Caltech and Berkeley Astronomers Identify a New Class of Cosmic Explosions

PASADENA, Calif.--Astronomers are announcing today the discovery of a new class of stellar explosions. The finding is based on observations of a flash seen in the Virgo cluster in a galaxy known as Messier 85.

According to Shrinivas R. Kulkarni, the team leader announcing the discovery of M85OT2006-1, the event is thought to have resulted from the merger of two ordinary stars 49 million years ago.

"The discovery of this enigmatic event is merely the proverbial tip of the iceberg for an emerging class of cosmic transients," says Kulkarni, the MacArthur Professor of Astronomy and Planetary Science at the California Institute of Technology. The team, which consists of astronomers from Caltech and the University of California at Berkeley, is announcing its findings in the current issue of the journal Nature.

The puzzling explosion was discovered during the Lick Observatory Supernova Search with the Katzman Automatic Imaging Telescope, carried out by Alex Filippenko and Weidong Li of UC Berkeley. "Though the primary scientific goal of the program is discovering supernovae and it's quite successful at doing that, it is gratifying to find new classes of transient objects such as M85OT2006-1," said Li, who is in charge of the daily operation of the supernova search.

Kulkarni and his Caltech colleagues had been speculating on possible new classes of cosmic explosions. They mounted a major follow-up program with the Palomar 60-inch telescope, the famous Hale 200-inch telescope, and the Keck telescopes atop Mauna Kea, Hawaii. Later, other telescopes in Hawaii and Chile were pressed into service.

The explosion was surprising because it was far too faint for a supernova, in which a star literally explodes, but clearly too bright for a nova or a thermonuclear explosion from the surface of a white dwarf star. Arne Rau, a postdoctoral fellow working with Kulkarni, said, "I was simply floored. In a short time we went from speculation to a real discovery. It was an exciting moment for me."

It took astronomers nearly a century to identify two major classes of cosmic explosions: novae and supernovae. Forty years ago gamma-ray bursts were added to the astronomical lexicon. M85OT2006-1 solidifies and defines a new class of cosmic explosions that the Caltech astronomers have dubbed as Luminous Red Novae. These events have very distinct (red) color and expand quite slowly when compared with novae, supernovae, and gamma-ray bursts.

The galaxy in which M85OT2006-1 exploded is composed mainly of old stars, which also indicates that the event probably arose from a population of stars with masses very similar to that of the sun. More than a decade ago, one other similar but poorly studied event was observed in the Andromeda galaxy.

Kulkarni speculates that the red luminous novae result when two stars merge and undergo what is called "common envelope evolution." Kulkarni added, "The common envelope phase has been inferred on strong theoretical grounds, but is now caught in flagrante delicto."

In a related study, Rau undertook observations of M85OT2006-1 with NASA's Spitzer Space Telescope. The object is detectable in the mid infrared a year after the explosion, long after it became too faint in the visual, even for the Hubble Space Telescope. The Spitzer telescope is particularly well suited for the study of cold matter in space. Rau added, "Spitzer was vital in confirming that this object is a cosmic oddball. It is hard to imagine both a bright explosion which is also so cold."

There is little doubt that the discovery of this new class of cosmic explosions will make astronomers inspect ongoing searches carefully for similar events. Future imaging surveys will likewise be energized by this discovery. Kulkarni added, "It is a nice feeling when you know you have created a new cottage industry in your field."

Besides Kulkarni and Rau, the other authors of the paper are Eran O. Ofek, Stephen B. Cenko, Alicia M. Soderberg, Avishay Gal-Yam, Peter L. Capak, and Dae-Sik Moon, all of Caltech; Derek B. Fox of the Pennsylvania State University; Li and Filippenko of UC Berkeley; Eiichi Egami of the Steward Observatory; and Jeyhan Kartaltepe and David B. Sanders of the University of Hawaii.

 

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Astronomers Obtain Highly Detailed Image of the "Red Square" By Using Adaptive Optics of Palomar and Keck Telescopes

Note to Editors: This news release is being issued simultaneously by the University of Sydney. The image is available at http://www.physics.usyd.edu.au/~gekko/redsquare/rsq_red.tiff

PASADENA, Calif.—Astronomers today announced the arrival of a new member in the pantheon of exotically beautiful celestial objects. Christened the "Red Square" by Peter Tuthill, leader of the team, the image was compiled with data from the 200-inch Hale Telescope at Palomar Observatory, owned and operated by the California Institute of Technology, and the Keck-2 Telescope atop Mauna Kea, Hawaii.

The findings will appear April 13 in the journal Science in an article titled "A symmetric bipolar nebula around MWC 922," written by Tuthill from the University of Sydney and coauthor James Lloyd of Cornell University.

