XRISM resolves a recurrent ultra-fast inflow and possible accretion cascade in ESP 39607
Alessandro Peca (Universidad Diego Portales)
Tuesday 13/10/2026 @ 14:00, Sala Antonio Sollima (IV piano Battiferro)
Ultra-fast inflows (UFIs) offer a rare view of how material may be delivered to the innermost regions of AGN, but convincing examples have been difficult to establish. I will present simultaneous XRISM, XMM-Newton, and NuSTAR observations of the luminous Seyfert 2 galaxy ESP 39607, which provide the first high-resolution X-ray view of its candidate UFI. XRISM resolves two absorption features consistent with redshifted Fe XXV and Fe XXVI Ka absorption from highly ionized gas inflowing at 16% of the speed of light. The absorption is robustly detected across multiple continuum models and matches earlier NuSTAR detections, implying the inflow has persisted for at least two years in the source rest frame. Combining the three epochs, the detection reaches 5.3 sigma, making ESP 39607 one of the clearest known cases of a recurrent UFI and, to our knowledge, the only one identified in a Type 2 AGN. Because the inferred dynamical timescale at tens of gravitational radii is only days, the absorber is unlikely to be a single long-lived cloud. Instead, the observations favor a continuously replenished accretion cascade that may supply a substantial fraction of the material needed to power the AGN. I will discuss the inflow energetics, tentative evidence for additional inflow and outflow components, and how high-resolution monitoring can help distinguish between chaotic cold accretion, magnetically guided inflow, and fallback scenarios.