{
  "bibcode": "2006GCN..5399....1C",
  "body": "Richard J. Cool (Arizona), Daniel J. Eisenstein (Arizona),\nDavid W. Hogg (NYU), Michael R. Blanton (NYU), David J. Schlegel\n(LBNL), J. Brinkmann (APO), Donald Q. Lamb (Chicago), Donald\nP. Schneider (PSU), and Daniel E. Vanden Berk (PSU) report:\n\nThe Sloan Digital Sky Survey (SDSS) imaged the field of burst\nGRB060805 prior to the burst.  As these data should be useful\nas a pre-burst comparison and for calibrating photometry,\nwe are supplying the images and photometry measurements for\nthis GRB field to the community.\n\nData from the SDSS, including 5 FITS images, 3 JPGS, and\n3 files of photometry and astrometry, are being placed at\nhttp://mizar.as.arizona.edu/~grb/public/GRB060805\n\nWe supply FITS images in each of the 5 SDSS bands of a 8'x8'\nregion centered on the GRB position (ra=220.932 (14:43:43.6),\ndec=12.5866 (12:35:11.8); Swift-BAT TRIGGER 222683), as well\nas 3 gri color-composite JPGs (with different stretches). The\nunits in the FITS images are nanomaggies per pixel.  A pixel\nis 0.396 arcsec on a side. A nanomaggie is a flux-density unit\nequal to 10^-9 of a magnitude 0 source or, to the extent that\nSDSS is an AB system, 3.631e-6 Jy.  The FITS images have WCS\nastrometric information.\n\nIn the file GRB060805_sdss.calstar.dat, we report photometry\nand astrometry of 379 bright stars (r<20.5) within 15' of the\nburst location.  The magnitudes presented in this file are asinh\nmagnitudes as are standard in the SDSS (Lupton 1999, AJ, 118,\n1406). Beware that some of these stars are not well-detected\nin the u-band; use the errors and object flags to monitor\ndata quality.\n\nIn the files GRB060805_sdss.objects_flux.dat and\nGRB060805_sdss.objects_magnitudes.dat, we report photometry\nof 1683 objects detected within 6' of the GRB position.\nWe have removed saturated objects and objects with model\nmagnitudes fainter than 23.0 in the r-band.  The fluxes listed\nin GRB060805_sdss.objects_flux.dat are in nanomaggies while\nthe magnitudes listed in GRB060805_sdss.objects_magnitudes.dat\nare asinh magnitudes.\n\nAll quantities reported are standard SDSS photometry, meaning\nthat they are very close to AB zeropoints and magnitudes are\nquoted in asinh magnitudes.  Photometric zeropoints are known\nto about 2% rms.  None of the photometry is corrected for\ndust extinction.  The Schlegel, Finkbeiner, and Davis (1998)\npredictions for this region are A_U=0.124 mag, A_g=0.092 mag,\nA_r = 0.066 mag, A_i=0.050 mag, and A_z=0.036 mag.\n\nThe file GRB060805_sdss.spectro.dat contains a list of the\n8 objects with SDSS spectroscopy within 6 arcminutes of the\nGRB position.  In addition to the redshift and 1-sigma error\nfor each object, this file also lists the object spectroscopic\nclassification.\n\nSDSS astrometry is generally better than 0.1 arcsecond per\ncoordinate.  Users requiring high precision astrometry should\ntake note that the SDSS astrometric system can differ from\nother systems such as those used in other notices; we have\nnot checked the offsets in this region.\n\nMore detailed information pertaining to our SDSS GRB releases\ncan be found in our initial data release paper (Cool et\nal. 2006, astro-ph/0601218).  See the SDSS DR4 documentation\nfor more details: http://www.sdss.org/dr5.\n\nThese data have been reduced using a slightly different\npipeline than that used for SDSS public data releases.\nWe cannot guarantee that the values here will exactly match\nthose in the data release in which these data are included.\nIn particular, we expect the photometric calibrations to differ\nby of order 0.01 mag.\n\nThis note may be cited, but please also cite the SDSS data\nrelease paper, Adelman-McCarthy et al. (2006, ApJS, in press,\nastro-ph/0507711), when using the data or referring to the\ntechnical documentation.",
  "circularId": 5399,
  "createdOn": 1154756023000,
  "email": "rcool@as.arizona.edu",
  "subject": "GRB 060805 - SDSS Pre-Burst Observations",
  "submitter": "Richard J. Cool at U.of AZ/Steward Obs  <rcool@as.arizona.edu>",
  "eventId": "GRB 060805"
}