theSpectr m VOLUME 4 ISSUE 01 / 2013
UNIVERSITY OF UTAH: Department of Physics & Astronomy
Andromeda Wants You!
Legendary Climber, George Lowe III, On Spanning The Gap Between Physics & Climbing
2013 Graduates Awards & Scholarships
You Didnâ€™t Know You Could Do With Cell Phones
PLUS: AN UPDATE ON THE W. M. KECK BISTATIC RADAR OBSERVATORY
SPECTRU CONTENTS 4. Awards, Grants, & Appointments 6. 2013 Graduates 7. 2013 Student Awards & Scholarships 8. When Galaxies Eat Galaxies
16. Andromeda Wants You!
Astronomers Ask Public to Find Star Clusters in Hubble Images
18. Young Universe Expanded Slowly
During Last 14 Billion Years, Expansion Slowed & Then Sped Up
20. Toward A Truly White Organic LED Utah Physicists Develop Polymer with Tunable Colors
Gravity Lenses Suggest Big Collisions Make Galaxies Denser
10. U Re-Enlists With Astronomy Project
University Joins Sky Survey’s 4th Phase with W.L. Eccles Grant
22. Wagon-Wheel Pasta Shape For Better LED
“Rotelle’”Molecules Depolarize Light, More Efficient than “Spaghetti”
12. Alumni Spotlight: George H. Lowe III
24. Department “Quarks”
14. First Light For W. M. Keck Bistatic
26. 5 Tricks You Didn’t Know You Could Do
With Cell Phones
By Adam Beehler, Dept. of Physics & Astronomy
15. High Pressure Melting Of Lithium
Hello Friends, In July, I was contacted by the Interim Sr. Vice President for Academic Affairs, Mike Hardman, to offer me the opportunity to serve the University as the Dean of the Graduate School. After consideration of the challenges and opportunities this position would bring, and after discussions with several faculty and staff members, I accepted this position, which became effective August 1, 2013. Pierre Sokolsky, the Dean of the College of Science, has appointed Professor Carleton DeTar to become the next Chair of the Department of Physics & Astronomy. I am very pleased to announce that he has accepted the position. Carleton has a long history of service to the department and is an outstanding theoretical physicist with a strong research effort. He was also the recipient of this year’s University of Utah Distinguished Carleton DeTar Teaching Award. I look forward to working closely Professor & New Chairman with Carleton to make sure that the department continues on its strong upward path. The Department of Physics & Astronomy is in excellent shape and we will do everything we can to keep it that way. In closing I want to say it has been a privilege to work with the Department of Physics & Astronomy faculty, staff, and students during the past six years. This is an amazing department, built upon open communication, mutual respect and trust, and a shared vision of opportunity, excellence and friendship. We have had phenomenal growth in terms of the quality of the teaching, research, and public outreach missions of the department. In my new position as Dean of the Graduate School, I will work with Chairman DeTar, Dean Sokolsky, Sr. Vice President for Academic Affairs Watkins, and President Pershing to continue the upward trajectory of the Department of Physics & Astronomy. With Best Regards,
Kathrine Skollingsberg firstname.lastname@example.org The Spectrum is the official newsletter of the Department of Physics & Astronomy at the University of Utah. The Spectrum seeks to provide friends, students, alumni, and the community at large with a broad spectrum of up-todate information on news, events, achievements, and scientific education relating to the department. Story suggestions, upcoming events, and comments are always welcome. Contact us at email@example.com
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and include the full name listed on the mailing label. Sorry for the inconvenience. © 2013 University of Utah
Promotion to Research Associate Professor
Distinguished Teaching Award
Promotion to Professor
Scialog Fellows Award
AWARDS, GRANTS &
Promotion to Research Associate Professor
Our world-class faculty are renowned scholars, recognized both nationally & internationally for their research achievements.
Department of Energy Early Career Award
Honors Professorship College of Science Professorship
YAN (SARAH) LI
New Assistant Professor in Experimental Condensed Matter. Joined the department in Jan. 2013 from Los Alamos National Lab
Promotion to Research Assistant Professor
Dist. Scholarly & Creative Research Award 2012 Utah Governorâ€™s Medal for Science & Technology
Promotion to Associate Professor
2013 GRADUATES General commencement ceremonies took place May 2, 2013. The College of Science convocation & Physics & Astronomy reception & awards ceremony took place the following day, May 3, 2013. The University of Utah graduated a total of 8,007 students. The Department of Physics & Astronomy graduated 36 undergraduates and 15 graduate students. The Department of Physics & Astronomy congratulates all of its graduates and welcomes them to our alumni family!
BACCALAUREATES Christopher Ahn Kyle Arslanian Matthew Baird Sean Burns Alexandria Burringo Keyton Clayson Brian Colson Trevor Dick Jon Drake Haleigh Van Eerden Emerson Dan Filler Eric Grimm Jeffrey Healey Pyong Hlaing Daniel Hoyt Brian Kimmig Gavin Kindall Wade Jensen 6
Richard Jones David Lawrence Samuel Leventhal Max Llamozas Gannon McDonald Michelle Miller Travis Nielsen Eric Peterson Brian Pfenning Matthew Shaw Eric Swenson Christopher Tellesbo Sky Blue Thai Shai Vardeny Mary Walton Branson Williams Thomas Woodland Sarah Yenchik
MASTERS OF SCIENCE Anil Ghimire Nabraj Sapkota Alex Thiessen
PhDâ€™s Tek Basel Jacqualine Butterfield Mahamadou Diakite Bhoj Gautam Jeff Hodges Yuting Hu Mark Limes Ella Oljenik Matt Olmstead Bill Pandit Kipp van Schooten Kamdem Thaddee
Department Awards Nick Borys
Bhoj Gautam Yuting Hu
Yuting Hu Rhett Zollinger
Swigart Scholarship for Outstanding Graduate Student
Outstanding Postdoctoral Research
Outstanding Graduate Students
Outstanding Graduate Teaching Assistants
Martin Hiatt Outstanding Undergraduate Research
Outstanding Undergraduate (Sr) Outstanding Undergraduate Teaching Assistant*
* Jon Drake also awarded, but not pictured.
Outstanding Undergraduate (Jr) Paul Gilbert Outstanding Undergraduate Research
Tyler Soelberg Memorial Award
Laurel Hales Christopher Harker Shawn Merrill Joshua Wolfe
Outstanding Undergraduate (Soph) Myriad Women in Science
College of Science Awards Graduate Research Fellowship Award Alex Thiessen
Crocker Science House Scholars Laurel Hales Ariel Herbert-Voss Ian Sohl
Myriad Academic Excellence Chaekyung Yoo
Deanâ€™s Scholarship Laurel Hales Christopher Harker
AWARDS & SCHOLARSHIPS
Gravity Lenses Suggest Big Collisions Make Galaxies Denser
sing gravitational “lenses” in space, University of Utah astronomers discovered that the centers of the biggest galaxies are growing denser – evidence of repeated collisions and mergers by massive galaxies with 100 billion stars. “We found that during the last 6 billion years, the matter that makes up massive elliptical galaxies is getting more concentrated toward the centers of those galaxies. This is evidence that big galaxies are crashing into other big galaxies to make even bigger galaxies,” says astronomer Adam Bolton, principal author of the new study. “Most recent studies have indicated that these massive galaxies primarily grow by eating lots of smaller galaxies,” he adds. “We’re suggesting that major collisions between massive galaxies are just as important as those many small snacks.” The new study – published recently in The Astrophysical Journal – was conducted by Bolton’s team from the Sloan Digital Sky Survey-III using the survey’s 2.5-meter optical telescope at Apache Point, N.M., and the Earth-orbiting Hubble Space Telescope. The telescopes were used to observe and analyze 79 “gravitational lenses,” which are galaxies between Earth and more distant galaxies. A lens galaxy’s gravity bends light from a more distant galaxy, creating a ring or partial ring of light around the lens galaxy. The size of the ring was used to determine the mass of each lens galaxy, and the speed of stars was used to calculate the concentration of mass in each lens galaxy. Bolton conducted the study with three other University of Utah astronomers – postdoctoral researcher Joel Brownstein, graduate student Yiping Shu and undergraduate Ryan Arneson – and with these members of the Sloan Digital Sky Survey: Christopher Kochanek, Ohio State University; David Schlegel, Lawrence Berkeley National Laboratory; Daniel Eisenstein, Harvard-Smithsonian Center for Astrophysics; David Wake, Yale University; Natalia Connolly, Hamilton College, Clinton, N.Y.; Claudia Maraston, University of Portsmouth, U.K.; and Benjamin Weaver, New York University.
