THE DUSTY EMISSION FILAMENTS OF M87

Emission-line and continuum images show that the Halpha + [N II] filam ents in M87 have a double stranded or ribbon-like morphology and that they are dusty. Spectroscopy of the filaments shows smoothly varying v elocities within individual features. The innermost filaments are blue shifted with respect to systemic velocity. The presence of absorption associated with the emission filaments and alignment with the radio/op tical jet suggests that this is foreground material, in which case it is flowing out from the nucleus rather than falling in. Conversely, li ne emitting gas associated with the more distant radio lobe, as deduce d from Faraday rotation observations, appears to be background materia l, in which case it is infalling and not outflowing. By assuming press ure equilibrium between the filaments and coronal X-ray emitting gas, we estimate a high dust-to-ionized ps ratio, indicating that either th e filaments are very dusty or there is a significant neutral fraction of gas. The amount of ionized gas in the filament system is estimated to be of order 10(5)-10(7) M.. If the filaments are overpressured with respect to the coronal ps, and fully ionized, e.g., if they are evapo rating debris, or if there is a large neutral fraction then the dust-t o-ps ratio is closer to the Galactic value. The apparent outflow near the nucleus may be a small-scale galactic wind within which the cooler 10(4) K material is entrained, or it may be due to the dynamical infl uence of the synchrotron jet. The capture of a small, dusty ps-rich dw arf may have occurred which has triggered the current activity, and wh ose gaseous remnant now forms the emission filament/dust system. If th e filaments have condensed from the coronal phase in a cooling flow, t hen the cooling must have proceeded to a point where dust has been abl e to form.