{
  "bibcode": "2006GCN..4749....1H",
  "body": "J. P. Halpern (Columbia U.) and N. Mirabal (U. Michigan) report\non behalf of the MDM Observatory GRB follow-up team:\n\n\"Follow-up observations summarized here support our original\nsuggestion in GCN 3891 of an optical afterglow for the Swift\nGRB 050826 (GCN 3884, 3888), and indicate the presence of a \nrelatively bright host galaxy for this long burst.\n\nFirst, the Swift XRT position of the afterglow, which was\noriginally determined to lie 8\" from the optical candidate\nwith an 90% uncertainty radius of 6\" (GCN 3889, 3891), was\nsubsequently refined (as were all XRT positions).  In the \nrevised catalog of Moretti et al. (astro-ph/0511604), the \nXRT position falls only 3.1\" from the optical position,\nconsistent with the improved 3.4\" X-ray uncertainty.\n\n    ---------------------------------------------------\n                    R.A. (2000)   Dec. (2000)   +/- (\")\n    ---------------------------------------------------\n     Swift XRT      05 51 01.49   -02 38 38.6     3.4\n     MDM 1.3m OT    05 51 01.58   -02 38 35.8     0.5\n     MDM 2.4m host  05 51 01.59   -02 38 36.2     0.5\n    ---------------------------------------------------\n\nSecond, image subtraction among observations obtained on three \nconsecutive nights on the MDM 1.3m reveals a point-like OT on\nthe first night only, and shows that the light is dominated by\nthe host galaxy on the second and third nights.  The OT is offset\n~0.4\" to the north of the brightest part of the galaxy.\n\n   ------------------------------------------------------\n                          MDM 1.3m\n   ------------------------------------------------------\n    Date(UT)   Time(UT)    t-t0(hours)    Diff OT R(mag)\n   ------------------------------------------------------\n    Aug. 26   10:42-11:57   4.40- 5.65    22.23 +/- 0.15\t\n    Aug. 27   10:43-11:58  28.42-29.67  > 22.8\n    Aug. 28   11:03-11:57  52.75-53.65                       \n   ------------------------------------------------------\n                          MDM 2.4m         Host R(mag)\n   ------------------------------------------------------\n    Dec. 25                               21.67 +/- 0.05\n   ------------------------------------------------------\n\nThird, using the MDM 2.4m, RETROCAM imager, and SDSS r' filter\non 2005 Dec. 25, a bright core and irregular extension of the\npresumed host galaxy are clearly resolved in seeing of 1\". \nThe host magnitude listed above is measured in a 1.8\" radius.\n\nOptical magnitudes were calibrated with Landolt standard stars,\nand positions were derived with respect to the USNO B1.0 catalog.\n\nThe MDM images are posted at \n\nhttp://www.astro.columbia.edu/~jules/grb/050826/\n\nSpectroscopy and deeper imaging are needed to measure the redshift \nand star-forming properties of the presumed host galaxy.\n\nThis message may be cited.\"",
  "circularId": 4749,
  "createdOn": 1139709194000,
  "email": "jules@astro.columbia.edu",
  "subject": "GRB 050826: Optical Afterglow and Host Galaxy",
  "submitter": "Jules Halpern at Columbia U.  <jules@astro.columbia.edu>",
  "eventId": "GRB 050826"
}