On Galaxy Merger History

Fifty years after pulsar discovery published, massive new data set moves closer to finding very-low-frequency gravitational waves, researchers say.
Gravitational waves are wrinkles in space-time that stretch and squeeze the distances between objects. In 2015, a hundred years after Albert Einstein realized that accelerating massive objects should produce them, these waves were finally detected from black holes with masses roughly 30 times the mass of our sun colliding with each other. However, Einstein’s theory also predicts another kind of wave, one that comes from the mergers of black holes with masses of hundred million times the sun’s.

Read the full release

Astronomers Solve Cosmic “Whodunit” with Interstellar Forensics

On the outskirts of our galaxy, a cosmic tug-of-war is unfolding. The players are two dwarf galaxies, the Large Magellanic Cloud and the Small Magellanic Cloud, both of which orbit our own Milky Way Galaxy. But as they go around the Milky Way, they are also orbiting each other. Each one tugs at the other, and one of them has pulled out a huge cloud of gas from its companion.

Read the full story

Solar System’s Largest Telescope Sees New Black Hole Details

a global array of telescopes allows scientists to see new details in Perseus A
Part of the global network of ground radio telescopes that participated in the observations. Credit: Paul Boven
(boven@jive.eu). Satellite image: Blue Marble Next Generation, courtesy of NASA Visible Earth (visibleearth.nasa.gov)

Using the RadioAstron Space VLBI Telescope, an international consortium of astronomers have been able to observe ten times closer to a black hole and see new details of the jet formation region of Perseus A. These observations challenge some of the current models by showing jets much wider than predicted. The Perseus jets are in their infancy and astronomers plan to continue these ultra-high resolution observations to see how the jets ‘mature’ and compare observations of other active Galactic Nuclei to see how these results compare with other black hole jets.

 

All of this is possible because the combination of the RadioAstron spacecraft’s 10 meter telescope in orbit between the Moon and Earth, combined with multiple ground telescopes, like the GBT which contributed to the Perseus A observation, is able to resolve details beyond the capabilities of any ground-based telescope or array. Whenever the spacecraft is viewable in our hemisphere, the science data and spacecraft data are conveyed back to Russia by way of the 140’ Telescope acting as a data downlink, often as the GBT is simultaneously observing the same source as the spacecraft. Green Bank is pleased to provide the vital data connection that make observations like these possible.

Coming this Summer – New GBO Post Docs

Natalie Butterfield and Will Armentrout join the GBO Scientific staff in August as our newest Post Docs. Natalie has been an NRAO Reber Fellow attending the University of Iowa, and Will is currently finishing his PhD at West Virginia University with advisor, Loren Anderson. We look forward to their arrival this summer.

GBT Publications, 2018

A complete list of publications are available on this page.

EPO Happenings

Green Bank Observatory Chosen for National Leap Into Science Project

A diverse group of educators from the Green Bank Observatory, West Virginia University Extension Service, Pocahontas County Libraries and the Morgantown Public Library System have teamed up to become The West Virginia Leap into Science State Leadership Team. Out of more than 20 applications from around the nation, West Virginia was one of four state teams selected.

Read the complete news post

Governor’s School Returns to Green Bank Observatory, under a New Name

After a two-year hiatus, the Green Bank Observatory successfully competed to host the West Virginia Governor’s STEM Institute (GSI) for the next 3 years. GSI invites students to delve into projects that allow them the time and opportunity to think and work like scientists and engineers, using high level mathematics and thinking skills while employing the latest technology. The Green Bank Observatory program “Investigating the Universe”, is an intensive two-week residential program that engages 60 talented rising ninth graders from all over West Virginia in radio astronomy research. Our program is truly unique in that is embedded within the day-to-day workings of a national research center. Our students will have the opportunity to join our professional STEM community; working in teams with scientist-mentors, rubbing elbows with undergraduate students, and using some of the most sophisticated radio astronomy technology on earth.

