1. Absolute flux G21.5-09 source region – circle radius 2.7 arcmin Best fit po x phabs model:  = 1.86 ± 0.04 Nh = 1.91 ± 0.04 x 10 22 cm -2 Flux (2-10 keV) = 5.1 x 10 -11 ergs cm -2 s -1 Ginga:  = 1.88, Nh = 1.3 x 10 22 cm -2 Flux (2-10 keV) = 5.2 x 10 -11 ergs cm -2 s -1 EXOSAT:  = 1.59-1.84, Nh = 1.08 – 1.83 x 10 22 cm -2 Flux (2-10 keV) = 6.5 x 10 -11 ergs cm -2 s -1

2. Cross-correlation with pn data Best fit po x phabs model:  = 2.06 ± 0.03 Nh = 2.08 ± 0.04 x 10 22 cm -2 Flux (2-10 keV) = 7.6 x 10 -11 ergs cm -2 s -1 (flux 50% greater) Light curve shows 30 ks available but calculated exposure = 10 ks?

3. MS0737.9+7441 source region – circle radius 34'' Best fit (2-10 keV) po x phabs model: MOS1  = 2.50 ± 0.07 Flux (2-10 keV) = 3.1 x 10 -12 ergs cm -2 s -1 PN  = 2.62 ± 0.05 Flux (2-10 keV) = 3.2 x 10 -12 ergs cm -2 s -1  2-10 keV flux agrees to within 3%

4. MOS Flux (0.2-2.0 keV) = 6.0x 10 -12 ergs cm -2 s -1 PN Flux (0.2-2.0 keV) = 7.0 x 10 -12 ergs cm -2 s -1 (17% difference)