Infrared Emission from the Nearby Cool Core Cluster Abell 2597

We observed the brightest central galaxy (BCG) in the nearby (z = 0.0821) cool core galaxy cluster Abell 2597 with the IRAC and MIPS instruments on board the Spitzer Space Telescope. The BCG was clearly detected in all Spitzer bandpasses, including the 70 and 160 μm wave bands. We report aperture photometry of the BCG. The spectral energy distribution exhibits a clear excess in the far-IR over a Rayleigh-Jeans stellar tail, indicating a star formation rate of ~4-5 M☉ yr-1, consistent with the estimates from the UV and its Hα luminosity. This large far-IR luminosity is consistent with that of a starburst or a luminous infrared galaxy, but together with a very massive and old population of stars that dominate the energy output of the galaxy. If the dust is at one temperature, the ratio of 70 to 160 μm fluxes indicates that the dust emitting mid-IR in this source is somewhat hotter than the dust emitting mid-IR in two BCGs at higher redshift (z ~ 0.2-0.3) and higher far-IR luminosities observed earlier by Spitzer in clusters Abell 1835 and Zwicky 3146.

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