We present observations of an extreme radio flare, VT J024345.70-284040.08, hereafter VT J0243, from the nucleus of a galaxy with evidence for historic Seyfert activity at redshift z=0.074. Between NRAO VLA Sky Survey observations in 1993 to VLA Sky Survey observations in 2018, VT J0243 rose from a ∼GHz radio luminosity of νLν≲1038 erg s−1 to νLν∼1040 erg s−1, and still continues to brighten. The radio spectral energy distribution (SED) evolution is consistent with a nascent jet that has slowed over ∼3000 days with an average 0.1<⟨β⟩<0.6. The jet is energetic (∼1051−52 erg), and had a radius ∼0.7 pc in Dec. 2021. X-ray observations suggest a persistent or evolving corona, possibly associated with an accretion disk, and IR and optical observations constrain any high-energy counterpart to be sub-Eddington. VT J0243 may be an example of a young, off-axis radio jet from a slowly evolving tidal disruption event. Other more mysterious triggers for the accretion enhancement and jet launching are possible. In either case, VT J0243 is a unique example of a nascent jet, highlighting the unknown connection between supermassive black holes, the properties of their accretion flows, and jet launching.
@article{arxiv.2207.02873,
title = {A candidate relativistic tidal disruption event at 340 Mpc},
author = {Jean J. Somalwar and Vikram Ravi and Dillon Z. Dong and Yuyang Chen and Shari Breen and Poonam Chandra and Tracy Clarke and Kishalay De and B. M. Gaensler and Gregg Hallinan and Sibasish Laha and Casey Law and Steven T. Myers and Tyler Parsotan and Wendy Peters and Emil Polisensky},
journal= {arXiv preprint arXiv:2207.02873},
year = {2023}
}