The HerMES sub-millimetre local and low-redshift luminosity functions

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We used wide area surveys over 39 deg² by the HerMES collaboration, performed with the Herschel Observatory SPIRE multi-wavelength camera, to estimate the low-redshift, 0.02<z<0.5, monochromatic luminosity functions (LFs) of galaxies at 250, 350 and 500μm. SPIRE flux densities were also combined with Spitzer photometry and multi-wavelength archival data to perform a complete SED fitting analysis of SPIRE detected sources to calculate precise k-corrections, as well as the bolometric infrared (8-1000μm) luminosity functions and their low-z evolution from a combination of statistical estimators. Integration of the latter prompted us to also compute the local luminosity density (LLD) and the comoving star formation rate density (SFRD) for our sources, and to compare them with theoretical predictions of galaxy formation models. The luminosity functions show significant and rapid luminosity evolution already at low redshifts, 0.02<z<0.2, with LIR* ∝ (1+z)⁶.⁰±⁰.⁴ and ΦIR* ∝ (1+z)⁻².¹±⁰.⁴, L₂₅₀* ∝ (1+z)⁵.³±⁰.² and Φ₂₅₀* ∝ (1+z)⁻⁰.⁶±⁰.⁴ estimated using the IR bolometric and the 250μm LFs respectively. Converting our IR LD estimate into an SFRD assuming a standard Salpeter IMF and including the unobscured contribution based on the UV dust-uncorrected emission from local galaxies, we estimate a SFRD scaling of SFRD₀+0.08 z, where SFRD₀≃ (1.9± 0.03)× 10⁻² [MMpc⁻³] is our total SFRD estimate at z 0.02.