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 \langle \sigma _ { a } v \rangle , and the annihilation channel .
Limits on \langle \sigma _ { a } v \rangle , 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 \langle \sigma _ { a } v \rangle = 2.18 \times 10 ^ { -26 } cm ^ { 3 } / s at the 2 \sigma level , for B > 0.6 \mu G ( 1.6 \mu G ) and D _ { 0 } = 0.1 ( 1.0 ) \times the Milky Way diffusion value .