"Discoveries as beautiful—and interesting—as this one don't come around very often in astronomy," said Tuthill, "and it took some of the world's most advanced telescopes, together with a good dose of luck, to find this jewel hidden among the myriad stars in the galaxy."

"The key to finding it was in the revolutionary new imaging technology of adaptive optics, which acts like a myopia cure for a telescope," agreed Lloyd. "Startlingly clear images capable of revealing objects like this are now possible without the blurring."

The pair were studying a hot star called MWC 922 in the constellation Serpens (the serpent mythologically associated with the origin of medicine). The image shown here combines data taken in near-infrared light (1.6 microns) and shows a region 30.8 arcseconds on a side around MWC 922. As the outer periphery of the nebula is very faint compared to the core, the image has been processed and sharpened to display the full panoply of detail and structure.

"The thing that really takes your breath away is the astonishing degree of symmetry within the intricate linear forms," said Tuthill. "If you fold things across the principal diagonal axis, you get an almost perfect reflection symmetry. This makes the Red Square nebula the most symmetrical object of comparable complexity ever imaged."

The overall architecture of twin opposed conical cavities (commonly known in astronomy as a "bipolar nebula") is seen to be adorned with a remarkable sequence of sharply defined linear rungs or bars. This series of rungs and conical surfaces lie nested, one within the next, down to the heart of the system, where the hyperbolic bicone surfaces are crossed by a dark lane running across the principal axis. One particularly fascinating feature visible in the images is a series of faint radial spokes, like teeth of a comb, pointing away from the center. "Structures such as this are rarely seen in nebulae, and the high degree of regularity in this case may point to the intriguing possibility that these bands are shadows cast by periodic ripples or waves on the surface of an inner disk close to the star at the heart of the system," said Lloyd. But the most compelling and important implication for astronomy comes from the three-dimensional structure implied by the Red Square images.

"If you can really get a mental grasp of the three-dimensional geometry implied by the Red Square images," said Tuthill, "then it is fascinating to take a second look at one of the most famous astronomical images of them all: SN1987A." An image of the supernova as seen by the Hubble Space Telescope is to the right, showing the beautiful and unexpected ring system revealed around SN1987A—the only naked-eye supernova since the discovery of the telescope.

"We are not saying that the star MWC 922 at the heart of the Red Square is about to explode as a supernova," said Lloyd, "but we're not ruling it out either, and if it did it would certainly put on quite a show as it kindles the outer reaches of its nebula."

Whatever the fate of the central star, the remarkable series of bars seen in the Red Square make it the best astrophysical laboratory yet discovered for studying the physics of generating the mysterious sharp polar-ring systems like that around SN1987A.

According to Tuthill, "This is just the beginning-a system as complex and fascinating as this is bound to keep us guessing for years to come."

The image was made possible by the Palomar Adaptive Optics System, built by Caltech Optical Observatories and Jet Propulsion Laboratory, and captured by its companion infrared camera, built by Cornell University.

Contact:

Richard Dekany rgd@astro.caltech.edu (626) 395-6798

Peter Tuthill p.tuthill@physics.usyd.edu.au +61 2 9566 1826

James Lloyd jpl@astro.cornell.edu

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Segment of Quantum Repeater Demonstrated; May Lead to Long-Distance Quantum Communications

PASADENA, Calif.—Physicists at the California Institute of Technology have succeeded for the first time in the distribution of "entanglement" in a way that could lead to long-distance quantum communications, scalable quantum networks, and even a quantum internet.

In the April 5 online publication Science Express, Caltech Valentine Professor of Physics H. Jeff Kimble and his colleagues report that they have devised a crucial building-block of a "quantum repeater." The team has demonstrated a way to create a segment of a channel that can distribute quantum entanglement over distances. The division into segments and storage of entanglement in material systems is necessary for long-distance quantum communications to take place.

"This work provides a first primitive version of a quantum repeater segment," says Julien Laurat, a postdoctoral scholar in physics and one of the authors of the paper. "It opens an avenue for further investigations into this promising and new quest of large-scale networks where the currency of the realm is no longer classical information but rather quantum information."

Entanglement, one of the most striking features of quantum mechanics, leads to strong correlations between the various components of a physical system, regardless of the distance separating them. Entanglement's distribution enables quantum protocols, such as quantum cryptography where the security is guaranteed by the law of physics or quantum teleportation where a quantum state is faithfully transferred from one place to another.

"Physicists for some time have understood that the entanglement of quantum states could be exploited for various advances that are impossible with devices that operate according to the laws of classical physics," says Chin-Wen Chou, a former doctoral student of Kimble's and the lead author of the paper.