Physics Inspiring the Next Generation (PING) Camp Accepting Applications

The Green Bank Observatory also hosts a similar camp for rising ninth graders with an interest in STEM from all over the nation. PING is free of charge, except for travel (we do offer shuttle service to and from Green Bank from DC, and Charlottesville VA). We encourage applications from youth who are traditionally under-represented in the STEM fields. Please help us spread the word.

More information and application

New Employees

Andrew Seymour

Andrew Seymour officially joined the GBO Scientific Staff in January, 2018. He has been a visiting scientist in Green Bank since hurricane Maria stopped by the Arecibo Observatory for an unwelcomed visit. We talked to Andrew about his career, life in Puerto Rico and his journey to GBO.

Could you briefly explain your Scientific Career journey?

My career has been a bit of a “random walk”. After earning my undergraduate degrees in Mechanical and Aerospace Engineering, I decided to go to graduate school for Physics. There I did research with lasers and optics, then moved on to Chaos theory, but eventually did my thesis work on Astronomy and Pulsars. After graduate school, I moved to Puerto Rico to use the William E. Gordon Telescope at Arecibo, famous for being in the films Goldeneye and Contact, to continue my pulsar work. While there, one of the collaborations that I work with found a millisecond extra-galactic radio source known as a Fast Radio Burst. Follow ups on this source have produced numerous events at Arecibo in the past three years. Yet, this is the sole source to date to repeat, and it is still unknown what is causing these events. All of which has kept the collaboration and me pretty busy.

What was the most fun about working at Arecibo?

Since Arecibo is in the tropics, there was a lot of beach fun to be had. Yet I think I had the most fun with my co-workers. It takes a special personality willing to move to Puerto Rico, and we grew to rely on each other. Be it through a hurricane or the uncertainty of a NSF-EIS, we learned to laugh our way through it all.

Were you involved with any of the projects where Arecibo and the GBT work together? If so, could you talk about them?

There are many projects that use the unique  capabilities of both the Arecibo and the Green Bank Telescope.The obvious ones are the Pulsar surveys and Pulsar timing projects. This is where measuring the radio burst from neutron stars can eventually detect gravitational waves from merging super massive black holes, like that found in the center of some galaxies. In order to achieve this, we need a large number of pulsars.

Therefore we want to search far and wide to find them. Arecibo was the largest radio telescope in the world, which allows it to search for very deep and weak pulsars. Yet because of its size, it cannot be tilted, limiting what part of the sky it can observe. Using the largest steerable structure, that is the GBT, is great for finding pulsars in the other part of the sky that Arecibo cannot reach. Arecibo searches the far, while GBT searches the wide.

What is the major difference between Puerto Rico and West Virginia?

The weather.

What are their similarities?

Puerto Rico and West Virginia have more in common than you first realize. Both have their unique dialects. The mountains can make it hard to get where you want to go. Not all the information you need can be found online. Be wary where the GPS sends you. Your cell phone might not work. In spite or maybe because of these “hardships”, both places have a tremendous amount of pride in the region they call home.

Upcoming Events

Remote Observer Training Workshops

May 24 – 25; September 17 – 18

Learn more

Single Dish Training Workshop, Formerly Single Dish Summer School

May 19 – 23
For grad students, post-docs and experts in other fields of astronomy.

Learn more

Chautauqua Short Course

May 30 – June 1
2½ day workshop, geared toward college faculty who teach at small non-research colleges or community colleges, and who have an interest in learning about radio astronomy research.

For more info, contact the GBO Education Officer, Sue Ann Heatherly at sheather@nrao.edu

Space Race Rumpus

June 8 – 10
Space Race Rumpus is weekend-long cycling festival, based at the Observatory that raises funds for a Community Wellness Center.

Learn more

Society of Amateur Radio Astronomy Conference

June 10 – 13

Learn more: [http://www.radio-astronomy.org]

REU Bootcamp

June 4 – 8
For all summer students at NRAO and GBO sites.

