Wide companions of low-mass stars and brown dwarfs

We searched a sample of 132 M7-L8 dwarfs to magnitude limits of J~20.5 and K~18.5, corresponding to secondary-to-primary mass ratios of ~0.5. No companions were found with separations between 2" and 31" (~40 to ~1000AU).

This null result implies a wide companion frequency below 2.3% at the 95% confidence level within the sensitivity limits of the survey. Preliminary modeling efforts indicate that we could have detected 85% of companions more massive than 0.05M_{sun}_ and 50% above 0.03M_{sun}_.