The Relation between Cool Cluster Cores and Herschel-detected Star Formation in Brightest Cluster Galaxies

Rawle, T.D.; Edge, A.C.; Egami, E.; Rex, M.; Smith, G.P.; Altieri, B.; Fiedler, A.; Haines, C.P.; Pereira, M.J.; Pérez-González, P.G.; Portouw, J.; Valtchanov, I.; Walth, G.; van der Werf, P.P.; Zemcov, M.

Abstract

We present far-infrared (FIR) analysis of 68 brightest cluster galaxies (BCGs) at 0.08 < z < 1.0. Deriving total infrared luminosities directly from Spitzer and Herschel photometry spanning the peak of the dust component (24-500 μm), we calculate the obscured star formation rate (SFR). 22+6.2 –5.3% of the BCGs are detected in the far-infrared, with SFR = 1-150 M ☉ yr–1. The infrared luminosity is highly correlated with cluster X-ray gas cooling times for cool-core clusters (gas cooling time <1 Gyr), strongly suggesting that the star formation in these BCGs is influenced by the cluster-scale cooling process. The occurrence of the molecular gas tracing Hα emission is also correlated with obscured star formation. For all but the most luminous BCGs (L TIR > 2 × 1011 L ☉), only a small (0.4 mag) reddening correction is required for SFR(Hα) to agree with SFRFIR. The relatively low Hα extinction (dust obscuration), compared to values reported for the general star-forming population, lends further weight to an alternate (external) origin for the cold gas. Finally, we use a stacking analysis of non-cool-core clusters to show that the majority of the fuel for star formation in the FIR-bright BCGs is unlikely to originate from normal stellar mass loss.

Citation

Rawle, T., Edge, A., Egami, E., Rex, M., Smith, G., Altieri, B., …Zemcov, M. (2012). The Relation between Cool Cluster Cores and Herschel-detected Star Formation in Brightest Cluster Galaxies. Astrophysical Journal, 747(1), Article 29. https://doi.org/10.1088/0004-637x/747/1/29

• Journal Article Type: Article
• Publication Date: Mar 1, 2012
• Deposit Date: Apr 8, 2013
• Publicly Available Date: Sep 4, 2013
• Journal: Astrophysical Journal
• Print ISSN: 0004-637X
• Electronic ISSN: 1538-4357
• Publisher: American Astronomical Society
• Peer Reviewed: Peer Reviewed
• Volume: 747
• Issue: 1
• Article Number: 29
• DOI: https://doi.org/10.1088/0004-637x/747/1/29
• Keywords: Galaxies, Clusters, Elliptical and lenticular, cD, Star formation, Infrared.