http://arxiv.org/abs/2304.11264
The stellar dynamic-based black hole mass measurement of M87 is twice that determined via ionized gas kinematics; they disagree by more than 3$\sigma$, being the former closer to the mass estimated from the diameter of the gravitationally-lensed ring around the black hole. Using a deeper and more comprehensive ionized gas kinematic dataset, we aim to better constrain the complex morphology and kinematics of the nuclear ionized gas. We use both Narrow and Wide Field Mode integral field spectroscopic data from the Multi Unit Spectroscopic Explorer instrument to model the kinematics of multiple ionized gas emission lines. The dataset reveals complexities in the nuclear ionized gas kinematics not seen in earlier observations. Several ionized gas filaments, some with large flow velocities, can be traced down into the projected sphere of influence. We also find evidence of a partially-filled biconical outflow, aligned with the jet. The nuclear rotating ionized gas ‘disk’ is well resolved in our datacubes. The complexity of the nuclear morphology precludes the measurement of an accurate black hole mass from the ionized gas kinematics. The ionized gas kinematics can be explained with either a 6.6 $\times 10^{9}\rm~M_{\odot}$ black hole with a disk inclination of 25\deg, or a 3.5 $\times 10^{9}\rm~M_{\odot}$ black hole with an inclination of 42\deg, with more support for the former. The velocity isophotes of the sub-arcsecond ionized gas disk are twisted, and the position angle of the innermost gas disk tends towards a value perpendicular to the radio jet axis. An inclination close to 25\deg\ for the nuclear gas disk, and the warp in the sub-arcsec ionized gas disk, help to reconcile the contradictory nature of key earlier results: the discrepancy between stellar and ionized gas measurements, and the mis-orientation between the axes of the ionized gas disk and the jet.
J. Osorno, N. Nagar, T. Richtler, et. al.
Tue, 25 Apr 23
72/72
Comments: 17 pages, 16 figures (3 of them in the appendix). Submitted to Astronomy & Astrophysics