However, entanglement as a resource is fragile, and achieving such protocols over very long-distance is a challenge for quantum physicists. To achieve in a reasonable time long-distance quantum communications, namely the distribution of entanglement over such a distance, the channel has to be divided into many segments and entanglement generated and stored into material systems before connecting all them together. The Caltech group achievement is demonstrating an initial version of one of these segments.

The experiment involves two quantum nodes separated by 3 meters, each formed by two atomic ensembles separated by 1mm. The ensembles are clouds of about 100,000 cooled cesium atoms. With real-time control of the quantum states, entanglement is generated, stored into the atoms, which play the role of a quantum memory, and finally converted to photons on demand. This entanglement is stored in a heralded way, a critical requirement for scalability. In addition, the released entanglement is a so-called "polarization entanglement," an appropriate form for quantum communication applications.

"We demonstrated the capability to distribute entanglement between two locations in a form suitable both for quantum network architectures and for entanglement-based quantum communication schemes," says Kimble.

"The import of our experiment goes well beyond quantum communication protocols," Laurat explains. "It incorporates many complex procedures, confirming the more and more efficient control we can have in our labs to address in a coherent way the quantum states of atoms and light, and their interface."

The new work reported by Chou, Laurat, Kimble, and their coworkers is a significant leap towards quantum networking. However, the researchers also emphasize that "the extension of their work to longer chains involving many segments becomes more complicated, and still out of reach of any current system. A fully functional quantum repeater is still a challenging task, and its future achievement will be rich in fruitful discoveries."

This demonstration builds upon previous advances in the Caltech Quantum Optics Group in recent years, including the first demonstration of unconditional quantum teleportation (http://pr.caltech.edu/media/Press_Releases/PR11935.html) and the initial demonstration of entanglement between two remote atomic ensembles (http://pr.caltech.edu/media/Press_Releases/PR12776.html), a crucial ingredient for the breakthrough reported here.

The title of the paper is "Functional Quantum Nodes for Entanglement Distribution over Scalable Quantum Networks." It will be available on the Science Express website at http://www.sciencexpress.org when the embargo lifts and will be published in the journal Science at a later date.

The other authors are Hui Deng, a postdoctoral scholar in physics; Kyung Soo Choi, a graduate student, and Hugues de Riedmatten and Daniel Felinto, both previous postdoctoral scholars at Caltech.

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Caltech Observatory Receives Science Education Award

PASADENA, Calif.- The Laser Interferometer Gravitational-Wave Observatory in Hanford, Washington, which was created by the California Institute of Technology and the Massachusetts Institute of Technology, and funded by the National Science Foundation, has received a science education award.

Washington State LASER (Leadership and Assistance for Science Education Reform) announced the recipients of the first-ever Science Education Advocate Awards.

The awards go to five individuals, organizations, and project teams who exhibited outstanding advocacy for science education in the state of Washington by promoting the importance of science education among the general public and/or the education system.

"The intent of the Science Education Advocate Awards is to recognize and raise public awareness of advocacy across the broadest possible spectrum of science education efforts," said Dennis Schatz, vice president for education and exhibits at Pacific Science Center and co-director of LASER. "Awardees are being recognized for their advocacy efforts--not necessarily their work as science educators. We want to stress how important strong community support and advocacy is to developing science literacy in our state."

Efforts at all levels of science education--including early learner, K-12, vocational, undergraduate, graduate, adult, and informal/public science education--were eligible for consideration.

The five awardees receive $5,000 each, which they can give to the not-for-profit organization or public education entity of their choice for use in science education. The award was funded by the Boeing Company.

Recipients will be recognized at local awards ceremonies to highlight their achievements among their peers and within their communities.

LIGO develops and collaborates in programs to promote science that are tailored to meet the needs of different ages, cultures, and academic circumstances. In these endeavors, the observatory partners with formal and informal education organizations and community groups whenever possible. LIGO's contributions to these programs emphasize the project's role in an international effort to make the first direct detection of gravitational waves.

For K-12 groups, LIGO offered field trips to about 900 children in 2006. In addition to learning about LIGO's search for gravitational waves, student guests interact with a dozen hands-on exhibits related to wave behavior and gravity. The exhibits are correlated to Washington State science standards. Nearly a dozen groups of science and education college students also visited in 2006.

LIGO also hosts field trips sponsored by regional chapters of educational programs aimed at encouraging low-income and minority students to explore science and math.

LIGO's $5,000 donation will be awarded to the LIGO Hanford Observatory to support transportation expenses for field trips to the observatory.

"LIGO is pleased to be part of NSF's investment in America's future, both in science and education," said Frederick J. Raab, head of the LIGO Hanford Observatory. "Through the expertise of our local institutional partners, the enthusiasm of our community members and the dedication of our staff, we have had the privilege to put some magic into the lives of thousands of residents of our region. One day, you have the idea to organize a bilingual astronomy event for our Latino families and, presto, the local astronomy club supplies telescopes and the local college contributes an interpreter for every astronomer we can muster. Whether helping us provide physics toys for kids at the Cinco de Mayo celebration, supporting visits by schools to LIGO or providing volunteers for our Perseid meteor parties, we can always count on our community partners to make it work."