Big Meals & Snacks for Massive Elliptical Galaxies The new study deals with the biggest, most massive kind of galaxies, known as massive elliptical galaxies, which each
contain about 100 billion stars. Counting unseen “dark matter,” they contain the mass of 1 trillion stars like our sun.
Adam Bolton Assistant Professor
“They are the end products of all the collisions and mergers of previous generations of galaxies,” perhaps hundreds of collisions,” Bolton says.
Despite recent evidence from other studies that massive elliptical galaxies grow by eating much smaller galaxies, Bolton’s previous computer simulations showed that collisions between large galaxies are the only galaxy mergers that lead, over time, to increased mass density on the center of massive elliptical galaxies. When a small galaxy merges with a larger one, the pattern is different. The smaller galaxy is ripped apart by gravity from the larger galaxy. Stars from the smaller galaxy remain near the outskirts – not the center – of the larger galaxy. “But if you have two roughly comparable galaxies and they are on a collision course, each one penetrates more toward the center of the other, so more mass ends up in the center,” Bolton says. Other recent studies indicate stars are spread more widely within galaxies over time, supporting the idea that massive galaxies snack on much smaller ones. “We’re finding galaxies are getting more concentrated in their mass over time even though they are getting less concentrated in the light they emit,” Bolton says. He believes large galaxy collisions explain the growing mass concentration, while galaxies gobbling smaller galaxies explain more starlight away from galactic centers. “Both processes are important to explain the overall picture,” Bolton says. “The way the starlight evolves cannot be explained by the big collisions, so we really need both kinds of collisions, major and minor – a few big ones and a lot of small ones.” The new study also suggests the collisions between large galaxies are “dry collisions” – meaning the colliding galaxies lack large amounts of gas because most of the gas already has congealed to form stars – and that the colliding galaxies hit each other “off axis” or with what Bolton calls “glancing blows” rather than head-on.
This image, taken by the Hubble Space Telescope, shows a ring of light from a distant galaxy created when a closer galaxy in the foreground – not shown in this processed image – acts as a “gravitational lens” to bend the light from the more distant galaxy into the ring of light, known as an Einstein ring. In a new study, University of Utah astronomer Adam Bolton and colleagues measured these Einstein rings to determine the mass of 79 lens galaxies that are massive elliptical galaxies, the largest kind of galaxy with 100 billion stars. The study found the centers of these big galaxies are getting denser over time, evidence of repeated collisions between massive galaxies.
The University of Utah joined the third phase of the Sloan Digital Sky Survey, known as SDSS-III, in 2008. It involves about 20 research institutions around the world. The project, which continues until 2014, is a major international effort to map the heavens as a way to search for giant planets in other solar systems, study the origin of galaxies and expansion of the universe, and probe the mysterious dark matter and dark energy that make up most of the universe. Bolton says his new study was “almost gravy” that accompanied an SDSS-III project named BOSS, for Baryon Oscillation Spectrographic Survey. BOSS is measuring the history of the universe’s expansion with unprecedented precision. That allows scientists to study the dark energy that accelerates expansion of the universe. The universe is believed to be made of only 4 percent regular matter, 24 percent unseen “dark matter” and 72 percent yet-unexplained dark energy. During BOSS’ study of galaxies, computer analysis of light spectra emitted by galaxies revealed dozens of gravitational lenses, which were discovered because the signatures of two different galaxies are lined up.
“They are the end products of all the collisions and mergers of previous generations of galaxies,” perhaps hundreds of collisions” Bolton’s new study involved 79 gravitational lenses observed by two surveys: The Sloan Survey and the Hubble Space Telescope collected images and emitted-light color spectra from relatively nearby, older galaxies – including 57 gravitational lenses – 1 billion to 3 billion years back into the cosmic past.
This Hubble Space Telescope image is the same as the previous image, but without the same processing. So the Einstein ring of light from the distant galaxy appears less sharp, and the closer “gravitational lens” galaxy is now visible in the middle of the image. Photo Credit: Joel Brownstein, University of Utah, for NASA/ESA & SDSS
If there is more matter concentrated near the center of a galaxy, the faster stars will be seen moving toward or being slung away from the galactic center, Bolton says.
Alternative Theories Bolton and colleagues acknowledge their observations might be explained by theories other than the idea that galaxies are getting denser in their centers over time:
Gas that is collapsing to form stars can increase the concentration of mass in a galaxy. Bolton argues the stars in these galaxies are too old for that explanation to work.
Gravity from the largest massive galaxies strips neighboring “satellite” galaxies of their outskirts, leaving more mass concentrated in the centers of the satellite galaxies. Bolton contends that process is not likely to produce the concentration of mass observed in the new study and explain how the extent of that central mass increases over time.
Another survey identified 22 lenses among more distant, younger galaxies from 4 billion to 6 billion years in the past. The rings of light around gravitational-lens galaxies are named “Einstein rings” because Albert Einstein predicted the effect, although he wasn’t the first to do so. “The more distant galaxy sends out diverging light rays, but those that pass near the closer galaxy get bent into converging light rays that appear to us as of a ring of light around the closer galaxy,” says Bolton. The greater the amount of matter in a lens galaxy, the bigger the ring. That seems counterintuitive, but the larger mass pulls with enough gravity to make the distant star’s light bend so much that lines of light cross as seen by the observer, creating a bigger ring.
The researchers merely detected the boundary in each galaxy between the star-dominated inner regions and the outer regions, which are dominated by unseen dark matter. Under this hypothesis, the appearance of growing galaxy mass concentration over time is due to a coincidence in researchers’ measurement method, namely that they are measuring younger galaxies farther from their centers and measuring older galaxies closer to their centers, giving an illusion of growing mass concentration in galactic centers over time. Bolton says this measurement difference is too minor to explain the observed pattern of matter density within the lens galaxies.
Sloan Meets Hubble: How the Study Was Conducted
U RE-ENLISTS WITH
University of Utah Joins Sky Survey’s Fourth Phase with W.L. Eccles Grant
Adam Bolton Assistant Professor
up for the fourth phase of the international effort to map the heavens – thanks to a $350,000 “challenge grant” from the Willard L. Eccles Charitable Foundation and a matching $350,000 from the university.
Five years after joining the third phase of the Sloan Digital Sky Survey, or SDSS-III, Utah’s largest research university is signing
The sky survey’s first phase began in 2000. The University of Utah joined the six-year third phase in 2008 with a $450,000 donation from the Eccles foundation and university match. SDSS-IV begins in July 2014 and will operate until mid-2020.
niversity of Utah astronomers will participate in a sixyear project to study the formation of our Milky Way galaxy; map stars, gas and supermassive black holes in 10,000 neighbor galaxies; and chart 1 million galaxies and quasars to learn about mysterious “dark energy” that makes the universe expand.
“We are eager to continue our support for astronomy at the University of Utah,” says Stephen Eccles Denkers, executive director of the Willard L. Eccles Charitable Foundation. Denkers noted that his family foundation’s support for University of Utah participation in the Sloan survey’s third phase “has been a key pillar of the establishment of the astronomy program at the university, and has led to multiple, high-profile results in research, education, outreach and external funding.” Indeed, the university’s $900,000 participation since 2008 in the third Sloan survey attracted another $1.7 million in grants for faculty members doing research for the survey, says Dave Kieda, chair of physics and astronomy. Adam Bolton and Kyle Dawson – both assistant professors of physics and astronomy – will serve as the U’s lead scientists in the fourth Sloan survey. More than 30 research institutions will participate in SDSS-IV. The Sloan surveys use the 2.5-meter-diameter telescope at Apache Point Observatory at Sunspot, N.M. That telescope “is the world’s most powerful facility for observing large volumes of space with the technique of spectroscopy,” Bolton says. “This technique breaks the light from stars and galaxies into its component wavelengths, allowing scientists to measure unique signatures of their orbital motions and chemical ingredients.” The University of Utah signed and finalized a memorandum of understanding June 18 with the Seattle-based Astrophysical Research Consortium, which operates the Sloan surveys and hopes to raise $59 million for the survey’s fourth phase. The consortium normally would charge the university $1.05 million to buy into SDSS-IV, but the price was reduced to $700,000 if the university fronted the full amount by June 30, which it did. The Eccles foundation will pay its $350,000 share to the university in installments of $120,000 this year and 2014, and $110,000 in 2015. The university’s Center for High Performance Computing will host a massive archive of data collected by the fourth Sloan survey.
