{
  "bibcode": "2002GCN..1324....1D",
  "body": "GRB011212: Optical Observations\n\nA. Dullighan, G. Monnelly, G. Ricker, R. Vanderspek, N. Morgan (MIT);\nand D. Tholen (U.Hawaii)\n\nwrite:\n\nWe have observed the error box of the HETE GRB011212 (GCN #1194) with\nthe Baade 6.5m telescope at Magellan on 2001 December 14.17 UT (Epoch\n1) and December 15.17 UT (Epoch 2) using the MagIC CCD detector.\nTwelve 360s R-band exposures were used to mosaic the entire HETE and\nRXTE/ASM joint error box on each night.  Both nights had a seeing of\n0.7\" with a limiting magnitude of 24.5, except for the last half of\nthe second night when the seeing decreased slowly to 1.3\", with a\nlimiting magnitude of 24.0 on the last frame.  Third epoch\nobservations were made with the University of Hawaii 2.2m telescope on\nMauna Kea on 2002 February 16.33 and 17.38 UT.  Three frames were used\nto mosaic the error box each with three 600s VR-band exposures under\nconditions of 1.3\" seeing, giving a limiting magnitude of 24.5 after\nsumming.\n\nAperture photometry was performed on all objects detected in the\nEpoch 1 images and then again at the same positions in the later\nepochs.  The absolute magnitude of each source was calculated using a\nnearby USNO catalog star: for each source, the same calibration star\nwas used in all epochs, and the quoted error in the magnitude does not\ninclude the uncertainty in the magnitude of the calibration star.\nComparison with Epoch 3 is complicated by the fact that it is in\nVR-band, whereas Epochs 1 and 2 are in R-band.  Four sources were\ndetermined to have faded between both Epochs 1 and 2 and between\nEpochs 1 and 3.  Their positions and magnitudes are listed below.\nSources 2, 3, and 4 faded to near the detection limit in Epoch 2, and\nto below the detection limit in Epoch 3.  The observed fading and\nupper limits are consistent with a temporal power law decay index\nbetween -1 and -2, except for source 1 in Epoch 3, but this flattening\nof the decay could be due to an underlying galaxy.\n\ngrb event: 2001 December 12.1695 UT\nEpoch 1:   2001 December 14.17\t2.0 days after\nEpoch 2:   2001 December 15.17 \t3.0 days\nEpoch 3:   2002 February 16.33 \t66.2 days\n            2002 February 17.38 \t67.2 days\n\nFading Sources\n     RA       Dec        Epoch 1 m(R)    Epoch 2 m(R)     Epoch 3 m(VR)\n1  4:59:58.1 +32:02:57  23.14 +/- 0.12  23.89 +/- 0.22   24.08 +/-0.24\n2  4:59:59.4 +32:03:43  23.80 +/- 0.18  24.65 +/- 0.39    > 24.5\n3  4:59:59.0 +32:09:04  23.75 +/- 0.18  24.80 +/- 0.48    > 24.5\n4  4:59:39.5 +32:08:34  23.38 +/- 0.12  24.41 +/- 0.38    > 24.5\n\nFinder charts have been prepared of the four sources from the Epoch 1\nobservations at http://space.mit.edu/HETE/Bursts/GRB011212.  The\ncharts contain the source, marked by crosshairs, a bright star (B)\nfrom the USNO catalogue, and a constant star (C) of comparible\nmagnitude to the source.  The charts have a width and height of 33\narcseconds in RA and Dec.  North is up and East is to the left.\n\nSource#    m(R)               Star B m(R)\t Star C m(R)\n  1         23.14 +/- 0.12     18.8(USNO)\t 23.65 +/- 0.15\n  2         23.80 +/- 0.18     16.9(USNO)\t 23.59 +/- 0.15\n  3         23.75 +/- 0.18     14.4(USNO)\t 23.48 +/- 0.14\n  4         23.38 +/- 0.12     16.8(USNO)\t 23.11 +/- 0.09\n\n\n  This message may be cited.",
  "circularId": 1324,
  "createdOn": 1017853862000,
  "email": "grr@space.mit.edu",
  "subject": "GRB011212: Optical Observations",
  "submitter": "George Ricker at MIT  <grr@space.mit.edu>",
  "eventId": "GRB 011212"
}