Chandra observations of SDSS J1004+4112: Constraints on the lensing cluster and anomalous X-ray flux ratios of the quadruply imaged quasar

We present results from Chandra observations of SDSS J1004+4112, a strongly lensed quasar system with a maximum image separation of 15. All four bright images of the quasar, as well as resolved X-ray emission originating from the lensing cluster, are clearly detected. The emission from the lensing cluster extends out to approximately 1′.5. We measure the bolometric X-ray luminosity and temperature of the lensing cluster to be 4.7 × 10 ⁴⁴ ergs s^-1 and 6.4 keV, consistent with the luminosity-temperature relation for distant clusters. The mass estimated from the X-ray observation shows excellent agreement with the mass derived from gravitational lensing. The X-ray flux ratios of the quasar images differ markedly from the optical flux ratios, and the combined X-ray spectrum of the images possesses an unusually strong Fe Ka emission line, both of which are indicative of microlensing.