Bolton Explains the Three Major Parts of SDSS-IV:
• The Apache Point Observatory Galactic Evolution Experi-
ment 2, or APOGEE-2, “will carry out the most massive survey ever of the chemistry and orbital motion of stars throughout our own Milky Way galaxy to reconstruct the complex story of the galaxy’s formation,” Bolton says. “Scientists believe that the
Milky Way was assembled from multiple generations of stars and multiple smaller galaxies. APOGEE-2 will provide direct access to the archaeological record of this history.”
Mapping Nearby Galaxies at Apache Point Observatory, or MaNGA, will observe about 10,000 galaxies in the “local” or neighboring part of the universe “and build two-dimensional maps of the motions of the stars, gas and supermassive black holes within them,” the researcher says. “MaNGA will be more than 10 times larger than any previous similar project, and will provide the most comprehensive census ever of the demographics and internal structure of galaxies in the present-day universe.”
The Extended Baryon Oscillation Spectroscopic Survey, or eBOSS, will assemble a three-dimensional map of the positions of more than 1 million distant galaxies and quasars, which are bright centers of galaxies powered by supermassive black holes.
“...this map will be a window onto the universe between 6 billion and 10 billion years ago, a cosmic epoch that has not yet been explored by a large survey like this.” “Scientists will analyze the features in this map to learn about the nature of ‘dark energy,’ a mysterious substance that is driving the expansion of the universe,” Bolton says. “Due to the time it takes light to reach us from these galaxies and quasars, this map will be a window onto the universe between 6 billion and 10 billion years ago, a cosmic epoch that has not yet been explored by a large survey like this.” Scientists believe only 5 percent of the universe is made up of visible matter, while 27 percent is made of still-unidentified “dark matter” and 68 percent is so-called dark energy that is working against gravity to make the universe expand. Bolton will serve as principal data scientist for SDSS-IV, and Dawson as instrument scientist for the eBOSS project. Kieda, who becomes dean of the U’s graduate school Aug. 1 – will serve on the Sloan collaboration’s advisory committee. The W.L. Eccles foundation played a key role in establishing the U’s astronomy program. In addition to donating half the university’s membership in the Sloan surveys, the foundation spent $88,000 to refurbish the observatory on the South Physics Building and $680,000 for the university’s 32-inch research telescope atop Utah’s Frisco Peak, SDSS-IV is described in “SDSS-IV: Mapping the Milky Way, Nearby Galaxies and the Distant Universe” at www.sdss3.org/ future/sdss4.pdf
Membership in the Sloan survey’s fourth phase is “a critical extension and expansion of the success achieved by the U’s astronomy program as a participant in SDSS-III,” says Michael Hardman, interim senior vice president for academic affairs.
GEORGE HENRY LOWE III
Dr. Lowe leading Tom Cat at Indian Creek Utah, 2008
All photos courtesy of George H. Lowe III
ith an abundance of first ascents under his belt, in a career spanning more than 50 years, Utah native George Henry Lowe III is a legend in the climbing community. He is also a highly skilled scientist and engineer, working for such firms as Argo Systems & Electromagnetic Systems Laboratory. With a background in physics, he developed strong problem solving skills that translated well to climbing, and learned skills in climbing that he applied to his scientific work. By navigating these diverse routes, George Lowe has made it his mission to take on and overcome obstacles both outdoors and in the lab. 12
Cover photo: Dr. Lowe at the Dhaulagiri massif mountain range
Raised in Ogden, Utah, George spent a lot of time outdoors, especially skiing the slopes of Snow Basin with his family. After two years at Harvey Mudd college in California, he earned his Bachelor’s degree in Physics at the University of Utah in 1966. In 1973, George received his PhD in physics at the University of Utah under the direction of Professor Jack W. Keuffel, a pioneer in Cosmic Ray research. Jack Keuffel was the director of the Cosmic Ray’s neutrino research project. On working with Dr. Keuffel, Dr. Lowe remarks, “Jack could do rough estimates on the back of an envelope that would take us days to repeat, and reach the same conclusion”. Dr. Lowe’s research was focused at the Utah Muon Detector, a large detector originally built to detect upward moving neutrinos that interacted with matter in the earth and produced muons in the process. The detector was built about 500 meters underground in an old Park City mine in order to reduce background radiation. His research culminated in his thesis, “Underground Muon Showers and Models of the Hadronic Interaction at Very High Energies”. After graduation, Dr. Lowe continued to work with the Cosmic Ray research group as a postdoctoral scholar until 1975 when he took a job in California at Electromagnetic Systems Laboratory (ESL) Inc., a defense-based firm, as a systems engineer and programmer. In 1982, he moved to Colorado to begin working at Argo Systems, where he stayed until 1999 when Lowe took an early retirement to become a consultant to the United States government, where he works to this day. He has won many awards over his career. He was one of two contractors who was awarded the 1999 intelligence community‘s seal medallion “in recognition of sustained superlative performance as a senior scientific consultant”.
Scaling the Gap Physics and science in general, are focused on developing dexterous, analytical problem-solving skills. The tools for solving various types of problems come from, not just the acquisition of knowledge, but the acquisition and subsequent application of knowledge to problem solve in any situation. This is a lesson Dr. Lowe has taken to heart. His climbing and technical careers have both centered on difficult problem solving. “You just have to keep plugging. You have to keep working with the problem until you solve it” Dr. Lowe said in a 1992 interview with Climbing magazine. He developed judicious skills as a climber that transposed well into engineering and other areas of his life, “One learns to think carefully about consequences, and not make mistakes“, he remarks. Recognizing that many of the limitations he faced existed solely in his own mind made Dr. Lowe on Everest’s East Face them easier to overcome. He was able to apply his skills as a physicist to his climbing career, “Climbing is mostly applied first semester mechanics with
many creative twists“. This logical approach to life has helped Dr. Lowe achieve success and become one of the most influential alpinists today.
Life in the Mountains Dr. Lowe enjoys rock climbing, alpine climbing and Himalayan climbing disciplines. His climbing accomplishments include a series of first ascents, such as Dorsal Fin, in Little Cottonwood Canyon, Utah, first winter ascents of many routes such as the North and West Faces of the Grand Teton in Wyoming, the North Face of North Twin in the Canadian Rockies, and the Infinite Spur on Mount Foraker in the Canadian Dr. Lowe: 2013 Haute Route 057 with the Rockies. His most famous Matterhorn in backgound first ascent was the still unrepeated east face of Mt. Everest in 1983, via the now-named “Lowe Buttress”. He, along with Alex Lowe (unrelated) climbed the Nose of El Capitan in a single day in 1993. “My finest climb was probably an attempt on the North Ridge of Latok I in the Pakistan Karakorum range. Latok I (7,300 meters) was unclimbed at the time (1978). Our team of four (Jeff Lowe, Jim Donini and Michael Kennedy) spent a total of 28 days on the previously un-attempted ridge climbing capsule style (no fixed ropes from the bottom of the route), and managed to get over the technical difficulties before being stopped about 150 meters from the top on a 2,500 meter route by my cousin Jeff becoming ill, plus a major storm. The route has been attempted more than 20 times since and no one else has reached our high point.”
“I always enjoyed science, and in my mind, physics is the fundamental science” Dr. Lowe is part of a family of famous alpine-style climbers, his cousin, Jeff Lowe has made over one thousand first ascents, and Greg Lowe, another climbing cousin, founded the outdoor equipment manufacturer Lowe Alpine. Currently, Dr. Lowe lives in the foothills above Golden, Colorado where elk and deer are often found grazing in his yard. He is an avid outdoorsman whom actively goes climbing, ski touring, backpacking, kayaking, canyoneering, and uses his Cessna T210 airplane to extend his weekend range to most of the Western states. He has two generations of children who are as creative and dedicated to the outdoors, as Dr. Lowe. He works full time as a consultant to the U.S. government. He still is a very active climber, having climbed the Nose of El Capitan in Yosemite moving continuously for about 30 hours at age 68 last spring with 69 year old Jim Donini.
