2025/07/11 by Yvette Cendes, Edo Berger, Cendes, Yvette +36 · 5 voices · 1 citation
Physics and Astronomy · #astro-ph.HE
paper · pdf · doi:10.48550/arxiv.2507.08998
We present ongoing radio observations of the tidal disruption event (TDE) AT2018hyz, which was first detected in the radio at 972 days after disruption, following multiple non-detections from earlier searches. The new observations presented here span approximately 1370-2160 days and 0.88-240 GHz. We find that the light curves continue to rise at all frequencies during this time period, following a power law of about F ~ t3 (compared to Fnu ~ t5.7 at 972-1400 days), and reaching a peak luminosity of L~ 1040 erg/s, comparable to the luminosity of the relativistic TDE Swift 1644+57 on the same timescale. The multi-frequency data indicate that the peak frequency does not significantly evolve over the 1030-day span of our observations, while the peak flux density increases by an order of magnitude. The observed behavior is consistent with two possible scenarios: (i) a delayed spherical outflow launched about 620 days post-disruption with a velocity of ~0.3c and an energy of ~1050 erg, and (ii) a highly off-axis (~80-90 deg) relativistic jet with a Lorentz factor of Gamma ~8 and EK ~ 1052 erg. Continued radio observations to capture the light curve peak, as well as VLBI observations, could distinguish between these scenarios.