A phenomenon of quasiperiodic ultrafast outflows: first detection and dynamical interpretation

Based on the observations of the transient event ASASSN-20qc associated with the nearby galactic nucleus, I will describe the phenomenon of a quasiperiodic ultrafast outflow (QPOut). The source exhibits periodic variations in the UFO column density and the ionization parameter every 8.5 days, yet no periodicity in the outflow velocity and the X-ray thermal continuum is detected. The QPOut generation appears to be consistent with the orbiting massive perturber, potentially an intermediate-mass black hole of ~100-10000 Solar masses (see Pasham, Tombesi, Suková, Zajaček et al. 2024, Science Advances, for details). I will discuss the dynamics of this and similar systems, their likelihood in the local Universe, and the implications of the quasiperiodic outflow feedback given the anticipated lifetime of the QPOut.