A Chandra observation of the z= 2.285 galaxy FSC 10214+4724: evidence for a Compton-thick quasar?

We present a ≈20 ks Chandra ACIS-S observation of the strongly lensed z = 2.285 ultraluminous infrared galaxy FSC 10214 + 4724. Although this observation achieves the equivalent sensitivity of an up to ≈ 4M sChandra exposure (when corrected for gravitational lensing), the rest-frame 1.6‐26.3 keV emission from FSC 10214 + 4724 is weak (L X ≈ 2 × 10 42 erg s −1 for a lensing boost of ≈100); a significant fraction of this X-ray emission appears to be due to vigorous star formation activity. If FSC 10214 + 4724 hosts a quasar, as previously suggested, then it must be obscured by Compton-thick material. We compare FSC 10214 + 4724 to high-redshift SCUBA galaxies and discuss the X-ray identification of Compton-thick AGNs at high redshift.

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