The H&alpha derived local star formation rate density from SINGG

The star formation rate density has decreased by an order of magnitude since z~2, and this evolution constrains all models of galaxy evolution.  However, other estimates of the local star formation rate density suffer from significant sample biases.  The selection method used by SINGG, focusing on HI mass instead of luminosity, allows us to derive luminosity densities without suffering from most of the optical biases common to other surveys.  As we observed each SINGG galaxy in R and H&alpha bands, our corresponding luminosity densities are:
l'R = (4.4 +/- 0.7) x 1037 h70 erg s-1 Å-1 Mpc-3
l'H&alpha = (9.4 +/- 1.8) x 1038 h70 erg s-1 Mpc-3

before correction for internal extinction.  The local star formation rate density, after a mean internal extinction correction of 0.82 mag, is:

log(&rhoSFR [Msolar yr-1 Mpc-3]) = -1.80  +0.13/-0.07 (random) +/- 0.03 (systematic) + log(h70)

To compare to the values from other surveys:

Star formation density vs. redshift
Star formation rate density, as a function of redshift, (a) before and (b) after corrections for internal extinction are applied.  Green circles are visual-wavelength emission line surveys, purple circles are UV surveys, and orange circles are IR or sub-mm surveys.  The star symbol at z~0 is the SINGG value.

While the corrected values appear to correlate well, this is somewhat misleading; the SINGG extinction correction (0.82 mag) is smaller than that of other surveys, and a more detailed comparison (see paper) finds that other surveys include few low-luminosity galaxies and bias heavily towards "starburst" galaxies.

Paper reference: Hanish et al. 2006, "The Survey for Ionization in Neutral Gas Galaxies: II. The Star Formation Rate Density of the Local Universe", ApJ, in press, astro-ph/0604442.