About Caltech Astronomy

Astronomer Royal of the United Kingdom, Martin Rees, summed up Caltech's legacy in astronomy when he said, "The universe of astronomy has no center, but the universe of astronomers does. For years that center has been in Pasadena, California."

As part of Caltech's Division of Physics, Mathematics and Astronomy, the astronomy department's primary mission is to perform cutting-edge research in astronomy and astrophysics while educating undergraduate and graduate students to become the scientific leaders of tomorrow.

Astronomy has been a major component of Caltech's scientific identity since the early days of the Institute. George Ellery Hale, the first director of the Mount Wilson Observatory, was elected to the board of trustees of Throop Polytechnic Institute (later to be renamed the California Institute of Technology) in 1907. Hale is largely responsible for shifting the institution's focus to engineering and science, fields in which Caltech would quickly become a world leader.

Among Caltech's major contributions to the field of astronomy is the first survey of the entire sky visible from the Northern Hemisphere, the Palomar Observatory Sky Survey. Conducted in l948, it revealed thousands of new stars, galaxies, and comets. This provided astronomers the world over with an atlas of the heavens to be used for the next three decades. Today, Palomar Mountain in San Diego County is home to the 200-inch Hale Telescope, which was for four decades the largest and most powerful optical telescope in the Western Hemisphere.

In 1964, Caltech astronomer Maarten Schmidt determined that quasars--a puzzling class of cosmic objects--were the most powerful and distant objects in the universe. Since quasar light travels for billions of years to reach Earth, Schmidt's discovery gave astronomers unprecedented insight into how the universe looked billions of years before the birth of the sun and its planets.

Today, the Caltech astronomy department--led by more than 30 faculty--continues to engage in a wide variety of astronomical research projects, with topics ranging from nearby stars to the most distant galaxies in the universe. To help maintain these research efforts, the department supports an interest in worldwide astronomical observatories at locations ranging from San Diego County to Hawaii to the Chilean Andes, including

The Palomar Observatory, located in San Diego County, was dedicated in 1948 and is home to the 200-inch Hale Telescope, as well as a 60-inch instrument, the 48-inch Samuel Oschin Telescope, and an 18-inch Schmidt Telescope.

The Laser Interferometer Gravitational-Wave Observatory, or LIGO, is dedicated to the detection of cosmic gravitational waves and the harnessing of these waves for scientific research. Albert Einstein predicted the existence of these waves in 1916, and LIGO--which was designed by Caltech and MIT physicists--began its search in 2001. LIGO consists of two widely separated installations within the United States--one in Hanford, Washington, and the other in Livingston, Louisiana--which are operated in unison as a single observatory.

The Keck Observatory is perched atop the dormant volcano Mauna Kea on the island of Hawaii. Keck is a joint effort of Caltech and the University of California, and consists of twin 10-meter telescopes, Keck I and Keck II. Recently, the two telescopes have been used in combination as the Keck Interferometer, with sufficient power and resolution to detect planetary systems around nearby stars.

The Caltech Submillimeter Observatory is a 10-meter dish atop Mauna Kea in Hawaii.

The Owens Valley Radio Observatory is located some five hours north of Pasadena, near the Sierra Nevada range. The observatory is home to a variety of dishes and interferometers, and is the operations base for the CARMA millimeter-wave interferometer (see below).

The Combined Array for Research in Millimeter-wave Astronomy, or CARMA, is the merger of two university-based millimeter arrays--the Owens Valley Radio Observatory (OVRO) millimeter array and the Berkeley-Illinois-Maryland Association (BIMA) millimeter array--which together form a powerful astronomical tool for the new millennium.

The Chajnantor Observatory is located at an altitude of over 16,000 feet in the Chilean Andes. It is the site of the Cosmic Background Imager (CBI) and will be the site of the Q/U Imaging Experiment (QUIET) project. The site is accessible year-round and provides superb conditions for cosmic microwave background observations.

The Thirty Meter Telescope is a collaboration between Caltech, the University of California, and the Association of Canadian Universities for Research in Astronomy (ACURA) to build a 30-meter-diameter telescope for astronomy at visible and infrared wavelengths.

The Big Bear Solar Observatory is a world center for observations of the sun. The facility is managed by the New Jersey Institute of Technology for a university consortium that includes Caltech.

Visit http://www.astro.caltech.edu to learn more about Caltech Astronomy.

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Caltech Researchers Interpret Asymmetry in Early Universe

PASADENA, Calif.--The Big Bang is widely considered to have obliterated any trace of what came before. Now, astrophysicists at the California Institute of Technology (Caltech) think that their new theoretical interpretation of an imprint from the earliest stages of the universe may also shed light on what came before.

"It's no longer completely crazy to ask what happened before the Big Bang," comments Marc Kamionkowski, Caltech's Robinson Professor of Theoretical Physics and Astrophysics. Kamionkowski joined graduate student Adrienne Erickcek and senior research associate in physics Sean Carroll to propose a mathematical model explaining an anomaly in what is supposed to be a universe of uniformly distributed radiation and matter.

