Serjeant, Stephen; Gruppioni, Carlotta and Oliver, Seb
The local star formation rate and radio luminosity density.
Monthly Notices of the Royal Astronomical Society, 330(3) pp. 621–624.
We present a new determination of the local volume-averaged star formation rate from the 1.4-GHz luminosity function of star forming galaxies. Our sample, taken from the Revised Shapley-Ames catalogue (231 normal spiral galaxies over an effective area of 7.1sr) has ~=100 per cent complete radio detections and is insensitive to dust obscuration and cirrus contamination. After removal of known active galaxies, the best-fitting Schechter function has a faint-end slope of in agreement with the local Halpha luminosity function, characteristic luminosity and density The inferred local radio luminosity density of (Poisson noise, large-scale structure fluctuations) implies a volume-averaged star formation rate ~2 times larger than the Gallego et al. Halpha estimate, i.e. for a Salpeter initial mass function from and Hubble constant of 50kms-1 Mpc-1 . We demonstrate that the Balmer decrement is a highly unreliable extinction estimator, and argue that optical-ultraviolet (UV) star formation rates (SFRs) are easily underestimated, particularly at high redshift.
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