Observational Evidence Linking A Quasar With An Optical Transient

We present evidence for the association of a QSO with a bright optical transient (OT). A V = 20.6 mag QSO with redshift z = 1.78 has been found within the 38'' x 62'' error ellipse of a bright OT discovered on a Harvard Patrol Camera plate taken in 1905. The chance of finding a random QSO at V less-than-or-equal-to 20.6 mag within this area is estimated as approximately 0.5%. Although the OT is within the error circle of the gamma-ray burst (GRB) GB 910219 position determined from the WATCH experiment, the localization for this same event determined from the Third Interplanetary Network does not include the OT or the QSO. Whether the GRB is related to the OT/QSO or not, the probable association of a bright OT with a QSO is a discovery that warrants further investigation.