The Hα luminosity function and star formation rate at z ≈ 0.24 based on Subaru deep imaging data

We have carried out a deep imaging survey for Halpha-emitting galaxies at z approximate to 0.24 using a narrowband filter tuned with the redshifted line. The total sky area covered is 706 arcmin(2) within a redshift range from 0.234 to 0.252 (deltaz = 0.018). This corresponds to a volume of 3.9 x 10(3) Mpc(3) when Omega(matter) = 0.3, Omega(A) = 0.7, and H-0 = 70 km s(-1) Mpc(-1) are adopted. We obtain a sample of 348 Halpha-emitting galaxies whose observed emission-line 10(-0.12)(39.65+0.08) ergs s(-1) Mpc(-3). Using the Kennicutt relation between the Halpha luminosity and the star formation rate, the star formation rate density in the covered volume is estimated to be 0.036(-0.012)(+0.006) M-circle dot yr(-1) Mpc(-3). This value is higher by a factor of 3 than the local star formation rate density.