Director’s News

A very happy Fourth of July to everyone, and I hope your summer is as filled with fun science and education as ours is here in Green Bank. Our summer hires have, as usual, added an additional 50% to the overall staff here, and span the range from people painting the telescope, interns with our plant maintenance program, tour guides, cafeteria and café workers, and students taking part in co-ops, interns, and Research Experience for Undergraduates (REU) positions on site. Our other summer visitors include participants in our undergraduate radio astronomy course, PING (Physics Inspiring the Next Generation) campers, Pulsar Search Collaboratory participants, West Virginia Science teachers taking part in the Earth/Space Science Passport development program, Chautauqua, StarQuest, and Southeastern Association for Research in Astronomy (SARA) attendees, and the annual undergraduate Arecibo Legacy Fast ALFA (ALFALFA) workshop participants. The 6th annual Space Race Rumpus also took place here the weekend of June 9-11, and attracted a record 170 participants from the eastern United States who biked, danced, and learned a little astronomy on the side.

Within the next 1-2 months we anticipate the release of the draft Environmental Impact Statement (EIS) report. Once the draft EIS report is released, a 45 day window will open for comments on the document, including 1-2 onsite meetings. Announcement of the report, information on how to provide comments, and the dates/times for the scheduled meetings will be release on the NSF website [nsf.gov]. A link to this information will also be provided on the Green Bank Observatory website.

Looking forward, we have a number of items coming up in the next few months. In addition to our annual open house which is taking place September 10, and another observer training workshop the following week, we also plan on attending the upcoming URSI (Union Radio Scientifique Internationale) General Assembly in Montreal this August. After that, we will begin preparations for our 60th birthday celebrations being held in October.

Enjoy your summer!
Dr. Karen O’Neil,
Director, Green Bank Observatory

Proposal News

The Green Bank Observatory (GBO) invites scientists to participate in the GBO’s 2018A Semester Call for Proposals for the Green Bank Telescope (GBT). The entire proposal call can be found on our proposals page.

The submission deadline for Semester 2018A proposals is Tuesday, 1 August 2017, at 17:00 EDT (21:00 UTC).

The GBO wishes to remind proposers of continuing opportunities for joint observations with the Chandra X-ray Observatory, the Hubble Space Telescope, the Swift Gamma-Ray Burst Mission and the Fermi Gamma-ray Space Telescope

Events

Jansky Lecture – Jacqueline van Gorkom (Columbia University)

July 31

The 2016 Jansky Lecture — Gas and Galaxy Evolution — will be given on July 31 at 7:00 PM in the Science Center Auditorium by Dr. Jacqueline van Gorkom of Columbia University. It is free and open to the public. The Jansky Lectureship is an honor established by the trustees of AUI to recognize outstanding contributions to the advancement of radio astronomy.

Professor van Gorkom is a longtime radio astronomer, specializing in studies of neutral hydrogen, the most abundant element in the Universe. Her observations have focused on the distribution and dynamics of hydrogen in and around nearby galaxies of varied types and in widely different environments, and how the gas affects the evolution of the galaxies. She currently leads an important Very Large Array observing project aimed at learning how these properties change over time by observing hydrogen at greater cosmic distances.

The Jansky Lectureship has been awarded annually since 1966. It is named in honor of the man who first detected radio waves from a cosmic source in 1932.

Eclipse Party

August 21

Have you heard?! The Green Bank Observatory in Green Bank, WV is hosting a Great American Eclipse viewing party. Don’t miss out on this rare event. It’s been 26 years since a partial solar eclipse was visible from West Virginia! West Virginians will be able to see a 90% partial eclipse this August. So join us from 11:00 a.m. until 4:00 p.m. for a day of food, fun, and education!

• Hands-on Activities from 11 a.m.- 12 p.m.
• Lunch and Exhibits from 12 p.m. – 1 p.m.

Safe eclipse viewing through telescopes and projections. Plus live streaming video of the eclipse provided by NASA.
We would love to know if you’re joining us! Visit our Great American Eclipse event page and let us know you’re attending today!

Green Bank Open House and Family Science Day

September 10

The Green Bank Science Center hosts our annual Open House and Family Science Day event. With past attendance reaching over 700 guests, this is the most popular way for our visitors to enjoy hands-on experiments and get to know the Green Bank Observatory.

