OPTICAL AND ULTRAVIOLET OBSERVATIONS OF 3C-279 DURING OUTBURST

An ongoing program of photometric monitoring of selected active galactic nuclei has revealed a significant outburst in the optically violently variable QSO 3C 279. The event occurred during May and June of 1992, and was characterized by a peak amplitude of 2.3 mag in the R band. We obtained nearly simultaneous optical and ultraviolet spectroscopy from 1150 to 8600 angstrom of the source at the approximate midpoint of the outburst. The outburst spectrum is well represented by a power law with index alpha = -1.77 (where F(nu) is-proportional-to nu(alpha)) which is relatively flat in comparison with typical quiescent spectra for this source. No emission features are discernable in our data, nor is there any significant Lyman-edge absorption. The observations and data analysis procedures are described, and the resulting photometric light curves and spectra are presented. We also present a long baseline photometric light curve for context. Comparisons with previously published optical-UV outburst and quiescent spectra are made, and luminosity-dependent spectral variations are discussed.