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Spinning black hole has rapidly pivoting jets

April 29, 2019

Astronomers, including Craig Sarazin from U.Va., have discovered jets shooting out at nearly the speed of light from the regions around a black hole, and which are changing their direction rapidly (minutes to hours).  This reorientation of the jets is due to the Lense-Thirring Precession, an effect predicted by Einstein's Theory of General Relativity.  This effect is expected to occur near a rotating black hole, and is caused by the rotating black hole dragging space and time around with it as it rotates.  This is believed to be the first direct observation of the Lense-Thirring Precession occurring around a black hole.  The black hole is surrounded by a disk of material (an accretion disk).   The rotation of this accretion disk and the spin of the black hole are misaligned.  The inner part of the accretion disk is wobbling (“precessing”) as a result of the very strong gravity of the black hole.  This wobble is similar to that of a spinning top as it slows down, but in this case it is due to the distortions of space and time from the rotating black hole, as predicted by Einstein’s theory.

The black hole is part of a binary star system with the rather unromantic name V404 Cygni.  The precessing jets were observed in radio emission with the Very Long Baseline Array (VLBA), a network of ten radio telescopes spread across the United States, from the Virgin Islands in the Caribbean to Hawaii. The VLBA is operated by the National Radio Astronomy Observatory (NRAO), whose headquarters are on the U.Va. grounds.

This research was published on Monday, April 29 in the journal Nature.  The research is part of a project originally conceived in Charlottesville by James Miller-Jones (originally a scientist at NRAO, now a professor at Curtin University in Perth, Australia), Greg Sivakoff (originally a graduate student and post-doc at U.Va., now a professor at the University of Alberta in Edmonton, Canada), and Sarazin.

The figure shows radio emission from the black hole V404 Cygni superposed on a model for the binary system, accretion disk, and precessing jets.

Video from the observations and simulations of the system are available at. https://vimeo.com/icrar/Cygni-animation

You can read more about the discovery in the article at UVAToday.

Reaching for the Stars in the UVA Community

April 24, 2019

A University of Virginia-led program, “Dark Skies, Bright Kids,” has been bringing astronomy to local schools in Albemarle County for more than 10 years, opening up a universe of possibilities and knowledge for children in the Charlottesville community.

You can watch the video at UVA Today: Reaching for the Stars in the UVA Community

Mengyao Liu Wins Two Prestigious Awards

April 23, 2019

Graduate student Mengyao Liu has been selected as a 2019-2020 Jefferson Scholars Foundation Dissertation Year Fellow. The merit based fellowships are designed to "identify Ph.D. and M.B.A. candidates who demonstrate outstanding achievement and the highest promise as scholars, teachers, public servants, and business leaders in the United States and beyond. Once selected, Jefferson Fellows are charged with furthering the quality of education, intellectual life, and mission of the University."

Mengyao also received the 2019 Allan Talbott Gwathmey Memorial Award, "an honor reserved for the most accomplished graduate students in the physical sciences at the University of Virginia in recognition of a distinguished scholarly publication.” 

Mengyao's research on luminous protostars was also recently featured in a SOFIA Spotlight article.

Spiraling Giants: Witnessing the Birth of a Massive Binary Star

March 18, 2019

An international group of astronomers, including Jonathan Tan from the University of Virginia, have made observations of a molecular cloud that is collapsing to form two massive protostars that will eventually become a binary star system. The observations showed that, even at this early stage, the cloud contains two objects: a massive “primary” central star and another “secondary” forming star, with a combined mass of at least 18 times that of our Sun. For the first time, the researchers were able to use these observations to deduce the dynamics of the system. The observations showed that the two forming stars are separated by distance of about 180 astronomical units (one astronomical unit is the distance from the Earth to the Sun) and they orbit each other with a period of, at most, 570 years.

According to Tan, "Massive stars are important throughout the universe, including for producing the heavy elements that make up our Earth and our own bodies, but their formation mechanism is literally shrouded in mystery, being so deeply embedded in dusty clouds.” 

You can read more at UVA Today. The results were published in Nature Astronomy.