Where else can you… build and launch a rocket, test your engineering skills, learn about liquid nitrogen, and see some of the biggest telescopes all in one day? Public site tours are available as well as rare peeks into the GBT Control Room. Each year, the Valley Aerospace Team builds custom launch pads, helps participants build their rockets, and even brings a few of their own custom rockets to launch. This event is free and fun for all ages. Plan to come early! Rocket kits are first come, first serve.

Observer Training Workshop

September 18 – 22

The Green Bank Observatory will host the next GBT observer training workshop September 18-22 2017. The workshop will provide an introduction to general radio astronomical techniques as well as onsite training for GBT observers. We especially encourage high frequency observers (i.e. those interested in observing at 8 GHz and above) to attend in preparation for the winter season. The workshop will include dedicated time for general purpose training on the GBT  in a compact, one week workshop and includes training to become qualified to observe remotely. For further information, please see the event page.

Transformative Science Workshop Updates

October 16 – 20

Big Questions, Large Programs, and New Instruments: With new instruments and excellent performance, the 100m Green Bank Telescope is only just reaching its full potential. On this 60th anniversary of the ground breaking for the Green Bank Observatory, we are holding a workshop looking toward the next 10, 20, and even 60 years of the Green Bank Observatory, and invite the community to attend and aid us in planning the future. For more information, please see the event page.

60th Anniversary of the Green Bank Observatory

October 17

On October 17 2017, the Green Bank Observatory turns 60 years old, and we would like to invite you to help us celebrate!  The celebration will take place on site the afternoon and evening of October 17, and will include tours, talks, discussions, and, of course, food. Information on the gathering will be posted online by mid-August.

News

Ammonia in Orion – Star Formation Press Release

A team of astronomers has unveiled a striking new image of the Orion Molecular Cloud (OMC) – a bustling stellar nursery teeming with bright, young stars and dazzling regions of hot, glowing gas.

The researchers used the National Science Foundation’s (NSF) Green Bank Telescope (GBT) in West Virginia to study a 50 light-year long filament of star-forming gas that is wending its way through the northern portion of the OMC known as Orion A.

Previously released – Read the full press release.

Latest commissioning observations with the Focal L-band Array for the GBT (FLAG) and the real-time beamformer

Following a successful test of the FLAG phased-array feed on the GBT in March, a team of astronomers and engineers from Brigham Young University (BYU) and West Virginia University (WVU) came to Green Bank in late May to work with National Radio Astronomy Observatory (NRAO) and GBO engineers in commissioning the broadband beamformer funded by a NSF ATI grant. All three modes of the beamformer were tested: a 150 MHz, coarse resolution mode for calibration, a 150 MHz real-time beamforming mode for pulsar timing and transient surveys, and a narrow-band, 10 MHz, spectral-line mode. The tests confirmed the excellent Tsys/η = 28 K at 1350 MHz, equivalent to the existing single pixel feed and with good sensitivity across the entire 30′ field of view. The FLAG beamformer system will be seven times faster for mapping projects than the current single pixel receiver.

Tests of the real-time beamformer included observations of the pulsar B1937+21 in the central beam, where individual giant pulses were detected (see figure). Multiple bright galaxies were observed using On/Off single-pointing maps in spectral line mode, but these data are still being processed.
Final commissioning observations will take place in August, including tests of the commensal spectral line and real-time transient detection mode, with the hope that the instrument will be available for shared-risk observing in the near future.

Beamformer Team: Brian Jeffs, Karl Warnick, Richard Black, Mitchell Burnett, Mark Rudzindana (BYU); Duncan Lorimer, Maura McLaughlin, D.J. Pisano, Nick Pingel, Kaustubh Rajwade (WVU); Richard Prestage, Paul Marganian, Thomas Chamberlin, Vereese van Tonder, Luke Hawkins, Jason Ray (GBO) and more.

The work of the FLAG (Phased Array Feed) Team is also acknowledged for the development of the new, low-noise cryogenic phased array feed receiver (PAF), including: D. Anish Roshi, William Shillue, J.R. Fisher, Matt Morgan, Jason Castro, Wavley Groves, Tod Boyd (NRAO); Bob Simon, Steve White, J.D. Nelson (GBO) and many others. The successful PAF commissioning was reported on in the April 2017 newsletter.

