An outburst in the quasar PG1244+026 from an energy source unrelated to accretion onto its supermassive black hole

The standard paradigm of active galactic nuclei (AGNs) is accretion onto a central supermassive black hole (SMBH) powering their enormous luminosity, and predicts significant reverberation of their broad-line regions (BLRs) and dusty tori with respect to variations of the accretion-powered continuum. Here we report evidence of an unusual outburst from extra energy sources in PG 1244+026 during 2021-2022 from a long-term monitoring campaign. The outburst is only detected in mid-infrared bands and broad emission lines, which are tightly correlate with each other, however, the optical bands show a monotonic decline during the outburst. The outburst is located at the inner edge of the torus, deduced from the light curves. Such a kind of outburst has never been reported before. The total energy of the outburst is ≈10 ⁵⁰ erg released in 3.4μm and could be driven by a 40 solar mass black hole.The present outburst suggests stellar-mass black holes (sMBHs) is consistent with growing evidence for mergers of high mass sMBHs detected by LIGO with potential associations with AGNs.