ATLAS OF QUASAR ENERGY-DISTRIBUTIONS

We present an atlas of the spectral energy distributions (SEDs) of nor mal, nonblazar, quasars over the whole available range ( radio to 10 k eV X-rays) of the electromagnetic spectrum. The primary (UVSX) sample includes 47 quasars for which the spectral energy distributions includ e X-ray spectral indices and UV data. Of these, 29 are radio quiet, an d 18 are radio loud. The SEDs are presented both in figures and in tab ular form, with additional tabular material published on CD-ROM. Previ ously unpublished observational data for a second set of quasars exclu ded from the primary sample are also tabulated. The effects of host ga laxy starlight contamination and foreground extinction on the UVSX sam ple are considered and the sample is used to investigate the range of SED properties. Of course, the properties we derive are influenced str ongly by the selection effects induced by quasar discovery techniques. We derive the mean energy distribution (MED) for radio-loud and radio -quiet objects and present the bolometric corrections derived from it. We note, however, that the dispersion about this mean is large (simil ar to one decade for both the infrared and ultraviolet components when the MED is normalized at the near-infrared inflection). At least part of the dispersion in the ultraviolet may be due to time variability, but this is unlikely to be important in the infrared. The existence of such a large dispersion indicates that the MED reflects only some of the properties of quasars and so should be used only with caution.