In addition to LIGO Hanford, Caltech alumnus and visiting associate in biology Leroy Hood, and his colleague Valerie Logan, were also recipients of the award. Hood, who earned a bachelor's degree in biology in 1960 and a PhD in biochemistry in 1968 from Caltech, is president of the Institute for Systems Biology in Seattle. Logan is community liaison and fund developer for the Center for Inquiry Science at the Institute for Systems Biology.

In 1992, Hood established the University of Washington's Department of Molecular Biotechnology. While Logan and Hood were at the university, they established several education reform programs, including the Partnership for Inquiry-based Science and the Family Science program.

In 2000, Hood left the University of Washington and started the independent, nonprofit, Institute for Systems Biology (ISB).

"Within ISB, we encourage our faculty members to engage in advocacy and programmatic activities related to K-12 science education," said Hood. "I have always believed that academics have four major responsibilities: scholarship, education, transfer of knowledge to society, and community leadership."

Their $5,000 donation will be awarded to the K-12 science education program at the Institute for Systems Biology.

### Contact: Jill Perry Caltech Media Relations (626) 395-3226 jperry@caltech.edu

Wendy Malloy Pacific Science Center (206) 443-2879 wendy_malloy@pacsci.org

Visit the Caltech Media Relations website at http://pr.caltech.edu/media.

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Astrophysicists Using Space Observatories Catch Magnetar in Gigantic Stellar Belch

PASADENA, Calif.—When it comes to eerie astrophysical effects, the neutron stars commonly known as magnetars are hard to beat. The massive remnants of exploded stars, magnetars are the size of mountains but weigh as much as the sun, and have magnetic fields hundreds of trillions of times more powerful than the earthly field that turns our compass needles north.

Now astrophysicists have managed to catch a recently discovered magnetar in a sort of giant stellar hiccup that still has them puzzled. In multiple reports in the Astrophysical Journal and Monthly Notices of the Royal Astronomical Society, the researchers describe the behavior of the body located in a star cluster about 15,000 light-years away in the Ara constellation in the southern hemisphere. The magnetar goes by the unwieldy official name CXOU J164710.2-455216, or more informally, the "Westerlund 1 magnetar."

"We only know of about a dozen magnetars," says Michael Muno, a scientist at the California Institute of Technology's Space Radiation Laboratory, and the original discoverer of the magnetar. "In brief, what we observed was a seismic event on the magnetar, which tells us a lot about the stresses these objects endure."

In September 2005, about a year after Muno found the magnetar, the object produced a burst that luckily came at a time when it was being heavily observed by several satellites, including NASA's Swift X-ray and gamma-ray observatory, and the European Space Agency's X-ray satellite, XMM-Newton. Just five days before the burst, Muno and collaborators had been looking at the magnetar with the XMM-Newton and seen it in the relatively calm state in which he had originally found it.

As most magnetars do, it produced a beam of X-ray light that, like the beam from a lighthouse, swept across Earth once every 10 seconds. This allowed its rotational rate to be determined very precisely. The event that produced the burst also caused the magnetar to shine 100 times more brightly, created three separate beams to sweep past Earth where previously only one had existed, and sped up its rotation rate by about a thousandth of a second.

Muno says more work is required to understand what happened with the magnetar, because it is built of matter far denser than anything on Earth, and its composition is still a mystery.

However, it is possible to make educated guesses by extending theories developed to explain other neutron stars. The magnetic fields inside the neutron star are probably wound up, like a twisted spring. In a manner somewhat similar to plate tectonics here on Earth, as the magnetic fields unwind, they put stress on the outer crust. The crust would resist these stresses for a while, but would eventually fracture, producing a seismic event. The fractures would cause the magnetar's surface to shine brightly from multiple sources.

Also, there is reason to think that part of the interior of the neutron star is liquid and may be rotating faster than the crust. The seismic event could cause this fluid to become attached to the crust, so that the outer crust would speed up slightly.

"So we think the crust cracked," Muno says, adding that the observations are important for two reasons. "First, we have now seen another way in which these exotic objects dissipate their internal fields as they age.

"Second, this event was only spotted because a team of us were concentrating hard on this newly discovered object," he adds. "The fact that we saw the event only a year after we discovered the magnetar implies that dozens more could be lurking in our galaxy."

"If we find many more of these magnetars, we will have to reevaluate our understanding of what happens when stars die," says GianLuca Israel, an Italian astronomer who is publishing a separate paper on the magnetar with his collaborators, appearing this week in the Astrophysical Journal.

