We present Herschel SPIRE-FTS observations of Arp 220, a nearby ultraluminous infrared galaxy. The FTS provides continuous spectral coverage from 1 The SPIRE beam shapes are not gaussian; the effective beam solid angle can be found in the Herschel Observer's manual.

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We use Spitzer Space Telescope and Herschel Space Observatory far‐infrared data along with ground‐based optical and near‐infrared data to understand how dust heating in the nearby face‐on spiral galaxies M81, M83 and NGC 2403 is affected by the starlight from all stars and by the radiation from star‐forming regions. We find that 70/160 m surface brightness ratios tend to be more strongly influenced by star‐forming regions. However, the 250/350 m and 350/500 m surface brightness ratios are more strongly affected by the light from the total stellar populations, suggesting that the dust emission at >250 m originates predominantly from a component that is colder than the dust seen at <160 m and that is relatively unaffected by star formation activity. We conclude by discussing the implications of this for modelling the spectral energy distributions of both nearby and more distant galaxies and for using far‐infrared dust emission to trace star formation.

We present Herschel observations of 62 early-type galaxies (ETGs), including 39 galaxies morphologically classified as S0+S0a and 23 galaxies classified as ellipticals using SPIRE at 250, 350 and 500 µm as part of the volume-limited Herschel Reference Survey (HRS). We detect dust emission in 24% of the ellipticals and 62% of the S0s. The mean temperature of the dust is T d = 23.9 ± 0.8 K, warmer than that found for late-type galaxies in the Virgo Cluster. The mean dust mass for the entire detected early-type sample is logM d = 6.1 ± 0.1 M ⊙ with mean dust-to-stellar mass ratio of log(M d /M * ) = −4.3 ± 0.1. Including the non-detections, these parameters are logM d = 5.6 ± 0.1 and log(M d /M * ) = −5.1 ± 0.1 respectively. The average dust-to-stellar mass ratio for the early-type sample is fifty times lower, with larger dispersion, than the spiral galaxies observed as part of the HRS, and there is an order of magnitude decline in M d /M * between the S0s and ellipticals. We use UV and optical photometry to show that virtually all the galaxies lie close to the red sequence yet the large number of detections of cool dust, the gas-to-dust ratios and the ratios of far-infrared to radio emission all suggest that many ETGs contain a cool interstellar medium similar to that in late-type galaxies. We show that the sizes of the dust sources in S0s are much smaller than those in early-type spirals and the decrease in the dust-to-stellar mass ratio from early-type spirals to S0s cannot simply be explained by an increase in the bulge-to-disk ratio. These results suggest that the disks in S0s contain much less dust (and presumably gas) than the disks of early-type spirals and this cannot be explained simply by current environmental effects, such as ram-pressure stripping. The wide range in the dust-to-stellar mass ratio for ETGs and the lack of a correlation between dust mass and optical luminosity suggest that much of the dust in the ETGs detected by Herschel has been acquired as the result of interactions, although we show these are unlikely to have had a major effect on the stellar masses of the ETGs. The Herschel observations tentatively suggest that in the most massive systems, the mass of interstellar medium is unconnected to the evolution of the stellar populations in these galaxies.

We present an analysis of the size growth seen in early-type galaxies over 10 Gyr of cosmic time. Our analysis is based on a homogeneous synthesis of published data from 17 spectroscopic surveys observed at similar spatial resolution, augmented by new measurements for galaxies in the Gemini Deep Deep Survey. In total, our sample contains structural data for 465 galaxies (mainly early-type) in the redshift range 0.2 < z < 2.7. The size evolution of passively-evolving galaxies over this redshift range is gradual and continuous, with no evidence for an end or change to the process around z ∼ 1, as has been hinted at by some surveys which analyze subsets of the data in isolation. The size growth appears to be independent of stellar mass, with the mass-normalized half-light radius scaling with redshift as R e ∝ (1 + z) −1. 62±0.34 . Surprisingly, this power law seems to be in good agreement with the recently reported continuous size evolution of UV-bright galaxies in the redshift range z ∼ 0.5 − 3.5. It is also in accordance with the predictions from recent theoretical models.