The Lowe Down
! DA TE UP
FIRST LIGHT FOR W. M. KECK
BISTATIC RADAR OBSERVATORY
he Telescope Array Radar (TARA) project is happy to announce that construction of the W.M. Keck Bistatic Radar Observatory has been completed. Data taking will commence with a “first-light” ceremony on Saturday May 25th, according to University of Utah physicist and TARA project director John Belz. The Observatory was created with the goal of developing a new technique for the study of the highest energy cosmic rays. A 40 kilowatt transmitter will broadcast a 54.1 MHz (corresponding to old analog channel 2) sounding wave over the Telescope Array (TA) surface detector in Millard County Utah. A high-gain transmitting antenna array will boost the effective radiated power to approximately 8 Megawatts. An array of receiver antennas 25 miles distant will search for evidence of radar scattering in coincidence with cosmic ray activity observed in the TA surface detector. The Keck Radar Observatory is the latest in a series of innovations in cosmic ray research at the University of Utah. The fluorescence technique, now employed in detectors around the world, was developed in the series of “Fly’s Eye” detectors built at Dugway Proving Ground starting in the 1980’s. The discoveries enabled by the fluorescence technique culminated in the first observation of the end of the cosmic ray energy spectrum by the High Resolution Fly’s Eye in 2008. Currently, University of Utah researchers are probing cosmic ray composition and arrival
directions using the TA and TA Lowenergy Extension (TALE) observatories in Millard County, Utah. In addition, the upcoming NICHE project (led by Utah physicist Douglas Bergman) will give TA seamless coverage over more than four orders of magnitude in cosmic ray energy. John Belz “With TARA we are hoping to demonstrate a new remote detection technique Research Assoc. Professor which will allow cosmic ray research to proceed to the next order-of-magnitude in sensitivity,” said Belz.
Other TARA researchers from Utah include: Behrouz FarhangBoroujeny, professor and associate chair of the Department of Electrical and Computer Engineering; Pierre Sokolsky, professor in the Department of Physics and Astronomy and Dean of the College of Science; and Gordon Thomson, the Jack W. Keuffel chair in experimental astrophysics at the Department of Physics and Astronomy. TARA project researchers from other institutions include David Besson, professor in the Department of Physics and Astronomy at the University of Kansas; and Helio Takai, physicist at Brookhaven National Laboratory. The W.M. Keck Bistatic Radar Observatory is supported by funds from the U.S. National Science Foundation, the W.M. Keck Foundation, and by donated analog television equipment from Salt Lake City’s KUTV Channel 2 and ABC4.
Permalink: http://www.telescopearray.org/tara/ index.html
High Pressure Melting of Lithium F or over two years, since we started our lab, we have been trying to measure the high pressure melting curve of lithium. Lithium is the lightest metal under ambient pressure. Because of its low atomic number and metallic properties, lithium has been considered for studying the dominant lattice quantum zero point energy in condensed matter and under compression. The project was a challenging problem. In general, measurements of melting curves of materials under high pressures, hundreds of thousands of atmospheres, are very difficult. In the case of lithium, the challenges were amplified since lithium is highly reactive with many materials, including the pressure chamber itself, which is made of precious diamonds. Also, lithium has an unusually low melting temperature under compression which excludes application of many available methods for remote thermometry. State of the art crystallography methods failed to provide solid Deemyad Lab (from left to right): Scott Temple, Anne Marie Schaeffer, Shanti Deemyad, & William Talmadge. proof for
the melting properties of lithium under pressure.
After trying many different existing methods, we have found a novel method that allowed us to accurately measure the melting of lithium to pressures above half million atmospheres. The experiments were arduous and required Shanti Deemyad several of months of around the clock Assistant Professor experimental runs. The experiments were successfully completed by a team of students led by graduate student Anne Marie Schaeffer and two undergraduate students William Talmadge, now a graduate student, and Scott Temple. The results appeared in the November issue of Physical Review Letters. In our recent studies, we have discovered a new lithium based superconductor, BaLi4, which becomes superconducting under pressures lower than both parent compounds. The results of this work, which has been led by Anne Marie Schaeffer in collaboration with Sivaraman Guruswuamy, is currently under review. The other coauthors of this work are Matthew DeLong, Zachary Anderson, and William Talmadge.
Andromeda Wants You! Astronomers Ask Public to Find Star Clusters in Hubble Images
stronomers at the University of Utah and elsewhere are seeking volunteers to explore the galaxy next door, Andromeda. The newly launched Andromeda Project will use people power to examine thousands of Hubble Space Telescope images of the galaxy to identify star clusters that hold clues to the evolution of galaxies.
To obtain faster results, Seth and colleagues want to “crowdsource” the problem and enlist volunteers from all walks of life to identify the star clusters. Registration isn’t required and a simple online tutorial helps volunteers quickly learn how to recognize and mark star clusters on www.andromedaproject. org.
Anyone can take part by going to www.andromedaproject.org.
“You don’t need to know anything about astronomy to participate, and it’s actually pretty fun, like playing an online game,” says Cliff Johnson, a University of Washington graduate student working on the project.
“We want to get people excited about participating. We’re hoping for thousands of volunteers,” says Anil Seth, an organizer of the Andromeda Project and an assistant professor of physics and astronomy at the University of Utah. “I love looking through these amazing Hubble Space Telescope images of Andromeda, the closest big spiral galaxy to our Milky Way galaxy,” he adds. “The Andromeda Project will give lots of people the opportunity to share in that amazement.” “Star clusters are groups of hundreds to millions of stars that formed from gas at the same time so all the stars have the same age,” Seth says. A goal of the Andromeda Project “is to study the history of the galaxy, and these clusters play an important role.” Finding star clusters is difficult work. Eight scientists spent more than a month each searching through 20 percent of the available Hubble images just to find 600 star clusters. This is less than a quarter of the 2,500 star clusters they believe exist in the full set of Hubble images of Andromeda, also known as galaxy M31. It would take too long for the astronomers to continue looking for star clusters on their own, and pattern-recognition software isn’t good at picking out star clusters.
The Andromeda Project is a collaboration that includes scientists and website developers at the University of Utah, University of Washington, Adler Planetarium in Chicago, Oxford University, University of Minnesota, University of Alabama and the European Space Agency. About 400 volunteers participated in a recent test of the new website.
All About Andromeda Pioneer astronomer Edwin Hubble observed Andromeda in the 1920s, confirming galaxies exist beyond the Milky Way and contain billions of stars. “Everyone wants to know where they came from, and part of that question involves understanding how galaxies like our own Milky Way form,” says Seth. “Andromeda is actually the best place to study that process. In the Milky Way, our position within the galaxy makes it hard to study our history.” “We have a good sense of how stars, once born, evolve,” he
The Andromeda galaxy, shown above, is the closest spiral galaxy to our own spiral, the Milky Way. Astronomers at the University of Utah and elsewhere have launched the Andromeda Project so thousands of volunteers can help them find star clusters in detailed images of Andromeda made by the Hubble Space Telescope. Photo Credit: Courtesy of Robert Gendler
Star clusters are important for understanding Andromeda’s history because their ages are easy to measure. Astronomers determine a star cluster’s age by the mass of its brightest, most massive stars. Massive stars mean a cluster is young, because “massive stars are like rock stars: they live fast and die young,” says Seth. Andromeda is about 2.4 million lights years away from Earth, or 14 billion billion miles (billion billion twice is correct). “There are other, closer galaxies, but Andromeda is the closest big spiral galaxy like our own Milky Way,” Seth says. “It’s almost a million times more distant than the nearest star to our sun, Alpha Centauri.” Andromeda contains hundreds of billions of stars, and has a diameter of about 160,000 light years, or about 940 million billion miles. The star clusters in Andromeda are typically about 20 light years across, which equals 118 trillion miles, tiny compared with the diameter of the galaxy. The Hubble images used in the Andromeda Project are part of a larger effort involving about 20 institutions and known as PHAT, the Panchromatic Hubble Andromeda Treasury survey. The Hubble Space Telescope began collecting the PHAT images in 2010. Since then, it has spent nearly two months of time making hundreds of orbits of Earth while taking pictures of the least dusty third of Andromeda. If all goes well, the Hubble will send the last batch of images back to Earth next summer. By then, the survey will have imaged one-third of Andromeda’s spiral disk at six wavelengths of
light: two ultraviolet, two visible and two infrared. The complete PHAT survey is expected to reveal 100 million individual stars. “We’re already starting to discover some amazing things about Andromeda from the PHAT data, but we expect people to be combing through this data for decades,” says University of Washington Professor Julianne Dalcanton, principal investigator of PHAT.
