NRAO/Socorro Colloquium Series
Sukanya Chakrabarti
Florida Atlantic University
A New Probe of Dark Matter in Galaxies
The
CDM paradigm of structure formation is successful at recovering the
basic skeletal structure of the universe -- the large-scale
distribution of galaxies. However, the agreement between theory and
observation is less secure when this model is applied to galactic (and
sub-galactic) scales. The "missing satellites problem" refers to the
excess of predicted CDM sub-structure relative to observed Local Group
dwarf galaxies. Recent discoveries of dark-matter dominated dwarf
galaxies, some fainter than some star clusters, makes one wonder
whether there may be a population of faint dwarf galaxies, lurking just
beyond our reach. The extended atomic hydrogen disks of galaxies
provide an unique probe of galaxy evolution. They are ideal tracers of
tidal interactions with satellites and the galactic gravitational
potential well. We have recently developed a method whereby one can
infer the mass, and relative position (in radius and azimuth) of
satellites from analysis of observed disturbances in outer gas disks,
without requiring knowledge of their optical light. I will present the
proof of principle of this method by applying it to galaxies with known
optical companions. I will also present our earlier prediction for a
dim and yet undiscovered companion of the Milky Way. I will end by
presenting preliminary work on the application of this method to
characterize the density profile of the dark matter halo in spiral
galaxies. December 14, 2012
11:00 am
Array Operations Center Auditorium
All NRAO employees are invited to attend via video, available in Charlottesville Room 230, Green Bank Room 137 and Tucson N525.
Local Host: Ravi Subrahmanyan