ALFALFA-U Workshop

June 19 – 23
This workshop engages undergraduates and their faculty on radio astronomy projects with the ALFALFA Survey data. The workshop is part of an NSF-sponsored program to promote undergraduate research within the ALFALFA project.

ESS Passport Workshop

June 17 – 30
Professional Development workshop to prepare WV teachers to teach 9th grade Earth and Space Science.

Learn More

For an overview of all upcoming local- and scientific-community events, be sure to visit our events calendar.

Print Version of the Newsletter

Download a printable (PDF) version of The Observer

The Observer: Volume II, Issue 1

Download a PDF of the newsletter

Director’s News

We have just finished our first full calendar year as the Green Bank Observatory. It has been an incredibly busy year filled with many accomplishments, including the first high frequency seasons of the MUSTANG-2 and ARGUS high frequency instruments, and the commissioning of FLAG (and its associated beam-former), the most sensitive phased array feed system in the world. Full commissioning of the VEGAS spectral line observing modes is complete and initial pulsar observing modes have been released. We have enjoyed an unprecedented level of visitors to and media interest in the Observatory and the work we do. This year we also celebrated the 60th anniversary of the dedication of the Observatory, with a party looking back on the many accomplishments the site’s telescopes have had over the years.
In addition to all the activities described above, this past October we held a workshop which looked toward the future of the Observatory over the next 5, 10, and even 20 years. Workshop participants laid out a number of possible ideas for the site, and, as discussed in the “Preparations for the Decadal Survey” article in this newsletter, we are now asking members of the community to help us turn those ideas into a plan for the next decade or longer. We hope all of you with an interest in the long term future of the GBT and the Green Bank Observatory will help us shape the coming decades.

Dr. Karen O’Neil
Director, Green Bank Observatory


News

ASTRO2020 Preparations

We are preparing a long-term plan for the scientific program of the Green Bank Observatory and the GBT for the period 2020 – 2030. This review of current and future instruments will provide input to the 2020 Decadal survey. If you have an interest in science at the GBT or GBO please join us in this process. We envision that there will be a few small workshops at various locations during 2018 to develop the science cases and instrumental specifications. You can signal your interest by signing up on our web site.

Transformative Science for the Next Decade with the Green Bank Observatory – Workshop Results

From October 16 through 18, approximately 40 people gathered together to discuss possible scientific and instrumentation plans for the Green Bank Observatory in the 1-2 decades. The format of the meeting was designed to encourage significant discussion on topics ranging from star and galaxy formation and evolution through gravitational waves, pulsars, transients, astrochemistry, solar physics, the search for life, and solar system science. Each group of talks was followed by a discussion period on both the science and also how the Observatory can aid in accomplishing the science goals.
At the end of the workshop, we discussed the unique roles the Green Bank Observatory could have in accomplishing the varied science objectives, and laid out a number of possible paths for the future. Over the next year we plan to turn many of these ideas into grants, instrumentation plans, and one or more submissions into the upcoming Astro 2020 decadal survey.
The majority of the talks from the workshop, as well as the summary slides, are available online.

Anyone who is interested in continuing to provide input or in working with us on our long term Observatory plans and Astro2020 submissions should go online and register your interest.

A new look at IC342

IC342 is a face-on weakly barred spiral galaxy with a young nuclear star cluster surrounded by several giant molecular clouds. However, the connection between the bright nuclear bar and low surface-brightness or extended emission has not been well explored in the past. Using 12CO lines to trace molecular gas at both low and high densities, a new map depicts a high signal-to-noise image of the inner part of IC342 that includes the first spiral arm. These fully-sampled images of the distribution of dense gas in star formation regions and their precursor flows will show whether the amount of dense gas is sufficient to fuel the star-forming process.

High resolution images of ground-state carbon monoxide spectral line
Figure 01: High-resolution images of the ground-state carbon monoxide spectral line at 115.27GHz. These panels show the overall distribution of CO as integrated intensity maps.

