{
  "bibcode": "2007GCN..6080....1C",
  "body": "Richard J. Cool (Arizona), Daniel J. Eisenstein (Arizona), David W. Hogg\n(NYU), Michael R. Blanton (NYU), David J. Schlegel (LBNL), J.  \nBrinkmann (APO),\nDonald Q. Lamb (Chicago), Donald P. Schneider (PSU), and Daniel E.  \nVanden Berk\n(PSU) report:\n\nThe Sloan Digital Sky Survey (SDSS) imaged the field of burst GRB070208\nprior to the burst.  As these data should be useful as a pre-burst  \ncomparison\nand for calibrating photometry, we are supplying the images and  \nphotometry\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/GRB070208\n\nWe supply FITS images in each of the 5 SDSS bands of a 8'x8' region  \ncentered\non the GRB position (ra=197.887 (13:11:32.8), dec=61.9653  \n(61:57:55.2); GCN\n6074), as well as 3 gri color-composite JPGs (with different  \nstretches). The\nunits in the FITS images are nanomaggies per pixel.  A pixel is 0.396  \narcsec\non a side. A nanomaggie is a flux-density unit equal to 10^-9 of a  \nmagnitude\n0 source or, to the extent that SDSS is an AB system, 3.631e-6 Jy.   \nThe FITS\nimages have WCS astrometric information.\n\nIn the file GRB070208_sdss.calstar.dat, we report photometry and  \nastrometry\nof 140 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  \nSDSS (Lupton\n1999, AJ, 118, 1406). Beware that some of these stars are not well- \ndetected\nin the u-band; use the errors and object flags to monitor data quality.\n\nIn the files GRB070208_sdss.objects_flux.dat and\nGRB070208_sdss.objects_magnitudes.dat, we report photometry of 329\nobjects detected within 6' of the GRB position.  We have removed  \nsaturated\nobjects and objects with model magnitudes fainter than 23.0 in the r- \nband.\nThe fluxes listed in GRB070208_sdss.objects_flux.dat are in nanomaggies\nwhile the magnitudes listed in GRB070208_sdss.objects_magnitudes.dat are\nasinh magnitudes.\n\nAll quantities reported are standard SDSS photometry, meaning that  \nthey are\nvery close to AB zeropoints and magnitudes are quoted in asinh  \nmagnitudes.\nPhotometric zeropoints are known to about 2% rms.  None of the  \nphotometry\nis corrected for dust extinction.  The Schlegel, Finkbeiner, and Davis\n(1998) predictions for this region are A_U=0.084 mag, A_g=0.062 mag,  \nA_r =\n0.045 mag, A_i=0.034 mag, and A_z=0.024 mag.\n\nThe file GRB070208_sdss.spectro.dat contains a list of the 3 objects  \nwith\nSDSS spectroscopy within 6 arcminutes of the GRB position.  In  \naddition 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  \nin other\nnotices; we have not checked the offsets in this region.\n\nMore detailed information pertaining to our SDSS GRB releases can be  \nfound\nin our initial data release paper (Cool et al. 2006, PASP, 118, 733).\nSee the SDSS DR4 documentation for more details: http://www.sdss.org/ \ndr5.\n\nThese data have been reduced using a slightly different pipeline than  \nthat\nused for SDSS public data releases.  We cannot guarantee that the  \nvalues 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  \norder\n0.01 mag.\n\nThis note may be cited, but please also cite the SDSS data release  \npaper,\nAdelman-McCarthy et al. (2006, ApJS, 162, 38), when using the data or\nreferring to the technical documentation.",
  "circularId": 6080,
  "createdOn": 1170947751000,
  "email": "rcool@as.arizona.edu",
  "subject": "GRB070208 - SDSS Pre-Burst Observations",
  "submitter": "Richard J. Cool at U.of AZ/Steward Obs  <rcool@as.arizona.edu>",
  "eventId": "GRB 070208"
}