University of Virginia, College and Graduate School of Arts and Sciences

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Oxygen-deficient Dwarf Galaxy Hints at Makings of Early Universe

September 25, 2017

Professor Trinh Thuan and colleagues recently discovered a dwarf galaxy in the constellation Lynx that is so oxygen-deficient that may serve well as a proxy for better understanding the developing chemistry of the early universe. Their new finding, to be published in the journal Monthly Notices of the Royal Astronomical Society, shows that the oxygen level in the little galaxy is the lowest yet discovered in any star-forming galaxy, likely resembling nascent galaxies in the early universe. The star-forming dwarf galaxy in the new study was found during an ongoing, large-scale inventory of the heavens, the Sloan Digital Sky Survey, which revealed it as a possible point of interest. The team of astronomers then targeted it for further scrutiny using the powerful Large Binocular Telescope in Arizona. Data from the that telescope revealed that the tiny star-forming galaxy, dubbed J0811+4730, is a record-breaker: It has 9 percent less oxygen than any other so far discovered.

The team found that a considerable fraction (80%) of the stellar mass of the galaxy was formed only a few million years ago, making this one of the best counterparts found of primordial galaxies. Because of its extremely low oxygen level, this galaxy serves as an accessible proxy for star-forming galaxies that came together within one to two billion years after the Big Bang, the early period of our nearly 14 billion-year-old universe. The dwarf galaxy also is of interest because it provides clues to how the early simple universe became re-ionized by early star formation, moving it from the so-called cosmic Dark Ages of neutral gases to the development of the complexly structured universe now in existence, where the gas between galaxies is ionized.

Thuan’s colleagues on the study are astronomers Yuri Izotov and Natalia Guseva of the Ukrainian National Academy of Sciences, and graduate student Sandy Liss of UVA.

For more details, see the New Scientist  article: 

https://www.newscientist.com/article/2146813-low-oxygen-dwarf-galaxy-shows-us-how-the-early-universe-looked/

and the UVA today article:

https://news.virginia.edu/content/oxygen-deficient-dwarf-galaxy-hints-makings-early-universe

 

UVA Astronomer Celebrates the Success of Cassini

September 14, 2017

After 20 years in space, and 13 years orbiting the planet Saturn, the Cassini mission is coming to an end. University of Virginia planetary astronomer Anne Verbiscer, a participating scientist with the mission, is attending this week's end-of-mission celebration at the California Institute of Technology, near NASA's Jet Propulsion Laboratory and is enjoying the final ride with hundreds of fellow Cassini scientists.

For more details, see the UVA Today article about the end of the Cassini mission.

August 21, 2017 Eclipse in Charlottesville

August 18, 2017

On Monday, August 21, 2017 residents of Central Virginia will be able to view the partial phases of the total solar eclipse crossing the United States.

Circumstances for Charlottesville:

  • Start of Partial Phases - 01:15:13 p.m. EDT
  • Maximum Eclipse - 02:41:33 p.m. EDT
  • End of Partial Phases - 04:01:47 p.m. EDT

The Astronomy Department does not have any eclipse glasses left. We do not know of any retailers in Charlottesville that still have them in stock.  For a list of chain stores that have pledged to only sell ones from reputable vendors, please see the AAS (American Astronomical Society) page on eclipse safety: https://eclipse.aas.org/eye-safety
specifically the vendor page: https://eclipse.aas.org/resources/solar-filters

For all eclipse related information, we suggest the AAS eclipse page: https://eclipse.aas.org

If you want to see the eclipse, we suggest visiting one of the following viewing events in Charlottesville:

  1. The Jefferson-Madison Regional Library will be holding a viewing party at the Central Library, 201 E. Market Street, starting at 1:30 p.m. They will be giving away eclipse glasses at the Library and you can stroll over to Emancipation Park to view the eclipse.
  2. The UVA Libraries will be loaning glasses at various libraries around Grounds, and will have a Sunspotter projection telescope and glasses at the "Ask a Librarian!" event outside Alderman Library. http://news.library.virginia.edu/2017/08/11/watch-the-eclipse-on-821-with-free-glasses-from-the-library/ 
  3. The Society of Physics Students and the Astronomy Club will be holding a viewing event on the North Lawn from 1:00 to 4:00 p.m. They will have an H-alpha telescope and a projection telescope to view the Sun in addition to eclipse viewing glasses.
  4. Finally, the eclipse will be televised. Both NASA and the Exploratorium will host live stream video of the eclipse. NASA's footage will be available at https://eclipse2017.nasa.gov/eclipse-live-stream, the Exploratorium's at https://www.exploratorium.edu/eclipse

Best wishes for clear weather Monday afternoon, wherever you are!