Their investigations turn on a phenomenon called inflation, first proposed in 1980, which posits that space expanded exponentially in the instant following the Big Bang. "Inflation starts the universe with a blank slate," Erickcek describes. The hiccup in inflation, however, is that the universe is not as uniform as the simplest form of the theory predicts it to be. Some parts of it are more intensely varied than others.

Until recently, measurements of the Cosmic Microwave Background (CMB) radiation, a form of electromagnetic radiation that permeated the universe 400,000 years after the Big Bang, were consistent with inflation--miniscule fluctuations in the CMB seemed to be the same everywhere. But a few years ago, some researchers, including a group led by Krzysztof Gorski of NASA's Jet Propulsion Laboratory, which is managed by Caltech, scrutinized data from NASA's Wilkinson Microwave Anisotropy Probe (WMAP). They discovered that the amplitude of fluctuations in the CMB is not the same in all directions.

"If your eyes measured radio frequency, you'd see the entire sky glowing. This is what WMAP sees," Kamionkowksi describes. WMAP depicts the CMB as an afterglow of light from shortly after the Big Bang that has decayed to microwave radiation as the universe expanded over the past 13.7 billion years. The probe also reveals more pronounced mottling--deviations from the average value--in the CMB in one half of the sky than the other.

"It's a certified anomaly," Kamionkowski remarks. "But since inflation seems to do so well with everything else, it seems premature to discard the theory." Instead, the team worked with the theory in their math addressing the asymmetry.

They started by testing whether the value of a single energy field thought to have driven inflation, called the inflaton, was different on one side of the universe than the other. It didn't work--they found that if they changed the mean value of the inflaton, then the mean temperature and amplitude of energy variations in space also changed. So they explored a second energy field, called the curvaton, which had been previously proposed to give rise to the fluctuations observed in the CMB. They introduced a perturbation to the curvaton field that turns out to affect only how temperature varies from point to point through space, while preserving its average value.

The new model predicts more cold than hot spots in the CMB, Kamionkowski says. Erickcek adds that this prediction will be tested by the Planck satellite, an international mission led by the European Space Agency with significant contributions from NASA, scheduled to launch in April 2009.

For Erickcek, the team's findings hold the key to understanding more about inflation. "Inflation is a description of how the universe expanded," she adds. "Its predictions have been verified, but what drove it and how long did it last? This is a way to look at what happened during inflation, which has a lot of blanks waiting to be filled in."

But the perturbation that the researchers introduced may also offer the first glimpse at what came before the Big Bang, because it could be an imprint inherited from the time before inflation. "All of that stuff is hidden by a veil, observationally," Kamionkowski says. "If our model holds up, we may have a chance to see beyond this veil."

The study appears December 16 in the journal Physical Review D. It was supported by the Department of Energy and by Caltech's Moore Center for Theoretical Cosmology and Physics.

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Caltech's David Baltimore and Fiona Harrison Named among America's Best Leaders for 2008

U.S. News Media Group and Harvard's Center for Public Leadership recognize 24 of the country's foremost professionals

PASADENA, Calif.--Two prominent researchers from the California Institute of Technology (Caltech) have been named among the country's 24 top leaders by U.S. News Media Group in association with the Center for Public Leadership (CPL) at Harvard Kennedy School. The 2008 edition of America's Best Leaders--available online at www.usnews.com/leaders and on newsstands Monday, November 24--includes honors for Caltech's David Baltimore and Fiona Harrison.

According to U.S. News, the Best Leaders issue features "some of the country's most visionary individuals," highlighting those professionals "who continue to offer optimism and hope through their work."

Nobel Laureate David Baltimore, the Robert Andrews Millikan Professor of Biology and former president of Caltech, was lauded by the magazine for the way he has "profoundly influenced national science policy on such issues as recombinant DNA research and the AIDS epidemic. He is an accomplished researcher, educator, administrator and public advocate for science and engineering, and is considered one of the world's most influential biologists."

Baltimore was awarded the Nobel Prize in Physiology or Medicine in 1975, at the age of 37. He served as president of Caltech for nine years and was named president emeritus in 2006. He had previously spent almost 30 years on the faculty of the Massachusetts Institute of Technology, where he contributed widely to the understanding of cancer, AIDS, and the molecular basis of the immune response, and where he served as founding director of the Whitehead Institute for Biomedical Research from 1982 until 1990. He served as president of the American Association for the Advancement of Science from 2007 to 2008, and is currently its chair.

Baltimore says he is "very honored to be named among this exceptional group of leaders."

Leadership, he says, "involves a vision of the future, and a generosity of spirit that allows the leader to take pleasure in the accomplishments of others." Leadership can't be about micromanaging every aspect of a large organization, he notes. "It's about picking the right people, motivating them, and encouraging them. You have to make sure those people are pulling in the same direction. You have to catalyze interaction between people so that they see a commonality of interests--so that they follow a common line."