Muno is lead author of a paper appearing this week in Monthly Notices of the Royal Astronomical Society.

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Caltech Physicist Marc Kamionkowski Named Winner of Ernest Orlando Lawrence Award

WASHINGTON, D.C.—Marc Kamionkowski, the Robinson Professor of Theoretical Physics and Astrophysics at Caltech, has been named one of eight winners of the Ernest Orlando Lawrence Award. The announcement was made today by U.S. Secretary of Energy Samuel W. Bodman in Washington, D.C.

The Lawrence Award honors scientists and engineers at mid-career for exceptional contributions in research and development that support the Department of Energy and its mission to advance the national, economic, and energy security of the United States. The award consists of a gold medal, a citation, and an honorarium of $50,000.

"These brilliant scientists and their varied and important research inspire us," Secretary Bodman said. "Their work reminds us of the importance of continued investment in science and the need for increased emphasis on basic research and math and science education programs."

Kamionkowski, who has been at Caltech since 1999, was cited as this year's sole winner in the physics category for describing how precise observations of the cosmic microwave background radiation can lead to deeper understanding of the origin and evolution of the universe. Kamionkowski and his collaborators have inspired a new generation of very sophisticated experiments that have begun the search for the signature of the cosmic gravitational-wave background.

He has also worked on particle dark matter, inflation, and cosmic acceleration, as well as neutrino and nuclear physics and astrophysics, large-scale-structure and galaxy formation, gravitational lensing, phase transitions in the early universe, alternative gravity theories, the first stars, the epoch of reionization, and stellar and high-energy astrophysics.

At Caltech, Kamionkowski is a member of the theoretical astrophysics group and the Moore Center for Theoretical Cosmology and Physics. He teaches classes in both physics and astronomy, including general relativity, cosmology, quantum mechanics, radiative processes, stellar structure and evolution, and the physics of stars.

A native of Cleveland, Kamionkowski earned his Bachelor of Arts degree in 1987 from Washington University and his doctorate in 1991 from The University of Chicago. He served a three-year postdoctorate at the Institute for Advanced Study and then joined the Columbia University faculty in 1994. He came to Caltech in 1999 as a full professor.

In addition to Kamionkowski, this year's winners are Paul Alivisatos, of the University of California at Berkeley and E.O. Lawrence Berkeley National Laboratory, and Moungi Bawendi, of MIT, jointly, for the materials research category (the winners of this joint award will share the honorarium); Malcolm J. Andrews, of Los Alamos National Laboratory, for the national security category; Arup K. Chakraborty, of MIT, for the life sciences category; My Hang V. Huynh, of Los Alamos National Laboratory, for the chemistry category; John Zachara, of Pacific Northwest National Laboratory, for the environmental science and technology category; and Steven Zinkle, of Oak Ridge National Laboratory, for the nuclear technology category.

The Lawrence Award was established in 1959 to honor the memory of the late Dr. Lawrence, who invented the cyclotron (a particle accelerator) and after whom two major Energy Department laboratories at Berkeley and Livermore, California, are named. The Lawrence Awards, given in seven categories, will be presented at a ceremony in Washington, D.C.

Additional information on the winners and their work is available on the Web at http://www.sc.doe.gov/lawrence. The DOE news release about the awards is at http://www.energy.gov/news/4769.htm.

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New Astrophysics Building Under Way

PASADENA, Calif.- In December 2008 astronomers and astrophysicists at the California Institute of Technology will have a new home for their offices, classes, and meetings. Construction on the Cahill Center for Astronomy and Astrophysics began Jan. 31 with a groundbreaking ceremony.

Caltech President Jean-Lou Chameau thanked the benefactors and the city for making the building possible. As a civil engineer, he said it was always exciting to be part of the birth of a new building, particularly one whose creation had been envisioned by Caltech faculty and administrators for so many years.

Donning hardhats for the actual groundbreaking were Pasadena Mayor Bill Bogaard; Chameau; building architect Thom Mayne; Dick Baptie of the general contractor Hathaway Dinwiddie; Physics, Mathematics, and Astronomy Division Chair Tom Tombrello; Caltech faculty planning chair Tom Phillips; and building benefactor Charles H. Cahill.

Thanks to Cahill, and other leadership support from the Sherman Fairchild Foundation; Michael M. Scott (BS '65); Caltech trustee Fred Hameetman (BS '62) and his wife Joyce, the Kenneth T. and Eileen L. Norris Foundation, more than $38 million has already been raised. The estimated 100,000-square-foot facility will provide a much-needed collective and collaborative home for astronomers, instrument builders, and theorists who now work in numerous buildings on campus.