Summer Student Workshop Attracts Future Scientists

During the first week of June the Green Bank Observatory welcomed 22 students from the GBO and NRAO for an annual summer student workshop. Young scientists and engineers enrolled in the Research Experience for Undergraduates (REU), Physicists Inspiring the Next Generation (PING), and the National Astronomy Consortium (NAC), as well as summer graduate students, gathered to prepare for summer research through talks, observing projects, team-building exercises, and behind the scenes tours of the observatory. The workshop also gives summer students from across AUI the chance to meet face-to-face and provides career development opportunities. This year’s students were treated to a historical site tour, hands on observing with the GBO’s 40-foot radio telescope, and a special science talk on fast radio bursts by Prof. Duncan Lorimer of West Virginia University. The workshop continues a long tradition of excellence in student education at GBO.

GBO Machine Shop Gives Atacama Large Millimeter/submillimeter Array (ALMA) a Lift

To perform routine receiver service and upgrades on ALMA’s 66 antennas, supercooled “Front End” containers that house the receivers and electronics for each antenna must be carefully removed. To handle that removal and transport, ALMA uses Front End Handling Vehicles (FEHV), which are large lift carts specifically designed to transport the ALMA Front Ends.

Each Front End package weighs approximately 750 kilograms (1,600 lbs) and must be lifted over 5 feet above the floor inside the highly confined receiver room of each antenna. FEHVs were designed specifically to make that task safer, quicker, and more routine.

The GBO Machine shop is in the midst of fabricating new FEHV chassis to help out ALMA North America.

Because of the weight and instrumentation these FEHVs need to carry, rigorous certification processes are being followed. Congratulations to Pat Schaffner, who successfully obtained an American Welding Society (AWS) structural welding certification on his first try, which was a prerequisite to proceeding with the work. The AWS representative that conducted the certification review reported that Pat did a “great job. Usually 1 out of 3 test samples will break at the weld but none of Pat’s did.”

The first chassis has been assembled, certified by an external inspector, and shipped to Chile where it will be integrated into a full handling vehicle for acceptance. The Machine Shop has been given the go ahead to proceed with the fabrication of three additional units.

Thanks to Pat, Roger Dickenson, Mike Hedrick and everyone in the Shop for the great work, and to Butch Wirt, Todd Wright, and the Maintenance team for building a custom shipping crate.

GBORS

Want to plan your visit? The new Green Bank Observatory Reservation System (GBORS) is now live! Our visitors can now create an account to track and manage all reservations from overnight stays and meal planning to meeting room requests and group visits. This tool makes visiting a cinch for our GBT users.

As always, please feel free to contact our reservationist for support at gro.y1696273901rotav1696273901resbo1696273901bg@sn1696273901oitav1696273901reser1696273901 or  304-456-2011. The new reservation tool is live now.

GBT Joins Goldstone and Allen Telescope Array in Radar Test

Use of the GBT as a radar receiver is a commonplace activity for Green Bank, but recently we participated in an interesting experiment with a bit of a different twist. We were contacted by the Advanced Physics Lab at Johns Hopkins to participate the Advanced Space Radar Experiment (ASRE) as a monitoring and recording station. The project tested the ability of the Allen Telescope Array (ATA) to receive X-Band signals bounced off commercial satellites in geosynchronous orbit. While the ATA used sets of antennas to correlate into multiple beams, the GBT used the JPL radar backend to receive all of the signals as a reference for the post-experiment analysis.

The ASRE project purchased six hours of GBT time to conduct the experiment using four different satellites as targets and varying radar transmission waveforms. One other interesting feature of the test was the use of three Deep Space Network (DSN) antennas with their radar transmitters phased together into a single higher power beam at the target. You may be familiar with a similar system long, long, ago.

After initial data analysis, the experiment appears to be a success and the GBT systems performed flawlessly. It is unclear if any follow-on experiments are planned, but a request for additional funds for the experiment is underway. Test participants included: Jet Propulsion Lab, SRI, GBO, Aerospace, MITRE, MIT Lincoln Laboratory, JHU/APL

The Frank Drake Lectureship

Dr. Frank Drake has had a long and distinguished career that began at the Observatory in Green Bank West Virginia in 1958. His scientific achievements include discovery of the radiation belts of Jupiter, some of the earliest measurements of pulsars, contributions to our understanding of the high surface temperature of Venus, and characterization of the radio sources at the center of the Milky Way.

