A new study shows that dark matter is about 1000 times less likely to bump into regular matter than previously expected.
From Symmetry magazine:
Scientists have narrowed down how strongly dark matter particles might interact with normal matter.
A team led by scientists from the US Department of Energy’s SLAC National Accelerator Laboratory and Stanford University found that, based on the number and distribution of small satellite galaxies seen orbiting our Milky Way, this interaction is at least a thousand times weaker than the strongest interaction allowed by previous astrophysical analyses.
“Improving our understanding of these interactions is important because it’s one of the factors that helps us determine what dark matter can and cannot be,” says Risa Wechsler, director of the SLAC/Stanford Kavli Institute for Particle Astrophysics and Cosmology and the study’s senior author.
Read full article here.
Risa Wechsler will participate in a conversation moderated by Brian Green at the World Science Festival on the search for the Universe's missing matter, May 29 at 8pm.
Oxossi Ayofemi, an Oakland- and San Francisco-based artist, was traveling on BART one day when a pair of turf dancers began to perform in her train car. Most people respond by staring in shock or wonder at the dancers’ contortions, or by looking down so they won’t feel obliged to fish in their pockets for change.
But Ayofemi did neither. She watched with curiosity and admiration. Then she spoke to them.
The upshot of that communication was an artistic collaboration that went far beyond the BART dancers’ wildest dreams. They became actors in her multimedia exploration of the topic “Black Matter,” in concert with Stanford University astrophysicist Risa Wechsler, at the Contemporary Jewish Museum. And on Aug. 9, they will visit the CJM for the first time as part of a public presentation of the exhibit, which opened July 26.
See full story here.
She’ll direct the future of astrophysics research at SLAC and Stanford for the next five years.
From SLAC Today, by Manuel Gnida
Risa Wechsler has been appointed director of the Kavli Institute for Particle Astrophysics and Cosmology (KIPAC), a joint institute of the Department of Energy’s SLAC National Accelerator Laboratory and Stanford University. On Sept. 15, she’ll take over from Tom Abel, whose five-year term at the helm of the institute is coming to an end.
Read full story here.
Risa Wechsler and Jeremy Tinker have published a review article on the connection between galaxies and their dark matter halos, covering roughly the last 15 years of this rapidly evolving field. The galaxy–halo connection provides a key test of physical galaxy-formation models; it also plays an essential role in constraints of cosmological models using galaxy surveys and in elucidating the properties of dark matter using galaxies. The review highlights techniques, applications, and outstanding questions in this exciting area.
An advanced draft is available here.
News, papers, and tidbits from Risa and her Galaxy Formation and Cosmology Group at KIPAC / Stanford University.