Infrared emission from intracluster dust grains and constraints on dust properties

For 117 clusters of galaxies, we explore the detectability of intracluster dust grains by current and future infrared facilities, taking into account both collisional heating and sputtering of grains by the ambient plasma. If the dust grains are injected into intergalactic space with the amount and size comparable to the Galactic values, the dust-togas ratio is typically 10(-6) and the mean dust temperature is similar to 30 K near the cluster center. The predicted infrared intensities lie marginally above the detection thresholds for Spitzer Space Telescope, ASTRO-F, Herschel, and SPICA missions. For some nearby clusters, such as Perseus, A 357 1, A 2319, A 3112, and A 2204, good detections of intracluster dust signals are expected in the 70 mu m band. Given rather tight constraints on the dust temperature from the observed electron density and the temperature, the dust mass can be inferred directly from infrared observations. Further constraints on the size distribution will be obtained once multi-band data are available. They will definitely provide a powerful probe of the dust injection processes and dust-gas interactions in intergalactic space.