TITLE:   GCN CIRCULAR
NUMBER:  17258
SUBJECT: Swift-XRT and UVOT follow-up of iPTF14jko (GRB 141230A)
DATE:    14/12/30 23:26:05 GMT
FROM:    Andrea Melandri at INAF-OAB  <andrea.melandri@brera.inaf.it>

A. Melandri, M.G. Bernardini, P. D’Avanzo (INAF-OAB), F. E. Marshall (NASA/GSFC), P.A. Evans and M.R. Goad (U. Leicester) report on behalf of the Swift team:

We have analysed 3 ks of Swift-XRT data for the optical transient iPTF14jko (Singer et al., GCN 17254) within the error circle of the Fermi/GBM GRB 141230A (Roberts, GCN Circ. 17257), from 29.2 ks to 41.9 ks after the GBM trigger. The data are all in Photon Counting (PC) mode. No X-ray afterglow is detected at the position of the iPTF14jko optical source reported by Singer et al. (GCN Circ 17254). The 3-sigma upper limit is 3.3 x 10^-3 cts/s.

The Swift-UVOT began settled observations of the field of GRB 141230A about 29.2 ks after the GBM trigger. No optical afterglow consistent with the optical position (Singer et al. GCN Circ. 17254) is detected in the initial UVOT exposures.The preliminary 3-sigma upper limit using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the initial exposures is:

Filter         T_start(s)   T_stop(s)      Exp(s)         Mag
w2               29202        41957         2928         >21.8

The magnitude in the table is not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.10 in the direction of the burst (Schlegel et al. 1998).