TITLE: GCN CIRCULAR NUMBER: 21530 SUBJECT: LIGO/Virgo G298048: DECam optical candidate DATE: 17/08/18 01:15:01 GMT FROM: Ryan Chornock at Ohio U S. Allam (Fermilab), J. Annis (Fermilab), E. Berger (Harvard), D. J. Brout (UPenn), D. Brown (Syracuse), R. E. Butler (Fermilab), H.-Y. Chen (Harvard), R. Chornock (Ohio University), E. Cook (TAMU), P. Cowperthwaite (Harvard), H. T. Diehl (Fermilab), A. Drlica-Wagner (Fermilab), M. R. Drout (Carnegie), R. J. Foley (UCSC), W. Fong (Northwestern), D. Fox (Penn State), J. Frieman (Fermilab/UChicago), R. Gruendl (NCSA), K. Herner (Fermilab), D. Holz (UChicago), R. Kessler (UChicago), R. Margutti (Northwestern), J. Marshall (TAMU), E. Neilsen (Fermilab), M. Nicholl (Harvard), F. Paz-Chincon (NCSA), A. Rest (STScI), M. Sako (UPenn), D. Scolnic (U Chicago), N. Smith (Arizona), M. Soares-Santos (BrandeisU), D. Tucker (Fermilab), V. A. Villar (Harvard), P. K. G. Williams (Harvard), B. Yanny (Fermilab) On behalf of the larger DESGW+community team: We have imaged the BAYESTAR localization map of LIGO/Virgo G298048 (GCN 21513) using DECam on the CTIO 4m in both i and z band. Visual inspection of unprocessed DECam images reveals a new source not present in Pan-STARRS 3Pi images north and east of NGC 4993 (d~40 Mpc, from NED), consistent with the source found by Coulter et al. (LVC GCN 21529). Analysis and further observations are ongoing.