{
  "bibcode": "2007GCN..6510....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), Donald Q. Lamb (Chicago), Donald P. Schneider (PSU), and Daniel\nE. Vanden Berk (PSU) report:\n\nThe Sloan Digital Sky Survey (SDSS) imaged the field of burst GRB070612\nprior to the burst.  As these data should be useful as a pre-burst\ncomparison and for calibrating photometry, we are supplying the images\nand photometry measurements 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/GRB070612\n\nWe supply FITS images in each of the 5 SDSS bands of a 8'x8' region\ncentered on the GRB position (ra=121.385 (08:05:32.4), dec=37.2660\n(37:15:57.6); GCN 6509), as well as 3 gri color-composite JPGs (with\ndifferent stretches). The units in the FITS images are nanomaggies\nper pixel.  A pixel is 0.396 arcsec on a side. A nanomaggie is a\nflux-density unit equal to 10^-9 of a magnitude 0 source or, to the\nextent that SDSS is an AB system, 3.631e-6 Jy.  The FITS images have\nWCS astrometric information.\n\nIn the file GRB070612_sdss.calstar.dat, we report photometry and\nastrometry of 396 bright stars (r<20.5) within 15' of the burst location.\nThe magnitudes presented in this file are asinh magnitudes as are standard\nin the SDSS (Lupton 1999, AJ, 118, 1406). Beware that some of these stars\nare not well-detected in the u-band; use the errors and object flags to\nmonitor data quality.\n\nIn the files GRB070612_sdss.objects_flux.dat and\nGRB070612_sdss.objects_magnitudes.dat, we report photometry of 1013\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 GRB070612_sdss.objects_flux.dat are in nanomaggies\nwhile the magnitudes listed in GRB070612_sdss.objects_magnitudes.dat\nare asinh magnitudes.\n\n\nAll quantities reported are standard SDSS photometry, meaning that\nthey are very close to AB zeropoints and magnitudes are quoted in\nasinh magnitudes.  Photometric zeropoints are known to about 2% rms.\nNone of the photometry is corrected for dust extinction.  The Schlegel,\nFinkbeiner, and Davis (1998) predictions for this region are A_U=0.281\nmag, A_g=0.207 mag, A_r = 0.150 mag, A_i=0.114 mag, and A_z=0.081 mag.\n\nThe file GRB070612_sdss.spectro.dat contains a list of the 2 objects with\nSDSS spectroscopy within 6 arcminutes of the GRB position.  In addition\nto the redshift and 1-sigma error for each object, this file also lists\nthe object spectroscopic classification.\n\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\nother notices; we have not checked the offsets in this region.\n\nMore detailed information pertaining to our SDSS GRB releases can be\nfound in our initial data release paper (Cool et al. 2006, PASP 118, 733).\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\nthat used for SDSS public data releases.  We cannot guarantee that the\nvalues here will exactly match those in the data release in which these\ndata are included.  In particular, we expect the photometric calibrations\nto differ by of order 0.01 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": 6510,
  "createdOn": 1181619269000,
  "email": "rcool@as.arizona.edu",
  "subject": "GRB070612 - SDSS Pre-Burst Observations",
  "submitter": "Richard J. Cool at U.of AZ/Steward Obs  <rcool@as.arizona.edu>",
  "eventId": "GRB 070612"
}