We present the discovery of a gravitationally lensed dust-reddened QSO at z = 2.517 discovered in a survey for red QSOs by infrared selection . Hubble Space Telescope imaging in the WFC3/IR F160W and F125W filters reveals a quadruply lensed system in a cusp configuration .
We find that compared to the central image of the cusp , the nearby , brightest image is anomalous by a factor of \sim 7 - 11 .
Although the source is extremely bright in the mid-infrared , a magnification by a factor of \sim 50 - 120 places an upper limit of 1.35 mJy on the intrinsic mid-infrared brightness , well below the WISE~ { } W 4 detection limit of 6 mJy .
We find that this QSO is moderately reddened , with E ( B - V ) = 0.7 and that \sim 1 \% of the intrinsic spectrum is leaked back into the line of sight resulting in an upturn in its UV spectrum .
We conclude that the QSO ’ s reddening is intrinsic and not due to the lens .
Consistent with previous red quasar samples , this source exhibits outflows in its spectrum as well as morphological properties suggestive of it being in a merger-driven transitional phase .
Depending on how L _ { bol } is computed , the quasar ’ s accretion rate may be as high as 0.26 ~ { } L _ { Edd } .
We detect two Lyman limit systems , at z = 2.102 and z = 2.431 , with absorption by metal lines likely at small impact parameter to the QSO , and a putative lens redshift of z = 0.599 .
Given the rarity of quad lenses , the discovery of this source allows detailed study of a less luminous , more typical infrared-selected quasar at high redshift .