Comparison of the UV emission line intensities in PG 0043+039 (upper panel) with respect to a composite HST/COS spectrum of 22 AGN (Shull et al. 2012, lower panel). We combined the two ultraviolet spectra of PG 0043+039 taken with the HST in the years 2013 and 1991. The UV line and continuum intensities increased by a factor of 1.8 between these two observations. We multiplied the UV spectral flux taken in 1991 with this factor to match the UV observations taken in 2013. The continua of both spectra are indicated as brown lines.
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