[Previous] | [Session 99] | [Next]

[99.02] STIS Spectra of M81's Nucleus

H.C. Ford, Z. Tsvetanov, C. Tremonti (The Johns Hopkins University), G. Jacoby (NOAO), N. Devereux (NMSU)

We observed M81 with the STIS 0.1 arc-sec slit stepped across the nucleus in seven contiguous positions. The spectrum covered 630 nm to 683 nm with a dispersion of 0.52 angstroms per pixel. The blue and redshfited rotation velocity in the apparent disk of ionized gas increases toward the nucleus, with a velocity discontinuity of approximately 100 km/s across the nucleus. The maximum observed rotation occurs within 0.3 arc-sec (5 parsecs) of the center. The extremely broad H\alpha line (FWZI \geq 10,000 km/s)is confined to the central 0.1 arc-sec. The preliminary central mass is ~5 \times 10⁶/{sin(i)} M_\odot.

We will discuss the observations, rotation models, and the implications for a massive black hole in the center of this nearest mini-Seyfert galaxy.