Early optical follow-up of the nearby active star DG CVn during its 2014 superflare

DG Canum Venaticorum (DG CVn) is a binary system in which one of the components is an M-type dwarf ultrafast rotator, only three of which are known in the solar neighbourhood. Observations of DG CVn by the Swift satellite and several ground-based observatories during its superflare event on 2014 allowed us to perform a complete hard X-ray-optical follow-up of a superflare from the red-dwarf star. The observations support the fact that the superflare can be explained by the presence of (a) large active region(s) on the surface of the star. Such activity is similar to the most extreme solar flaring events. This points towards a plausible extrapolation between the behaviour from the most active red-dwarf stars and the processes occurring in the Sun. © 2015 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.