Mrk 1216 is a nearby , early-type galaxy with a small effective radius of 2.8 kpc and a large stellar velocity dispersion of 308 km s ^ { -1 } for its K -band luminosity of 1.4 \times 10 ^ { 11 } L _ { \odot } .
Using integral-field spectroscopy assisted by adaptive optics from Gemini North , we measure spatially resolved stellar kinematics within \sim 450 pc of the galaxy nucleus .
The galaxy exhibits regular rotation with velocities of \pm 180 km s ^ { -1 } and a sharply peaked velocity dispersion profile that reaches 425 km s ^ { -1 } at the center .
We fit axisymmetric , orbit-based dynamical models to the combination of these high angular resolution kinematics , large-scale kinematics extending to roughly three effective radii , and Hubble Space Telescope imaging , resulting in a constraint of the mass of the central black hole in Mrk 1216 .
After exploring several possible sources of systematics that commonly affect stellar-dynamical black hole mass measurements , we find a black hole mass of M _ { \mathrm { BH } } = ( 4.9 \pm 1.7 ) \times 10 ^ { 9 } M _ { \odot } and a H -band stellar mass-to-light ratio of \Upsilon _ { H } = 1.3 \pm 0.4 \Upsilon _ { \odot } ( 1 \sigma uncertainties ) .
Mrk 1216 is consistent with the local black hole mass – stellar velocity dispersion relation , but is a factor of \sim 5 - 10 larger than expectations from the black hole mass – bulge luminosity and black hole mass – bulge mass correlations when conservatively using the galaxy ’ s total luminosity or stellar mass .
This behavior is quite similar to the extensively studied compact galaxy NGC 1277 .
Resembling the z \sim 2 quiescent galaxies , Mrk 1216 may be a passively evolved descendant , and perhaps reflects a previous era when galaxies contained over-massive black holes relative to their bulge luminosities/masses , and the growth of host galaxies had yet to catch up .