In 1960, using a radio telescope at Green Bank, Dr. Drake made the first modern search for radio signals from extraterrestrial civilizations. He thus began an area of scientific research that has continued and is flourishing today, engaging creative minds worldwide. The Drake equation, first introduced in Green Bank in 1961, has caught the public imagination and continues to draw audiences around the world to discuss and learn about science and astronomy.

In recognition of the work Dr. Drake has done, the Frank Drake Lectureship was created to recognize individuals from the sciences, arts or humanities in recognition of their contributions to advancing human knowledge and creativity in the scientific realm.

The Frank Drake Lectureship is awarded to one individual annually. The recipient of this award will present the annual Frank Drake Lecture in Green Bank, West Virginia. The public lecture will promote scientific knowledge or literacy. All costs associated with the awardee’s travel will be covered through the lecture series, as well a dinner, held in the awardee’s honor. The awardee will receive both a plaque honoring his/her award and a $1,000 honorarium.

Nominations for the 2017 Frank Drake Lectureship are now open, and should be sent to: gro.y1696273901rotav1696273901resbo1696273901bg@er1696273901utcel1696273901ekard1696273901

Venus is hot!

Frank Drake is famous for having done the first SETI search, using the 85-foot Tatel telescope at Green Bank, in 1961. About the same time, he also used the 85-foot telescope to measure microwave radiation from some of the planets at a wavelength of 3 cm.

The radiation from most planets is due to the temperature of the surface of the planet. Previous work by others measured the optical and near infrared radiation from the planets from which one can estimate the temperature. It was expected that the radio radiation would indicate the same temperature as the infra-red.
But Venus was quite a surprise – the 3 cm radiation indicated a temperature much higher than expected, about 600 degrees Kelvin (curiously, when you convert that to Fahrenheit, it is also near 600 degrees).

Venus has a very thick atmosphere which prevents seeing the surface of the planet in the optical and near infrared; the infrared temperature is from the upper part of the atmosphere. On the other hand, the microwave radiation at 3 cm and longer wavelengths comes from the solid surface unhindered by the atmosphere.
The conclusion was that the surface of Venus was very hot, much hotter than the top of her atmosphere. How can that be?

The answer was worked out by Carl Sagan, who calculated how the atmosphere can provide a “greenhouse effect”. Energy from the Sun comes through the atmosphere at a wavelength of a few microns and warms up the surface. The surface radiates the energy back up at longer infrared wavelengths but the radiation is absorbed by the water vapor in the atmosphere and kept near the surface. Whatever oceans Venus may have had in the past have evaporated and formed the thick atmosphere of mostly water vapor. This keeps the surface of Venus uncomfortably hot.

The Earth’s atmosphere also has a greenhouse effect, but much less extreme than on Venus, due to the Earth being somewhat farther from the Sun. Although we worry about the Earth warming up too much, we depend on the effect to keep the Earth comfortable. Without any water vapor and other greenhouse gases, the Earth’s average temperature would be around -20 C (or -2 F).

In 1962, the US launched the first spacecraft to fly by Venus, Mariner 2. An article in “The Observer” (reprinted in “But It Was Fun”, page 83) noted that Mariner 2 measurements got similar results to those that had been found earlier at Green Bank by Dr. Frank Drake with the 85-1. But, of course, Mariner 2 cost enormously more than the observations done at Green Bank.

The Observatory had “scooped” the space mission at very low cost!

Reference: Physics Today, April 1961, page 30

Career Opportunities

Scientist Position

We are seeking an enthusiastic and energetic scientist to join the staff of the Green Bank Observatory in Green Bank, West Virginia.
Duties will include providing support for GBT observers as well as developing thorough theoretical and practical knowledge of the microwave holography system which is used for measurement and improvement of the GBT primary surface, working in the area of data reduction and post-processing mathematical analysis. The applicant would eventually assume primary responsibility in this area. Over time, the successful applicant will join other projects, potentially including the development and commissioning of new instrumentation on the telescope, working with the engineering staff to improve the overall telescope performance, and aiding with the data reduction pipelines needed for the GBT.

The Green Bank Observatory employs 100 people on a year round basis, and an additional 40 people in the summer time. We are committed to a diverse and inclusive work place culture that accepts and appreciates all individuals.

Please check out all our current listings.

