{
  "bibcode": "2007GCN..6374....1P",
  "body": "J. Prieto (Ohio State), P. Garnavich (Notre Dame), J. Hill (LBTO/UAz),\nX. Fan, J. Harris, J. Bechtold (U Ariz), X. Dai,  P. Martini,\nK. Z. Stanek (Ohio State), R. M. Wagner (LBTO/OSU),\nJ. Rhoads (Ariz State), E. Pian (INAF) report:\n\nThe Large Binocular Telescope (LBT) imaged the position of the GRB 070412\nafterglow (Romano et al, GCN 6273; Romano et al. GCN 6282) with the\nLBC-blue CCD camera (http//lbc.mporzio.astro.it) and 8.4-m SX mirror on\n2007 April 12.18 (UT) and again on April 20.31 (UT). These are 2.8 hours\nand 8.2 days after the burst respectively.  On the first visit,\nten dithered, 200 second exposures were obtained\nwith the Sloan-r filter in 1.7\" seeing while on the second visit, five\nexposures were obtained in 1.0\" seeing.\n\nImage matching, PSF correction and subtraction of the two images shows\nno variable sources within 30\" of the corrected XRT position\n(Romano et al. GCN 6282). We place a 3-sigma upper-limit on any\noptical afterglow at R>25.2 around 2.8 hours post-burst.\n\nNo new source is detected in our second epoch image\n(also see Rol et al. GCN 6353) and we place a similar detection\nupper-limit as our April 12 image. If the burst is associated\nwith the bright elliptical galaxy near the XRT position (Ofek &\nBerger GCN 6275), then we find any supernova or other GRB progenitor\nwould have an absolute magnitude fainter than -11 mag eight days\nafter the burst.\n\nA comparison of the two images after unsharp masking to\nreduce the elliptical galaxy light variations can be found at:\nhttp://www.nd.edu/~pgarnavi/grb070412/grb070412_LBT.jpg\n\nThe LBT is an international collaboration among institutions in the\nUnited States, Italy and Germany. The LBT Corporation partners are:\n*  The University of Arizona on behalf of the Arizona university system\n*  Istituto Nazionale di Astrofisica, Italy\n*  LBT Beteiligungsgesellschaft, Germany, representing the Max Planck\nSociety, the Astrophysical Institute Potsdam, and Heidelberg University\n*  The Ohio State University\n*  The Research Corporation, on behalf of The University of Notre Dame,\nUniversity of Minnesota and University of Virginia\n\n\nThis message may be cited",
  "circularId": 6374,
  "createdOn": 1178321984000,
  "email": "pgarnavi@nd.edu",
  "subject": "GRB 070412, deep LBT imaging",
  "submitter": "Peter Garnavich at U of Notre Dame  <pgarnavi@nd.edu>",
  "eventId": "GRB 070412"
}