Using far-infrared imaging from the “ Herschel Lensing Survey ” , we derive dust properties of spectroscopically-confirmed cluster member galaxies within two massive systems at z \sim 0.3 : the merging Bullet Cluster and the more relaxed MS2137.3-2353 .
Most star-forming cluster sources ( \sim 90 % ) have characteristic dust temperatures similar to local field galaxies of comparable infrared ( IR ) luminosity ( T _ { dust } \sim 30 K ) .
Several sub-LIRG ( L _ { IR } < 10 ^ { 11 } L _ { \odot } ) Bullet Cluster members are much warmer ( T _ { dust } > 37 K ) with far-infrared spectral energy distribution ( SED ) shapes resembling LIRG-type local templates .
X-ray and mid-infrared data suggest that obscured active galactic nuclei do not contribute significantly to the infrared flux of these “ warm dust ” galaxies .
Sources of comparable IR-luminosity and dust temperature are not observed in the relaxed cluster MS2137 , although the significance is too low to speculate on an origin involving recent cluster merging .
“ Warm dust ” galaxies are , however , statistically rarer in field samples ( > 3 \sigma ) , indicating that the responsible mechanism may relate to the dense environment .
The spatial distribution of these sources is similar to the whole far-infrared bright population , i.e .
preferentially located in the cluster periphery , although the galaxy hosts tend towards lower stellar masses ( M _ { * } < 10 ^ { 10 } M _ { \sun } ) .
We propose dust stripping and heating processes which could be responsible for the unusually warm characteristic dust temperatures .
A normal star-forming galaxy would need 30–50 % of its dust removed ( preferentially stripped from the outer reaches , where dust is typically cooler ) to recover a SED similar to a “ warm dust ” galaxy .
These progenitors would not require a higher IR-luminosity or dust mass than the currently observed normal star-forming population .