The $50 million center will be located on the south side of California Boulevard, between the Institute's athletic facilities on the south and the rest of the campus on the north.

Internationally recognized architect Thom Mayne and his firm, Morphosis, based in Santa Monica, designed the visually impressive, yet functional structure.

Plans call for the Cahill Center to be composed of three floors and a basement. The building will contain space for offices, laboratories, remote observing rooms, conference rooms, a library, an auditorium, and classrooms.

For almost 100 years, Caltech has been at the forefront of astronomy and astrophysics, pioneering research that has led to greater understanding of the earth, the solar system, and the Universe. This facility will help its world-renowned astronomers and other investigators continue their groundbreaking discoveries well into the 21st century.

Since the time of George Ellery Hale, Caltech astronomers have been housed in the elegant Robinson building, opened in 1932 and distinguished by its rooftop astronomical dome.

Generations of occupants have discovered remarkable phenomena, including the cosmological nature of quasars, the incredibly bright beacons in the sky indicating the presence of very distant galaxies, millisecond pulsars, and brown dwarfs, also known as "failed stars." This year alone, Caltech astronomers announced that they have the first look at the weblike large-scale distribution of dark matter in the universe and they discovered the first known triplet of quasars.

Over the years, the Institute's astronomy program has increased in size, overfilling the Robinson building, so that other astrophysical programs began to occupy neighboring physics laboratories.

Despite their many successes, Caltech astronomers and astrophysicists have been limited by the physical separation between research groups.

"Pulling together the division's many activities in astronomy and astrophysics to achieve optimal synergy has been our goal for some time," says Tombrello. "The Cahill Center is an essential step in this progression and, naturally, a top priority for us. We greatly appreciate the gift by the Cahills and other Caltech friends that will help us tackle some of the remaining questions in astronomy."

Caltech's observing facilities, which span almost the entire electromagnetic spectrum, are unmatched by any other institution in the world.

Its optical observatories stretch from the Palomar Observatory, which includes the famous 200-inch telescope built in the 1930s, to the twin 10-meter Keck telescopes on Mauna Kea. The Thirty Meter Telescope, which will be the largest in the world, is now being designed. To this impressive list of world-leading optical telescopes is added the nation's largest millimeter wave radio interferometer, and submillimeter wave single dish. The list goes on, including balloon-borne and land-based cosmic background detection facilities, an ultraviolet sky survey satellite, European Space Agency satellites and NASA satellites, and an airborne telescope.

"The Cahill Center will enable the inventors of all these devices to be brought together under one roof, no doubt fostering exciting new discoveries," says Tombrello. "Caltech is known worldwide for its leadership in astronomy. It's the unique quality of Caltech's education that promotes these discoveries, which will help improve our understanding of the Universe."

According to Chameau, "If not for the extraordinary generosity of several supporters, our faculty would still be waiting for this wonderful the project to begin. Now that the building phase is underway, we still need almost $13 million to reach our goal and several attractive naming opportunities remain."

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Jill Perry (626) 395-3226 jperry@caltech.edu

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Protoplanetary Disk Found Encircling Mira B

SEATTLE—Astronomers generally assume that the dusty disks where planets form are found around young stars in stellar nurseries. Now, for the first time, a protoplanetary disk has been found in the environment of a dying star.

A team of astronomers is reporting today at the winter meeting of the American Astronomical Society that material from the dying star Mira A is being captured into a disk around Mira B, its companion. Michael Ireland of the California Institute of Technology and his coauthors, John Monnier from the University of Michigan, Peter Tuthill from the University of Sydney, and Richard Cohen from the W. M. Keck Observatory, say that the finding implies that there should be many similar undiscovered systems in the solar neighborhood, providing a myriad of new places to look for young extrasolar planets.

Located 350 light-years away in the constellation of Cetus, Mira (christened the "miracle star") first shook the foundations of the astronomy world 400 years ago with its changing brightness. Visible to the naked eye for about one month at a time, it becomes 1,000 times fainter and disappears from view, only to reappear again on an 11-month cycle.

"When looking at one of the most celebrated and well-studied stars in the galaxy, I was amazed to find something new and unexpected," says Ireland. "The discovery not only changes the way we think about a star that's important historically, but also how we'll look at similar stars in the future."

Although Mira was once a star very similar to the sun, it is now in its death throes as it loses its dusty outer layers at a rate of one Earth-mass every seven years. If Mira were a single star, all this material would travel into outer space. However, like two out of every three star systems, Mira has a companion star that orbits around it, in this case with a period of about 1,000 years. This companion, Mira B, has a gravitational field that catches nearly one percent of the material lost from Mira A.

By using specialized high-contrast techniques at the 10-meter Keck I telescope in Hawaii and the 8-meter Gemini South telescope in Chile, Ireland's team discovered heat radiation coming not only from Mira B itself, but also from a location offset from Mira B by a distance equivalent to Saturn's orbit.