Fiona Harrison, a professor of physics and astronomy at Caltech, was chosen for her work as principal investigator of the NuSTAR (Nuclear Spectroscopic Telescope Array) Mission, a pathfinder mission that will "open the high energy X-ray sky for sensitive study for the first time," she says. She started developing the technologies necessary to realize NuSTAR more than a decade ago, and assembled and led a team of scientists and engineers to design and implement the mission. NuSTAR was selected by NASA through a competitive process and will launch in mid-2011.

Harrison "has devoted her career to studying energetic phenomena in the Universe, including massive black holes and stellar explosions, and developing advanced instrumentation for focusing and detection of X-rays and gamma-rays," notes U.S. News. She is a recipient of a NASA Graduate Student Research Fellowship and winner of the Robert A. Millikan Prize Fellowship in Experimental Physics, and was awarded a Presidential Early Career Award for Scientists and Engineers by President Clinton. She joined the faculty of Caltech in 1995.

"It is an honor to be recognized among such a diverse and distinguished group of people," says Harrison.

"Most aspiring scientists don't focus on leadership as a quality necessary to accomplish their research," she adds. "As experiments and projects get larger and more complex, however, good leadership is often necessary in order to make progress. For me, creating and motivating an effective team were skills I learned in order to make the science I am passionate about happen."

In a collaborative effort between U.S. News and Harvard's CPL, the leaders were selected by a nonpartisan and independent committee, convened and organized by the center, without the participation of U.S. News editors. The selection criteria used by the committee in choosing the honorees included the ability to set direction, achieve results, and cultivate a culture of growth.

"Even though Americans have lost confidence in current leadership, over the past year they have had unique opportunities to observe and debate the qualities of strong leaders," says Brian Kelly, editor of U.S. News & World Report. "With our Best Leaders issue, we widen the lens to examine people who are showing leadership in unexpected ways across a wide variety of fields."

Other honorees include Lance Armstrong, founder of the Lance Armstrong Foundation; Herbie Hancock, chairman of the Thelonious Monk Institute of Jazz Performance Arts; Marian Wright Edelman, founder and president of the Children's Defense Fund; Anthony Fauci, director of the National Institute for Allergy and Infectious Disease; Robert Gates, U.S. Secretary of Defense; and Steven Spielberg, director and producer, and founder of the Shoah Foundation.

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W.M. Keck Foundation Gift to Enable Caltech and JPL Scientists to Research the Universe's Violent Origin

PASADENA, Calif.--The W.M. Keck Foundation has awarded $2.3 million to the California Institute of Technology (Caltech) to fund the Keck Array--a suite of three microwave polarimeters at the South Pole--and the corresponding research initiative, "Imaging the Beginning of Time: A Search for the Signature of Inflation in the Cosmic Microwave Background."

Andrew Lange, Marvin L. Goldberger Professor of Physics, chair of Caltech's Division of Physics, Mathematics and Astronomy, and senior research scientist at the Jet Propulsion Laboratory (JPL), will lead the project. Lange believes that the Keck Foundation's gift could lead to breakthroughs for both cosmology and high-energy physics. "We may be able to probe the very moment at which the universe sprang into existence and explore energies far higher than will ever be achieved in terrestrial accelerators," says Lange.

The polarimeters will analyze radiation that is a relic of the primeval fireball that filled the early universe. Now cooled from visible light to faint microwaves, this primordial radiation still fills the universe as the cosmic microwave background (CMB), first detected in 1965. The CMB bears rich information about the embryonic universe, information that Lange's research teams have successfully explored for 20 years. With the Keck Array, they're closing in on one of cosmology's most daunting problems.

Based largely on observations of the CMB, cosmologists now believe that the entire universe sprang from a subnuclear volume in a violent expansion known as inflation. Einstein's general theory of relativity predicts that such a violent space-time disturbance would have generated strong gravitational waves that would persist to this day as a cosmic gravitational-wave background (CGB)--a gravitational analog to the CMB. Though no instrument has detected unambiguous evidence of gravitational waves, their existence has been proved by inference. The Keck Array, far more sensitive than its predecessors, may be able to detect the faint signature of the CGB imprinted on the polarization of the CMB. (The Laser Interferometer Gravitational-Wave Observatory (LIGO), an NSF-funded collaboration between Caltech and MIT, uses different instrumentation in an effort to directly detect much higher frequency gravitational waves from comparatively nearby sources.)

Caltech and JPL scientists successfully tested the methodology with BICEP, a prototype polarimeter in operation at the South Pole since January 2006, while they developed detectors that will be able to map the sky 10 times faster and with more frequency coverage than the prototype. The Keck Foundation's gift makes it possible for Lange's team to upgrade to a full-scale instrument. All three polarimeters will be in operation by 2011.

"Caltech and the W.M. Keck Foundation share a focus on bold research that can transform our understanding of the world," says Caltech president Jean-Lou Chameau. "The foundation's support for research at Caltech has already made a tremendous difference to science. This new gift will allow Caltech researchers--who lead the world in CMB-related observation, theory, and technology--to make observations with a precision that seemed impossibly out of reach just a few years ago. This single, generous gift could have profound impacts on cosmology and high-energy physics."