DIRECTOR’S NEWS

The last few months have seen many exciting developments at the Green Bank Observatory. Two new 3-mm wavelength instruments are having an excellent first full high frequency season – ARGUS, a 16-pixel spectroscopy contend, and MUSTANG-2, a 223-pixel feedhorn bolometer – and we are looking forward to publication of the instrument’s science results. World-class science coming from both our NSF-funded “open skies” time and the telescope time used by our partner organizations continues to be outstanding. Pressure for use of the GBT’s time also continues to increase, and with 17% of the proposers being new to the GBT! We also have a major new educational initiative underway, First Two, which works to increase retention of STEM students in their first two years of college, with a particular focus on first generation college students.

Looking forward, we are preparing for the many and varied educational programs coming up, which range from REU students arriving for the summer, the PING (Physicist Inspiring the Next Generation) camp for students, a new Research Experience for Teachers program, and many, many more activities. And, of course, we are beginning to ramp up our plans for the fall workshop “Transformative Science for the Next Decades with the Green Bank Observatory,” and the accompanying 60th anniversary of sciences from our facility.

Hope to see many of you at one or more of these exciting events!

Karen O’Neil
Green Bank Observatory Director

UPCOMING EVENTS

SETI Tours

Our new SETI Tour celebrates Green Bank’s historic Search for Extra Terrestrial Intelligence. Piloted last summer, the tour sold out all but three offerings. The tour lasts about 3 hours and takes guests into the telescope control rooms where Project OZMA and Phoenix took place-just to name a few!

Check out our summer tour schedule for 2017 online at: greenbankobservatory.org/events/

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Chautauqua Short Courses

May 22nd-25th, 2017

This 2.5 day course is designed to celebrate more than 50 years of contributions to the forefront of astronomy by the telescopes of the Green Bank Observatory and is open to educators of all disciplines. Presentations will emphasize recent research at Green Bank in two areas: pulsar studies, that could lead in the near future to direct detection of gravitational radiation and hydrogen studies that reveal the structure and evolution of galaxies and their dark matter halos.

Learn more: greenbankobservatory.org/education/teachers

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Space Race Rumpus

June 9th-11th, 2017

It’s a festival. It’s a race. It’s group rides. It’s a clinic. It’s a fundraiser. It’s a tradition. The 6th Annual Space Race Rumpus is a 3-day family music and cycling festival hosted by the Northern Pocahontas Wellness Center at the Green Bank Observatory. If you’ve ever wanted to bring your bike to explore the site trails or miles of scenic roads in Pocahontas County, now’s the time! Registration is now open. Find out more: www.spaceracerumpus.org

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ESS Teacher’s Passport

June 18th-July 1st, 2017

ESS Passport is an amazing professional development program for West Virginia science teachers to prepare them to teach Earth and Space Science. Funded by the West Virginia Math Science Partnership program, the Earth/Space Science Passport workshop provides West Virginia science teachers with professional development in Geology, Meterology and Astronomy concepts that will enable them to teach a new mandated ninth grade Earth/Space Science course. Over a twoweek residential workshop teacher groups rotate through three-day directed studies in each of these content areas. The Green Bank Observatory provides the Astronomy course.

Learn more at greenbankobservatory.org/education/teachers/

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Pulsar Search Collaboratory Camp

July 10th-17th, 2017

The Pulsar Search Collaboratory (PSC) is a joint project between the Green Bank Observatory and West Virginia University (WVU), funded by the National Science Foundation (NSF). The goal of the PSC is to give high school students, and their teachers experience doing real research.

Learn more at greenbankobservatory.org/education/student-research/

Just last year, a new documentary (www.lgmfilm.com) called “Little Green Men” was released. The film follows PSC high school students searching for pulsars using data from the Green Bank Telescope.

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Physics Inspiring the Next Generation: Investigating the Cosmos Summer Camp Experience

July 30th- August 5th, 2017

Current 8th graders (rising 9th-graders) will be on location in Green Bank, WV, at NRAO’s world famous Green Bank Telescope. Students will be immersed in the research activities of this national research center. While in residence, students will work in small teams supported by an undergraduate student mentor and an NRAO staff scientist (astronomer, physicist, engineer, etc.) to conduct research by observing the universe with a 40-foot diameter radio telescope.