"Observing Mira in the infrared is like staring straight down the barrel of one of the brightest searchlights in the galaxy. It came as a real revelation to see this faint mote of dust, harboring all the possibilities of new worlds in formation, against the hostile environment of the Red Giant," says Tuthill.

Monnier agrees, saying "Our new imaging method at Keck is revealing new details that were thought to be impossible to detect due to the blurring by atmospheric turbulence. In this case, the 'detail' we discovered is potentially a whole new class of planetary system in formation."

The intense radiation from Mira A, 5,000 times brighter than the sun, heats the edge of the disk to about Earth's temperature and causes it to glow in the infrared. The researchers were able to show that the material was indeed the edge of a disk and not just a "clump" in the wind from Mira A. By modeling the way that this system captures the outflow from Mira A, the researchers were also able to confirm that Mira B is simply an ordinary star like the sun, although about half as massive.

The key part of this result is what will happen when Mira A finishes its death throes and becomes a white dwarf in about one million years. The disk-creating process will have finished and the disk itself will be capable of forming new planets.

"This discovery opens up a new way to search for young planets, by searching in double star systems that contain white dwarfs," Ireland says. "The expected abundance of these systems means that we can find planets that we know are young around stars like our sun."

Astronomers associate the death of a star with the death of its planetary system. Here, the opposite is happening. Ireland adds, "An aging star is laying the foundation for a new generation of planets."

Similar systems could be discovered and studied by future instruments such as the Thirty-Meter Telescope (TMT).

The work was supported by the Australian Research Council and the NASA Navigator Program.

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New 3-D Map of Dark Matter Reveals Cosmic Scaffolding

SEATTLE—An international team of astronomers has created a comprehensive three-dimensional map that offers a first look at the weblike large-scale distribution of dark matter in the universe. Dark matter is an invisible form of matter that accounts for most of the universe's mass, but that so far has eluded direct detection, or even a definitive explanation for its makeup.

The map is being unveiled today at the 209th meeting of the American Astronomical Society, and the results are being published simultaneously online by the journal Nature.

According to Richard Massey, an astronomer at the California Institute of Technology who led in the map's creation, the map provides the best evidence yet that normal matter, largely in the form of galaxies, forms along the densest concentrations of dark matter. The map reveals a loose network of filaments that grew over time and which intersect in massive structures at the locations of clusters of galaxies.

Massey calls dark matter "the scaffolding inside of which stars and galaxies have been assembled over billions of years."

Because the formation of the galaxies depicted stretches halfway to the beginning of the universe, the research also shows how dark matter has grown increasingly clumpy as it continues collapsing under gravity. The new maps of dark matter and galaxies will provide critical observational underpinnings to future theories for how structure formed in the evolving universe under the relentless pull of gravity.

Mapping dark matter's distribution in space and time is fundamental to understanding how galaxies grew and clustered over billions of years, as predicted by cosmological models. Tracing the growth of clustering in the dark matter may eventually also shed light on dark energy, a repelling form of gravity that influences how dark matter clumps.

The map was derived from the Hubble Space Telescope's widest survey of the universe, called COSMOS (for Cosmic Evolution Survey), led by Nick Scoville, the Moseley Professor of Astronomy at Caltech. In making the COSMOS survey, the Hubble imaged 575 slightly overlapping views of the universe using the onboard Advanced Camera for Surveys (ACS). It took nearly 1,000 hours of observations and is the largest project ever conducted with the Hubble.

The three-dimensional map was developed by measuring the shapes of as many as half a million faraway galaxies. These shapes are distorted by the bending of light paths by concentrations of dark-matter mass in the foreground along the line of sight. Then, the observed subtle distortion of the galaxies' shape was used to reconstruct the distribution of intervening mass projected along the Hubble's line of sight.

Richard Ellis, Steele Professor of Astronomy at Caltech explains that the analysis utilized the remarkable phenomenon of gravitational lensing, first predicted by Einstein and now a major tool of cosmological research.

"The depth of the COSMOS image and the superior resolution of Hubble Space Telescope are the key ingredients enabling this detailed map," adds Ellis. "The COSMOS field also covers a wide enough area for the large-scale filamentary structure to be clearly evident."

"The unique advance in our work is that we have made a three-dimensional map," adds Jason Rhodes of JPL, a coauthor of the study. "Because the distances to the faint background galaxies are known in the COSMOS field, we can examine the distortion as a function of the background distance."

The results also show that several of the early universe's cosmic structures inside the dark matter "scaffolding" are clusters of galaxies in the process of assembly, says Scoville. These structures can be traced over more than 80 million light-years in the COSMOS survey-approximately five times the extent of the nearby Virgo galaxy cluster.

