TITLE: GCN CIRCULAR NUMBER: 15891 SUBJECT: GRB 140226A / iPTF14yb: Swift-XRT confirms a fading X-ray source DATE: 14/02/28 15:11:10 GMT FROM: Andy Beardmore at U Leicester A.P. Beardmore (U. Leicester) reports on behalf of the Swift-XRT team: The Swift-XRT has continued to observe the source GRB 140226A / iPTF14yb (Cenko et al., GCN Circ. 15883; Cucchiara et al., GCN Circ. 15886; Varela et al., GCN Circ. 15887; Hurley et al., GCN Circ. 15888) and has now accumulated 9.1ks of data in Photon Counting (PC) mode. The X-ray light curve shows that the source announced by Beardmore et al. (GCN Circ. 15884) has faded, with a powerlaw decay index of 1.47 +0.29 -0.25 (with respect to the Konus-Wind T0; Golenetskii et al., GCN Circ. 15889). Taken together with the fading optical source and IPN localisation, the decaying X-ray source confirms the GRB origin of the object. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00033157.