The herschel fornax cluster survey II: FIR properties of optically selected Fornax cluster galaxies

Abstract

The Herschel Fornax Cluster Survey is a deep, far-infrared (FIR) survey of the Fornax cluster. The survey is in five Herschel bands (100-500 μm) and covers an area of 16 deg2 centred on NGC 1399. This paper presents photometry, detection rates, dust masses, and temperatures using an optically selected sample from the Fornax ClusterCatalogue. Our results are compared with those previously obtained using data from the Herschel Virgo Cluster Survey (HeViCS). In Fornax, we detect 30 of the 237 (13 per cent) optically selected galaxies in at least one Herschel band. The global detection rates are significantly lower than Virgo, reflecting the morphological make up of each cluster- Fornax has a lower fraction of late-type galaxies. For galaxies detected in at least three bands, we fitted a modified blackbody with a β =2 emissivity. Detected early-type galaxies (E/S0) have amean dustmass, temperature, and dust-to-stars ratio of log10((Mdust)/M⊙) = 5.82 ± 0.20, (tdust) = 20.82 ± 1.77 K, and log10(Mdust/Mstars) = -3.87 ± 0.28, respectively. Late-type galaxies (Sa to Sd) have a mean dust mass, temperature, and dust-to-stars ratio of log10((Mdust)/M⊙) = 6.54 ± 0.19, (tdust) = 17.47 ± 0.97 K, and log10(Mdust/Mstars) = -2.93 ± 0.09, respectively. The different cluster environments seem to have had little effect on the FIR properties of the galaxies and so we conclude that any environment-dependent evolution has taken place before the cluster was assembled. © 2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.