{
  "bibcode": "2000GCN...887....1G",
  "body": "J. Greiner (AIP, Potsdam), B. Stecklum, S. Klose (both TLS, Tautenburg), \nA.J. Castro-Tirado (LAEFF-INTA, Madrid and IAA-CSIC, Granada), \nF.J. Vrba, A.A. Henden (both US Naval Observatory, Flagstaff),\nM. Feldt (MPIA, Heidelberg), L. Montoya, A. Aguire (both Calar Alto),\nJ. Fliri (LMU, Muenchen), J.M. Castro Ceron (ROA, San Fernando), \nreport:\n\nStarting at about 9 hrs after the  occurence of GRB 001109 we have observed its\n50 arcsec radius error box (GCN #879, #885, IAUC 7519) in the B, R, I and H \nband with the Calar Alto (CA), and Naval Observatory Flagstaff Station (NOFS) \ntelescopes  as detailed below:\n\n--------------------------------------------------------------------\n   Date (UT)      Telescope    filter  exposure    seeing   limiting\n   (Start)                              (sec)     (arcsec)    mag.\n--------------------------------------------------------------------\n  Nov. 09.7712    CAHA 1.23      R      7 * 500      1.0     20.9\n  Nov. 09.7846    CAHA 1.23      B      3 * 600      1.0     19.8\n  Nov. 10.0980    NOFS 1.0       I       1800        1.9     21.0\n  Nov. 10.7623    CAHA 1.23      R      9 * 500      1.0     20.9\n  Nov. 10.8379    CAHA 3.5       H     10 * 300      1.5     20.5\n  Nov. 13.0664    NOFS 1.0       I       1800        2.6     21.0\n--------------------------------------------------------------------\n\nPhotometric calibration of the images was done based on USNO magnitudes \nin the B and R band, and with selected area SA 113 for the I band.\nA comparison of the two epochs of (summed) R-band and I-band images, \nrespectively, reveals no fading object in the GRB error box down to the \nlimiting magnitudes as given in the table. The summed B band image does not \ncontain any source which is not visible on the blue DSS-2. The H band image, \nwhen compared to the H band images of Vreeswijk et al. (GCN #886) also \nshows no fading object in the GRB error box.\n\nThe optical source coincident with the radio source mentioned in GCN #880 is \ndetected at R=20.70+/-0.15 (Nov. 9), I=20.07+/-0.1 and R=20.63+/-0.15 (Nov. 10)\nand I=20.13+/-0.1 (Nov. 13). The constancy of this source as well as the\nextended shape (GCN #886) make it possible that it could be the host galaxy of\nGRB 001109. If true, (i) this burst could be similar to GRB 981226 with a \nradio, but no optical/IR counterpart, and (ii) it would be the brightest host \ngalaxy of any GRB. If, in addition, the GRB occured within that galaxy without\nsubstantial offset, the optical afterglow would not have to be particularly\nfaint to be hidden by the light of the galaxy. Under these assumptions,\nwe estimate that we can place a limit of only R > 21.5 mag at 9 hrs and\nI > 22 mag at 17 hrs after the GRB.\n\nWe finally note that we don't see very many obvious galaxies in these images.  \nPerhaps there is higher extinction than would normally be expected at this\nhigh galactic latitude (bII=+24.96).",
  "circularId": 887,
  "createdOn": 974563968000,
  "email": "jgreiner@aip.de",
  "subject": "Optical/NIR observations of GRB001109",
  "submitter": "Jochen Greiner at Astrophys.Inst. Potsdam,Germany  <jgreiner@aip.de>",
  "eventId": "GRB 001109"
}