TITLE: GCN CIRCULAR NUMBER: 19481 SUBJECT: GRB 160530A: Swift follow-up and X-ray afterglow candidate DATE: 16/06/01 16:58:01 GMT FROM: Valerio D'Elia at ASDC V. D’Elia (ASDC), L. Izzo (IAA-CSIC), P. A. Evans (U. Leicester), A. A. Breeveld (UCL-MSSL), J.A. Kennea (PSU), D. Malesani (DARK/NBI), C. B. Markwardt (NASA/GSFC) report on behalf of the Swift team: Swift has performed follow-up observations of the COSI-detected burst GRB 160530A (Tomsick, GCN Circ. 19473) in a series of observations tiled on the sky. The total exposure time is 24 ks, distributed over 46 tiles; the maximum exposure at a single sky location was 1.4 ks. The data were collected between T0+19.0 ks and T0+158 ks, and are entirely in Photon Counting (PC) mode. One uncatalogued X-ray source has been detected by XRT in the intersection of the COSI and the IPN error regions (Svinkin et al., GCN Circ. 19476), however, this source is below the RASS limit at its location, and we cannot currently determine whether it is fading. Therefore, at the present time we cannot state if it is the afterglow. The source was imaged and detected in the time interval T0+145 ks to T0+158 ks and comprises 920 s of exposure time. More XRT data are expected in the forthcoming days. Further details of this source are given below: RA (J2000.0): 118.9741 = 07:55:53.77 Dec (J2000.0): -25.4638 = -25:27:49.7 Error: 6.6 arcsec (radius, 90% conf.) Count-rate: 0.0222 +/- 0.0070 ct s^-1 Flux: (6.3 +/- 2.0)e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV) No optical afterglow consistent with the XRT source position is detected in the initial UVOT exposures. The preliminary 3-sigma upper limit for the summed U-band exposures (926 s) is 20.8 mag.