 

AAS 233 Chambliss Student Awards Winners

January 30, 2019

 

The Chambliss Astronomy Achievement Student Awards are given to recognize exemplary research by undergraduate and graduate students who present at one of the poster sessions at the meetings of the AAS. Awardees are honored with a Chambliss medal or, in the case of honorable mention, a certificate. Three University of Virginia student were among the winners! Graduate students H. Thankful Cromartie and Molly Finn were both Medal winners, and undergraduate Eric Rohr was an Honorable Mention. More information and full list of winners can be found here: https://aas.org/posts/news/2019/01/congratulations-aas-233-chambliss-student-awards-winners

Total Lunar Eclipse - Jan 2019

January 17, 2019

Late Sunday night into early Monday morning, the moon will “go from full, to nearly disappearing, to being full again in the course of a few hours,” University of Virginia astronomy professor Ed Murphy said. Learn more at this UVA Today Article.

“Lazy” Start of Star Formation Find from SDSS

January 9, 2019

Astronomers from the Sloan Digital Sky Survey (SDSS) reached the conclusion that after a “lazy” start of star formation for the first few billion years of their lives, both the Large and Small Magellanic Clouds are now forming new stars at a rapid rate. They made the first-ever detailed chemical maps of galaxies beyond our own. UVA graduate and study leader, David Nidever said, “Reading these maps helps us reconstruct the history of how these galaxies formed their stars.” “Both the Magellanic Clouds started off by making stars very slowly,” says Christian Hayes, a key member of the research team and current graduate student at UVA. Read more here: https://www.sdss.org/press-releases/its-never-too-late-to-get-active/

 

Image: Rachael Beaton, Borja Anguiano and Steve Majewski

The Heart of the Lion

January 8, 2019

This Hubble image taken by University of Virginia astronomer Craig Sarazin of the nearby elliptical galaxy Messier 105 (also called NGC 3379) is currently the Hubble Space Telescope Picture of the Week (January 7 - 11).   Although the image was taken primarily to study the relationship between stellar mass black holes and globular star clusters, it has also been used to study the 200 million solar mass supermassive black hole at the galaxy center and star formation in and near this galaxy.  More information and images are available at: https://spacetelescope.org/images/potw1901a/

UVa Astronomer Helps to Image Ultima Thule

January 5, 2019

Anne Verbiscer,  Research Professor in Astronomy, is the Assistant Project Scientist for NASA’s New Horizons Mission, which flew by Ultima Thule on January 1, producing the picture shown above.  Ultima Thule is the most distant object ever visited by a spacecraft.  Verbiscer was interviewed for the NOVA TV program which aired the following night.  She said: "When I first saw the images, I think I probably said ‘wow’ a million times.”  The NOVA program is available at https://www.pbs.org/wgbh/nova/video/pluto-and-beyond/, and a much longer news item was featured on UVaToday.

Ultima Thule Occultation in Senegal

September 12, 2018

University of Virginia astronomers Mike Skrutskie and Anne Verbiscer led a group of undergraduate UVA students to Sénégal to participate in a campaign to observe the occultation of a distant star by the Kuiper Belt object Ultima Thule. Ultima Thule is the target of a flyby by the New Horizons spacecraft on January 1, 2019. The occultation can reveal details about Ultima Thule, such as its diameter and may reveal whether it is surrounded by a ring or moons.

You can learn more in this NASA Press Release or in the New York Times

Galaxy Stars

Rapid Results from the Gaia Data Release 2

May 14, 2018

UVA astronomer Nitya Kallivayalil was interviewed on German public radio about the very rapid prepartion and submission of papers just after the second data release from the European Space Agency's Gaia mission. Kallivayalil's paper featured the discovery of satellite galaxies that are falling into the Milky Way with the Magellanic Clouds (http://lanl.arxiv.org/abs/1805.01448). The paper was submitted within a week of the data release!

You can listen to the full interview (in German) at http://ondemand-mp3.dradio.de/file/dradio/2018/05/14/offener_sternenkatalog_neue_wege_bei_der_auswertung_gaia_dlf_20180514_1640_0a2233e1.mp3

