Variability of the X-ray obscuring wind in Mrk 335 with XMM-Newton/RGS
Transient X-ray obscuration in Seyfert 1 galaxies likely arises from clumpy accretion-disk winds near the broad-line region (BLR), but the wind structure and short-timescale variability are difficult to measure because high-resolution spectra are often suppressed during deep low states. We analyse a coordinated XMM-Newton/NuSTAR campaign on Mrk 335 in June 2021, with long-term Swift monitoring, capturing the source in an intermediate-flux state with strong RGS absorption features. We model the broadband SED to determine the ionising continuum for self-consistent photoionisation modelling of the RGS spectra. The stacked RGS spectrum requires three photoionised absorbers with log xi ~ 3.69, 2.97, and 1.91, outflowing at |v_out| ~ 5800, 3200, and 2100 km/s, respectively. Their properties are consistent with the three-phase obscurer reported in 2009, indicating that a similar multi-phase obscuring wind can persist over decade timescales. Using five consecutive RGS observations, we track the wind evolution on day timescales and find strong variability in column density and ionisation in all phases, together with smaller but coherent velocity changes. During a flare, the low-ionisation phase shows a significant drop in opacity, while in the subsequent epoch all phases show increased outflow velocities, suggesting a possible connection between continuum variability and changes in the line-of-sight absorber. The high-ionisation phase responds most directly to changes in ionising luminosity, while the lowest-ionisation phase shows at most a delayed response. Order-of-magnitude constraints place the obscurer at BLR scales, ~10^3-10^5 Rg, with kinetic power potentially reaching the percent level of L_bol for plausible assumptions on geometry and clumpiness.