{
  "bibcode": "2015GCN.18310....1P",
  "body": "K.L. Page (U. Leicester), M. H. Siegel (PSU) and P.A. Evans (U.\nLeicester) report on behalf of the Swift-XRT team:\n\nSwift-XRT has performed follow-up observations of the INTEGRAL-detected\nburst GRB 150912A (Mereghetti et al. GCN Circ. 18291), collecting 4.7\nks of Photon Counting (PC) mode data between T0+32.6 ks and T0+50.4 ks.\n\n\nNo X-ray sources have been detected inside or close to the INTEGRAL\nerror region. The 3-sigma upper limit in the field ranges from ~0.002\nto ~0.004 ct s^-1, corresponding to a 0.3-10 keV observed flux of\n9.0e-14 to 1.5e-13 erg cm^-2 s^-1 (assuming a typical GRB spectrum).\n\nTwo uncatalogued sources were detected too far from the GRB position to\nbe likely afterglow candidates.\n\nThe results of the XRT-team automatic analysis of the XRT observations,\nincluding a position-specific upper limit calculator, are available at\nhttp://www.swift.ac.uk/ToO_GRBs/00020557.\n\nSwift-UVOT also began settled observations of the field of GRB 150912A\n32.6 ks after the INTEGRAL trigger. No optical afterglow consistent\nwith the INTEGRAL position is detected in the initial UVOT exposures.\nPreliminary 3-sigma upper limits using the UVOT photometric system\n(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the initial\nexposures are:\n\nFilter\t       T_start(s)   T_stop(s)\t   Exp(s)\t  Mag\n\nw2\t\t 32643\t      50446\t    4789\t >21.2\n\nThe magnitudes in the table are not corrected for the Galactic\nextinction due to the reddening of E(B-V) = 0.42 in the direction of\nthe burst (Schlegel et al. 1998).\n\nThis circular is an official product of the Swift-XRT and UVOT teams.",
  "circularId": 18310,
  "createdOn": 1442237908000,
  "email": "klp5@leicester.ac.uk",
  "subject": "GRB 150912A: Swift-XRT and UVOT observations",
  "submitter": "Kim Page at U.of Leicester  <klp5@leicester.ac.uk>",
  "eventId": "GRB 150912A"
}