Photometric Properties of AGNs from the Absolute Spectrophotometry of De Bruyn and Sargent

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The absolute spectrophotometry of 66 AGNs (de Bruyn and Sargent, 1978) is used to compute synthetic magnitudes and colors, and K-corrections in the UBV system. In our preliminary contribution (Kalinkov et al., 1988) only some results of (U-B)_s and (B-V)_s colors were given. Here we use the whole observational data given by de Bruyn and Sargent. Synthetic spectra for 41 Sy1, 7 Sy1.5 and 15 Sy2 galaxies are constructed in relative units, assuming f(λ5470) = 1000. Colors and K-corrections are obtained from the synthetic spectra. The variations with the redshift are presented in the polynomial approximation form X = a_izⁱ, i = 0,1,‥, where X = (U-B)_ss, (B-V)_ss, K_B, K_V (Table 1). The largest deviation in mag. from the computed curves is denoted by Q. The relations in Table 1 are very good approximations in the corresponding redshift ranges.