Scuba Local Universe Galaxy Survey

Abstract

We present new results from the SCUBA Local Universe Galaxy Survey (SLUGS), the first large statistical submillimetre survey of the local Universe. Following our initial survey of a sample of 104 IRASselected galaxies we now present the results of a sample of 80 Optically-Selected galaxies. This new sample, by definition free from temperature selection effects, allows us for the first time to determine how the amount of cold dust in galaxies varies with Hubble type. We detect 6 ellipticals in the sample and find them to have dust masses in excess of 10 7 M ⊙ . We derive local submillimetre Luminosity Functions and Dust Mass Functions, both directly for the OpticallySelected SLUGS and by extrapolation from the IRAS PSCz survey, and find excellent agreement.

Point source confusion in SZ cluster surveys

“…Radio sources tend to have falling spectra with α < 0 (Herbig & Readhead 1992;Taylor et al 2001;Mason et al 2003), but flat and inverted spectra with α ≥ 0 appear more prominent with observing frequency (Bennett et al 2003;Trushkin 2003). At millimeter wavelengths we observe the dust emission of IR galaxies in the Rayleigh-Jeans with rising spectra characterized by α ∼ 3−4 (Vlahakis et al 2004). As will be seen, we need information on these extragalactic sources down to mJy flux densities and below; unfortunately, neither the distribution of α nor the source counts are well known for either population at these flux densities and at frequencies of interest for SZ observations (∼10−300 GHz).…”

“…The SCUBA Local Universe Galaxy Survey (SLUGS, Vlahakis et al 2004) finds a broad distribution for the dust emissivity index with β ∼ 1 and a dispersion we take to be σ β ∼ 0.2. According to the SLUGS observations, optical galaxies tend to have lower spectral indexes than IRAS-selected objects; we eye-balled the above numbers to be representative of the population as a whole.…”