For more details, visit: greenbankobservatory.org/education/student-research/

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Observer Training Workshop

September 18 – 23, 2017

The Green Bank Telescope (GBT) Observer Training Workshop series provides the essential skills and knowledge needed to use the GBT and maximize its scientific output. We’ve reached capacity for the Spring 2017 training, but there will be plenty of openings for the next session, set for the week of September 18th, 2017.

A separate announcement will be made when registration opens for this event.

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Transformative Science for the Next Decades with the Green Bank Observatory

October 16 – 20, 2017

Big Questions, Large Programs, and New Instruments: With new instruments and excellent performance, the 100m Green Bank Telescope is only just reaching its full potential. On this 60th anniversary of the ground breaking for the Green Bank Observatory, we are holding a workshop looking toward the next 10, 20, and even 60 years of the Green Bank Observatory, and invite the community to attend and aid us in planning the future.

For more information, please visit our Web site at greenbankobservatory.org/transformative-science/

NEWS

ARGUS camera for GBT 3mm spectroscopy swings into action

Throughout the winter months of 2016-2017 the new ARGUS 16-pixel camera for 3mm spectroscopy has been in regular use on the GBT. The camera was developed by Sarah Church (Stanford University) and collaborators under a grant from the NSF. The first map made during commissioning was shown in the previous GBO newsletter (https://greenbankobservatory.org/green-bank-observer-vol-1-issue-1/). Data from a number of projects are now in the hands of the PIs for reduction and analysis.

Read full article online:
greenbankobservatory.org/newscontent/observer04.17.html

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INCLUDES program

In October 2016, the Green Bank Observatory received an award from the INCLUDES initiative (NSF #1649323), to build the First Two Network. The problem First Two addresses is post-secondary attrition. Degree completion is key to producing a diverse STEM workforce: Increasing the retention of STEM majors by 25% will “generate three quarters of the targeted 1 million additional STEM degrees needed over the next decade” (PCAST, 2012). Well-shy of half of all undergraduate students who enter STEM majors complete degrees in STEM, and that it is during the first two years of college that most students drop out of the STEM The effects are worse with First Generation College (FGC) students, who not only leave STEM programs but often quit their post-secondary education altogether. Since roughly one third of all post-secondary students are FGC students, addressing the underlying challenges they face could significantly broaden participation in the STEM workforce.

The First Two Network targets rural first generation students who major in a STEM related course of study. Beginning summer 2017, we pilot two early research experiences (for rising freshmen), and an academic year course that builds science process skills, communication skills and leadership expertise. An innovative component of FIRST TWO is the creation of Hometown STEM ambassadors—students who participate will be prepared to mentor their peers, and also conduct outreach in their home school districts.

Finally, there are many studies that inquire into the factors that correlate with post-secondary retention in general, and with STEM attrition specifically but few that focus on rural students. One of our working groups is developing a rigorous educational research project that can advance understanding of the factors affecting rural students’ entry into and persistence in STEM career pathways. For more information about our INCLUDES program, please visit our Education pages at greenbankobservatory.org/education

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GBT helps find Lost Spacecraft

Finding a tiny lost space-craft at a distance of 270,000 miles away may seem impossible, but NASA scientists have done just that. Using a new radar technique, they have located India’s Chandrayaan-1 spacecraft which has been lost since August 2009, the last time any communication was received from it.

Read full story here: greenbankobservatory.org/newscontent/observer04.17.html

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GBT Observations Compound Intersellar Helium Ionization Problem

Warm ionized gas is a major constituent of the Galactic interstellar medium, observable through both optical and radio emission lines. To maintain its ionization it requires about 80% of the ionizing radiation from all OB stars in the Galaxy; this is presumably supplied by UV photons leaking from HII regions.

This UV leakage should be sufficient to fully ionize Helium in the diffuse ionized gas, but instead, the fractional ionization of He appears to be relatively low, in the range of 10-20%.

Recent observations with the Green Bank Telescope (GBT) compound this problem. A set of H and He recombination lines was observed toward the envelopes of three ultra-compact HII regions that are still embedded in their molecular clouds. The envelopes have emission measures an order of magnitude greater than that of the warm ionized gas, and are just a few parsecs away from the central stars, which have type O5 or earlier. The data indicate that He is not uniformly ionized in the HII region envelopes. In two cases helium in the envelope is only 30% and 50% ionized. After ruling out the possibility that the helium may be doubly ionized, the authors conclude that the most likely explanation for the discrepancy is selective absorption of helium-ionizing photons by dust.

