Infrared Emission from Intracluster Dust Grains and Constraints on Dust Properties

For 117 clusters of galaxies, we explore the detectability of intraclusterdust grains by current and future infrared facilities, taking into account bothcollisional heating and sputtering of grains by ambient plasma. If the dustgrains are injected into the intergalactic space with the amount and sizecomparable to the Galactic values, the dust-to-gas ratio is typically $10^{-6}$and the mean dust temperature is $\sim 30$ K near the cluster center. Thepredicted infrared intensities lie marginally above the detection thresholdsfor Spitzer Space Telescope, ASTRO-F, Herschel and SPICA missions. For somenearby clusters such as Perseus, A3571, A2319, A3112 and A2204, good detectionsof intracluster dust signal are expected in the 70 $\mu$m band. Given rathertight constraints on the dust temperature from observed electron density andtemperature, the dust mass can be inferred directly from the infraredobservations. Further constraints on the size distribution will be obtainedonce multi-band data are available. They will definitely provide a powerfulprobe of the dust injection processes and dust-gas interactions in theintergalactic space.Comment: 9 pages, 10 figures. Accepted for publication in PAS