The Herschel Fornax Cluster Survey II: FIR properties of optically selected Fornax cluster galaxies

Abstract

The Herschel Fornax Cluster Survey (HeFoCS) is a deep, far-infrared (FIR) survey of the Fornax cluster. The survey is in 5 Herschel bands (100 -500 µm) and covers an area of 16 deg 2 centred on NGC 1399. This paper presents photometry, detection rates, dust masses and temperatures using an optically selected sample from the Fornax Cluster Catalogue (FCC). 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 %) 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 3 bands we fit a modified blackbody with a β = 2 emissivity. Detected early-type galaxies (E / S0) have a mean dust mass, temperature, and dustto-stars ratio of log 10 (< M dust > /M ) = 5.82 ± 0.20, < T dust >= 20.82 ± 1.77 K, and log 10 (M dust /M stars ) = −3.87 ± 0.28, respectively. Late-type galaxies (Sa to Sd) have a mean dust mass, temperature, and dust-to-stars ratio of log 10 (< M dust > /M ) = 6.54 ± 0.19, < T dust >= 17.47 ± 0.97 K, and log 10 (M dust /M stars ) = −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. Drinkwater et al. (2001) showed that despite Fornax's apparent state of relaxation, it still contains substructure, e.g. a small, in-falling group centred on NGC 1316, 3 • to the southwest. However, compared to the Virgo cluster, Fornax is very centrally concentrated and probably at a much later epoch of formation. This is also suggested by the strong morphological segregation that has taken place, leaving the cluster almost entirely composed of early-type galaxies. Drinkwater et al. (2001) also noted that there exist two different populations, suggesting that while the giant galaxies are virialised, the dwarf population is still in-falling.

The ALMA Fornax Cluster Survey I: stirring and stripping of the molecular gas in cluster galaxies

“…**These galaxies were observed but later found to be background objects. They are therefore omitted in Figures 8 and 9, and stellar masses were therefore not determined for them; † Stellar masses from Fuller et al (2014); † Stellar masses derived from 3.6 µm images, (see §4.3).…”

“…where b = 0.96, α L = 3.10 ± 1.33, and x = 8.69 the solar metallicity (Asplund et al 2009). The gas-to-dust ratio is derived using the HI and H 2 masses stated above, and a dust mass of 4.2 × 10 6 M from Fuller et al (2014). Since our upper limit on the H 2 mass depends on X CO , we combine the relation above and that between X CO and metallicity (Equation 2) to estimate the metallicity (and thus the resulting X CO ) in this object.…”

“…In this work we revisit the CO(J=1-0) in the Fornax cluster and investigate whether these observations can be confirmed. The ALMA Fornax Cluster Survey is a complete survey of the 30 Fornax cluster members that were detected in 3 or more Herschel Space Observatory (Pilbratt et al 2010) bands with the Herschel Fornax Cluster Survey (Fuller et al 2014) or in HI (Waugh et al 2002, Loni et al in prep. based on ATCA data). The CO(1-0) rotational line (rest frequency: 115.271 GHz) was observed to create spatially resolved maps of the cold molecular gas and its kinematics in these galaxies.…”

The MeerKAT Fornax Survey

“…The most recent efforts include: i) the FDS survey, a deep optical imaging survey carried out with OmegaCAM on ESO VST (P.I. 's Iodice and Peletier; [69]) covering our full MeerKAT Fornax mosaic (and more) down to a surface brightness sensitivity of ∼ 28 mag/arcsec 2 in u, g, r and i bands (and even deeper with moderate smoothing of the images); this survey provides a key dataset to look for the optical counterpart of low-surface-brightness H I features (and vice versa), and to study the optical and H I properties of the faintest galaxies in the cluster, including the newly discovered large population of ultra-diffuse galaxies (e.g., [70]); ii) a Herschel survey of Fornax, which covers the central 16 deg 2 of the cluster and resulted in the detection of cold dust in 30 galaxies of both early-and late morphological type ( [71,72]); iii) several observations of the CO (J=1-0) molecular gas line in galaxies within Fornax using the Mopra single-dish (P.I. Smith) and ALMA (P.I.…”

Evolution of star-forming dwarf galaxies in different environments

“…6). Some of these dEs also host a dust (Fuller et al 2014) and a molecular gas component (Zebel et al 2018). Thus they could represent a link between more vigorously star-forming dwarfs and quenched dEs in Fornax, and the ongoing surveys of the cluster will allow to shed light on the evolutionary history of these systems.…”