Quasi-simultaneous optical and UV observations of OJ 287 during an active period in 1983.

Abstract

Far UV spectra (1200 - 3000 Å) of OJ 287 were taken with IUE on Feb. 15th, 1983. Optical spectrophotometry (4500 - 7800 Å) was obtained three days later with the 1.8 m telescope of the Asiago Observatory. The source was in an intermediate state, m_V ≅ 14, between quiescence and the maximum reported in January (m_V ≅ 13). A power law (F_ν ∝ ν^-α) best fit of the UV spectra with the interstellar absorption as an additional free parameter yields α_UV = 1.45±0.05 and A_V = 0.1±0.05. For the optical spectrum with A_V = 0.1, the best fit spectral index is α_opt = 0.70±0.15, indicating a pronounced spectral steepening between the two ranges, Δα = 0.75±0.15.