THE VARIABLE SOURCE RESPONSIBLE FOR THE PHOTOMETRIC BEHAVIOR OF OJ-287 IN THE IR-OPTICAL-UV REGION DURING THE 1980S

The relative spectral energy distributions of the variable source that produced the variability of blazar OJ 287 in near infrared between 19 79 and 1986 have been found from the published multicolour (JHKL) phot ometric data. Contrary to the optical region there are differences bet ween the distributions for the low and high flux levels. In the plane log Phi(v) divided by log v the former is linear while the latter is p robably curved and undoubtedly more flat. By the comparison of the dat a in K and B bands the spectra of these sources were combined with tha t of an earlier separated variable source responsible for the variabil ity in the optical-UV region. For the low flux levels the spectrum of the variable source in the range from L to lambda 1500 is reasonably w ell represented by the spectrum of a homogeneous synchrotron source. F or the higher flux levels synchrotron self-absorption (well seen in L) may be present.