Success! New Horizons Team Sees Occultation by 2014 MU69

July 19, 2017

On July 17, a primitive solar system object that’s more than 6.5 billion kilometers away passed in front of a distant star as seen from Earth. Twenty-four telescopes and dozens of astronomers, including UVA faculty, staff, and students, were deployed by the New Horizons team to a remote part of Argentina in an effort to catch the shadow of the object - an event that's known as an occulation. Several telescopes, including one operated by UVA astronomer Anne Verbiscer, were in precisely the right place at the right time to catch its fleeting shadow.

2014 MU69 is the target of a January 1, 2019 flyby by the New Horizons spacecraft, which encountered Pluto in the summer of 2015. UVA Astronomers Mike Skrutskie and Matt Nelson led the development of three fast and precisely timed telescope imaging systems and recruited and trained several UVA undergraduates to take part in three opportunities this summer to see occultations by 2014 MU69.

Read the full article at NASA.gov.

UVA Students, Faculty, and Staff Chase Shadow of Kuiper Belt Object Across South Africa

June 8, 2017

Three UVA undergraduates along with Astronomy faculty and staff mentors have returned from South Africa, data in hand, after an attempt to place three UVA telescopes in the path of the shadow of the faint distant Kuiper Belt Object 2014 MU69 as it passed in front of a distant star. This Kuiper Belt object is the target of a January 1, 2019 flyby by the New Horizons spacecraft, which encountered Pluto in the summer of 2015. UVA Astronomers Mike Skrutskie and Matt Nelson led the development of three fast and precisely timed telescope imaging systems and recruited and trained several UVA undergraduates in the art of being in exactly the right place at exactly the right time with a telescope and electronic camera pointed in exactly the right direction.

UVA's contribution was a modest part of a much larger effort involving 22 additional telescopes, 10 more in South Africa and 12 in Argentina, directed by the NASA New Horizons team with lead investigators at Southwest Research Institute in Boulder, CO. Dr. Anne Verbiscer, also with UVA Astronomy, managed the 13 South African observing teams comprising 28 people, dealing with every eventuality from fitting large telescope crates into not quite large enough trucks, to security for all of the observing teams, to ultimately making sure the teams identified "friendly" observing sites in exactly the right locations, interacting with  the U.S. Embassy in Pretoria, the U.S. Consulate in Cape Town, among others the South African Astronomical Observatory.

After three nights of telescope setup and practice, the UVa teams ended up driving inland more than 300 miles to avoid potentially bad weather on the west coast. They were rewarded with clear skies, light winds, and terrific atmospheric stability, just the right conditions to squeeze every bit of precious sensitivity out of the observing systems. All three UVA telescopes recorded optimal data during the 45 minute observing window, and especially the 5 or so seconds(!) when the object itself was predicted to pass in front of the star. Of the 25 telescope dragnet set up for this event only one or two would catch MU69's shadow as the object is estimated to be only between 15 and 30 miles across and the telescopes had to be spread over a 200 mile range to account for the uncertainty in the predictions. Data are now under analysis and it will be some time before we know just who caught the shadow. Catching it provides critical information for New Horizons as the observation will pin down the position and size of this distant object that is so faint that it has not been previously detected from the ground and appears only as a dim dot in sensitive Hubble Space Telescope images.

Read more about the expedition in Sky and Telescope.

