The Supermassive Black Hole of M87 and the Kinematics of Its Associated Gaseous Disk
Abstract
We have obtained long-slit observations of the circumnuclear region of M87 at three different locations, with a spatial sampling of 0.028" using the Faint Object Camera f/48 spectrograph on board HST. These data allow us to determine the rotation curve of the inner ~1" of the ionized gas disk in [O II] λ3727 to a distance as close as 0.07" (~=5 pc) to the dynamic center, thereby significantly improving on both the spatial resolution and coverage of previous FOS observations. We have modeled the kinematics of the gas under the assumption of the existence of both a central black hole and an extended central mass distribution, taking into account the effects of the instrumental PSF, the intrinsic luminosity distribution of the line, and the finite size of the slit. We find that the central mass must be concentrated within a sphere whose maximum radius is 0.05" (~=3.5 pc) and show that both the observed rotation curve and line profiles are consistent with a thin disk in Keplerian motion. We conclude that the most likely explanation for the observed motions is the presence of a supermassive black hole and derive a value of MBH = (3.2 +/- 0.9) × 109 M⊙ for its mass.
Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS 5-26555 and by STScI grant GO-3594.01-91A.- Publication:
-
The Astrophysical Journal
- Pub Date:
- November 1997
- DOI:
- 10.1086/304823
- arXiv:
- arXiv:astro-ph/9706252
- Bibcode:
- 1997ApJ...489..579M
- Keywords:
-
- Black Hole Physics;
- Galaxies: Individual: Messier Number: M87;
- Galaxies: Kinematics and Dynamics;
- Galaxies: Nuclei;
- Astrophysics
- E-Print:
- 43 pages, 5 Tables and 19 Postscript figures (included), requires AASTeX style files, in press on the Astrophysical Journal