LoCuSS: A Herschel view of obscured star formation in Abell 1835

TL;DR

This study uses Herschel, MMT, and XMM-Newton observations to analyze star formation and galaxy dynamics in the Abell 1835 cluster, revealing complex accretion processes and interactions influencing star formation.

Contribution

It provides new insights into the distribution and triggers of star formation in a relaxed galaxy cluster with ongoing accretion activity.

Findings

Star-forming dusty galaxies are dynamically segregated from the cluster population.

Most Herschel sources are near the virial radius, often within a filament feeding the cluster.

Luminous infrared galaxies are likely triggered by galaxy interactions.

Abstract

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.