Celebrating Our Undergraduate Prize Winners

May 20, 2017

The Deparartment of Astronomy is pleased to announce the following awards presented at Final Exercises on May 20, 2017:

Renato Mazzei has been selected as the 2017 recipient of the D. Nelson Limber Prize for the most distinguished undergraduate major. Renato has been working with Professor Craig Sarazin on an XMM-Newton X-ray observation of an Ultra-Luminous X-ray source (ULX) in a S0 galaxy, only the second ULX to be found in a globular cluster.  ULXs have X-ray luminosities which apparently exceed the Eddington luminosity for a stellar mass black hole.  The current hypotheses are that ULXs are X-ray binaries which either (a) contain an intermediate mass black hole (IMBH) or (b) a stellar mass black hole whose emission is beamed. Renato found a possible orbital period in the light curve of NGC 1380 ULX-1, which would imply that it contains a stellar mass black hole in a very compact binary, which may indicate that the black hole is accreting from a white dwarf star. Renato has also worked on numerical simulations of clusters of galaxies with NSF Postdoctoral Fellow Rukmani Vijayarajhavan and Professor Craig Sarazin. He is using the simulations to predict the abundances of heavy elements in a cluster produced by ram pressure stripping of galaxies. 

The award is named for D. Nelson Limber, a faculty member in the Astronomy Department who was a popular teacher and passed away at a very young age in 1977.

Martine Lokken has been selected as the 2017 recipient of the Vyssotsky Prize that recognizes an outstanding third-year undergraduate student. Martine has been working with Assistant Professor Nitya Kallivayalil and Research Associate Tobias Fritz on measuring the proper motion of Segue 1, one of the least luminous, dark-matter dominated small galaxies in the Local Group of galaxies. It has been held up as the prototypical galaxy that might be used as a probe of reionization, because it is so low-mass that its star formation was possibly turned off by the high UV background of the reionization era. That was however, in the absence of velocity data that could elucidate its past orbit. Based on Martine’s work, we now know that Segue is likely a very long-term companion of the Milky Way, and thus was probably quenched by its proximity to the Milky Way rather than being a relic of the reionization era. Attempts to claim it is such a relic should be therefore met with skepticism. Additionally, Martine has volunteered to help with Public Night at McCormick over the past year. At nearly every Public Night, she comes up to McCormick to help control and educate the crowds.

The award is named for Alexander Vyssotsky, a faculty member in Astronomy at the University of Virginia from 1923-1958. He surveyed the sky for faint nearby M-dwarf stars opening the door to the systematic study of the Sun's nearest neighbors and furthering the study of the structure of the Milky Way. The award was made possible by a generous gift from David Stedman who benefited from Vyssotsky's guidance and friendship.

Chris Hayes has won the Laurence W. Fredrick Teaching Assistant Award. This award recognizes graduate students that made outstanding contributions to the teaching efforts of the Department. As the teaching assistant for Associate Professor Kelsey Johnson's ASTR 1270 Unsolved Mysteries course, Chris has been an outstanding TA. He has excellent report with the students in the class, has given a number of substitute lectures and has worked seamlessly with the instructor to coordinate classroom activities. To sum up his work, Kesley Johnson reports that he "is truly amazing."

The award is named for Larry Fredrick on the occasion of his retirement from the faculty.

Congratulations to the award winners!

 

UVa Astronomers Track Distant Star Cluster with Adaptive Optics

May 11, 2017

Research Associate Tobias Fritz, along with graduate students Sean Linden and Paul Zivick in Nitya Kallivayalil’s Near-field Cosmology group, combined images from Gemini South’s wide-field adaptive optics system with data from the Hubble Space Telescope to determine the proper motion of a distant cluster of stars. The observations, the first to use ground-based adaptive optics to precisely measure the motion of a cluster at such a large distance, allowed astronomers to set a lower limit for the mass of our Milky Way while providing clues about the cluster’s origin.

Read the Gemini press release for more details.

Astronomers Make Detailed Map of Lava Lake on Jupiter's Moon Io

May 11, 2017

Scientists, including UVA astronomer Mike Skrutskie, have used the UVA built LMIRCAM on the Large Binocular Telescope in Arizona to make a detailed map of the Loki Patera lava lake on Jupiter's moon Io. They have found evidence for two waves of overturning lava propogating around the lake.

Read the press release or read a nice summary at UVA Today.  Follow this link to read the paper in Nature.

Kelsey Johnson Named Director of Echols Scholars Program

May 9, 2017

Associate Professor Kelsey Johnson will be the next director of the Echols Scholars Program. She is an award-winning teacher and advocate for public astronomy education, whose research on galaxy evolution has earned a National Science Foundation CAREER Award and other prominent honors.

