UCLA astronomer Andrea Ghez named MacArthur Fellow
Andrea Ghez, a UCLA professor of physics and astronomy, has been selected as a 2008 MacArthur Fellow, the John D. and Catherine T. MacArthur Foundation announced today. Ghez is among 25 new recipients of the annual "genius" fellowship, each of whom will receive $500,000 in unrestricted support over the next five years to use as they see fit.
Ghez uses novel, ground-based telescopic techniques to identify thousands of new star systems and illuminate the role of supermassive black holes in the evolution of galaxies.
"I am really thrilled," Ghez said. "I will be able to take more risks with my research than I could before. The current shortage of federal funding for science can lead scientists to take fewer risks, but my selection as a MacArthur Fellow will allow me to pursue new ideas; it says to me that I should be brave and take risks."
The mother of two sons — Evan, 7, and Miles, who will turn 3 in October — says the MacArthur funding is "particularly exciting" for women in science.
"The MacArthur Foundation funding will allow me to be much more effective and flexible and will definitely help with the balancing act," she said. "I'm frequently away from home and from my children, conducting research. Now I will be able to bring them with me more often."
"For 26 years, the MacArthur Fellows Program has recognized and supported individuals who inspire us," said MacArthur Foundation President Jonathan Fanton. "This new group of MacArthur Fellows illustrates our conviction that talented and creative individuals, free to follow their insights and instincts, will reveal new discoveries and make a difference in shaping our future."
Ghez said she views it as a challenge to live up to the confidence the foundation has placed in her. If her previous success is any guide, she should have little difficulty.
In 1998, Ghez answered one of astronomy's most important questions, showing that a monstrous black hole resides at the center of our Milky Way galaxy, some 26,000 light-years away, with a mass more than 3 million times that of the sun. The question had been a subject of raging debate among astronomers for more than a quarter of a century.
"Our galaxy is rather mild mannered and quiet and was one of the least likely galaxies to have a black hole at its center," Ghez said at the time.
The Milky Way is one of approximately 100 billion galaxies, each containing at least 100 billion stars.
One reason astronomers had been unable to determine whether a black hole was at the Milky Way's galactic center is that the Earth's atmosphere distorts the images of stars. Ghez uses a technique she refined known as speckle interferometry, which involves taking thousands of very quick, high-resolution snapshots that correct for these distortions. She has developed algorithms — specific computer commands based on sophisticated mathematics — and software for analyzing the data.
While traditional imaging techniques at the center of the galaxy cause the stars closest to the galactic center to look fuzzy and indecipherable, Ghez's technique improves the resolution by a factor of at least 20.
"The atmosphere blurs your vision," Ghez said, "but speckle interferometry clears the picture up; it's like putting on glasses. Think of seeing a coin that looks distorted at the bottom of a pond. We take thousands of freeze-frames and then can determine what is distorted and what is really at the bottom of the pond."
In 2000, Ghez and colleagues reported that for the first time astronomers had seen stars accelerate around a supermassive black hole. Their research demonstrated that three stars had accelerated by more than 250,000 miles per hour a year as they orbited the black hole at the center of the Milky Way. They also reported, based on five years of measurements, that the star closest to the black hole had turned a corner in its orbit.
"We are actually seeing stars begin to curve in their orbits," Ghez said at the time. "One of these stars may complete its orbit around the supermassive black hole in as little as 15 years."
In 2003, Ghez reported that the case for the Milky Way's black hole had been strengthened substantially and that all of the proposed alternatives could be excluded.
"The case for the supermassive black hole was strong before, and we have substantially improved it," she said. "Now it's a 99.99 percent certainty. We can rule out every alternative that has been proposed."
One surprising result of Ghez's research is the finding that the stars closest to the black hole appear to be very young — less than 10 million years old. In contrast, our galaxy is more than 10 billion years old.
"One possible explanation may be that the stars are not really that young and that their proximity to the black hole has altered their appearance," she said. "That is, they may be old stars masquerading as young stars, stars that have experienced astronomical Botox.
"However, it is difficult to invoke any mechanism where the black hole could have that much influence on the surrounding stars. The alternative is that the stars really are young, but how you get stars to form that close to the black hole is very difficult. One idea is that they formed farther out and migrated inwards by interactions with other stars, that their orbits were altered. Because they are so young, however, they didn't have much time for that to happen."
