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NGC 4278, a Low-luminosity active galactic nucleus (AGN), is generally classified as a low-ionization nuclear emission line region (LINER) type AGN. Recently, it is reported to be associated with a very high energy (VHE) -ray source 1LHAASO J1219+2915 in the first Large High Altitude Air Shower Observatory (LHAASO) source catalog. However, no associated counterpart has been detected by Fermi-LAT. By analyzing its X-ray observation data from Swift-XRT, we find it is in a high-flux state on MJD 59546, with the X-ray flux more than one order of magnitude higher than that observed 11. 7 year earlier by Chandra. We propose that the detection of VHE -rays from NGC 4278 may be attributed to the presence of an active nucleus displaying behavior similar to that of a BL Lac. To reproduce its spectral energy distribution (SED), we employ a one-zone leptonic model, typically used for fitting broadband SEDs of BL Lacs, and find that smaller values for both Doppler factor () and magnetic field strength (B) are required than that of typical TeV BL Lacs. Furthermore, NGC 4278 exhibits significantly lower luminosity in both radio and TeV bands when compared with typical TeV BL Lacs. In the radio-luminosity vs. Eddington-ratio plane, NGC 4278 shows greater similarity to Seyfert galaxies and LINERs rather than BL Lacs; however, it still roughly follows the extension towards lower luminosity seen in BL Lacs.
Lian et al. (Wed,) studied this question.