SUBWAYS VI links soft X-ray excess strength to ultra-fast outflow velocities in 22 AGN

The SUBWAYS collaboration examined high-resolution XMM-Newton EPIC and RGS data for 22 type-1 AGN at z<0.3, fitting self-consistent photoionization models for both the soft excess and UFO absorption lines. They measured outflow velocities between 0.1c and 0.3c and found that sources with stronger soft excesses host UFOs with higher ionization parameters and larger covering fractions. This suggests the soft excess may arise from the same inner accretion disk wind that launches the UFOs rather than from distant reflection. Prior SUBWAYS papers focused on detection rates; this work adds the first quantitative link between the two spectral components across the sample. The main limitation is the modest sample size and reliance on single-epoch observations, which cannot separate intrinsic variability from source-to-source differences. Multi-epoch XRISM spectra would test whether the correlation holds within individual objects.