A ROSAT observation of the high-redshift galaxy IRAS ${\rm F}10214+4724$

A 20-ks ROSAT observation of the extremely luminous IRAS galaxy IRAS F10214+4724 shows a very weak X-ray source, significant only at ∼2σ. This immediately refutes the hypothesis that F10214+4724 is simply a quasar with modest (A V ∼1) line-of-sight reddening, as we would then have expected thousands of counts. The X-ray absorbing column, assuming solar abundances, required to reduce the (redshifted) ∼3-keV emission to that expected from a normal quasar is ∼5×10 23 cm −2 . We compare the overall energy distribution of F10214+4724 with that of NGC 1068. The optical-UV-X-ray emission is very closely similar to that of the type 2 Seyfert nucleus of NGC 1068 (both show S ν ∞ν −2 , and very high polarization), but the IR-millimetre spectrum is a good match to that of the starburst ring