Bounds on Dark Matter Properties from Radio Observations of Ursa Major
  II using the Green Bank Telescope
  Radio observations of the Ursa Major II dwarf spheroidal galaxy obtained
using the Green Bank Telescope are used to place bounds on WIMP dark matter
properties. Dark matter annihilation releases energy in the form of charged
particles which emit synchrotron radiation in the magnetic field of the dwarf
galaxy. We compute the expected synchrotron radiation intensity from WIMP
annihilation to various primary channels. The predicted synchrotron radiation
is sensitive to the distribution of dark matter in the halo, the diffusion
coefficient D_0, the magnetic field strength B, the particle mass m_\chi, the
annihilation rate <\sigma v>, and the annihilation channel. Limits on <\sigma
v>, m_\chi, B, and D_0 are obtained for the e^+ e^-, \mu^+ \mu^-, \tau^+
\tau^-, and b \bar b channels. Constraints on these parameters are sensitive to
uncertainties in the measurement of the dark matter density profile. For the
best fit halo parameters derived from stellar kinematics, we exclude 10 GeV
WIMPs annihilating directly to e^+ e^- at the thermal rate <\sigma v> = 2.18 x
10^{-26} cm^3/s at the 2\sigma level, for B > 0.6 microGauss (1.6 microGauss)
and D_0 = 0.1 (1.0) x the Milky Way diffusion value.