Lange's team at Caltech includes cosmologists Marc Kamionkowski, Robinson Professor of Theoretical Physics and Astrophysics, who pioneered the theory behind the measurement, Christopher Hirata, a Sloan Research Fellow and assistant professor of astrophysics, and Sunil Golwala, assistant professor of physics, who contributed to the project proposal. Golwala shares major responsibility for the development of the state-of-the-art instrumentation. Jamie Bock leads the project at JPL.

Astrophysicists and engineers from institutions in the U.S., Canada, and the U.K.--including Case Western Reserve, the University of Chicago, Stanford, the National Institute of Standards and Technology (NIST), the University of Toronto, and Cardiff University--will collaborate with Caltech and JPL on this project.

Additional funding comes from the Gordon and Betty Moore Foundation, the National Science Foundation, the James and Nelly Kilroy Foundation, and the Balzan Foundation (research support linked to the prestigious Balzan Prize, awarded to Lange for his contributions to cosmology). All of the Keck funds will be used at Caltech.

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About Caltech: Caltech is recognized for its highly select student body of 900 undergraduates and 1,200 graduate students, and for its outstanding faculty, which currently includes several Nobel laureates and numerous members of the National Academy of Engineering and the National Academy of Sciences. In addition to its prestigious on-campus research programs, Caltech operates the W. M. Keck Observatory in Mauna Kea, the Palomar Observatory, and JPL. Caltech is a private university in Pasadena, California. For more information, visit http://www.caltech.edu.

About the W.M. Keck Foundation: One of the nation's largest philanthropic organizations, the W.M. Keck Foundation was established in 1954 in Los Angeles by William Myron Keck. The foundation funds the work of leading researchers, the establishment of unique laboratories and research centers, and the purchase of sophisticated instruments, laying the groundwork for discoveries and new technologies that save lives, solve complex problems, and add immeasurably to human understanding of life and our place in the universe.

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"Einstein's Cosmic Messengers" Multimedia Concert Inspired by Quest for Gravitational Waves

PASADENA, Calif.--Join two world-renowned California Institute of Technology (Caltech) physicists and an award-winning composer for the world premiere of "Einstein's Cosmic Messengers," an inventive multimedia concert. Inspired by Caltech's involvement with the Laser Interferometer Gravitational-wave Observatory (LIGO), the presentation takes an innovative approach to communicating scientific exploration and discovery to the general public. The event takes place Thursday, October 30, at 8 p.m., in Beckman Auditorium on the Caltech campus.

This unique event will feature noted physicist Kip Thorne, Feynman Professor of Theoretical Physics and LIGO cofounder; Jay Marx, LIGO executive director and senior research associate in physics; and Andrea Centazzo, award-winning composer, percussionist, and multimedia artist. The program is based on LIGO's quest for the detection of gravitational waves--ripples in the fabric of space and time produced by violent events in the distant universe. Albert Einstein predicted the existence of these waves in 1916. LIGO, which was designed by Caltech and MIT physicists, began its search in 2001 with funding from the National Science Foundation.

Thorne will open the program by explaining how gravitational waves can reveal the fundamental nature of gravity and open a new window onto the "warped" side of the universe, shining light on previously inaccessible events such as violent coalescences of black holes and neutron stars. Marx will follow with a discussion on the history, achievements, and promise of LIGO's search for gravitational waves. Centazzo will then perform his world premiere of "Einstein's Cosmic Messengers," the multimedia concert he created with Jet Propulsion Laboratory scientist Michele Vallisneri. The presentation blends music and sounds played live with images and animations inspired by LIGO's facilities, the universe, and Einstein's genius and obsessions, creating a one-of-a-kind live performance.

Vallisneri initially conceived the concert and Centazzo made it a reality. "'Einstein's Cosmic Messengers' is the result of exposing professional composer and video artist Andrea Centazzo to my narrative of the birth of astronomy and the great revolutions in our understanding of the cosmos," says Vallisneri. "The performance includes evocative images, projected on a cinema screen, complemented by synchronized music played live on a vast array of percussive instruments, both acoustic and digital.

"I hope the concert can expose the public, whether artistically or scientifically inclined, to the quest to measure gravitational waves, an extremely engaging intellectual and technological adventure that I work on every day. I love to see human creativity transcend the boundaries between science and the arts and humanities. This will be a breathtaking journey through magnificent visions of the universe."

Visit http://events.caltech.edu/events/event-5781.html, www.ligo.caltech.edu, and www.andreacentazzo.com/ecm for more information, including images and a sample video at Centazzo's site. Admission and parking are free. No tickets or reservations are required.

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Martin Voss
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Keck Telescope and "Cosmic Lens" Resolve Nature and Fate of Early Star-Forming Galaxy

The combination demonstrates the eventual power of the Thirty Meter Telescope

PASADENA, Calif.--Astronomers at the California Institute of Technology (Caltech) and their colleagues have provided unique insight into the nature of a young star-forming galaxy as it appeared only two billion years after the Big Bang and determined how the galaxy may eventually evolve to become a system like our own Milky Way.

