March 11, Tuesday
Speaker: Andrey Kravtsov, Chicago
Location: UCB, Hearst Field Annex B-1 – 1:10 pm
Title: “Order out of chaos: stellar masses and sizes of galaxies and their host dark matter halos”
Abstract: Galaxy formation is a complex, hierarchical, highly non-linear process, which involves gravitational collapse of dark matter and baryons, supersonic, highly compressible and turbulent flows of gas, cooling and heating of gas, star formation, and stellar feedback. Nevertheless, despite the apparent complexity of these processes, galaxies exhibit a number of striking regularities, such as tight correlations between galaxy sizes and stellar masses and the mass and extent of their parent halos dominated by dark matter. I will discuss our current understanding of halo structure and physical motivation for the definition of halo radius and mass. I will also summarize the relations between stellar mass and halo mass and galaxy sizes and halo virial radius. I will show that the latter relation is close to linear, which indicates that sizes of galaxies of all types are set by specific angular momentum induced by gravitational torques during galaxy formation. In addition, I will show that stellar surface density profiles of galaxies of different morphological types at radii beyond half-mass radius have similar shape. The stellar mass-halo mass relation is tight, but its shape is complex and is determined by the complicated physics of star formation and feedback. I will show that the current generation of galaxy formation simulations is capable of reproducing the shape of this relation with reasonable set of assumptions about feedback physics.
For future BCCP talks, see this page.
BCCP Workshop: 5th annual Essential Cosmology for the Next Generation Meeting
BCCP and the Instituto Avanzado de Cosmologia Mexico held the 5th annual Essential Cosmology for the Next Generation meeting January 13-17, 2014, popularly known as Cosmology on the Beach. The conference blends a winter school of lecture courses by world-leading scholars with plenary talks on hot research topics. This year, topics included CMB polarization, gravitational wave cosmology, particle physics, tests of gravity, and statistical and experimental methods.
For slides from the BCCP/IAC meeting Essential Cosmology for the Next Generation 2014 workshop, click here. They are also available on the Presentations Page.
There are no open job opportunities at BCCP at this time. Please check back for future job postings.
A $2.1 million grant from the Gordon and Betty Moore Foundation to the University of California at Berkeley, through the Berkeley Center for Cosmological Physics (BCCP), will fund the development of revolutionary technologies for BigBOSS, a project now in the proposal stage designed to study dark energy with unprecedented precision. BigBOSS is based at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab).
“BigBOSS is the next big thing in cosmology,” says Uroš Seljak, Director of the BCCP, who is a professor of physics and astronomy at UC Berkeley and a member of Berkeley Lab’s Physics Division. “It would map millions and millions of galaxies, allowing us to measure dark energy to high precision – and would yield other important scientific results as well, including determining neutrino mass and the number of neutrino families.”
Dark energy is the unknown something that appears to account for almost three-quarters of the mass-energy of the universe and is the cause of its accelerating expansion. The discovery of the accelerating universe, announced in 1998 by two teams, resulted in the 2011 Nobel Prize in Physics, divided between Berkeley Lab and UC Berkeley astrophysicist Saul Perlmutter, leader of the Supernova Cosmology Project, and Brian Schmidt and Adam Riess of the competing High‑z Supernova Search team.
“After we won the Nobel Prize, the question we all heard most was, ‘Now that you’ve discovered dark energy, what comes next?’” says Perlmutter, who is the Executive Director of the BCCP as well as principal investigator for the Moore Foundation’s BigBOSS grant. “The answer is pretty clear: we have to find out what dark energy is. There’s no end of theories. To know which are possible, what we need most is the kind of accurate observational evidence that only BigBOSS and other advanced experiments can give us.”
New data from the South Pole Telescope indicates that the birth of the first massive galaxies that lit up the early universe was an explosive event, happening faster and ending sooner than suspected.
Extremely bright, active galaxies formed and fully illuminated the universe by the time it was 750 million years old, or about 13 billion years ago, according to Oliver Zahn, a postdoctoral fellow at the Berkeley Center for Cosmological Physics (BCCP) at the University of California, Berkeley, who led the data analysis.