We present results of 2 mm observations of the Crab Nebula , obtained using the Goddard-IRAM Superconducting 2 Millimeter Observer ( GISMO ) bolometer camera on the IRAM 30 m telescope .
Additional 3.3 mm observations with the MUSTANG bolometer array on the Green Bank Telescope are also presented .
The integrated 2 mm flux density of the Crab Nebula provides no evidence for the emergence of a second synchrotron component that has been proposed .
It is consistent with the radio power law spectrum , extrapolated up to a break frequency of \log ( \nu _ { b } [ GHz ] ) = 2.84 \pm 0.29 or \nu _ { b } = 695 ^ { +651 } _ { -336 } GHz .
The Crab Nebula is well-resolved by the \sim 16 \farcs 7 beam ( FWHM ) of GISMO .
Comparison to radio data at comparable spatial resolution enables us to confirm significant spatial variation of the spectral index between 21 cm and 2 mm .
The main effect is a spectral flattening in the inner region of the Crab Nebula , correlated with the toroidal structure at the center of the nebula that is prominent in the near–IR through X-ray regime .