“Helium Ionization in the Diffuse Ionized Gas Surrounding UCHHII Regions” D. Anish Roshi, E. Churchwell and L. D. Anderson, accepted by the Astrophysical Journal.

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GBT hits new performance milestone at 109 GHz

With the installation of the Argus 16-pixel receiver covering 75-115 GHz on the Green Bank Telescope (GBT), it is now possible to characterize the antenna beam above 100 GHz, where the use of the active surface and out-of-focus holography are critical to the telescope’s performance. A recent measurement (2017 March 23) in good weather conditions at 109.4 GHz yielded a FWHM beam of 6.7 arcsec and 6.4 arcsec in azimuth and elevation, respectively. This corresponds to 1.16 Lambda/D at 109.4 GHz, which agrees well with the low-frequency value measured at 9.0 GHz. After applying the standard antenna corrections (focus and active surface), we find no measurable degradation of the beam of the GBT at its highest operational frequencies.

These results are discussed in more detail in the GBT Memo #296: library.nrao.edu/public/memos/gbt/GBT_296.pdf

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GBO Post-doc Jennifer Weston Wins dissertation prize

Jennifer Weston has just won the 2016 Robert L. Brown Outstanding Doctoral Dissertation Award. The award presentation, and her talk on the research which led to the award, will be in Charlottesville on April 13.

The Robert L. Brown Outstanding Doctoral Dissertation Award is administered by AUI and the NRAO on behalf of Bob Brown’s friends and family to honor Bob’s life and career. The Award is given each year to a recent recipient of a doctoral degree from any recognized degree granting institution in the United States, and is substantially based on new observational data obtained at any AUI operated facility and considered to be of an exceptionally high scientific standard.

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Featured Receiver – ASIAA 800 MHz HIM Receiver Array

In November of last year, a collaborative effort involving representatives of the Academia Sinica Institute of Astronomy and Astrophysics, University of Wisconsin, NRAO, and the Green Bank Observatory gathered to review designs for a proposed focal plane array for the GBT. The proposed receiver system improves the observing efficiency in the 700 to 900 MHz band by replacing the single corrugated prime focus feed with seven short backfire antennas each with an individually cooled cryogenic dewar. The group faced many technical challenges, especially the weight and moment limits of the GBT prime focus feed arm. Some of the margins were razor thin and thus the group plans more modeling of the structure for a better understanding of the wind load analysis.

Read full story online: greenbankobservatory.org/newscontent/observer04.17.html

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New Phased Array Feed Successfully Commissioned on the GBT

The L-band cryogenic Phased Array Feed (PAF) receiver, with nineteen dual-polarization crossed dipoles located in the focal plane of a reflector antenna, was commissioned on the GBT in March 2017. The testing has confirmed the predicted excellent performance of the PAF, and has also commissioned the unformatted digital link technology developed by NRAO’s Central Development Lab.

Phased Arrays employ a technique in which many small antennas can be combined together to perform the function of a single large antenna. By combining the small antennas together with adjustable phase and amplitude, the properties of the composite antenna beam can be changed (beamwidth and beam direction). Since the beamforming is accomplished by FPGA-based digital signal processing, multiple beams can be simultaneously formed increasing telescope throughput (in this case seven beams in each polarization were formed).

The PAF was developed as part of a collaboration consisting of NRAO, GBO, West Virginia University, and Brigham Young University. More information will be forthcoming as data results are analyzed.

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Students track anomalies in the fading of Cassiopeia A

Every summer since 1992, Prof. Dan Reichart of the University of North Carolina (UNC) and a small group of astronomy faculty have taken 15 mostly undergraduate students through an intense, one-week workshop at the Green Bank Observatory called “Educational Research in Radio Astronomy” (ERIRA). While on site the students are engaged in several observing projects with the 40 Foot Telescope including observations of Cassiopeia A, Taurus A, and Cygnus A.

