Unveiling the Cosmic Dance of Repeated Nuclear Transient ASASSN-14ko: Insights from Multiwavelength Observations

TL;DR

This study presents multiwavelength observations of the repeating nuclear transient ASASSN-14ko, revealing recurrent features and their evolution, which suggest a partial tidal disruption event interacting with the accretion disk.

Contribution

It provides new insights into the multiwavelength behavior and physical mechanisms of repeated nuclear transients, highlighting similarities with X-ray quasiperiodic eruptions.

Findings

Recurrent early bumps and rebrightenings in UV/optical light curves.

Inverse pattern of X-ray outbursts compared to UV/optical bands.

Correlation between luminosity and blackbody temperature/radius.

Abstract

ASASSN-14ko is a periodically repeating nuclear transient. We conducted high-cadence, multiwavelength observations of this source, revealing several recurrent early bumps and rebrightenings in its UV/optical light curves. The energy released during these bumps and rebrightenings shows a diminishing trend in recent UV/optical outbursts, which we monitored through multiwavelength observations. These features can be ascribed to the interaction between stream debris and the expanded disk in the repeated partial tidal disruption event. The X-ray light curve exhibits an inverse pattern compared to the UV/optical bands, displaying sporadic outbursts. Furthermore, our observations demonstrate that the blackbody temperature and radius in each outburst increase with the UV/optical luminosity, and such evolution resembles that observed in X-ray quasiperiodic eruptions, whereas distinguishing it from typical tidal disruption events.