VLASS Tidal Disruption Events with Optical Flares. II. Discovery of Two TDEs with Intermediate Width Balmer Emission Lines and Connections to the Ambiguous Extreme Coronal Line Emitters

Abstract The multiwavelength properties of radio-emitting tidal disruption events (TDEs) are poorly understood. In a previous paper, we presented the first sample of radio-selected, optically detected TDEs, which included two events (VT J1008 and VT J2012) associated with late-time (∼2 yr post-optical flare) intermediate width emission lines that are largely unprecedented from TDEs. In this paper, we investigate these two events in detail. The multiwavelength properties of these events are otherwise consistent with optically selected TDEs. They are hosted by green valley, E+A/Balmer dominated galaxies with low star formation rates and black holes masses M BH ≈ 10 5−6 M ⊙ . The optical flare shapes are fully consistent with those of optically selected TDEs, although they are slightly faint and cool at peak. The radio emission from both events is consistent with wide-angle, nonrelativistic outflows with L R (GHz) ∼ 10 38 erg s −1 . Balmer and helium emission lines are detected from both events with FWHM ∼700 km s −1 and asymmetric line profiles. VT J1008 additionally shows coronal line emission with a similar width. The lines from VT J2012 are redshifted by ∼700 km s −1 relative to the host galaxy. We show that these events share many characteristics in common with the ambiguous class of extreme coronal line emitters. We argue that the lines are likely associated with a radiative shock or dense, photoionized clumps of outflowing gas in the circumnuclear medium.