An observation of the gravitationally lensed system 2016+112 with the Chandra X-ray Observatory has resolved a mystery regarding the proposed presence of a dark matter object in the lens plane of this system .
The Chandra ACIS observation has clearly detected the lensed images of 2016+112 with positions in good agreement with those reported in the optical and also detects 13 additional X-ray sources within a radius of 3.5 arcmin .
Previous X-ray observations in the direction of 2016+112 with the ROSAT HRI and ASCA SIS have interpreted the X-ray data as arising from extended emission from a dark cluster .
However , the present Chandra observation can account for all the X-ray emission as originating from the lensed images and additional point X-ray sources in the field .
Thus cluster parameters based on previous X-ray observations are unreliable .
We place a 3 \sigma upper limit on the 2-10keV flux and luminosity of the cluster of 1.6 \times 10 ^ { -14 } erg s ^ { -1 } cm ^ { -2 } and 1.7 \times 10 ^ { 44 } erg s ^ { -1 } , respectively .
We estimate an upper limit on the mass-to-light ratio within a radius of 800 h _ { 50 } ^ { -1 } kpc of M /L _ { V } < 190 h _ { 50 } ( M / L _ { V } ) _ { \odot } .
None of the additional point X-ray sources are associated with the galaxy cluster members recently detected in deep optical and IR observations ( Soucail et al .
2000 ) .

The lensed object is quite unusual , with reported narrow emission lines in the optical that suggest it may be a type-2 quasar ( Yamada et .
al .
1999 ) .
Our modeling of the X-ray spectrum of the lensed object implies that the column density of an intrinsic absorber must lie between 3 and 85 \times 10 ^ { 22 } cm ^ { -2 } ( 3 \sigma confidence level ) .
The 2-10 keV luminosity of the lensed object , corrected for the lens magnification effect and using the above range of intrinsic absorption , is 3 \times 10 ^ { 43 } - 1.4 \times 10 ^ { 44 } erg s ^ { -1 } .