Dust-obscured star-formation in the outskirts of XMMU J2235.3-2557, a
  massive galaxy cluster at z=1.4
  Star-formation in the galaxy populations of local massive clusters is reduced
with respect to field galaxies, and tends to be suppressed in the core region.
Indications of a reversal of the star-formation--density relation have been
observed in a few z >1.4 clusters. Using deep imaging from 100-500um from PACS
and SPIRE onboard Herschel, we investigate the infrared properties of
spectroscopic and photo-z cluster members, and of Halpha emitters in XMMU
J2235.3-2557, one of the most massive, distant, X-ray selected clusters known.
Our analysis is based mostly on fitting of the galaxies spectral energy
distribution in the rest-frame 8-1000um. We measure total IR luminosity,
deriving star formation rates (SFRs) ranging from 89-463 Msun/yr for 13
galaxies individually detected by Herschel, all located beyond the core region
(r >250 kpc). We perform a stacking analysis of nine star-forming members not
detected by PACS, yielding a detection with SFR=48 Msun/yr. Using a color
criterion based on a star-forming galaxy SED at the cluster redshift we select
41 PACS sources as candidate star-forming cluster members. We characterize a
population of highly obscured SF galaxies in the outskirts of XMMU
J2235.3-2557. We do not find evidence for a reversal of the SF-density relation
in this massive, distant cluster.
