A Candidate Relativistic Tidal Disruption Event at 340 Mpc
Jean J. Somalwar, Vikram Ravi, Dillon Dong, Yuyang Chen, S. L. Breen, P. Chandra, T. E. Clarke, Kishalay De, B. M. Gaensler, Gregg Hallinan, Sibasish Laha, Casey Law, S. T. Myers, Tyler Parsotan, Wendy Peters, Emil Polisensky
Abstract
Abstract 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 Very Large Array (VLA) Sky Survey observations in 1993 to VLA Sky Survey observations in 2018, VT J0243 rose from a ∼ GHz radio luminosity of ν L ν ≲ 10 38 erg s −1 to ν L ν ∼ 10 40 erg s −1 , and still continues to brighten. The radio spectral energy distribution 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 (∼10 51–52 erg), and had a radius ∼0.7 pc in 2021 December. 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.