Virginia Initiative on Cosmic Origins

May 1, 2018

The Virginia Initiative on Cosmic Origins (VICO) officially began operations on May 1st. VICO is an interdisciplinary research program focussed on the formation of stars, planets and life in the Universe and supported by $1 million from UVa’s Strategic Investment Fund. Led by Prof. Eric Herbst, VICO brings together faculty from the Depts. of Astronomy, Chemistry, Computer Science, Environmental Sciences, and Materials Science & Engineering, as well as the National Radio Astronomy Observatory. VICO is also partnering with Chalmers University of Technology in Gothenburg, Sweden and the Max Planck Institute for Extraterrestrial Physics in Garching, Germany. Several new Origins postdoctoral researchers have been recruited, who will join UVa in 2018. VICO is also supporting student research opportunities, including eight summer undergraduate fellowships, including placements at Chalmers University in Sweden. Look out for future announcements about VICO positions and events in the near future! (Image courtesy of Tyler Jones)

Unraveling the Mysteries of Colossal Stars

January 10, 2018

A team of astronomers, including Jonathan Tan of Chalmers University of Technology, Gothenburg, Sweden and the University of Virginia, are using NASA's Stratospheric Observatory for Infrared Astronomy to study the births of massive stars in our Milky Way Galaxy. “Understanding the birth process of massive stars is one of the most important unsolved problems of modern astrophysics, since these stars are so influential throughout our galaxy and beyond.” says Tan. “The unique ability of the SOFIA telescope to see at infrared wavelengths – wavelengths that are 100 times longer than those of visible light -- is crucial for progress on this research, since this is the part of the spectrum where the stars emit most of their energy.”

Read more about the project at NASA.gov

UVA Astronomy People

Ilse Cleeves Wins the Annie Jump Cannon Award

January 10, 2018

Incoming University of Virginia astronomy faculty member Ilse Cleeves has been awarded the Annie Jump Cannon Award of the American Astronomical Society for "her groundbreaking work on planet formation and protoplanetary disks. She has established herself as an expert in astrochemical signatures in circumstellar disks."

 

Read more about the Annie Jump Cannon Award

Charlottesville Ed Murphy McCormick Observatory

Unafraid to Ask More: APOGEE

December 13, 2017

The UVa-led APOGEE project to study the structure and evolution of our Milky Way galaxy is featured in a new video Unafraid to Ask More.

UVA Astronomy Awards

John Wilson Awarded the Muhlmann Prize of the Astronomical Society of the Pacific

October 28, 2017

Dr. John Wilson, a Senior Research Scientist in the Department of Astronomy, is the recipient of the 2017 Maria and Eric Muhlmann award of the Astronomical Society of the Pacific. This award recognizes recent significant observational results made possible by innovative advances in astronomical instrumentation, software, or observational infrastructure and is one of the few in the astronomical world focused on instrumentation.

The award highlights John Wilson’s leadership in the design and development of the state-of-the-art spectrograph for the Sloan Digital Sky Survey’s Apache Point Observatory Galactic Evolution Experiment (APOGEE) as well as the contributions of the entire APOGEE  team.   This spectrograph is capable of dispersing the light of 300 stars simultaneously, providing a detailed examination of their elemental constituents. Doing so has enabled one of the first comprehensive experiments to reconstruct the assembly history of our Milky Way galaxy since these elemental ratios are a fingerprint pointing to the individual star’s origins. John led the development of not just one, but two spectrographs – one deployed to Apache Point Observatory in New Mexico and one to Las Campanas Observatory in Chile. By covering both the northern and southern hemispheres the two instruments provide access to the entire celestial sphere.  The spectrographs employ novel technologies such as 300 fiber optic feeds bringing infrared light into the vacuum-cryogenic instrument, refractive silicon optics larger than previously possible, and the largest volume-phase holographic grating ever produced for an astronomical instrument.   Constructing the instrument required the input of roughly one hundred engineers and scientists and a number of private companies, all masterfully coordinated by Wilson to produce these spectrographs within their $5 million budgets and in the time allotted.  To date the instruments are responsible for data that has led to the publication of more than 200 scientific papers and the publication rate continues to increase, particularly given the start of operations of the second APOGEE spectrograph at Las Campanas Observatory.   The APOGEE spectrograph represents just one (actually two, technically) of Wilson’s instrumentation successes over the nearly 15 years he has worked at UVa, where he has been central to the delivery of a variety of unique infrared cameras and spectrographs all over the world.

You can read more at the ASP announcement of the Award.

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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

 

NASA Satellite

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.

Solar and Lunar Eclipse

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!

Galaxy Stars

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 Astronomy Students

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.

UVA Lawn Graduation

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!

 

Stars

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.

Europa

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.

UVA Astronomy People

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

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