{
  "bibcode": "2003GCN..2271....1G",
  "body": "J. Greiner, A. Rau (both MPE Garching) and S. Klose \n(Thueringer Landessternwarte Tautenburg) report for the GRACE collaboration:\n\nWe have observed the original, 2 arcmin radius error box of GRB 030528 \n(=H2724) (Atteia et al, GCN 2256) with the near-infrared camera SOFI \nat the NTT (La Silla, ESO) on three epochs as given below:\n\n   Date (Start UT)   Filters   Exposure time   Seeing    \n  -------------------------------------------------------\n  2003-05-29 04:58    JHKs      15 min each     0.6\"\n  2003-05-30 04:54    JHKs      20 min each     1.0\"\n  2003-06-01 04:07     Ks       60 min          0.7\"\n\nThe Chandra sources #1 and #10 (Butler et al., GCN 2269) are within\nour field of view, the other two Chandra sources from within the \nshifted GRB location (Villasenor et al, GCN 2261) are outside our \nimages. Comparing the Ks band images of the first and third epoch \nreveals a counterpart for each of the two Chandra sources. One of \nthese two sources, i.e. #1 = CXOU J170400.3-223710 shows a fading \nby about 0.9 mag. The other of these two Chandra sources, \n#10 = CXOU J170354.0-223654 is about 4 magnitudes brighter in Ks, and\nconstant to within 0.1 mag (provisional photometric calibration was \ndone against the 2MASS catalog, taken from the NASA/ IPAC Infrared \nScience Archive).\n\nWe therefore propose Chandra source #1 = CXOU J170400.3-223710 and \nits near-infrared counterpart as the tentative afterglow of GRB 030528.\nK band images of two epochs for this source will be displayed at\nhttp://www.mpe.mpg.de/~jcg/grb030528.html\n\nSince we are missing two of the Chandra sources due to the shift of the\nGRB location, only a second Chandra observation can (dis)prove this\ntentative counterpart. We note, that the proposed counterpart is\nthe brightest X-ray source in the previous Chandra image, so a second\nChandra observation of the same exposure time can already be decisive.",
  "circularId": 2271,
  "createdOn": 1054826503000,
  "email": "jcg@mpe.mpg.de",
  "subject": "GRB 030528: tentative NIR counterpart",
  "submitter": "Jochen Greiner at MPI  <jcg@mpe.mpg.de>",
  "eventId": "GRB 030528"
}