The team made their observations by coupling two techniques, gravitational lensing--which makes use of an effect first predicted by Albert Einstein in which the gravitational field of massive objects, such as foreground galaxies, bends light rays from objects located a distance behind, thus magnifying the appearance of distant sources--and laser-assisted guide star (LGS) adaptive optics (AO) on the 10-meter Keck Telescope in Hawaii. Adaptive optics corrects the blurring effects of Earth's atmosphere by real-time monitoring of the signal from a natural guide star or an artificial guide star. Gravitational lensing enlarged the distant galaxy in angular size by a factor of about 8 in each direction. Together with the enhanced resolution using adaptive optics, this allowed the team to determine the internal velocity structure of the remote galaxy, located 11 billion light-years from Earth, and hence its likely future evolution.

The researchers found that the distant galaxy, which is typical in many respects to others at that epoch, shows clear signs of orderly rotation. The finding, in association with observations conducted at millimeter wavelengths, which are sensitive to cold molecular gas (an indicator of galactic rotation), suggests that the source is in the early stages of assembling a spiral disk with a central nucleus similar to those seen in spiral galaxies at the present day.

Using the Hubble Space Telescope, the team located a distinctive galaxy dubbed the "Cosmic Eye" because its form is distorted into a ring-shaped structure by the gravitational field of a foreground galaxy.

"Gravity has effectively provided us with an additional zoom lens, enabling us to study this distant galaxy on scales approaching only a few hundred light-years. This is 10 times finer sampling than hitherto possible," explains postdoctoral research scholar Dan Stark of Caltech, the leader of the study. "As a result, we can see, for the first time, that a typical-sized young galaxy is spinning and slowly evolving into a spiral galaxy much like our own Milky Way," he says.

The research, described in the October 9 issue of the journal Nature, provides a demonstration of the likely power of the future Thirty Meter Telescope (TMT), the first of a new generation of large telescopes designed to exploit AO.

When completed in the latter half of the next decade, TMT's large aperture and improved optics will produce images with an angular resolution three times better than the 10-meter Keck and 12 times better than the Hubble Space Telescope, at similar wavelengths. Because of the significant improvement in angular resolution provided by AO, the TMT will be able to study the internal properties of small distant galaxies, seen as they were when the universe was young.

Likewise, the Atacama Large Millimeter Array (ALMA), a large interferometer being completed in Chile, will provide a major step forward in mapping the extremely faint emission from cold hydrogen gas--the principal component of young, distant galaxies and a clear marker of cold molecular gas--compared to the coarser capabilities of present facilities. In their recent research, the Caltech-led team has provided a glimpse of what can be done with the superior performance expected of TMT and ALMA.

The key spectroscopic observations were made with the OSIRIS instrument, developed specifically for the Keck AO system by astrophysicist James Larkin and collaborators at the University of California, Los Angeles. Stark and his coworkers used the OSIRIS instrument to map the velocity across the source in fine detail, allowing them to demonstrate that it has a primitive rotating disk.

To aid in their analysis, the researchers combined data from the Keck Observatory with data taken at millimeter wavelengths by the Plateau de Bure Interferometer (PdBI), located in the French Alps. This PdBI instrument is sensitive to the distribution of cold gas that has yet to collapse to form stars. These observations give a hint of what will soon be routine with the ALMA interferometer.

"Remarkably, the cold gas traced by our millimeter observations shares the rotation shown by the young stars seen in the Keck observations. The distribution of gas seen with our amazing resolution indicates we are witnessing the gradual buildup of a spiral disk with a central nuclear component," explains coinvestigator Mark Swinbank of Durham University, who was involved in both the Keck and PdBI observations.

This work demonstrates how important angular resolution has become in ensuring progress in extragalactic astronomy. This will be the key gain of both the TMT and ALMA facilities.

"For decades, astronomers were content to build bigger telescopes, arguing that light-gathering power was the primary measure of a telescope's ability," explains Richard S. Ellis, Steele Family Professor of Astronomy at Caltech, a coauthor on the Nature study, and a member of the TMT board of directors. "However, adaptive optics and interferometry are now providing ground-based astronomers with the additional gain of angular resolution. The combination of a large aperture and exquisite resolution is very effective for studying the internal properties of distant and faint sources seen as they were when the universe was young. This is the exciting future we can expect with TMT and ALMA, and, thanks to the magnification of a gravitational lens, we have an early demonstration here in this study," he says.

Coauthors on the paper, "The formation and assembly of a typical star-forming galaxies at redshift z~3," are Simon Dye of Cardiff University in Cardiff, Wales; Ian R. Smail of Durham University in Durham, England; and Johan Richard of Caltech.

The W. M. Keck Observatory operates twin 10-meter telescopes located on the summit of Mauna Kea. The observatory, made possible by grants from the W. M. Keck Foundation totaling over $138 million, is managed as a nonprofit corporation whose board of directors includes representatives from Caltech and the University of California.