Citizen Scientists: Eyes on Andromeda Seth expects children, retirees, and workers on their lunch breaks to volunteer for the Andromeda Project.
A trained volunteer will take about 20 seconds per image, he adds. What if some of the volunteers are bad at identifying star clusters? “We have our original sample of 600 star clusters as a test case, and we’ll use that to see how well they do,” ranking individuals, Seth says. As another double-check, some images will contain completely fabricated images of “synthetic” star clusters with a wide range of sizes and masses. That will help the astronomers determine how small a cluster can be detected. Once the clusters all are identified, “it will be the largest sample of clusters known in any spiral galaxy, including our own Milky Way galaxy,” Seth says.
“We’ll definitely have some astronomy buffs, but hopefully there are a lot of people who, rather than looking at Facebook, will do this in their down time,” he says, adding that the Andromeda project wants “people who are interested in looking at a lot of pretty pictures and wondering about what’s out there.” “There are lots of images, so we’re going to need a lot of volunteers,” says Seth. Some high school and college students will participate for class assignments. Among them: students in Seth’s observational astronomy class. “We have about 10,000 images we are feeding to the users through the site,” he says. “We want them each to be viewed as many as 20 times.” Each image is 725 pixels by 500 pixels. Images are both in color and black-andwhite. Young star clusters have bright blue stars. Older clusters have more red stars. “A lot of images won’t have any clusters on them, or will have one,” Seth says. “You might think it’s really difficult to pick out clusters, but after looking at a few images, you really learn to see the patterns the clusters make.”
This Hubble Space Telescope image shows a very small section of the Andromeda galaxy. Astronomers at several institutions, including the University of Utah, have launched www.andromedaproject.org to seek volunteers to help them find star clusters in such images. In this picture, there is a bright red star cluster on the right edge and two blue clusters at the bottom of the image near the middle. Photo Credit: Zolt Levay, Space Science Telescope Institute
Anil Seth’s website is at: www.physics.utah.edu/~aseth/ The PHAT project’s website is: www.astro.washington.edu/groups/ phat/Home.html The Andromeda Project is part of the Zooniverse family of citizen science projects: www.zooniverse.org
University of Utah astronomer Anil Seth is helping launch the Andromeda Project so that citizen volunteers can help scientists look for star clusters in Hubble Space Telescope images of Andromeda, the nearest large spiral galaxy to our own Milky Way, which also is a spiral galaxy. Star clusters provide clues to the evolution of galaxies. Photo Credit: Lee J. Siegel, University of Utah
adds. “But we don’t really know the details of how galaxies form and how stars form within those galaxies. This project will help address both of those questions.”
The Young Universe Expanded Slowly
During Last 14 Billion Years, Expansion Slowed & Then Sped Up
ike a roller coaster that crawls slowly uphill and then zooms downhill, the universe expanded at a much slower rate 11 billion years ago than it has during the past 5 billion years, says a new study co-authored by a University of Utah astrophysicist. Light from 60,000 super-bright objects known as quasars served as flashlights to illuminate hydrogen gas between Earth and objects in the distant, early universe. “We reconstructed a 3-D map of the hydrogen gas, and from the map, we learned about the processes by which the universe expanded and grew in the first 3 billion years,” says Kyle Dawson, an assistant professor of physics and astronomy at the University of Utah and a member of the third Sloan Digital Sky Survey, or SDSS-III, which conducted the study. Scientists believe the universe formed some 13.8 billion years ago in a sudden expansion of matter and energy known as the Big Bang. Previous research showed its expansion has been speeding up for the past 5 billion years. The new study – performed using the 2.5-meter Sloan Telescope at Apache Point Observatory in New Mexico – is the first to make measurements showing expansion of the universe was slowing for the first 3 billion years after the Big Bang. The expansion later
crested the top of the “roller coaster” and began to expand more rapidly some 5 billion years ago.
The Great Space Coaster Astronomers Measure the Deceleration of the Universe before Dark Energy For the past 5 billion years, the expansion of the universe has been speeding up, powered by the mysterious repulsive force known as “dark energy.” But thanks to a new technique for measuring the three-dimensional structure of the distant universe, astronomers from the third Sloan Digital Sky Survey (SDSS-III) have made the first measurement of the cosmic expansion rate just 3 billion years after the Big Bang. “If we think of the universe as a roller coaster, then today we are rushing downhill, gaining speed as we go,” says Nicolas Busca of the Laboratoire Astroparticule et Cosmologie of the French Centre National de la Recherche Scientifique (CNRS), one of the lead authors of the study. “Our new measurement tells us about the time when the universe was climbing the hill – still being slowed by gravity.” The results were presented in a paper submitted to the journal
University of Utah astrophysicist Kyle Dawson stands in front of the 2.5-meter Sloan Telescope at Apache Point Observatory in New Mexico. Dawson is part of the Sloan Digital Sky Survey-III, a collaborative effort by some 300 scientists from about 30 research institutions worldwide. Dawson and other members of the Sloan survey are publishing a new study that made the first direct measurement of how fast the universe expanded about 11 billion years ago, or only 3 billion years after scientists say the universe formed during the Big Bang. Photo Credit: Dan Long, Apache Point Observatory
But using that ruler comes with its own difficulties. “If we want to make a measurement at early times, then we need to map structure that is very far away,” says Jim Rich of Centre de Saclay Institute of Research into the Fundamental Laws of the Universe (IRFU), another member of the analysis team. “If we used galaxies, it would be very hard, because galaxies that are far away are also very faint. So we have to try something else.”
“We reconstructed a 3-D map of the hydrogen gas, and from the map, we learned about the processes by which the universe expanded and grew in the first 3 billion years” The new measurement does not look at galaxies at all. Instead, it makes use of the clustering of intergalactic hydrogen gas in the distant universe. We can see this gas because it absorbs some light from quasars lying behind. When we measure the spectrum of a quasar, we see not only the light emitted by the quasar, but also what happened to that light in its long journey to Earth. When we look at a quasar’s spectrum, we can see how the intervening gas absorbs some of the quasar’s light. Measuring this absorption – a phenomenon known as the Lyman-alpha Forest – yields a detailed picture of the gas between us and the quasar. “It’s a cool technique, because we’re essentially measuring the shadows cast by gas along a single line billions of lightyears long,” says Anze Slosar of Brookhav-
en National Laboratory. “The tricky part is combining all those one-dimensional maps into a three-dimensional map. It’s like trying to see a picture that’s been painted on the quills of a porcupine.” Last year, Slosar and his colleagues used the first 10,000 quasars from SDSS-III’s Baryon Oscillation Spectroscopic Survey (BOSS) to make the first large-scale map of the structure of the faraway “Lymanalpha forest” gas. As enormous as that map was, it was still not large enough to detect the subtle variations of BAOs. But the new map is big enough – it measures the Lyman-alpha forest using light from 50,000 quasars all over the sky. When SDSS-III researchers began to study this bigger map more than a year ago, they didn’t know whether or not this technique would work. “When we started, we didn’t want to bias ourselves into seeing what we wanted to see,” says team member Timothee Delubac of Centre de Saclay IRFU. “We only looked at scales where we didn’t expect to see BAOs. But as we moved in on the right scale, we had a very exciting moment. The BAO peak was sitting there in our plot, right where it would be if dark energy were a constant property of space itself.” The team’s new measurement of the BAO peak, combined with measurements of the same peak at other points in the universe’s history, paints a picture of how the universe has evolved over its history. The picture that emerges is consistent with our current understanding of the universe – that dark energy is a constant part of space throughout the cosmos. What is fascinating about the new result is that, for the first time, we see how dark energy worked at a time before the universe’s current acceleration started. “Our goal for BOSS was to measure the expansion of the universe. We planned to make that measurement in two ways – one a sure thing and one a risky new idea,” says University of Utah astrophysicist Kyle Dawson, the BOSS survey scientist who ensures that good data is taken for each of the 1.8 million galaxies and quasars that BOSS will observe during the six years of SDSS-III. “It’s really excit-
ing that, thanks to the dedicated work of so many people, we know that both methods work. We have shown that the Lyman-alpha forest can accurately measure the expansion of the universe when it was only one-fifth its current age.” The BOSS measurements show that the expansion of the universe was slowing down 11 billion years ago due to the mutual gravitational attraction of all of the galaxies in the universe – but that as the universe expanded, the constant repulsive force of dark energy began to dominate as matter was diluted by the expansion of space. Thus, more than 80 years after Edwin Hubble and Georges Lemaitre first measured the expansion rate of the nearby universe, the SDSS-III has made the same measurement of the expansion rate of the universe 11 billion years ago. “No technique has ever been able to probe this ancient era before,” says BOSS principal investigator David Schlegel of the Lawrence Berkeley National Laboratory. “Back then, the expansion of the universe was slowing down; today, it’s speeding up. How dark energy caused the transition from deceleration to acceleration is one of the most challenging questions in cosmology.” SDSS-III will continue to learn more about dark energy as it collects data on more than 1.5 million galaxies and more than 160,000 quasars by the end of the survey. By the time SDSS-III is complete, it will have helped transform the Lymanalpha forest technique from a risky idea into a standard method by which astronomers explore the nature of the faraway universe.
