A Multifrequency Catalog of Liners

We present the first Catalog of Low Ionization Emission Line Galaxies (LINE Rs or Liners, which is the simplest name, and which we shall adopt in what follows). The Catalog "MCL" (Multifrequency Catalog of Liners), contains 47 6 entries and contains both broad-band and monochromatic emission data (ran ging from radio to X-ray frequencies) of colors, and other data compiled fr om the literature and various data bases, as indicated in the references. M ost of the galaxies can be considered "pure" Liners on the basis of the Vei lleux & Osterbrock (1987) classification as suggested by Ho, Filippenko, & Sargent (1997). However, a considerable number of transition (Liners-HII or Liners-Starburst) objects are also included. One of the open questions, is whether Liners should be considered as a class of galaxies (like Seyfert g alaxies for instance) or rather, as an heterogeneous group Of objects. We b elieve the study of Liners as a group is very interesting, precisely becaus e they very likely represent a transition between non-thermal and starburst activity, and probably also between "active" and "non- active" galaxies. T his catalog may be used as a basis for statistical research. A preliminary discussion of the main statistical properties of Liners, in the range from radio to X-ray frequencies, is given here.