Interstellar matter in the core of M87

We present spectra at intermediate and high spectral resolution of the interstellar Na i D lines in the nucleus of M87. The equivalent width in the interstellar component at the redshift of M87 is 2.25 Å, measured at intermediate resolution. At high resolution the lines resolve into a number of discrete, narrow components, with a velocity range of the order of 300 km s−1. Most of the equivalent width measured at the lower resolution is contained in a large number of components too weak to be detected individually at high resolution. The individually detectable clouds are optically thick, and may just be the larger members of a population of small dense clouds in the galaxy core.