Learn more in the annoucement from the Arts and Sciences Office of the Dean

Universe of Mysteries

April 26, 2017

Professor Kelsey Johnson teaches her students to ask deep, meaningful, and provocative questions in her ASTR 1270 Unsolved Mysteries in the Universe course. See more about this amazing course from an inspirational teacher in this video at UVA Today.

UVA Astronomy-Physics Student Named Goldwater Scholar

April 7, 2017

University of Virginia astronomy-physics major Bridget Andersen has been awared a 2017 Barry M. Goldwater Scholarship. Arvind Gupta, another astronomy-physics major, was one of two UVA students to receive honorable mentions. Congratulations to both Bridget and Arvind.

Read the full article in UVAToday.

Sky Surveyors

March 27, 2017

With the APOGEE team celebrating first light at APOGEE-South, UVA Today looks back on the critical role that Mike Skrutskie and the Virginia Astronomy Instrumentation Lab has played in making the Astronomy Department at the University of Virginia a world leader in instrument design, construction, and research.

 

Read the full article at UVA Today.

Written in the Stars

March 25, 2017

Associate Professor Kelsey Johnson hosted authors Dava Sobel (The Glass Universe, Galileo’s Daughter, Longitude, The Planets) and Margot Lee Shetterly (Hidden Figures) for a sold out show at the Paramount Theater on March 25th as part of the Virginia Festival of the Book.  Their lively discussion on issues related to women and minorities in the history science and space exploration received a standing ovation.

See the Festival of the Book website for more details.

Mergers and Acquisitions

January 23, 2017

A Wall Street Journal article features the work of a team of NRAO and UVA astronomers led by Sabrina Stierwalt. The team has found seven isolated groups of dwarf galaxies that shed light on how large galaxies grow from the merger and accretion of smaller dwarf galaxies.

Read the full story in the Wall Street Journal.

Read more in the UVA Today Article.

If you want the full set of details, you can read their full article at arXiv.org astro-ph arXiv:1701.01731

UVA APOGEE-South Team Installs Spectrograph

January 20, 2017

A team of astronomers and instrument scientists are installing the APOGEE-South spectrograph at the Irénée du Pont Telescope at Las Campanas Observatory in Chile. APOGEE-South will measure the chemical compositions and motions of hundreds of thousands of stars in the southern sky as part of the Sloan Digital Sky Survey to help astronomers answer questions about the formation of our Milky Way Galaxy. 

Read the full article, and watch the video, at UVA Today

Setting An Example

January 17, 2017

Rukmani Vijayaraghavan, a National Science Foundation Astronomy and Astrophysics Postdoctoral Fellow in the Department of Astronomy at the University of Virginia, was interviewed by the website 500 Women Scientists about her Girls Exploring the Universe summer science camp for middle school girls. 

Read the full interview at 500 Women Scientists.

Kelsey Johnson interviewed after NSF talk

December 22, 2016

UVA astronomer Kelsey Johnson delivered a talk at the National Science Foundation's Distinguished Lectures series titled "How were the most ancient objects in the universe formed?". After her talk, she was interviewed by the NSF about her research, "Dark Skies, Bright Kids", and her views on the future of astronomy.

Read the full interview on the NSF website

APOGEE: A $6 MILLION SPECIAL DELIVERY FROM UVA TO CHILE

November 16, 2016

 

A 4,000-pound astronomy instrument called APOGEE-2, built in the last two years at the University of Virginia, will soon be crated up and transported on an 8,000-mile, two-month journey to its new home at the Las Campanas Observatory in the northern Chilean desert. The instrument – an infrared spectrograph - is designed to peer through cosmic dust to stars at the farthest reaches of our home galaxy, the Milky Way.

Read the full article at UVA Today

Kelsey Johnson Inspires the Next Generation at Girls Day in STEM-H

November 10, 2016

University of Virginia astronomer Kelsey Johnson inspired 400 girls to pursue careers in science, technology, engineering, mathematics, and health at the first Girls Day in STEM-H at the University of Virginia's College at Wise.

Read more about the event in the article in the Kinsport Times-News

Balloon Flight to the Stratosphere

September 22, 2016

On September 22, 2016, an astronomy student led balloon project carried a custom payload to an altitude of 111,028 feet above Central Virginia. The goal of the project was to give undergraduate students experience with designing, building and flying a balloon based research platform. 

Click here to read more about the flight in UVA Today.

Click here for more information on the flight, including many amazing pictures.

