Archive
Solving a Dark Puzzle
Animation: Click the image to watch this animation of how a galaxy like the Milky Way is built up according to the cold dark matter model, as well as how many dwarf galaxies (the small bright dots) there should be surrounding the Milky Way. Courtesy of J. Diemand, M. Kuhlen, P. Madau, Zemp, Moore, Potter and Stadel (UCSC). Send your comments on this issue of Cosmic Matters to .(JavaScript must be enabled to view this email address).
Image: This dwarf galaxy known as Leo II, seen in the Sloan Digital Sky Survey (SDSS), is one of the brighter dwarf galaxies near the Milky Way. The newly discovered dwarfs recently studied at Keck are up to 100 times fainter than Leo II. Courtesy of SDSS.
Photo: Observations made by Keck astronomer Josh Simon are being used to further understand the nature of dark matter. Credit: S. Anderson/WMKO.
But in total, this regular matter makes up only about 15 percent of the matter in our Universe. The other 85 percent is dark matter, a mysterious substance that has not yet been detected directly because it does not give off any light. Astronomers first recognized its existence about 30 years ago by detecting its gravitational pull on things that they could see, such as stars and gas. According to the best current cosmological models, dark matter plays a crucial role in the early universe in pulling together ordinary matter to form the first galaxies, and even today remains the dominant component of galaxies like our Milky Way
Recent measurements of stars’ velocities using the Keck II telescope and its leading wide field multi-object spectrograph, DEIMOS, have provided new clues to the behavior of dark matter in nearby “dwarf” galaxies. These observations by Caltech astronomer Josh Simon and his Yale colleague Marla Geha have demonstrated that at least twice as many dwarf galaxies orbit around the Milky Way as was previously recognized, and are reshaping our understanding of the link between our Galaxy and its smallest neighbors.
Listen as Dr. Simon describes the history of dark matter research.
Discovery of an Extreme Asteroid Moon
Click on the image to watch this animation of the orbit of Daphne and its satellite. The fly-by begins with our vantage point from Earth on the night of the discovery, We then fly up to view the satellite’s orbit edge-on, being occasionally eclipsed by Daphne. Lastly, we fly directly above the orbit to see that the orbit is circular. The 3-dimensional shape of Daphne used here was determined from past light curves analysis (Kaasalainen, et al) and confirmed with the Keck AO images. Animation courtesy of Jack Drummond/PSI and Al Conrad/WMKO.
An image flashed up on the display. It was the second group of exposures of the night for a large main-belt asteroid called Daphne. W. M. Keck Observatory Support Astronomer Al Conrad had been working from a remote control room in Waimea while his research partner, Principal Scientist Bill Merline, looked at the same image from his computer at the Southwest Research Institute in Boulder, Colorado.
The scientists were working on two research programs, one to learn about the shapes and sizes of asteroids, and the other to look for moons. The two programs use different approaches to determine the basic properties of asteroids.
Conrad had been helping Merline use an image-correction technology called adaptive optics (AO) on the 10-meter Keck II telescope. This world-leading system uses high-speed computers and deformable optics to correct the blurring effects of the Earth’s atmosphere.
Tonight, Merline and Conrad were looking at four large main-belt asteroids: Sylvia, Camilla, Kalliope, and Daphne. The plan was to look at each asteroid in round-robin fashion. They would make a “group” of exposures of one asteroid, consisting of perhaps a dozen pictures, taking a total of about 10 minutes. Then they would move to the next asteroid, cycling through all four every 40 minutes.
Each asteroid would rotate on its axis once every four to six hours. By the end of the night, the researchers would have enough data to see the outline of each asteroid. From there, they could begin to narrow down important and elusive characteristics of these cosmic targets.
Conrad and Merline had just looked at three asteroids and were finishing the fourth. It was time for Daphne’s second session. They moved the telescope to Daphne, and set the exposure time. A minute or so passed. When the first image appeared on the screen, something unusual appeared on the display.
“Holy Cow,” Merline said. Conrad looked up. He saw a dot, just a few pixels wide, very close to the outer edge of the asteroid, near the two-o’clock position.
They had discovered an asteroid moon!
Honors for Senior Keck Astronomer Richard Ellis
Photo: Richard Ellis, whose research focuses on galaxy evolution and observational cosmology, is pictured here with his wife, Barbara, at Buckingham Palace following the ceremony where he became a member of the Order of the British Empire. Courtesy of Caltech.
Richard Ellis, whose research focuses on galaxy evolution and observational cosmology, recently travelled not to the Hawaiian Isles but to the British Isles to be invested as a Commander of the British Empire (CBE). In a ceremony at Buckingham Palace on July 3, Ellis was honored for “for services to international science.” The CBE is Great Britain’s highest civilian honor other than knighthood, and dates back to a British order of chivalry established by King George V in 1917. It is rarely given to nonresident British citizens.
Ellis, who is Caltech’s Steele Family Professor of Astronomy, is a senior observer at Keck and was recently a presenter for the Observatory’s distinguished Evenings with Astronomers lecture series in January, 2008.
Photo: Evenings with Astronomers presenter Richard Ellis captivates his Hawai’i audience with his presentation on how he uses the Keck telescopes to find the most distant galaxies in the universe. Courtesy of WMKO.