ABOUT SDSS-III Funding for SDSS-III has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation, and the U.S. Department of Energy Office of Science. The SDSS-III web site is www.sdss3.org.
Astronomy & Astrophysics.The paper was also posted today on the arXiv.org preprint site. The new measurement is based on data from the Baryon Oscillation Spectroscopic Survey (BOSS), one of the four surveys that make up SDSS-III. It utilizes a technique pioneered by the SDSS in 2005 called “baryon acoustic oscillations (BAO).” The BAO technique uses small variations in matter left over from the early universe as a “standard ruler” to compare the size of the universe at various points in its history.
TOWARD A TRULY WHITE
Utah Physicists Develop Polymer with Tunable Colors
y inserting platinum atoms into an organic semiconductor, University of Utah physicists were able to “tune” the plastic-like polymer to emit light of different colors – a step toward more efficient, less expensive and truly white organic LEDs for light bulbs of the future. “These new, platinum-rich polymers hold promise for white organic light-emitting diodes and new kinds of more efficient solar cells,” says University of Utah physicist Z. Valy Vardeny, who led a study of the polymers published online Friday, Sept. 13 in the journal Scientific Reports. Certain existing white light bulbs use LEDs, or light-emitting diodes, and some phone displays use organic LEDs, or OLEDs. Neither are truly white LEDs, but instead use LEDs made of different materials that each emit a different color, then combine or convert those colors to create white light, Vardeny says. In the new study, Vardeny and colleagues report how they inserted platinum metal atoms at different intervals along a chain-like organic polymer, and thus were able to adjust or tune the colors emitted. That is a step toward a truly white OLED generated by multiple colors from a single polymer. Existing white OLED displays – like those in recent cell phones – use different organic polymers that emit different colors, which are arranged in pixels of red, green and blue and then combined to make white light, says Vardeny, a distinguished professor of physics. “This new polymer has all those colors simultaneously, so no need for small pixels and complicated engineering to create them.” “This polymer emits light in the blue and red spectral range, and can be tuned to cover the whole visible spectrum,” he adds. “As such, it can serve as the active [or working] layer in white OLEDs that are predicted to replace regular light bulbs.” Vardeny says the new polymer also could be used in a new type of solar power cell in which the platinum would help the polymer convert sunlight to electricity more efficiently. And because the platinum-rich polymer would allow physicists to “read” the information stored in electrons’ “spins” or intrinsic angular momentum, the new polymers also have potential uses for computer memory.
Not Quite Yet an OLED In the new study, the researchers made the new platinum-rich
polymers and then used various optical methods to characterize their properties and show how they light up when stimulated by light. The polymers in the new study aren’t quite OLEDs because they emit light when stimulated by other light. An OLED is a polymer that emits light when stimulated by electrical current. “We haven’t yet fabricated an OLED with it,” Vardeny says. “The paper shows we get multiple colors simultaneously from one polymer,” making it possible to develop an OLED in which single pixels emit white light. Vardeny predicts about one year until design of a “platinumrich pi-conjugated polymer” that is tuned to emit white light when stimulated by light, and about two years until development of true white organic LEDs. “The whole project is supported by the U.S. Department of Energy for replacing white light from regular [incandescent] bulbs,” he says. The University of Utah conducted the research with the department’s Los Alamos National Laboratory. Additional funding came from the National Science Foundation’s Materials Research Science and Engineering Center program at the University of Utah, the National Natural Science Foundation of China, and China’s Fundamental Research Funds for the Central Universities.
Using Platinum to Tune Polymer Color Emissions Inorganic semiconductors were used to generate colors in the original LEDs, introduced in the 1960s. Organic LEDs, or OLEDs, generate light with organic polymers which are “plastic” semiconductors and are used in many of the latest cell phones, digital camera displays and big-screen televisions. Existing white LEDs are not truly white. White results from combining colors of the entire spectrum, but light from blue, green and red LEDs can be combined to create white light, as is the case with many cell phone displays. Other “white” LEDs use blue LEDs, “down-convert” some of the blue to yellow, and then mix the blue and yellow to produce light that appears white.
theSpectrum At left: Z. Valy Vardeny, Distinguished Professor Right: A sample of the yellowish-colored, platinum-rich polymer known as Pt-1, emits light as a laser beam hits it at a University of Utah physics laboratory. The light appears white because the polymer emits a combination of broad-spectrum violet and yellow, which combine to appear white. The polymer and its relatives hold promise for use in a new generation of organic light-emitting diodes, or OLEDs, which could produce white light for more efficient LED light bulbs of the future. Photo Credit: Lee SIegel & Tek Basel
“These new, platinum-rich polymers hold promise for white organic lightemitting diodes and new kinds of more efficient solar cells” The new platinum-doped polymers hold promise for making white OLEDs, but can convert more energy to light than other OLEDs now under development, Vardeny says. That is because the addition of platinum to the polymer makes accessible more energy stored within the polymer molecules. Polymers have two kinds of electronic states: A “singlet” state that can be stimulated by light or electricity to emit higher energy, fluorescent blue light. Until now, OLEDs derived their light only from this state, allowing them to convert only 25 percent of energy into light – better than incandescent bulbs but far from perfect.
• A normally inaccessible “triplet” state that theoretically could emit lower energy phosphorescent red light, but normally does not, leaving 75 percent of electrical energy that goes into the polymer inaccessible for conversion to light. Vardeny says he and his colleagues decided to add platinum atoms to a polymer because it already was known that “if you put a heavy atom in molecules in general, it can make the triplet state more accessible to being stimulated by light and emitting light.”
Ideally, a new generation of white OLEDs would not only produce true white light, but also be much more energy efficient because they would use both fluorescence and phosphorescence, he adds. For the study, the researchers used two versions of the same polymer. One version, Pt-1, had a platinum atom in every unit or link in the chain-like semiconducting polymer. Pt-1 emitted violet and yellow light. The other version, Pt-3, had a platinum atom every third unit, and emitted blue and orange light. By varying the amount of platinum in the polymer, the physicists could create and adjust emissions of fluorescent and phosphorescent light, and adjust the relative intensity of one color over another. “What is new here is that we can tune the colors the polymer emits and the relative intensities of those colors by changing the abundance of this heavy atom in the polymer,” Vardeny says. “The idea, ultimately, is to mix this polymer with different platinum units so we can cover the whole spectrum easily and produce white light.” Vardeny conducted the new study with former University of Utah postdoctoral researcher Chuanxiang Sheng, now at Nanjing University of Science and Technology in China; Sergei Tretiak of Los Alamos National Laboratory; and with University of Utah graduate students Sanjeev Singh, Alessio Gambetta, Tomer Drori and Minghong Tong. The physicists hired chemist Leonard Wojcik to synthesize the platinum-rich polymers.
