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We present dynamical measurements of the central mass-to-light ratio ($M/L$)of a sample of 27 low-mass early-type ATLAS$^{3D}$ galaxies. We consider allATLAS$^{3D}$ galaxies with 9.7$<$log(M$_\star/$M$_\odot)$$<$10.5 in ouranalysis, selecting out galaxies with available high-resolution Hubble SpaceTelescope (HST) data, and eliminating galaxies with significant central colorgradients or obvious dust features. We use the HST images to derive mass modelsfor these galaxies and combine these with the central velocity dispersionvalues from ATLAS$^{3D}$ data to obtain a central dynamical $M/L$ estimate.These central dynamical $M/L$s are higher than dynamical $M/L$s derived atlarger radii and stellar population estimates of the galaxy centers in$\sim$80\% of galaxies, with a median enhancement of $\sim$14\% and astatistical significance of 3.3$\sigma$. We show that the enhancement in thecentral $M/L$ is best described either by the presence of black holes in thesegalaxies or by radial IMF variations. Assuming a black hole model, we deriveblack hole masses for the sample of galaxies. In two galaxies, NGC 4458 and NGC4660, the data suggests significantly over-massive BHs, while in most othersonly upper limits are obtained. We also show that the level of $M/L$enhancements we see in these early-type galaxy nuclei are consistent with thelarger enhancements seen in ultracompact dwarf galaxies (UCDs), supporting thescenario where massive UCDs are created by stripping galaxies of these masses.

Detection of Enhanced Central Mass-to-Light Ratios in Low-Mass Early-Type Galaxies: Evidence for Black Holes?