This simulated image shows the dark
matter satellites (bright clumps) that can be found around our Milky Way galaxy. The central
region corresponds to luminous matter.
Scientists Elucidate the Origin of the Darkest Galaxies in the Universe
Ghostly galaxies composed almost entirely of dark matter speckle the universe. Unlike normal galaxies, these extreme systems contain very few stars and are almost devoid of gas. Most of the luminous matter, so common in most galaxies, has been stripped away, leaving behind a dark matter shadow. These intriguing galaxies—known as dwarf spheroidals—are so faint that, although researchers believe they exist throughout the universe, only those relatively close to Earth have ever been observed. And until recently, no scientific model proposed to unravel their origin could simultaneously explain their exceptional dark matter content and their penchant for existing only in close proximity to much larger galaxies.
Now, SLAC's Stelios Kazantzidis, a Kavli Institute for Particle Astrophysics and
Cosmology researcher, in collaboration with Lucio Mayer of the Swiss Federal Institute of Technology in Zurich
and the University of Zurich, Chiara Mastropietro of the University of Munich in Germany, and James Wadsley of McMaster University in Canada, has developed an elegant explanation for how galaxies come to be dominated by dark matter. Kazantzidis, who completed part of the study as a Fellow in the University of Chicago's Kavli Institute for Cosmological Physics,
reports his findings in the February 15 issue of
SLAC SULI Student
to Present at AAAS
2006 SULI student Alessondra Springmann
Few college students spend
an afternoon presenting their research to world-class scientists. This Saturday, one of SLAC's Science Undergraduate Laboratory Internship (SULI) students will do just that. Alessondra Springmann, a summer 2006 SULI alumna, will share her research on extragalactic radio sources at the
annual meeting of the American Association for the Advancement of Science (AAAS) in San Francisco.
"I'm really excited to present my research," said Springmann, who spent 10 weeks studying x-shaped radiogalaxies
with KIPAC's Teddy Cheung. "It's a really unique opportunity to show my research to scientists from around the world."
The Department of Energy selected a handful of students as candidates for publication in its
Journal of Undergraduate Research, and is treating these students to a trip to San Francisco to show their research posters at the AAAS meeting. Springmann, a Marin County native and senior astronomy student at Wellesley College, isn't nervous.
"Teddy has been really supportive," Springmann said. "He knows what it's like to be doing this kind of thing as an undergraduate, and he has really helped me prepare." On Cheung's recommendation, she cut her teeth presenting her summer research to leading astronomers at last year's American Astronomical Society meeting in Seattle. With some experience behind her, Springmann has plenty to anticipate at the meeting besides nerves.
"I'm excited to hear the climate change sessions and to meet other researchers. I really want to meet some of my textbook authors!"
Springmann will display her work during the student poster presentation from 1
p.m. until 5 p.m. on Saturday, February 17th, at the Hilton Hotel in San Francisco.
Stats Lecture Series
Begins Next Week
Beginning Tuesday, Louis Lyons, a particle physicist from Oxford University and author of
Statistics for Nuclear and Particle Physicists, will
give a series of four lectures at SLAC on research statistics. The "Practical Statistics for Physicists" series will show ways to extract better results from data analysis.
The non-cumulative lectures will be given from February 20th to 23rd in Panofsky Auditorium. The first of the lectures, "Learning to Love the Error Matrix," will be followed by "Parameter Determination by Likelihood: Do's and Don'ts," and "Chi-Squared and Goodness of Fit." Lyons hopes the final talk, "Discovery and p-Values," will be especially relevant for
future observations from the Gamma Ray Large Area Space Telescope (GLAST). Although
the lectures will be given at a level suitable for post-docs and graduate students with some experience
in data analysis, all are welcome to attend.
Lyons, who is visiting SLAC for three months from Oxford University, encourages anyone with questions to
seek him out. "The reason I'm at SLAC is to help people with statistical problems they may be having in their research," he said. "I'm here until the end of March, and I'm more than happy to talk."
In the News: 2007 Budget Passes Senate
Congress approved increased funding for education grants, veterans' health care, law enforcement and international AIDS relief as part of a $463.5 billion spending measure, completing work on the 2007 budget more than four months late.
The measure increases funding for basic scientific research, providing $200 million more for the Department of Energy's Office of Science, $335 million more for the National Science Foundation and $50 million more for the National Institute of Standards and Technology.
SLAC Research Makes News Around the Globe
This week, SLAC published two highly newsworthy papers in Nature:
Energy Doubling of 42 GeV Electrons in a
Meter-scale Plasma Wakefield Accelerator and
Early Gas Stripping as the Origin of the
Darkest Galaxies in the Universe. See a partial list of related news links
Congratulations to the authors of these papers!
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