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tokens: components. We first performed a maximum likelihood analysis over the full time range considered here, that is 2008 Aug. 04 15:43:36.000 UTC to 2018 Sep 01 00:00:00.000 UTC (MET 1 239557417 to 557452805). In the initial fit, we modeled the ROI sources adopting the spectral shapes and parameters reported in the 3FGL catalog. We fit as free parameters the normalization and spectral index of the target source, and the normalization of all sources within 5° of the ROI center, in addition to the isotropic diffuse and Galactic components. Since our data set more than doubles the integration time with respect to the 3FGL catalog, we looked for potentially new sources, present in the ROI, with an iterative procedure. We produced a Test Statistic (TS) map. The TS is defined as 2log( L / L 0 ) where L is the likelihood of the model with a point source at a given position, and L 0 is the likelihood without the source. A value of TS = 25 corresponds to a significance of 4.2 σ , when accounting for two degrees of freedom ( Mattox et al. 1996 ). A TS map was produced by including a test source at each map pixel and evaluating its significance over the current model. We looked for significant (TS > 25) peaks in the TS map, with a minimum separation of 0.3°, and added a new point source to the model at the position of the most significant peak found, assuming a power-law spectrum. We then fit again the ROI, and produced a new TS map. This process was iterated until no more significant excesses were found 2 . We also performed a best-fit position localization for the target source and all new sources with TS > 25 found in the ROI. In order to investigate the temporal variability of PKS 0346−27, we computed several light curves with different time binning (see Sect. 3.1 ). In each light curve, we performed a full likelihood fit in each time bin. The number of free parameters in the fit depends on the statistics in each bin. We first attempted a fit leaving the normalisation and index of the target source and the normalization of all sources in the inner 3° of the ROI free to vary. If the fit did not converge or resulted in a non-detection (TS 25), we progressively restricted the number of free parameters in the fit in an iterative fashion. First we reduced the radius including sources with free normalization to 1°, then we left only the spectrum of the target source free to vary, and finally we fixed all parameters to their average values except for the target source’s normalization. We consider the target source to be detected if TS > 9 in the corresponding bin, and the signal-to-noise ratio (that is, flux over its error, or F /Δ F ) in that bin is larger than two. If this is not the case, we reported a 95% confidence upper limit. 2.2. Swift-XRT/UVOT PKS 0346−27 was observed with the Neil Gehrels Swift Observatory ( Gehrels et al. 2004 ) as a Target of Opportunity (ToO), following the detection of the first γ -ray flare ( Angioni 2018 ). The Swift data were