Confirmation of Intervening Filaments of Galaxies at the Redshifts of $Chandra$ WHIM Absorption Features

We report the $aposteriori$ confirmation of two large-scale filaments along the sight-line of the blazar 1ES~1553+113, which correspond to Warm-Hot Intergalactic Medium (WHIM) absorption features in the X-ray and far ultraviolet. We use the WISE-SuperCOSMOS photometric catalog to map the cosmic-web in the direction of the blazar, and find significant filaments at redshifts of $z=0.23\pm 0.02$ and $z=0.31\pm 0.02$, which roughly align with the absorption redshifts. A third X-ray absorption feature at $z_X=0.133$ did not have any corresponding structures in the photometric catalog.