A new flaring high-energy γ-ray source

¹ INFN/LNF, via E. Fermi 40, 00044 Frascati, Roma, Italy
e-mail: enrico.bernieri@lnf.infn.it
² Department of Physics, University of Roma Tre, via della Vasca Navale 84, 00146 Roma, Italy
³ INAF/IAPS, via Fosso del Cavaliere 100, 00133 Roma, Italy
⁴ INAF/IASF-Bologna, via Piero Gobetti 101, 40129 Bologna, Italy
⁵ Department of Physics, University of Roma “La Sapienza”, Piazzale A. Moro 2, 00185 Roma, Italy
⁶ Harvard-Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138, USA
⁷ ISDC, University of Geneva, Chemin d’Ecogia 16, Versoix, 1290, Switzerland

Received: 3 December 2012
Accepted: 25 December 2012

Abstract

We report the detection of a new γ-ray source in the Fermi-LAT sky using a source detection tool based on the minimal spanning tree algorithm. The source, not reported in previous LAT catalogues but very recently observed in the X-rays and optical bands, is characterized by an increasing γ-ray activity in 2012 June–September that reached a weekly peak flux of (3.3 ± 0.6) × 10^-7 photons cm^-2 s^-1. A search for a possible counterpart provides indication that it can be associated with the radio source NVSS J141828+354250, whose optical SDSS colours are typical of a blazar.