This new look at the galaxy was obtained with Argus, a 16-pixel focal plane array on the Green Bank Telescope. This millimeter-wave radio camera is able to make large-scale images of astronomical objects in a fraction of the time, and with higher image quality, that a conventional single-pixel reciever takes. Graduate student Jialu Li, in collaboration with the Argus instrument team and DEGAS project, made these images (the highest frequency spectral line observations the Green Bank Telescope has ever made) in only 10 hours on 2017 October 25 and 26. The combination of the GBT’s 100-meter diameter and the short observing wavelength produces images with an unprecedented 4 arcsecond resolution for single-dish observations. This image, which is part of the DEGAS study of dense gas in nearby galaxies, shows the power of the GBT for observations of extended objects beyond our Galaxy.

moments 1 and 2
Figure 02: The “Moment 1” panel shows the change of velocity across the galaxy, indicating a smooth rotation, while “Moment 2” gives the spectral line’s width, here showing a broad line toward the turbulent star-forming nuclear bar and more ordered motion in the arms themselves.

The Argus millimeter-wave camera on the GBT produces data cubes of the emission from spectral lines with high spectral and spatial resolution. Data cubes have two spatial dimensions and a third dimension of spectral information, providing images of astronomical objects that show both the distribution and motions of gas. Figures 01 and 02 summarize the information from IC342’s 12CO J = 1-0 spectral line data cube. Both IC342’s nuclear bar as well as its inner spiral arms are clearly visible.

The Argus144 Project at the GBT

The GBT is now into its second winter season with Argus, the 16-pixel camera for spectroscopy in the molecule-rich 3mm atmospheric window between 74 – 116 GHz. Argus is the brainchild of Sarah Church of Stanford University and collaborators, who received an NSF ATI grant to design a modular receiver system for the GBT that could be replicated and expanded in a straightforward way. With the unique combination of angular resolution (6.5 – 9 arcseconds), sensitivity, and field of view of the GBT, Argus is being used for ground-breaking surveys of dense gas in galaxies and nearby star-forming regions. Some recent Argus results will be highlighted at the upcoming winter meeting of the American Astronomical Society in Washington D.C.

The Green Bank Observatory and the original Argus team are now collaborating on the Argus144 project, which would take advantage of the technical development afforded by Argus to produce a camera with ten times the mapping speed. Argus144 will also include a new spectrometer and improvements to the GBT metrology that would double the time available for 3mm spectroscopy each year. Argus144 will routinely produce spectral line maps of key species such as CO, HCN, and HCO+ with a spatial dynamic range (map area / pixel size) of 104 to 105.

As part of the Argus144 project the community will be invited to participate in legacy surveys with the new instrument. There will be a spectroscopic survey of the Gould Belt molecular clouds, and a survey of dense gas tracers in nearby star-forming galaxies. The legacy surveys will produce unique data of lasting value. Argus144 data will also be displayed in exhibits at the GBO Science Center, and will be incorporated into a range of programs in STEM education throughout the region.
The plan for Argus144 has been submitted to the National Science Foundation’s call for pre-proposals to the Major Scientific Instrument Program (MSIP) with Felix J. Lockman (GBO) and Sarah Church (Stanford) as co-PIs. The project will leverage the NSF’s investment in the prototype Argus to produce a uniquely powerful scientific instrument accessible to the U.S. scientific community.

Information on Argus144 is available on the ASTRO2020 web site.

2018A Proposal Call Results

The 2018A call for proposals to use the GBT elicited requests for 4843 hours in 52 individual proposals. Twenty two proposals were approved for a total of 1748 hours.
The Time Allocation Committee Report for 18A can be found on the 2018A Proposal Call Results web page. A listing of the accepted 18A proposals can be found on the 2018A Science Program web page.

Summer Student Programs and Applications

The Green Bank Observatory summer student programs for undergraduate students runs from 10-12 weeks over the summer, from late May to mid-August. At the end of the summer, participants present their research results as a short talk and submit a written report. Financial support is available for students to present their summer research at a meeting of the American Astronomical Society, generally at the winter meeting following their appointment.

