Letter to the Editor

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

M. J. Pereira¹, C. P. Haines², G. P. Smith², E. Egami¹, S. M. Moran³, A. Finoguenov^4,5, E. Hardegree-Ullman⁶, N. Okabe⁷, T. Rawle¹ and M. Rex¹

¹ Steward Observatory, Tucson, 85716 Arizona, USA e-mail: mpereira@as.arizona.edu
² School of Physics and Astronomy, University of Birmingham, Edgbaston, B15 2TT, UK
³ Dept of Physics and Astronomy, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218, USA
⁴ Max-Planck-Institut für extraterrestrische Physik, Giessenbachstraße, 85748 Garching, Germany
⁵ University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA
⁶ Rensselaer Polytechnic Institute (RPI) 110 Eighth Street, Troy, NY 12180, USA
⁷ Academia Sinica Institute of Astronomy and Astrophysics, PO Box 23-141, 10617 Taipei, Taiwan

Received: 1 April 2010
Accepted: 6 May 2010

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.