The researchers further found that galaxies in the densest early universe structures have older stellar populations, implying that these galaxies formed first and accumulated the greatest masses in a bottom-up assembly of galaxies. The COSMOS survey shows that galaxies with on-going star formation, even to the present epochs, dwell in less populated cosmic filaments and voids.

"Both the maturity of the stellar populations and the 'downsizing' of star formation in galaxies vary strongly with the epoch when the galaxies were born as well as their dark-matter environment." says Scoville. His team's paper is to appear in the Astrophysical Journal at a later date.

Extremely deep color images of the two-degree COSMOS field were obtained in 30 nights of observing with the 8.2-meter Subaru telescope in Hawaii. Thousands of galaxies' spectra were obtained by using the European Southern Observatory's Very Large Telescope and the Magellan telescope in Chile. The distances to the galaxies were accurately determined from their redshifts, which were derived from galaxy colors and spectra. The distribution of the normal matter was partly determined with the European Space Agency's XMM-Newton telescope, looking at the hot gases emitting X-rays in the densest clusters.

Writer: 
Robert Tindol
Writer: 

New Type of Black-Hole Explosion Has Astrophysicists Wondering About Its Origin

PASADENA, Calif.—Scientists are announcing this week their detection of a June 14 gamma-ray burst that probably signals a hitherto undetected type of cosmic explosion. The hybrid gamma-ray burst probably created a new black hole, but the details of how the explosion occurred are unclear.

In several companion articles appearing in the December 21 issue of the journal Nature, the researchers present observations of the burst leading them to suggest that the event was a new type of cosmic explosion.

"We're still trying to figure out precisely what caused this event to come about, but its very mystery shows how much we still have to learn about the universe," says Avishay Gal-Yam, an astronomer at the California Institute of Technology, who is lead author of the paper on the Hubble Space Telescope's observations of the event. "The detection certainly speaks well of NASA's commitment to putting up satellites that can study such cataclysmic events as this one in detail."

The burst was discovered by NASA's Swift satellite and has since been studied with over a dozen telescopes, including the Hubble Space Telescope and telescopes at various ground-based observatories.

As with other gamma-ray bursts, this hybrid burst is likely signaling the birth of a new black hole. It is unclear, however, what kind of object or objects exploded or merged to create the black hole or, perhaps, something even more bizarre. The hybrid burst exhibits properties of the two known classes of gamma-ray bursts yet possesses features that cannot be explained.

"We have lots of data on this, dedicated lots of observation time, and we just can't figure out what exploded," said Neil Gehrels of NASA Goddard Space Flight Center in Greenbelt, Maryland, lead author of another of the Nature reports. "All the data seem to point to a new, but perhaps not so uncommon, kind of cosmic explosion."

Gamma-ray bursts represent the most powerful known explosions in the universe. Yet they are random and fleeting, never to appear twice, and only in recent years has their nature been revealed.

Gamma-ray bursts fall into two categories, long and short. The long bursts are longer than two seconds and appear to be from the core collapse of massive stars forming a black hole. Most of these bursts come from the edge of the visible universe. The short bursts, under two seconds and often lasting just a few milliseconds, appear to be the merger of two neutron stars or a neutron star with a black hole, which subsequently create a new or bigger black hole.

The hybrid burst, called GRB 060614 after the date it was detected, was discovered in the constellation Indus. The burst lasted for 102 seconds, placing it soundly in long-burst territory. But the burst lacked the hallmark of a supernova, or star explosion, commonly seen shortly after long bursts. Also, the burst's host galaxy has a low star-formation rate with few massive stars that could produce supernovae and long gamma-ray bursts.

"This was close enough to detect a supernova if it existed," added Gal-Yam. "Even Hubble didn't see anything."

Certain properties of the burst concerning its brightness and the arrival time of photons of various energies, called the lag-luminosity relationship, suggest that burst behaved more like a short burst (from a merger) than a long burst. Yet no theoretical model of mergers can support a sustained release of gamma-ray energy for 102 seconds.

"This is brand new territory; we have no theories to guide us," said Gehrels.

Scientists remain divided on whether this was a long short burst from a merger or a long burst from a star explosion with no supernova for whatever reason. Most conclude, however, that some new process must be at play: either the model of mergers creating second-long bursts needs a major overhaul, or the progenitor star from an explosion is intrinsically different from the kind that make supernovae.

"While we don't yet know what GRB 060614 was, we have learned that the simple picture we had before, with long GRBs coming from supernova explosions and short GRBs from mergers of neutron stars, cannot be the whole story. This hybrid burst is telling us that we have at least one more mystery to solve," concludes Gal-Yam.

Writer: 
Robert Tindol
Writer: 

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