SHAPE FOR BETTER LED
‘Rotelle’ Molecules Depolarize Light, More Efficient than ‘Spaghetti’
ne problem in developing more efficient organic LED light bulbs and displays for TVs and phones is that much of the light is polarized in one direction and thus trapped within the light-emitting diode, or LED. University of Utah physicists believe they have solved the problem by creating a new organic molecule that is shaped like rotelle – wagonwheel pasta – rather than spaghetti. The rotelle-shaped molecule – known as a “pi-conjugated spoked-wheel macrocycle” – acts the opposite of polarizing sunglasses, which screen out glare reflected off water and other surfaces and allow only direct sunlight to enter the eyes. The new study showed wagon-wheel molecules emit light randomly in all directions – a necessary feature for a more efficient OLED, or organic LED. Existing OLEDs now in some smart phones and TVs use spaghetti-shaped polymers – chains of repeating molecular units – that emit only polarized light. “This work shows it is possible to scramble the polarization of light from OLEDs and thereby build displays where light doesn’t get trapped inside the OLED,” says University of Utah
physicist John Lupton, lead author of a study of the spoked-wheel-shaped molecules published online Sunday, Sept. 29 in the journal Nature Chemistry. “We made a molecule that is perfectly symmetrical, and that makes the light John Lupton it generates perfectly random,” he adds. Research Professor “It can generate light more efficiently because it is scrambling the polarization. That holds promise for future OLEDs that would use less electricity and thus increase battery life for phones, and for OLED light bulbs that are more efficient and cheaper to operate.” Lupton emphasizes the study is basic science, and new OLEDs based on the rotelle-shaped molecules are “quite a way down the road.” He says OLEDs now are used in smart phones, particularly the Samsung Galaxy series; in pricey new super-thin TVs being introduced by Sony, Samsung, LG and others; and in lighting.
Images of molecules for light-emitting diodes are compared with similar shaped pasta. The left electron microscope image shows spaghetti-shaped organic polymers now used for organic light-emitting diodes, or OLEDs. The left image shows new molecules – created by scientists at the University of Utah and two German universities – that are shaped like wagon-wheel or rotelle pasta and emit light more efficiently than the spaghetti-shape polymers. Photo Credit: Molecule images by Stefan Jester, University of Bonn. Pasta images courtesy Wikimedia Commons.
Lupton says. “Because those light waves only oscillate in one direction, the light can get trapped inside the OLED, which is a little bit like an optical fiber.”
The large rotelle-shaped molecules also can “catch” other molecules and thus would make effective biological sensors; they also have potential use in solar cells and switches, he adds.
“The rotelle – technically called oligomers – are basically wrapped-up polymers,” Lupton says. “They all have the same shape, but they do not emit polarized light because they are round. They generate waves that vibrate in all directions. The light doesn’t have a fixed polarization; it doesn’t vibrate in a fixed direction. It always can get out.”
The study was funded by the Volkswagen Foundation, the German Chemical Industry Fund, the David and Lucille Packard Foundation and the European Research Council. Lupton is a research professor of physics and astronomy at the University of Utah and also on the faculty of the University of Regensburg, Germany. He conducted the study with Utah physics graduate student Alexander Thiessen; Sigurd Höger, Vikas Aggarwal, Alissa Idelson, Daniel Kalle and Stefan-S. Jester of the University of Bonn; and Dominik Würsch, Thomas Stangl, Florian Steiner and Jan Vogelsang of the University of Regensburg.
Freeing Trapped Light While conventional LEDs use silicon semiconductors, OLEDs in some of the latest cell phones and TVs are made with “pi-conjugated polymers,” which are plastic-like, organic semiconductors made of a chain of repeating molecular units. “Conjugated polymers are a terrible mess,” Lupton says. “They now make only mediocre OLEDs, although people like to claim the opposite.” For one thing, three-quarters of the light energy is in a state that normally is inaccessible – a problem addressed by another recent University of Utah study of OLEDs. Lupton says his study deals with another problem, which exists even if the other problem is overcome: the polarization of light in pi-conjugated polymers that leads to the “trapping” or loss of up to 80 percent of the light generated.
That, he adds, is why even with the latest OLED smart phones, “your battery is dead in two days because the display uses a lot of the electricity.”
Lupton compares the ability of the wagon-wheel molecules to emit unpolarized light in all directions to what happens when a pencil is balanced perfectly on its tip and falls in a different, random direction each time.
Cooking up a Wagon WheelShaped Molecule The international team of physicists and chemists set out to make molecules that generate light waves in all directions rather than in a fixed direction. In the new study, they report how the created the spoked-wheel molecules, made images of them and did single-molecule experiments, including looking at photons, or light particles, emitted one at a time from a single molecule. In those experiments, they shined an ultraviolet light on the rotelle-shaped molecules to generate visible light photons. “We showed that every photon that comes out has a scrambled polarization, the polarization changes randomly from photon to photon,” Lupton says. The emitted light is blue-green, Lupton says, but images accompanying the paper – taken with a scanning tunneling electron microscope – show the rotelle- and spaghetti-shaped molecules with a false yellow-brown color to provide good contrast.
“Light is an oscillating field like a wave, and a wave moves in a certain direction,” Lupton says. “We call this direction of oscillation a polarization.”
Each wagon-wheel molecule measures only six nanometers wide, which is large for a molecule but tiny compared with the 100,000 nanometer width of a human hair.
“In principle, we should be able to double the efficiency of getting the light out”
Using rotelle-shaped oligomers instead of spaghetti-shaped polymers, “in principle, we should be able to double the efficiency of getting the light out” – although that remains to be proved, Lupton says.
Because polymers are long molecules like spaghetti, when an electrical current is applied to a polymer, “the electrons can only flow in one direction and that generates the light waves,”
“Even if we scramble the polarization, we’re always going to have a bit of light trapped in the OLED,” he says. “Those losses are now 80 percent, and we probably could get down to 50 or 60 percent.”
“OLEDs in smart phones have caught on because they are somewhat more efficient than conventional liquid-crystal displays like those used in the iPhone,” he says. “That means longer battery life. Samsung has already demonstrated flexible, full-color OLED displays for future roll-up smart phones.” Lupton says smart phones could produce light more efficiently using molecules that don’t trap as much light.
From left to right: Can Liao, Daniel Painter, Lyman Owen, Chris Dances, Gregory Moffitt, Samuel Brown, Stefan Badza, Joseph Santora at the American Nuclear Society Student Conference
The Ups, Downs, Tops, Bottoms, Charms, & Strangeness of the Department
Special thanks to Stefan Badza, Ben Bromley, Carleton DeTar, Dave Kieda, John Matthews, & Harold Simpson
ndergraduate Stefan Badza (above) was awarded Best Paper in Environmental Sciences track at the American Nuclear Society Student Conference for his paper, “Neutron Activation Analysis of Californian & Japanese Rice.“ The conference was organized by MIT student chapter and held in Boston between the 4th and 6th of April. “What caught my attention the most about this conference is the diversity of application of nuclear technology. From fundamental research in reactor physics to applications in medicine“ stated Badza. Over 300 graduate and undergraduate students from over 40 universities from 10 countries participated. Assistant Professor Pearl Sandick, presented her talk, “Particle Smashers, Higgs Hunters and the Fundamental Theory of Nature” at the November 2012 College of Science Frontiers of Science Lecture Series.
Linda Strubbe (CITA)
Dr. Linda Strubbe, a post-doctoral researcher at the Canadian Institute for Theoretical Astrophysics (CITA) presented her talk, “Snack Time for Hungry Black Holes” at a free public astronomy lecture at Snowbird Ski & Summer Resort as a part of the 5th annual Snowbird Workshop on Particle Astrophysics, Astronomy, and Cosmology (SnowPAC). Over 100 members of the community attended and more than double that watched it online.
In the middle of May 2013, Physics & Astronomy’s Adam Beehler, Ben Bromley, and Kathrine Skollingsberg, along with Academy of Math Engineering & Science’s Paul Ramsey and members of the Utah Geological Survey explored what was first thought to be the site of a meteor crater near the Investigating the strange rock formation Salt Lake International Airport. The secure site, immediately to the south of SLC’s active runways, hosted moderately magnetic rocks with signs of high-temperature surface melting--objects that did not appear to be naturally formed here on Earth. These rocks turned out to be mining by-products used to pack a runway drain from back in the late 1950’s. Professor Shanti Deemyad has received a research award from the Utah Research Foundation for her proposal, “Formation of Hydrocarbons at Extreme Pressures.” The research will focus on the isotope effect in abiotic process’s in transformation of hydrocarbons at extreme pressures and will search Shanti Deemyad for theoretically predicted transformation of Benzene to graphene (hydrogenated graphite).
