Abstract
With the possible spacial association to the Fermi/LAT source 3FGL J1330.0--3818, TOL 1326--379 may be the first one that is identified as a $\gamma$-ray emitting Fanaroff--Riley type 0 radio galaxy (FR0 RG). We analyze the $\sim$12 yr Fermi/LAT observation data of this $\gamma$-ray source and examine its association to TOL 1326--379. We show that the $\gamma$-ray source (named as J1331.0--3818) is tentatively detected with a TS value of 28.7, 3FGL J1330.0--3818 is out of the 95\% containment of J1331.0--3818, and their positions are spatially separated with 0.2$\degr$. 4FGL J1331.3--3818 falls into the 68\% containment of J1331.0--3818, suggesting that our result agrees with that reported in the Fourth Fermi LAT Source Catalog. TOL 1326--379 is out of the 95\% containment of J1331.0--3818, and their positions are spatially separated with 0.4$\degr$, indicating that the association between J1331.0--3818 and TOL 1326--379 is quite ambiguous. However, we do not find other possible potential radio and X-ray counterparts within the circle centered at J1331.0--3818 with a radius of 0.4$\degr$. The spectral energy distribution (SED) of TOL 1326--379 shows a bimodal feature as seen in the $\gamma$-ray emitting RGs. We fit the SED with the one-zone leptonic model and find that the average energy spectrum of J1331.0--3818 agrees with the model prediction. Assuming that J1331.0--3818 is an unidentified $\gamma$-ray source, we derive the upper-limit of the $\gamma$-ray flux for TOL 1326--379. It is not tight enough to exclude this possibility. Based on these analysis results, we cautiously argue that the $\gamma$-ray source J1331.0--3818 is associated with TOL 1326--379 and its jet radiation physic is similar to those $\gamma$-ray emitting RGs.
