  We present Herschel/PACS, MMT/Hectospec and XMM-Newton observations of Abell
1835, one of the brightest X-ray clusters on the sky, and the host of a strong
cool core. Even though Abell 1835 has a prototypically "relaxed" X-ray
morphology and no signs of ongoing merger activity in strong- and weak-lensing
mass maps, it has a complex velocity distribution, suggesting that it is still
accreting significant amounts of mass in the form of smaller satellite systems.
Indeed, we find strong dynamical segregation of star-forming dusty galaxies
from the optically selected cluster population. Most Herschel sources are found
close to the virial radius of the cluster, and almost a third appear to be
embedded within a filament feeding the cluster from the SW. We find that the
most luminous infrared galaxies are likely involved in galaxy-galaxy
interactions that may have triggered the current phase of star formation.
