We analyze the optical , UV , and X-ray microlensing variability of the lensed quasar SDSS J0924+0219 using six epochs of Chandra data in two energy bands ( spanning 0.4–8.0 keV , or 1–20 keV in the quasar rest frame ) , 10 epochs of F275W ( rest-frame 1089Å ) Hubble Space Telescope data , and high-cadence R -band ( rest-frame 2770Å ) monitoring spanning eleven years .
Our joint analysis provides robust constraints on the extent of the X-ray continuum emission region and the projected area of the accretion disk .
The best-fit half-light radius of the soft X-ray continuum emission region is between 5 \times 10 ^ { 13 } and 10 ^ { 15 } cm , and we find an upper limit of 10 ^ { 15 } cm for the hard X-rays .
The best-fit soft-band size is about 13 times smaller than the optical size , and roughly 7 GM _ { BH } / c ^ { 2 } for a 2.8 \times 10 ^ { 8 } M _ { \odot } black hole , similar to the results for other systems .
We find that the UV emitting region falls in between the optical and X-ray emitting regions at 10 ^ { 14 } cm < r _ { 1 / 2 , { UV } } < 3 \times 10 ^ { 15 } cm .
Finally , the optical size is significantly larger , by 1.5 \sigma , than the theoretical thin-disk estimate based on the observed , magnification-corrected I -band flux , suggesting a shallower temperature profile than expected for a standard disk .