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

Alan Loh (1) , Stéphane Corbel (1, 2) , Guillaume Dubus (3)

1 AIM (UMR7158 / UMR_E_9005 / UM_112) - Astrophysique Interprétation Modélisation
2 USN - Unité Scientifique de la Station de Nançay
3 IPAG - Institut de Planétologie et d'Astrophysique de Grenoble

Solar flares are regularly detected by the Large Area Telescope (LAT) on board the Fermi satellite, however no γ-ray emission from other stellar eruptions has ever been captured. The Swift detection in 2014 April 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 γ-ray emission is detected from DG CVn in 2014, but we report a significant γ-ray excess in 2012 November, 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 γ-ray source. We argue that the γ-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.

Mots clés: acceleration of particles; stars: flare; stars: individual (DGCVn); gamma-rays: stars.

Domaines: Astrophysique stellaire et solaire [astro-ph.SR]

Alan Loh, Stéphane Corbel, Guillaume Dubus. Fermi/LAT detection of a transient gamma-ray flare in the vicinity of the binary star DG CVn. Monthly Notices of the Royal Astronomical Society, 2017, 467 (4), pp.4462-4466. ⟨10.1093/mnras/stx396⟩. ⟨insu-01520677⟩