A new force in the Dark Sector?
Glennys Farrar ( NYU ) - Nov. 13
PPT at 12:00 noon
The dynamics of dark matter is studied using the massive cluster of
galaxies 1E0657-56. The velocity of the ``bullet" subcluster has been
measured by X-ray emission from the shock front, and the masses and
separation of the main and sub-clusters have been measured by gravitational
lensing. The velocity with gravity alone is calculated in a variety of
models of the initial conditions, mass distribution and accretion history;
it is much higher than expected, by at least 2.4 sigma. The probability of
so large a subcluster velocity in cosmological simulations is, following
Hayashi and White, <10^{-7}. A long range force with strength ~ 0.4 - 0.8
times that of gravity would provide the needed additional acceleration.
The seminar will be held in 544 Campbell Hall.
Return to seminar schedule