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omy judged four different events and provided scholarships to several of the winning teams: Astronomy: Paul Ricketts, Mary Harges, & Tim Hutchinson Reach for the Stars: Tabitha Buehler & Nick Traeden Sounds of Music: Adam Beehler, Doug Baird, Kathrine Skollingsberg Technical Problem Solving: Wesley Sanders & Matt DeLong
The University of Utah was host to the 2013 Science Olympiad. More than 900 local junior high and high school students competed in a battle of the brains Saturday, April 13, 2013 at the University of Utah as part of the Utah Science Olympiad, a state science education competition. High school and middle school students competed in teams to build helicopters, magnetic trains that levitate, cars made from mousetraps, and much more. Utah students vied for over $100,000 in scholarship prizes. Nationwide, 6,800 teams participate in Science Olympiad competitions, designed to expose youngsters to science and engineering careers while bringing classroom science to life. “These challenges test students’ ingenuity and intellect in a fun, academic track meet-type environment,” says Ashley Nicholes, Utah Science Olympiad coordinator. The Utah Science Olympiad is one of 50 state competitions culminating in the Science Olympiad National Tournament on May 17 and 18, 2013 at Wright State University in Dayton, Ohio. The winning junior high and high school teams from each state go on to the national competition in Dayton. The Department of Physics & Astron-
The department is sad to announce the loss of three important members. Emeritus Professor Jim Ball, Cosmic Ray technician Al Larson, & Staff Member John Viner. The department extends its deepest sympathies to their families. Jim Ball (Emeritus) passed away July 29, 2013. Jim received his undergraduate degree from Caltech in 1956 and his Ph.D from UC Berkeley in 1960. After a postdoctoral appointment at UCSD and a professorship at UCLA, Jim joined the Physics Department at the University of Jim Ball Utah in 1968 as an associate professor, and was promoted to the rank of full professor in 1972. Jim worked in the field of theoretical particle physics with an emphasis on understanding the strong interactions, and reconciling theoretical models of the strong interaction with experimental observations at accelerators. In recognition of this work, Jim was awarded an A.P. Sloan Fellowship in the 1960’s. Jim was also elected Fellow of the American Physical Society in 1995 in recognition of his pioneering work in the theory of the strong force. Jim retired from the department in 1997 and spent a good deal of his retirement with his wife Janet in his beautiful mountain home he built near Torrey, Utah. Al Larsen a key technician in the early days of the department’s Cosmic Ray research group (Fly’s Eye, HiRes Fly’s
Eye, and Casa-MIADice-Blanca arrays), passed away July 22, 2013, the day after his birthday. He was 75 years old. Many of the successes of the Fly’s Eye research directly deAl Larsen rived from Al’s hard work and innovation. He was known as a very kind person with a sharp wit and a positive attitude that kept things moving forward even when confronted with gigantic challenges. Staff member John M. Viner, who was in charge of the undergraduate and graduate labs for more than 20 years, passed away on August 15, 2013. John received his Master’s degree in Physics at the University of Michigan in 1980. He was hired by the University of Utah in July 1983 as a research associate professor. In 1990, John Viner he became a Senior Research Specialist and later Senior Lab Specialist, developing and teaching the advanced undergraduate and graduate labs. In 2010, he retired to pursue other interests. John was a quiet, devoted, mild-mannered man with an exceptionally brilliant mind. He was extremely talented in the experimental lab. As a teacher, he was very methodical and patient. Having spent time as both a high school physics and math teacher, as well as teaching in the Peace Corps, he was well experienced in pedagogy. John was detail oriented in his approach, making him very rigorous with students. He was good at challenging students without leaving them feeling helpless. His deep interest in science, his off-beat sense of humor, and his gentle way of pursuing excellence were a rare combination. John’s contributions to the teaching and research missions of the Department will be long remembered.
The Jazan University started in January 2011, offering up to five graduate student fellowships each year to highly-qualified incoming students. This one-year $3000 fellowship occurs during their first year of graduate studies, and it enhances their normal graduate student stipend and provides extra recognition for these highly qualified students.
“Listen” to its Radio Waves
EM Wave Emitter
Lecture Demonstration Specialist email@example.com
Adam Beehler’s Demolicious Physics presents:
Handheld radios pick up radio waves - go figure. These electromagnetic waves are emitted by many different sources, other than just your favorite radio station. A cellphone should be an obvious choice as such a source. So tune your radio to some static noise, so that one radio station does not dominate the signal. Then simply walk around and hold the radio up to different sources to “hear” the waves they are emitting. You might be surprised which objects give off so many radio waves. To help hear a signal more clearly, you may need to slowly scan through the AM and FM ranges. You may also slowly re-orient the radio next to the object in question. Try your cellphone in its different modes - GPS, WiFi, Bluetooth. Some other suggested objects to “listen” to are transformers, spark plugs, and calculators while computing.
TRICKS YOU DID NOT KNOW YOU COULD DO WITH
Check your Batteries Your remote emits infrared light (IR)
I wanted to follow in the same vein as last that your eyes cannot detect, but digital cameras can see it quite edition’s, “5 Things You Did Not Know You easily. Justmost aim the camera at the top of the Could Do With Lasers” - simple, fun, and remote, and push a button on the remote while looking into the camera. If the batteries are practical for just about anyone. I have been dead you wouldn’t see any light emitted from using some of the following tricks for years the remote control. and people seem to be amazed when I use them. I think it is time everyone knows and uses some of these tricks, as they are both neat and very useful in certain situations. For materials, I just used a regular cell phone with a camera capability. 26
Polarizer Detector A Source of Polarized Light
NU Detect Health Problems
Holding about any cheap lens in front of the camera will get one closer (and thus more magnified) images. I even tried a water drop on the camera’s lens and it worked (although I cannot attest to your camera’s waterproofness, so I do not suggest trying it). In the picture above, I used an old telescope eyepeice. However, you can use anything from a magnifying glass, the optical lens from an old CD player, or even the contact lens cases with the magnifying glass on the lid (this one is neat because it gives you a microscope and a fish-eye lens in one unit).
Ruler + Scale
Have you ever been in a situation where you needed to do a quick measurement or quickly judge the weight of something small? One trick is to use your cellphone as a point of reference. This makes sense, as many people keep their cell phones with them all the time, and it is very handy to use when you are in a spot. I weighed my phone on a postage scale and used a ruler to figure out the size. Then, I just rounded those results to the nearest easily-remembered number. My cell phone weighs about a quarter of a pound (4 ounces or 120 grams). I also know that my cell phone is roughly 5 inches tall, 2.5 inches wide, and nearly a half an inch thick. With these measurements in mind, I can more accurately judge the size or weight of something without having to cart around a ruler and scale.
Point of Reference
Most cellphone screens utilize polarizers to allow users to see what the cellphone wants them to see and not extraneous glare and reflections. What this means is that the light emitted from your cellphone is polarized light. Ergo, you have your own polarization detector, too. This emitted polarized light can become unpolarized though as it passes through a screen protector, so to see this effect, you may need to lift your screen protector. You can now verify whether or not those sunglasses are really polarizers or not, by looking through one lens of the glasses at your cellphone screen. Simply rotate the lens (or phone) and see if light becomes blocked. Since most glare is horizontally polarized, polarized sunglasses have their polarization axis vertical. Knowing this, you can determine the polarization axis of your cellphone screen, which could then help you determine the polarization axis of another polarizer later. You can also now insert different transparent objects in between your cell phone screen and your polarized sunglasses and see if the object affects its transmitted polarized light or not. Here is a picture of the stresses seen in a pair of normal eyeglasses.
Okay, I realize this one is not quite available to everyone yet. I threw this one in here because it was really neat and it will not be long before everyone will be able to spot health problems using their cell phones. Most people are already aware of the “Red Eye Effect” where pupils appear red in photographs of eyes. This is caused by light reflecting off the eye’s retina, making the eyes appear red. However, sometimes only one eye appears red, and the other eye appears white (see above image). This is often an indicator for many dangerous health problems including melanoma and retinoblastoma - very dangerous cancers. There has been research into other devices that connect to your cell phone that can also detect cancers, malaria, and diabetes from your breath; test water quality for pathogens; andmonitor lung function in patients. The aim of these devices is to be low-cost, easy to use, and to save lives by detecting serious health problems earlier and getting treatment sooner - to which I think we can all agree is incredibly innovative.
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