The Thirty Meter Telescope is currently in a detailed design and development phase and represents a collaboration between Caltech, the University of California, and the Association for Canadian Universities Research in Astronomy. It has received generous support from the Gordon and Betty Moore Foundation.

Further information on the Thirty Meter Telescope is available at http://www.tmt.org.

and: http://www.tmt.org/news/cosmic-lens.htm

Information on the Atacama Large Millimeter Array is available at http://www.alma.nrao.edu.

Further information on the Keck telescopes, their adaptive optics systems, and the OSIRIS instrument are available at: https://www.keckobservatory.org/.

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Kathy Svitil
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Caltech Scientist Proposes Explanation for Puzzling Property of Night-Shining Clouds at the Edge of Space

PASADENA, Calif.-- An explanation for a strange property of noctilucent clouds--thin, wispy clouds hovering at the edge of space at 85 km altitude--has been proposed by an experimental plasma physicist at the California Institute of Technology (Caltech), possibly laying to rest a decades-long mystery.

Noctilucent clouds, also known as night-shining clouds, were first described in 1885, two years after the massive eruption of Krakatoa, a volcanic island in Indonesia, sent up a plume of ash and debris up to 80 km into Earth's atmosphere. The eruption affected global climate and weather for years and may have produced the first noctilucent clouds.

The effects of Krakatoa eventually faded, but the unusual electric blue clouds remain, nestled into a thin layer of Earth's mesosphere, the upper atmosphere region where pressure is 10,000 times less than at sea level. The clouds, which are visible during the deep twilight, are most often observed during the summer months at latitudes from 50 to 70 degrees north and south--although in recent years they have been seen as far south as Utah and Colorado. Noctilucent clouds are a summertime phenomenon because, curiously, the atmosphere at 85 km altitude is coldest in summer, promoting the formation of the ice grains that make up the clouds.

"The incidence of noctilucent clouds seems to be increasing, perhaps because of global warming," says Paul M. Bellan, a professor of applied physics at Caltech.

Twenty-five years ago, researchers at Poker Flat, Alaska, discovered that the clouds were highly reflective to radar. This unusual property has long puzzled scientists. Bellan, reporting in the August issue of the Journal of Geophysical Research-Atmospheres, now has an explanation: the ice grains in noctilucent clouds are coated with a thin film of metal, made of sodium and iron. The metal film causes radar waves to reflect off ripples in the cloud in a manner analogous to how X-rays reflect from a crystal lattice.

Sodium and iron atoms collect in the upper atmosphere after being blasted off incoming micrometeors. These metal atoms settle into a thin layer of vapor that sits just above the altitude at which noctilucent clouds occur. Astronomers recently have been using the sodium layer to create laser-illuminated artificial guide stars for adaptive optics telescopes that remove the distorting affects of atmospheric turbulence to produce clearer celestial images.

Measurements of the density of sodium and iron atomic vapor layers show that the metal vapor is depleted by over 80 percent when noctilucent clouds are present. "Noctilucent clouds have been shown to act very much like a flycatcher for sodium and iron atoms," Bellan says. Indeed, in laboratory experiments, other researchers have found that at the frigid temperatures (-123 degrees Celsius) within noctilucent clouds, atoms in sodium vapor quickly become deposited on the surface of ice to form a metallic film.

"If you have metal-coated ice grains in noctilucent clouds, the radar reflectivity can become enormous" he says. "This reflectivity is not the sum of reflections from individual ice grains, which would not produce a very large reflection. Instead, what happens is that ripples in the cloud of metal-coated ice grains reflect in unison and reinforce each other, somewhat like an army marching in step across a bridge causes the bridge to vibrate."

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MacArthur Foundation Names Alexei Kitaev Latest Caltech "Genius"

Notes that his work brings us "closer to the realization of the full potential of quantum computing"

PASADENA, Calif.-- Alexei Kitaev, a California Institute of Technology (Caltech) faculty member, has been named a MacArthur Fellow, winning one of the five-year, $500,000 grants that are awarded annually to creative, original individuals and that are often referred to as the "genius" awards. 

With a joint appointment at Caltech as professor of theoretical physics and computer science in the Divisions of Physics, Mathematics and Astronomy and of Engineering and Applied Science, Kitaev explores the mysterious behavior of quantum systems and their implications for developing practical applications, such as quantum computers. He has made important theoretical contributions to a wide array of topics within condensed-matter physics, including quasicrystals and quantum chaos.

More recently, Kitaev has devoted considerable attention to the use of quantum physics for performing computation. Upon learning of the first algorithm for factoring numbers (an important aspect of cryptography) with quantum computers, he independently developed an alternative approach using "phase estimation," a solution that generalizes to an even wider range of calculations.

Though his work is focused mainly at the conceptual level, he also participates in "hands-on" efforts to develop working quantum computers.

Kitaev says he was "very surprised" when he received the call from Daniel Socolow, director of the MacArthur Fellows Program, telling him of his selection for the award. "I didn't know what the award was at first," admits Kitaev, who was born and educated in Russia. "But then I looked up the names of people who have previously received a MacArthur award, and saw that they are very good scientists. I am excited and honored to be in the same group with them."