Besides their research, students take part in other activities, including a number of social events and excursions, as well as an extensive summer lecture series which covers aspects of radio astronomy and astronomical research. Students, may in their application materials, also indicate a willingness to participate in PING, an opportunity to mentor rising ninth grade students who will be onsite for 2 weeks.

The deadline for applications for 2018 is February 1, 2018. We will accept and review applications in conjunction with the NRAO summer student program again this year.

Green Bank Observatory Featured in Radio Astronomy Course

The Green Bank Observatory, and the GBT, feature prominently in a new course released by “The Teaching Company.” The course, part of their “Great Courses” series is authored by GBO astronomer, Jay Lockman, and is called “Radio Astronomy: Observing the Invisible Universe”. The “Great Courses” are not academic courses in the usual sense, but are intended to provide a college-level view of a subject for those outside the field, with no homework or tests. The company has over 200 courses on science and mathematics, and one of the newest is Jay’s 24-lecture set on radio astronomy.

Besides providing a general overview of radio astronomy, the new course spends two “lectures” on an actual tour of the Green Bank Observatory. The first covers some of the historic telescopes like the Reber, Tatel, and 140 Foot. The second lecture is devoted entirely the GBT and includes a tour from the track to the top of the receiver room.

The course goes on sale every few months and is available online.

Recent GBT Publications

Sample publications based on GBT data that appeared within the last few months. A complete list for 2017 is available on our Web site. If your paper should be in that list but is not, please let us know.

  • Long-term Variability of H2CO Masers in Star-forming Regions, Andreev, N., et al. 2017, ApJS, 232, 29
  • The Breakthrough Listen Search for Intelligent Life: 1.1-1.9 GHz Observations of 692 Nearby Stars, Enriquez, J.E. et al. 2017, ApJ, 849, 104
  • The High-frequency Radio Emission of the Galactic Center Magnetar SGR J1745–29 during a Transitional Period, Gelfand, J.D. et al. 2017, ApJ, 850, 53
  • A Radio Counterpart to a Neutron Star Merger, Hallinan, G. et al. 2017, Science, 10.1126 aap9855
  • 2MTF – VI. Measuring the velocity power spectrum, Howlett, C. et al. 2017, MNRAS, 471, 3135L
  • The Green Bank Ammonia Survey: Observations of Hierarchical Dense Gas Structures in Cepheus-L1251, Keown, ,J. et al. 2017, ApJ, 850, 3
  • Diffuse Ionized Gas in the Milky Way Disk, Luisi, M. et al. 2017, ApJ, 849, 117
  • Probing the Outflowing Multiphase Gas ~1 kpc below the Galactic Center, Savage, B.D. et al 2017, ApJS, 232, 25
  • Temperature structure and kinematics of the IRDC G035.39-00.33, Sokolov, V. et al. 2017, A&A, 606A, 133
  • The Green Bank Ammonia Survey: Unveiling the Dynamics of the Barnard 59 star-forming Clump, Redaelli, E. et al., 2017, ApJ, 850, 202
  • Deep K-band observations of TMC-1 with the Green Bank Telescope: Detection of HC7O, non-detection of HC11N, and a search for new organic molecules, Cordiner, M.A. et al., 2017, ApJ, 850, 187

History

Scheduling Telescopes: Astronomers and Their Science

by Dr. David Hogg, printed with permission

It was my hope that by looking at how the NRAO developed its relationship with the users community I could better understand the way the Observatory evolved from its modest beginnings into the institution which has such a broad influence in global radio astronomy research. In the very beginning there was much controversy about the need for a national radio observatory and about how it should be operated. Eventually a process was developed under which a visiting scientist could submit a proposal to use one of the telescopes and obtain the data needed for his or her research. This process, developed in the early days at Green Bank, has endured throughout the history of the NRAO, albeit with modifications, some of them substantial.