In 2006, his research applying gravitational lensing to detect the most distant galaxies in the universe was featured as the cover story in Time magazine’s September issue.
According to Observatory Director Taft Armandroff, Richard Ellis pushes the Keck telescopes and instruments to their absolute limits to discover and understand the faintest and most distant galaxies in the universe. The light that he measures from these galaxies has been travelling to us for over 90% of the age of the universe. He is a passionate initiator and contributor to continually improving Keck’s capabilities. In addition, he has served as a member of both the Keck Observatory’s Science Steering Committee and our governing Board of Directors. His scientific, technical, and organizational contributions to Keck have played a significant role in the Observatory’s renown. On behalf of the Observatory, congratulations Richard on this well deserved recognition.
Photo: Richard Ellis describes one of the fascinating discoveries our universe holds to an inspired lecture guest. Courtesy of WMKO.
Ellis received his undergraduate degree from University College London and his Ph.D. from Oxford University. Before becoming a professor at Caltech in 1999, he was a distinguished member of the astronomical community in the United Kingdom. He served as the prestigious Plumian Professor of Astronomy and Experimental Philosophy at Cambridge.
He and his wife, Barbara, live in Pasadena, California.
Cosmic Honu
Photo: Jon Lomberg created Cosmic Honu to benefit the W. M. Keck Observatory in the Hawaii Island public art exhibit called “It’s a Honu World.” On the turtle’s back is a representation of the entire universe. Courtesy of WMKO.
It started in Zurich, Switzerland in 1998. Large fiberglass cows were painted into masterpieces by local artists and infused the landscape with color and creativity. Quickly spreading to America, the public art idea evolved and flourished cows in Chicago, salmon in Seattle, pigs in Petaluma, hearts in San Francisco, and geckos in Honolulu, the whimsical collections were later auctioned off to benefit local charities. Anyone living on Hawai’i Island knows that this potent phenomenon arrived in full living color in March, 2008, as It’s a Honu World. Organized by Karen and Errol Kaufman, of Hilo, the program garnered 35 Big Island artists to decorate large sea turtle forms in support of local organizations including the W. M. Keck Observatory. The painted turtles are on display across the island through September, 2008.
Photo: At home in his Galaxy Garden, Jon Lomberg stands in front of a fountain symbolizing the massive black hole at the center of the Milky Way Galaxy. Courtesy of Jon Lomberg.
Jon Lomberg, one of the world’s leading artists inspired by science, created Cosmic Honu for Keck. Lomberg is a painter who has lived with his family in Honaunau since 1987. Also an Emmy Award winning art director for “Cosmos,” he was deeply involved in Carl Sagan’s work for over 25 years, a journey that culminated with designing the astronomical innovation for the film, Contact.
According to Lomberg’s description on the Honu exhibit page, “The artist has the unique distinction of having created artwork carried aboard 5 different NASA spacecraft. With work now on Mars and far beyond Pluto, Jon Lomberg can claim the title of Earth’s most far-flung and enduring artist. His work will last over a thousand millions years.” Lomberg is also the creator of the Galaxy Garden, a 100 foot diameter walk-through scale model of our Galaxy at the Paleaku Peace Gardens Sanctuary.
Cosmic Honu is currently on exhibit at Keck Observatory headquarters and will be available for purchase at an island wide Honu auction in September. Please visit http://www.itsahonuworld.com for auction details or call Joan Campbell at Keck Observatory at 808.881.3854.
Click the learn more button to read Jon Lomberg’s artist statement for Cosmic Honu.
An Eye on the Next Generation
Photo: An upside down reflection of Emily Rice, graduate astronomy student at UCLA as she and other workshop participants explore compelling ways to teach basic principles in science and engineering. Credit: S. Anderson/WMKO.
Since 2005 the W. M. Keck Observatory has participated in the Akamai Observatory Internship Program, funded by the National Science Foundation’s Center for Adaptive Optics (CfAO). The Akamai education program is designed to rigorously prepare Hawai’i undergraduate students for future Observatory careers through a summer program that includes an intensive academic short course, inquiry-based activities and workplace internships with the observatories on Mauna Kea. To date Keck Observatory has sponsored 17 students in the Akamai program and has also participated in the CfAO’s Professional Development Program (PDP), an initiative to improve science and technology teaching methods and delivery. The 2008 CfAO PDP offered a workshop which took place this past spring on Maui and some of the participants took what they learned right into practice for the summer 2008 Akamai academic short course.
Emily Rice, a graduate student in astronomy at the University of California at Los Angeles, summed up her CfAO experiences by saying, “The CfAO professional development program is an extraordinary opportunity to learn about the latest research in cognitive science and learning theory and apply it to developing curriculum and practicing facilitation techniques. It is wonderful to meet other scientists and engineers who are passionate about learning, teaching, and promoting a fair and diverse academic community. The Akamai program is my favorite to work with because it also helps me share my passion for astronomy and communicate to students and the community the importance of the observatories in Hawai’i. It sends the message that people with a variety of backgrounds can make important contributions to a successful observatory and that a successful observatory can have a positive impact on the community.”