"We are thrilled that Alexei has received this well-deserved honor," says Andrew Lange, the Marvin L. Goldberger Professor of Physics and chair of the Division of Physics, Mathematics and Astronomy at Caltech. "He is a stunningly original thinker who has made profound theoretical contributions to both quantum computing and condensed-matter physics. Alexei forged a deep connection between these two disparate subjects by proposing the 'topological quantum computer,' an idea now being aggressively pursued in laboratories around the world. Fostering such interdisciplinary insights is a central part of Caltech's mission, and we are proud to have Alexei on our faculty."

Kitaev received a diploma from the Moscow Institute of Physics and Technology in 1986, and his PhD from Russia's Landau Institute for Theoretical Physics in 1989. He served as a researcher at Microsoft Research from 1999 until 2001. He first came to Caltech as a visiting associate and a lecturer in 1998, and he was named professor of theoretical physics and computer science in 2002.

The MacArthur awards traditionally come out of the blue--most awardees have no idea that they are even being considered--and with no strings attached. MacArthur Fellows are not required to account for the ways in which they spend the money. Still, Kitaev says he feels it is important for him to use the award to do work that is "innovative and creative," and expects to take some time to figure out just what will fit the bill.

"The MacArthur Fellows Program celebrates extraordinarily creative individuals who inspire new heights in human achievement," says MacArthur president Jonathan Fanton. "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."

Kitaev is one of 25 newly named 2008 Fellows--a list which includes UCLA astronomer Andrea Ghez, who received her MS in 1989 and her PhD in 1993 from Caltech, and Harvard Medical School neurobiologist Rachel Wilson, who was a postdoctoral fellow at Caltech from 2001 to 2004. Kitaev also joins the ranks of previous Caltech MacArthur Fellows, including its two 2007 awardees, Michael Elowitz and Paul W. Rothemund.

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Caltech Astronomers Describe the Bar Scene at the Beginning of the Universe

PASADENA, Calif.--Bars abound in spiral galaxies today, but this was not always the case. A group of 16 astronomers, led by Kartik Sheth of NASA's Spitzer Science Center at the California Institute of Technology, has found that bars tripled in number over the past seven billion years, indicating that spiral galaxies evolve in shape.

The thought of spiral galaxies invokes images of star-studded arms trailing off of spinning disks. But more than two-thirds of spiral galaxies, including our own Milky Way, have a bar-shaped path through their middles. Barred galaxies are shaped more like a tiger's eye, with two starry arms trailing off either end of a long, dark stardust lane. They take shape as stellar orbits in a disk become unstable and deviate from a circular path.

"The formation of a bar may be the final important act in the evolution of a spiral galaxy," says Sheth, a Spitzer staff scientist and lead author on a study examining the evolution of barred galaxies. "Galaxies are thought to build themselves up through mergers with other galaxies. After settling down, the only other dramatic way for galaxies to evolve is through the action of bars."

According to new observations of over 2,000 spiral galaxies, made with NASA's Hubble Space Telescope, the bar scene was dramatically different seven billion years ago, when the universe was half as old as it is today. The study is part of the Cosmic Evolution Survey (COSMOS), Hubble's largest survey ever, in which Sheth and his team of 15 scientists is examining how galaxies form and evolve.

COSMOS covers an area of sky nine times larger than the full moon, surveying 10 times more spiral galaxies than previous studies, which Sheth says typically yielded ambiguous clues to barred galaxy evolution.

The astronomers discovered that while spiral galaxies were around in the distant past, only around 20 percent of them possessed the bars that are so common in their modern counterparts. The tripling rate does not proceed in an even-handed way, either. "They are forming mostly in the small, low-mass galaxies," says Sheth, adding that among the most massive galaxies, the proportion of bars to no bars is the same as it is today.

"We know that evolution is generally faster for more massive galaxies--they form their stars early and fast and then fade into red disks," Sheth explains. "Low-mass galaxies were also known to form more slowly, but now we see that they also made their bars slower."

Survey team member Bruce Elmegreen, an astrophysicist with IBM's Research Division, describes how a bar grows after stellar orbits in a spiral galaxy begin to deviate from a circular path. "It locks more and more of these elongated orbits into place, making the bar even stronger. Eventually a high fraction of the stars in the inner disk join the bar."

Bars are perhaps the most important catalysts for changing a galaxy, Sheth says. They force a large amount of gas towards the galactic center, fueling new star formation, building bulges--spheres in the centers of galaxies made only of stars--and feeding massive black holes.

Indeed, bars may even contribute to the growth of black holes, says Nicholas Scoville, Caltech's Moseley Professor of Astronomy and COSMOS principal investigator. "They pull stars and gas out of their normal circular orbits into the central regions, perhaps even funneling gas to the central supermassive black hole. Without this fueling, the black holes would be starved and the central regions of galaxies devoid of young stars."

"The new observations suggest that instabilities are faster in more massive galaxies, perhaps because their inner disks are denser and their gravity is stronger," adds team member Lia Athanassoula of the Laboratoire d'Astrophysique de Marseille.

