{
  "bibcode": "2010GCN.10661....1H",
  "body": "S. T. Holland (CRESST/USRA/GSFC), F. E. Marshall (NASA/GSFC),\nM. Page (MSSL-UCL), M. de Pasquale (MSSL-UCL), and\nM. H. Siegel (PSU) report on behalf of the Swift/UVOT team:\n\n     Swift/UVOT white photometry of GRB 100418A reveals a light curve\nwith a rise and decay that are broadly similar to the white light\ncurve of GRB 060218/SN2006aj.  The UVOT spectral energy distribution\nat 6400 s is consistent with a power law with a spectral index of beta\n= 0.2 (f = nu^-beta), which is similar to the UVOT spectral energy\ndistribution for GRB 060218/SN2006aj at 9300 s.  In addition, the\nX-ray light curve of GRB 100418A is broadly similar to the X-ray light\ncurves of GRB 100316D and GRB 060218, both of which had supernova\ncomponents.  Therefore, we suggest that the brightening of the\nafterglow of GRB 100418A seen at approximately 10,000 s (Bikamev et\nal. 2010, GCNC 10635; Siegel et al. 2010, GCNC 10645) may be the shock\nbreakout from a supernova associated with this burst.  If this is the\ncase, and the supernova is similar to SN1998bw, then the supernova has\nnot yet reached maximum light.  Ground based observations to determine\nif a supernova is present are encouraged.",
  "circularId": 10661,
  "createdOn": 1272050314000,
  "email": "Stephen.T.Holland@nasa.gov",
  "subject": "GRB 100418A: Possible Evidence for a Supernova",
  "submitter": "Stephen Holland at USRA/NASA/GSFC/SSC  <Stephen.T.Holland@nasa.gov>",
  "eventId": "GRB 100418A"
}