2014MNRAS.444.2270B

We report an X-ray flare from 3XMM J014528.9+610729, serendipitously detected during the observation of the open star cluster NGC 663. The colour-colour space technique using optical and infrared data reveals the X-ray source as a candidate spiral galaxy. The flare shows fast rise and exponential decay shape with a ratio of the peak and the quiescent count rates of ∼ 60 and duration of ∼ 5.4 ks. The spectrum during the flaring state is well fitted with a combination of thermal (apec) model with a plasma temperature of 1.3±0.1 keV and non-thermal (power-law) model with power-law index of 1.9±0.2. However, no firm conclusion can be made for the spectrum during the quiescent state. The temporal behaviour, plasma temperature and spectral evolution during flare suggest that the flare from 3XMM J014528.9+610729 cannot be associated with tidal disruption events.