Minority Students Rave About Science Research

August 10, 2016

Assistant Professor of Astronomy Nitya Kallivayalil has started a five-year collaboration with Spelman College, the nation’s oldest historically black college for women in Atlanta, as part of the NSF Early Career Development Award she received last year. Across the University of Virginia, about 20 minority students are participating in research programs in science, technology, engineering and math through a collaboration between UVA programs including Kallivayalil's program, the Leadership Alliance, and the Virginia-North Carolina Alliance for Minority Participation.

Read the full article at UVA Today.

Searching the Kuiper Belt

June 10, 2016

UVA astronomer Anne Verbiscer helped find a new target in the Kuiper Belt, the icy body 2014 MU69, for the NASA New Horizons spacecraft. New Horizons will pay a visit to 2014 MU69 on January 1, 2019.

Read the full article at UVA Today.

Posthumous Paper Resolves Century-Old Mystery of How Stars Evolve

May 19, 2016

The discovery of subgaint stars opened the field of observational stellar evolution. Alan Sandage (Carnegie Institution) teamed up with Steven Majewski (University of Virginia), and Majewski’s student, Rachael Beaton (now a postdoc at Carnegie Institution) to delve into the history of the discovery of subgiant stars. They showed that the observations of the subgiants discovered at the Mount Wilson Observatory in 1935 were remarkably accurate. Sandage was diagnosed with pancreatic cancer, yet still worked feverishly on the project right until he died in 2010. Majewski and Beaton received his last handwritten comments two days later. And they doggedly continued the work in his honor.

See more at Gizmodo

First Annual Astronomy Undergraduate Research Symposium

May 9, 2016

On April 22, 2016, seven Department of Astronomy undergraduates participated in the department's first Annual Astronomy Undergraduate Research Symposium. Their names and poster titles are listed below. These students presented their research to the rest of the department in a fashion similar to larger astronomy conferences, such as an AAS meeting. From professors to fellow undergraduates, the event was very well attended and provided an excellent opportunity for the students to share and discuss their projects, while celebrating their accomplishments. We were also joined by a high school student from Central Virginia Governor's School, Ryan Henderson, whose presentation is also listed below. As part of the symposium, the most exceptional poster was awarded a prize and this year's winner is 4th-year Avery Bailey. Congratulations to Avery and the rest of the presenters!

Bridget Anderson
"An XMM-Newton X-Ray Observation of the Galaxy Cluster Abell 3653: The Origin of High Velocity BCGs"

Avery Bailey
"The Merger Dynamics of Abell 2061"

Alex Bixel
"Measuring the Dark Matter Content of Galaxies with SALT"

Shawn ‘Tom’ Booth:
"Investigating the Spatial Structure of HCN Emission in Comet C/2012 F6 (Lemmon)"

Arvind Gupta:
"Measurement of Distances to RR Lyrae Stars in the Sagittarius Dwarf Core"

Duy Nguyen
"False Positive Detection within the APOGEE Catalog of Extrasolar Companion Candidates"

Christopher Wiens
"The Importance of Compact Group Environments Over Cosmic Time"

Ryan Henderson
"Measuring the mass of the black hole in galaxy NGC 5765b using H2O maser spectra"

UVA Astronomers Find Oasis in Brown Dwarf Desert

April 21, 2016

In a new paper published last month in The Astronomical Journal, a team of astronomers led by Department of Astronomy graduate student Nicholas Troup has shown that the brown dwarf desert is not as barren as previously thought. UVA faculty members Steven Majewski, Michael Skrutskie and John Wilson in the Department of Astronomy collaborated on the findings as part of the Apache Point Observatory Galactic Evolution Experiment, itself part of the Sloan Digital Sky Survey. Astronomers had long expected that the universe would be teeming with brown dwarfs, and plenty have been found in isolation. Until recently, however, so few brown dwarfs have been found orbiting close to other stars that astronomers referred to the phenomenon as the “brown dwarf desert.” This created a problem for theorists, who have been scrambling to explain why astronomers have found so few. So when Sloan Digital Sky Survey astronomers started sifting through their data looking for companions to stars, they never expected such a bountiful harvest. While only 41 close-in brown dwarf companions to stars had been detected previously, in their new work Troup and the Sloan astronomers report the discovery of 112 more.

Read the full article at UVA Today

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