Secular Evolution in the Nearest Tidal Disruption Event

Tidal disruption events (TDEs) occur when a star passes close enough to a galaxy's supermassive black hole to be disrupted by tidal forces.We discuss new observations of IGRJ12580+0134, a TDE observed in NGC 4845 (d=17Mpc), with the VLA, VLBA and ALMA. We also discuss a reanalysis of observations from 2010-2011 with Swift ad XMM-Newton, as well as late-time observations from those telescopes.IGRJ12580+0134's proximity offers us a unique close-up of the TDE and its aftermath. Our VLBA observations show a jetted milliarcsecond-scale nuclear source, while our {\sl ALMA} observations show an unresolved, arcsecond-scale nuclear source. A source 45 milliarcsec from the nucleus that appeared in the 2015 L-band map is shown to be spurious. This map and our earlier data suggest a jet expansion velocity of ~ 0.3 c between 2015-2017. This is consistent with the model of Perlman et al. (2017) and Irwin et al. (2015), which holds that while the jet started out moving at close to c, it decelerated to sub-relativistic speed within months due to interactions with the circumnuclear medium. They also show that while the decay of the GHz nuclear flux is consistent with the predictions of this model ($\propto t^{-5/3}$), the GHz spectral index $\alpha_r=0.94$ (which has remained constant since 2015) overpredicts the ALMA flux by a factor of three. Wediscuss the implications for TDE models, as well as models which suggest that a similarly dense nuclear medium could have asignificant effect on the propagation of AGN jets. A reanalysis of the Swift and XMM-Newton data from 2011 January shows significant evidence for thermal emission from a disk. Later observations with Swift only detect the source when stacked. We use Fermi observations to set an upper limit on the GeV gamma-ray flux. We discuss the implications for both the nature of the source and its continued evolution, which continues to be consistent with a jet-circumnuclear interaction model.