Searching for binary Y dwarfs with the Gemini Multi-Conjugate Adaptive Optics System (GeMS)

The NASA Wide-field Infrared Survey Explorer (WISE) has delivered an exceptional harvest of new ultra-cool Y-type brown dwarfs. We present results from a diffraction-limited study of the binary status of a sample of Y dwarfs observed with the Gemini GeMS Multi-Conjugate Adaptive Optics system. We report no evidence of equal mass/luminosity binaries at separations larger than ~ 0.5 -2.0 AU for six Y dwarfs.