A test of SDSS aperture corrections using integral-field spectroscopy

Corrections for fibre aperture losses in modern surveys such as the Sloan Digital Sky Survey are at the foundation of statistical studies of galaxy properties, yet these corrections are not well understood. We compare direct measurements of the total (aperture-free) Hα-based star formation rate from integral-field spectroscopy with Brinchmann et al. and Gilbank et al. derived estimates of the star formation rate from fibre-aperture spectroscopy for the same z ≃ 0.07 star-forming galaxies drawn from the Sloan Digital Sky Survey. This comparison reveals that aperture-corrected star formation rates are underestimated for more highly star-forming galaxies: specifically by 0.3 and 0.6 dex at rates of star formation of 10 and 100M ⊙ yr -1 , respectively, while the underestimate vanishes at 1 M ⊙ yr -1 . Furthermore, previous estimates of the aperture loss for Hα emission onlymarginally correlate with direct measurements of the aperture loss for individual galaxies. The primary limitation of our work is the lack of spatially resolved dust attenuation corrections. We conclude that corrections for aperture losses should be considered with caution.