Fermi/LAT detection of a transient gamma-ray flare in the vicinity of the binary star DG CVn

Abstract: Solar flares are regularly detected by the Large Area Telescope (LAT) on board the Fermi satellite, however no gamma-ray emission from other stellar eruptions has ever been captured. The Swift detection in April 2014 of a powerful outburst originating from DG CVn, with associated optical and radio emissions, enticed us to search for possible 0.1-100 GeV emission from this flaring nearby binary star using the Fermi/LAT. No gamma-ray emission is detected from DG CVn in 2014, but we report a significant gamma-ray excess in November 2012, at a position consistent with that of the binary. There are no reports of contemporary flaring at other wavelengths from DG CVn or any other source within the error circle of the gamma-ray source. We argue that the gamma-ray flare is more likely to have been associated with a background blazar than with DG CVn and identify a candidate for follow-up study.