We present a detailed study of the nuclear star clusters ( NSCs ) and massive black holes ( BHs ) of four of the nearest low-mass early-type galaxies : M32 , NGC 205 , NGC 5102 , and NGC 5206 .
We measure dynamical masses of both the BHs and NSCs in these galaxies using Gemini/NIFS or VLT/SINFONI stellar kinematics , Hubble Space Telescope ( HST ) imaging , and Jeans Anisotropic Models .
We detect massive BHs in M32 , NGC 5102 , and NGC 5206 , while in NGC 205 , we find only an upper limit .
These BH mass estimates are consistent with previous measurements in M32 and NGC 205 , while those in NGC 5102 & NGC 5206 are estimated for the first time , and both found to be < 10 ^ { 6 } M _ { \odot } .
This adds to just a handful of galaxies with dynamically measured sub-million M _ { \odot } central BHs .
Combining these BH detections with our recent work on NGC 404 ’ s BH , we find that 80 % ( 4/5 ) of nearby , low-mass ( 10 ^ { 9 } -10 ^ { 10 } M _ { \odot } ; \sigma _ { \star } \sim 20 - 70 km s ^ { -1 } ) early-type galaxies host BHs .
Such a high occupation fraction suggests the BH seeds formed in the early epoch of cosmic assembly likely resulted in abundant seeds , favoring a low-mass seed mechanism of the remnants , most likely from the first generation of massive stars .
We find dynamical masses of the NSCs ranging from 2 - 73 \times 10 ^ { 6 } M _ { \odot } and compare these masses to scaling relations for NSCs based primarily on photometric mass estimates .
Color gradients suggest younger stellar populations lie at the centers of the NSCs in three of the four galaxies ( NGC 205 , NGC 5102 , and NGC 5206 ) , while the morphology of two are complex and are best-fit with multiple morphological components ( NGC 5102 and NGC 5206 ) .
The NSC kinematics show they are rotating , especially in M32 and NGC 5102 ( V / \sigma _ { \star } \sim 0.7 ) .