Read Full Story online: greenbankobservatory.org/newscontent/observer04.17.html

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Student Art Exhibit

To show support for the Green Bank Telescope, Green Bank Middle School students created some amazing 2-D and 3-D art projects. From intricate Popsicle-stick GBT models to precise blueprint-style charcoal drawings, works included a wide variety in chosen mediums. This project was lead by the art teacher, Alison Flegal, who created the project as a way for students to voice their support for the Green Bank Telescope in response to 2016’s Environmental Impact Statement (EIS) Call for Public Comments. In fact, a few of the works were submitted formally and included among the hundreds of letters. In March, the Green Bank Science Center hosted an art exhibit opening for these works, which are now on display in the lobby. During the opening, these young artists presented their work to both staff and the public. The Green Bank Observatory is an education partner of the Green Bank Elementary Middle School as part of our outreach program.

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New online reservation system coming soon!

Coming Soon! The Green Bank Software Development Division will soon release the new Green Bank Observatory Reservation System (GBORS), replacing the previous BOS system and offering expanded capabilities. GBORS will accept reservation requests for everything from an overnight stay to planning a conference. When launched, look for it on our website!

Proposal NEWS

Upcoming call for GBT proposals (18A)

The Green Bank Observatory (GBO) will invite scientists to participate in the next Call for Proposals for the Green Bank Telescope (GBT). The deadline is August 1st, 2017 for Semester 2018A.

Response to the 17B Call for GBT proposals

The 1 February 2017 call for proposals to use the GBT beginning the second semester of 2017 elicited requests for 6647 hours in 100 individual proposals. In the 3mm band there were requests for 1,148 hours for spectroscopy and continuum using the new ARGUS and MUSTANG2 cameras, as well as an additional 191 hours for spectroscopy and VLBI with the 2-pixel”W band” receiver which covers the lower part of the band. Demand for the7-pixel “K-band” camera that covers 18-26 GHz continued to be strong, at 645 hours. More than 3,000 hours were also requested at frequencies below 2 GHz for programs of spectroscopy and pulsar studies.

There were a number of proposals for joint observations with ALMA, the JVLA,Fermi, and other instruments.
More than 17% of the proposers had not previously been on a GBT proposal, showing the continued strong growth of the scientific community’s interest in the GBT. Proposals are now undergoing review and results should be available in early May.

HISTORY

A bit of history: The Green Bank Interferometer confirmed Einstein’s theory

Einstein’s theory of gravity (also known as General Relativity) predicts that the path of a ray of light (or that of a radio wave) will bend when it passes near a massive object. This was first tested in 1919 by Sir Arthur Eddington, who organized an expedition to observe star positions during an eclipse of the Sun from islands near the coast of Africa.

Observing stars close to the edge of the Sun is normally impossible, but during an eclipse, the Sun is blocked out and stars nearby can be observed. The 1919 experiment confirmed the theory and made an instant celebrity of Einstein and of General Relativity.

Read full story online: greenbankobservatory.org/newscontent/observer04.17.html

MEET THE STAFF

Thomas Chamberlain, Software Engineer

How long have you worked at GBO?
Just under two years now; I started February 23rd, 2015, right after I graduated.

What led you to applying for the position?
Well, I guess there’s some backstory here. My grandfather worked here in the late fifties and early sixties as an operator before moving on to JPL, Socorro, and later Charlottesville. My mother was actually born in Marlinton in 1961, although they left early enough that she doesn’t remember it. She’s an accountant and she was looking for jobs online when, as she tells it, just happened to think of checking out the NRAO for any openings. She’s wanted to get out of the Atlanta suburbs for a while, and I think she has fond memories of this area, going to the summer picnic as a kid and such. She saw a software engineering position open, thought “I think Thomas does that”, and passed it along to me.

Learn more about Thomas here:
greenbankobservatory.org/newscontent/observer04.17.html

ENGAGE

Become a Member

Want to help support the Green Bank Observatory? We now have a new Membership and Donation program! Check out the variety of opportunities found at greenbankobservatory.org/engage/

Careers

The Green Bank Observatory employs 100 people on a year round basis, and an additional 40 people in the summer time. While most people tend to think of Green Bank as hiring scientists and astronomers, it takes a village to run the scientific and educational programs. While we have staff from all around the world, the majority of our employees (80%) were born in West Virginia, and roughly 60% of the staff are from Pocahontas County. Of the astronomy staff, 40% are female (compared to the national average of less than 30%). We are committed to a diverse and inclusive work place culture that accepts and appreciates all individuals.
Career opportunities can be found at a new website!Please check out our current listings here: greenbankobservatory.org/careers/