The Principles of the Scheduling System

Once the 300-foot became available as a complement to the first 85-foot, the Tatel Telescope, it became necessary to formulate a policy which guided the selection and scheduling of observing proposals. A primitive first step had been taken in 1960 when the proposals were reviewed by Dave Heeschen, then the chair of the Astronomy Department. However, as the volume of proposals increased it became obvious that a more rigorous system was required.
Heeschen and AUI set out to develop a system which ensured that the proposals offering the best chance of producing important research would be awarded time on the NRAO telescopes. There was little guidance to be gained from the experience in optical astronomy, where the major instruments generally were managed by the sponsoring institutions, and the observing time was generally used by the staff of those institutions. AUI of course was managing the Brookhaven accelerators, and thus some of that experience informed the NRAO policy. In the end, the system was constructed on three principles:

  • Acceptance of an observing proposal would not be based on institutional affiliation. This concept is often known as “open skies”.
  • All proposals, whether from visitors or staff, would be considered together, and would be peer reviewed.
  • There would be no charge for telescope time.

Let me say a few words about each of these points.

The first principle, “open skies”, was not without controversy. It was intended to bring the best ideas to the telescope, but there was criticism that the policy was not reciprocated by many foreign observatories, so that US observers felt that they were being treated unfairly. In addition, there were occasional inquiries from Washington about what fraction of time went to non-US observers. The principle has been reviewed several times over the years, and undoubtedly will continue to be so.
The election to use peer review was made both to ensure that the NRAO staff was not treated more favorably, and of course to try to maximize the use of the telescope time.

There continues to be no charge for basic science although more recently both the GBT and the VLBA do undertake some directed programs for which funding is received.

No scheduling system is perfect. The early days of molecular astronomy presented a special challenge, because it was pretty wild and woolly. A new detection often earned a paper in the ApJ Letters, providing motivation for keen competition.

Simply having access to the telescopes is necessary but is not sufficient. The instrumentation has to work, and the data have to be saved in a form suitable for the observer to work on and eventually publish. A structure was created in Green Bank to accomplish this. There would be an engineering division to design and supervise the construction of telescopes. There would be an electronics division to develop advanced instrumentation which exploited the most recent technologies. There would be telescope operations since the typical visiting scientist would be unfamiliar with these structures. Binding it all together was a support staff who understood that the success of the observatory is totally dependent on the success of the observer, and who therefore were dedicated to helping the observer achieve that success. I was reminded of this just a few days ago when Mike Balister recalled an especially challenging night during which he was called out to each of the three telescopes in turn. There are many familiar names from these times – Bill Horne and Sidney Smith, Hein Hvatum, Sandy Weinreb, and Art Shalloway, Fred Crews and Bob Vance – so many that I am not able to mention them all, but as a group they worked hard to keep the telescopes at the cutting edge. This institutional ethos, if I may call it that, has been at the core of the Observatory and I regard it as the reason for the success of the NRAO.

Dave Hogg served as Assistant Director for Green Bank Operations from 1970-1974 and again from 1992-1993. He was involved in the development of the Green Bank Interferometer between 1962 and 1970, and was actively involved in the planning and development of the Green Bank Telescope (GBT). As a member of the GBT Commissioning group, David focused on correlator checkout, served on the team which defended NRAO in the GBT Arbitration proceedings, and was a member of the GBT Azimuth Track Review Panel. He became NRAO Scientist Emeritus upon retiring in 2005.


Events

Deadline for GBT Proposals

February 1, 2018

Proposals for Proposal Call 2018b for GBT Observers are due Feburary 1, 2018.

Summer Student Applications

Deadline for Application, February 1, 2018
For undergraduate students.

Remote Observer Training Workshops

January 15-16; May 24-25; September 17-18
Learn more.

Single Dish Training Workshop (Formerly Single Dish Summer School)

May 19-23
For grad students, post-docs and experts in other fields of astronomy. Learn more.

Pulsar Search Collaboratory Online Workshop

February 1 – March 15, 2018
For High school teachers and high school students
Learn more.

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