The Milky Way, possibly the best-known barred galaxy, is a massive one whose bar probably formed somewhat early, like the bars in other massive galaxies, Sheth suggests. "Understanding how this occurred in the most distant galaxies will eventually shed light on how it occurred here, in our own backyard," he adds.

Analysis of the Hubble data was augmented by investigations of a sample of local spiral galaxies from the Sloan Digital Sky Survey. Other Caltech members of the bar study team are staff scientist Peter Capak; Steele Family Professor of Astronomy Richard Ellis; astronomy postdoc Mara Salvato; and undergraduate Lori Spalsbury. Other team members include Debra Elmegreen of Vassar College; Roberto Abraham of the University of Toronto; Bahram Mobasher of UC Riverside; Eva Schinnerer of the Max Planck Institut für Astronomie in Heidelberg; Michael Rich of UCLA; Marcella Carollo of Eidgenössische Technische Hochschule in Zurich; and Linda Strubbe and Andrew West of UC Berkeley.

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Rare 'Star-making Machine' Found in Distant Universe

Astronomers have uncovered an extreme stellar machine -- a galaxy in the very remote universe pumping out stars at a surprising rate of up to 4,000 per year. In comparison, our own Milky Way galaxy turns out an average of just 10 stars per year.

The discovery, made possible by several telescopes including NASA's Spitzer Space Telescope, goes against the most common theory of galaxy formation. According to the theory, called the Hierarchical Model, galaxies slowly bulk up their stars over time by absorbing tiny pieces of galaxies -- and not in one big burst as observed in the newfound "Baby Boom" galaxy.

"This galaxy is undergoing a major baby boom, producing most of its stars all at once," said Peter Capak of NASA's Spitzer Science Center at the California Institute of Technology, Pasadena. "If our human population was produced in a similar boom, then almost all of the people alive today would be the same age." Capak is lead author of a new report detailing the discovery in the July 10th issue of Astrophysical Journal Letters.

The Baby Boom galaxy, which belongs to a class of galaxies called starbursts, is the new record holder for the brightest starburst galaxy in the very distant universe, with brightness being a measure of its extreme star-formation rate. It was discovered and characterized using a suite of telescopes operating at different wavelengths. NASA's Hubble Space Telescope and Japan's Subaru Telescope, atop Mauna Kea in Hawaii, first spotted the galaxy in visible-light images, where it appeared as an inconspicuous smudge due to is great distance.

It wasn't until Spitzer and the James Clerk Maxwell Telescope, also on Mauna Kea in Hawaii, observed the galaxy at infrared and submillimeter wavelengths, respectively, that the galaxy stood out as the brightest of the bunch. This is because it has a huge number of youthful stars. When stars are born, they shine with a lot of ultraviolet light and produce a lot of dust. The dust absorbs the ultraviolet light but, like a car sitting in the sun, it warms up and re-emits light at infrared and submillimeter wavelengths, making the galaxy unusually bright to Spitzer and the James Clerk Maxwell Telescope.

To learn more about this galaxy's unique youthful glow, Capak and his team followed up with a number of telescopes. They used optical measurements from Keck to determine the exact distance to the galaxy -- a whopping12.3 billion light-years. That's looking back to a time when the universe was 1.3 billion years old (the universe is approximately 13.7 billion years old today).

"If the universe was a human reaching retirement age, it would have been about 6 years old at the time we are seeing this galaxy," said Capak.

The astronomers made measurements at radio wavelengths with the National Science Foundation's Very Large Array in New Mexico. Together with Spitzer and James Clerk Maxwell data, these observations allowed the astronomers to calculate a star-forming rate of about 1,000 to 4,000 stars per year. At that rate, the galaxy needs only 50 million years, not very long on cosmic timescales, to grow into a galaxy equivalent to the most massive ones we see today.

While galaxies in our nearby universe can produce stars at similarly high rates, the farthest one known before now was about 11.7 billion light-years away, or a time when the universe was 1.9 billion years old.

"Before now, we had only seen galaxies form stars like this in the teenaged universe, but this galaxy is forming when the universe was only a child," said Capak. "The question now is whether the majority of the very most massive galaxies form very early in the universe like the Baby Boom galaxy, or whether this is an exceptional case. Answering this question will help us determine to what degree the Hierarchical Model of galaxy formation still holds true."

"The incredible star-formation activity we have observed suggests that we may be witnessing, for the first time, the formation of one of the most massive elliptical galaxies in the universe," said co-author Nick Scoville of Caltech, the principal investigator of the Cosmic Evolution Survey, also known as Cosmos. The Cosmos program is an extensive survey of a large patch of distant galaxies across the full spectrum of light.

"The immediate identification of this galaxy with its extraordinary properties would not have been possible without the full range of observations in this survey," said Scoville.

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology, also in Pasadena. Caltech manages JPL for NASA. For more information about Spitzer, visit http://www.spitzer.caltech.edu/spitzer and http://www.nasa.gov/spitzer.

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