Simultaneous observations of the continuum emission of the quasar 3C 273 from radio to γ‐ray energies

From June 15–28, 1991 the Compton Gamma‐Ray Observatory (CGRO) observed the radio‐loud quasar 3C 273. All four CGRO instruments detected radiation from this quasar in their relevant energy range (from 20 keV to 5 GeV). Simultaneous and quasi‐simultaneous observations by instruments sensitive at other wavelengths have also been obtained. The data from all these observations, spanning the frequency range from ∼109 Hz–∼102 6 Hz, were collected and analyzed. Details of the observations and an overall energy‐density spectrum are presented. This spectrum shows two maxima of nearly equal strength. One is in the UV, while the other one is found at low‐energy γ‐rays. The implications of these simultaneous observations on some theoretical models will be discussed