In 2005, Ghez and her colleagues took the first clear picture of the center of the Milky Way, including the area surrounding the black hole, using laser virtual star technology at the W.M. Keck Observatory in Hawaii.
"Everything is much clearer now," Ghez said at the time. "We used a laser to improve the telescope's vision — a spectacular breakthrough that will help us understand the black hole's environment and physics. It's like getting Lasik surgery for the eyes and will revolutionize what we can do in astronomy."
Astronomers are used to working with images blurred by the Earth's atmosphere, but the laser virtual star, launched from the Keck telescope, corrects the atmosphere's distortions and clears up the picture. The technology, known as Laser Guide Star adaptive optics, will lead to important advances in the study of planets both inside and outside our solar system, as well as of galaxies, black holes, and how the universe formed and evolved, Ghez said.
"We have worked for years on techniques for beating the distortions in the atmosphere and producing high-resolution images," she said of the research. "We are pleased to report the first Laser Guide Star adaptive optics observations of the center of our galaxy."
The research was conducted using the Keck II Telescope, the world's first 10-meter telescope to be equipped with a laser. Laser Guide Star allows astronomers to "generate an artificial bright star" exactly where they want it, which reveals the atmosphere's distortions.
In 2006, Ghez and UCLA astronomy graduate student Jessica Lu reported that they could determine, for the first time, the orbits of massive young stars located a few light-months from the Milky Way's enormous black hole — stars that hold an imprint of how they were born. The origin of young stars at the center of our galaxy has puzzled astronomers, but the orbits may be the key to unlocking the mystery. The astronomers again used laser virtual star technology at the Keck Observatory in their research.
Since 1995, Ghez has been using the Keck Observatory, which sits atop Hawaii's dormant Mauna Kea volcano, to study the rotational center of the Milky Way and the movement of 200 stars close to this galactic center.
"The Keck Observatory is the best facility in the world for this research and enables us to track stars very precisely," she said.
Black holes are collapsed stars so dense that nothing can escape their gravitational pull, not even light. They cannot be seen directly, but their influence on nearby stars is visible and provides a signature, Ghez said.
The supermassive black hole at the center of the Milky Way is in the constellation Sagittarius. The galactic center is located due south in the summer sky.
The black hole came into existence billions of years ago, perhaps as very massive stars collapsed at the end of their life cycles and coalesced into a single, supermassive object, Ghez said.
Ghez's research is supported by the National Science Foundation and the Packard Foundation.
Nominations for MacArthur Fellowships are accepted only from invited nominators, who identify people who demonstrate "exceptional creativity and promise."
Among the other new MacArthur Fellows are a neurobiologist, a saxophonist, a critical-care physician, an urban farmer, an optical physicist, a sculptor, a geriatrician, a historian of medicine and an inventor of musical instruments. All were selected for their creativity, originality and potential to make important contributions in the future.
"The MacArthur Fellows Program celebrates extraordinarily creative individuals who inspire new heights in human achievement," Fanton said. "With their boldness, courage, and uncommon energy, this new group of Fellows, men and women of all ages in diverse fields, exemplifies the boundless nature of the human mind and spirit."
Including this year's winners, 781 people, ranging in age from 18 to 82 at the time of their selection, have been named MacArthur Fellows since the program's inception in 1981.
Previous UCLA MacArthur Fellows include mathematician Terence Tao (2006), who holds UCLA's James and Carol Collins Chair in the College of Letters and Science; Saul Friedlander (1999), who holds UCLA's 1939 Club Chair in History; Elinor Ochs (1998), professor of anthropology and applied linguistics; Susan McClary (1995), professor of musicology; Rogers Brubaker (1994), professor of sociology; Richard Turco (1986), professor of atmospheric and oceanic sciences and a member of UCLA's Institute of the Environment; Jared Diamond (1985), professor of geography and environmental health sciences; and Peter Sellars (1983), professor of world arts and cultures.
For more information, see the MacArthur Foundation's web site at www.macfound.org.
For more about Ghez's research, visit www.astro.ucla.edu/~ghez/.
UCLA is California's largest university, with an enrollment of nearly 37,000 undergraduate and graduate students. The UCLA College of Letters and Science and the university's 11 professional schools feature renowned faculty and offer more than 300 degree programs and majors. UCLA is a national and international leader in the breadth and quality of its academic, research, health care, cultural, continuing education and athletic programs. Four alumni and five faculty have been awarded the Nobel Prize.