J/A+A/310/384 J/A+A/310/384 Optical brightness of 3 ROSAT Seyfert galaxies J Greiner R Danner N Bade G A Richter P Kroll S Komossa Astron. Astrophys. 310 384 1996 1996A&A...310..384G Active gal. nuclei Galaxies, optical Galaxies, photometry galaxies: active galaxies: individual (RX J1225.7+2055, RX J1239.3+2431) galaxies: individual (RX J1250.2+1923, RX J1257.5+2412) X-rays: general The printed version of this paper describes the X-ray and optical properties of four new active galaxies discovered in the ROSAT All-Sky Survey. While one object (RX J1257.5+2412) is identified as a BL Lac object, the other three (RX J1239.3+2431, RX J1225.7+2055, and RX J1250.2+1923) are narrow line Seyfert 1 galaxies. Three of these four objects are bright enough to be studied on archival photographic plates of Sonneberg Observatory. The present list contains the individual brightness measurements of these objects all of which turned out to be variable on timescales of weeks to years. Some lightcurves (long-term as well as short-term) are given in the printed version.

ROSAT RX J1225.7+2055S1094212 25.7 +20 55 RX J1257.5+2412S1094112 57.5 +24 12 RX J1239.3+2431S1094012 39.3 +24 31

HJD Julian date of middle of exposure time. The exposure time ranges between 40-60 min. d Mag1 Brightness estimate for RX J1225.7+2055 mag n_Mag1 Comment on accuracy of brightness estimate of RX J1225.7+2055 number=1 No entry in the comment column means an accurate brightness estimate (error of +/-0.08 mag), while the five different signs have the following meanings: < denotes an upper limit, : denotes a slightly increased error (+/-0.14 mag), :: denotes an increased error (+/-0.20 mag), ? denotes an uncertain measurement, ?? denotes a doubtful measurement. --- Mag2 Brightness estimate for RX J1257.5+2412 mag n_Mag2 Comment on accuracy of brightness estimate of RX J1257.5+2412 number=1 No entry in the comment column means an accurate brightness estimate (error of +/-0.08 mag), while the five different signs have the following meanings: < denotes an upper limit, : denotes a slightly increased error (+/-0.14 mag), :: denotes an increased error (+/-0.20 mag), ? denotes an uncertain measurement, ?? denotes a doubtful measurement. --- Mag3 Brightness estimate for RX J1239.3+2431 mag n_Mag3 Comment on accuracy of brightness estimate of RX J1239.3+2431 number=1 No entry in the comment column means an accurate brightness estimate (error of +/-0.08 mag), while the five different signs have the following meanings: < denotes an upper limit, : denotes a slightly increased error (+/-0.14 mag), :: denotes an increased error (+/-0.20 mag), ? denotes an uncertain measurement, ?? denotes a doubtful measurement. --- Patricia Bauer CDS 1995Dec20 J_A+A_310_384.xml