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We present results from the Large Adaptive optics Survey for SubstellarObjects (LASSO), where the goal is to directly image new substellar companions(<70 M$_{Jup}$) at wide orbital separations ($\gtrsim$50 AU) around young($\lesssim$300 Myrs), nearby (<100 pc), low-mass ($\approx$0.1-0.8 M$_{\odot}$)stars. We report on 427 young stars imaged in the visible (i') andnear-infrared (J or H) simultaneously with Robo-AO on the Kitt Peak 2.1-mtelescope and later the Maunakea University of Hawaii 2.2-m telescope. Toundertake the observations, we commissioned a new infrared camera for Robo-AOthat uses a low-noise high-speed SAPHIRA avalanche photodiode detector. Wedetected 121 companion candidates around 111 stars, of which 62 companions arephysically associated based on Gaia DR2 parallaxes and proper motions, another45 require follow-up observations to confirm physical association, and 14 arebackground objects. The companion separations range from 2-1101 AU and reachcontrast ratios of 7.7 magnitudes in the near infrared compared to the primary.The majority of confirmed and pending candidates are stellar companions, with~5 being potentially substellar and requiring follow-up observations forconfirmation. We also detected a 43$\pm$9 M$_{Jup}$ and an 81$\pm$5 M$_{Jup}$companion that were previously reported. We found 34 of our targets haveacceleration measurements detected using Hipparcos-Gaia proper motions. Ofthose, 58$^{+12}_{-14}$% of the 12 stars with imaged companion candidates havesignificant accelerations ($\chi^2 >11.8$), while only 23$^{+11}_{-6}$% of theremaining 22 stars with no detected companion have significant accelerations.The significance of the acceleration decreases with increasing companionseparation. These young accelerating low-mass stars with companions willeventually yield dynamical masses with future orbit monitoring.

Large Adaptive Optics Survey for Substellar Objects (LASSO) Around Young, Nearby, Low-mass Stars with Robo-AO