{
  "bibcode": "2006GCN..5481....1C",
  "body": "Richard J. Cool (Arizona), Daniel J. Eisenstein (Arizona), David W. Hogg\n(NYU), Michael R. Blanton (NYU), David J. Schlegel (LBNL), J. Brinkmann\n(APO),\nDonald Q. Lamb (Chicago), Donald P. Schneider (PSU), and Daniel E. Vanden\nBerk\n(PSU) report:\n\nThe Sloan Digital Sky Survey (SDSS) imaged the field of burst GRB060826\nprior to the burst.  As these data should be useful as a pre-burst comparison\nand for calibrating photometry, we are supplying the images and photometry\nmeasurements for this 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/GRB060826\n\nWe supply FITS images in each of the 5 SDSS bands of a 8'x8' region centered\non the GRB position (ra=208.219 (13:52:52.6), dec=11.8710 (11:52:15.6);\nSwift-BAT TRIGGER 226614), as well as 3 gri color-composite JPGs (with\ndifferent stretches). The units in the FITS images are nanomaggies per pixel.\nA pixel is 0.396 arcsec on a side. A nanomaggie is a flux-density unit equal\nto 10^-9 of a magnitude 0 source or, to the extent that SDSS is an AB system,\n3.631e-6 Jy.  The FITS images have WCS astrometric information.\n\nIn the file GRB060826_sdss.calstar.dat, we report photometry and astrometry\nof 293 bright stars (r<20.5) within 15' of the burst location.  The\nmagnitudes\npresented in this file are asinh magnitudes as are standard in the SDSS\n(Lupton\n1999, AJ, 118, 1406). Beware that some of these stars are not well-detected\nin the u-band; use the errors and object flags to monitor data quality.\n\nIn the files GRB060826_sdss.objects_flux.dat and\nGRB060826_sdss.objects_magnitudes.dat, we report photometry of 1042\nobjects detected within 6' of the GRB position.  We have removed saturated\nobjects and objects with model magnitudes fainter than 23.0 in the r-band.\nThe fluxes listed in GRB060826_sdss.objects_flux.dat are in nanomaggies\nwhile the magnitudes listed in GRB060826_sdss.objects_magnitudes.dat are\nasinh magnitudes.\n\nAll quantities reported are standard SDSS photometry, meaning that they are\nvery close to AB zeropoints and magnitudes are quoted in asinh magnitudes.\nPhotometric zeropoints are known to about 2% rms.  None of the photometry\nis corrected for dust extinction.  The Schlegel, Finkbeiner, and Davis\n(1998) predictions for this region are A_U=0.139 mag, A_g=0.102 mag, A_r =\n0.074 mag, A_i=0.056 mag, and A_z=0.040 mag.\n\nThe file GRB060826_sdss.spectro.dat contains a list of the 1 objects with\nSDSS spectroscopy within 6 arcminutes of the GRB position.  In addition to\nthe redshift and 1-sigma error for each object, this file also lists the\nobject spectroscopic classification.\n\nSDSS astrometry is generally better than 0.1 arcsecond per coordinate.\nUsers requiring high precision astrometry should take note that the SDSS\nastrometric system can differ from other systems such as those used in other\nnotices; we have not checked the offsets in this region.\n\nMore detailed information pertaining to our SDSS GRB releases can be found\nin our initial data release paper (Cool et al. 2006, astro-ph/0601218).\nSee the SDSS DR4 documentation for more details: http://www.sdss.org/dr5.\n\nThese data have been reduced using a slightly different pipeline than that\nused for SDSS public data releases.  We cannot guarantee that the values here\nwill exactly match those in the data release in which these data are\nincluded.\nIn particular, we expect the photometric calibrations to differ by of order\n0.01 mag.\n\nThis note may be cited, but please also cite the SDSS data release paper,\nAdelman-McCarthy et al. (2006, ApJS, 162, 38), when using the data or\nreferring to the technical documentation.",
  "circularId": 5481,
  "createdOn": 1156601788000,
  "email": "rcool@as.arizona.edu",
  "subject": "GRB060826 - SDSS Pre-Burst Observations",
  "submitter": "Richard J. Cool at U.of AZ/Steward Obs  <rcool@as.arizona.edu>",
  "eventId": "GRB 060826"
}