Observed 0.5–2 keV (top) and 2–10 keV (bottom) fluxes of Mrk 273 (crosses) and Mrk 273x (open circles) from 1994 to 2006 as determined from ASCA, BeppoSAX, XMM-Newton, Chandra, and Suzaku data. Each asterisk represents the sum of the fluxes from Mrk 273 and Mrk 273x. In the top panel, the dashed line represents the weighted average of the data points for Mrk 273 and Mrk 273x from 1994, 2000, and 2002 and the dotted lines represent a single standard deviation away from that mean. In the bottom panel, the dashed line represents the weighted average of the data points for Mrk 273 and Mrk 273x from 1994, 1998, 2002, and 2006 and the dotted lines denote one standard deviation away from the mean. Small flux increases in Mrk 273 may be observed in 2006 in the 0.5–2 keV band and in 2000 in the 2–10 keV band. The ASCA (1994) and BeppoSAX (1998) values are drawn from Iwasawa (1999) and Risaliti et al. (2000), respectively. The Chandra (2000) and XMM-Newton (2002) values are derived from our modeling of the archived spectra with the scattering model (see Section 5.2). The error bars to the total flux are the sums of the errors in the measured fluxes of Mrk 273 and Mrk 273x added in quadrature. A small horizontal offset was applied to the Mrk 273 data points to better display the measurement errors. Since the errors on the BeppoSAX measurements are not published, they are assumed to be ± 20% based on the results on F05189 − 2524 by Severgnini et al. (2001).