SIMBAD references

We have carried out a deep imaging survey for Hα-emitting galaxies at z~0.24 using a narrowband filter tuned with the redshifted line. The total sky area covered is 706 arcmin² within a redshift range from 0.234 to 0.252 (δz=0.018). This corresponds to a volume of 3.9x10³ Mpc³ when Ω_matter=0.3, Ω_Λ=0.7, and H₀=70 km/s/ Mpc are adopted. We obtain a sample of 348 Hα-emitting galaxies whose observed emission-line equivalent widths are greater than 12 Å. We find an extinction-corrected Hα luminosity density of 10^39.65+0.08-0.12_^ ergs/s/Mpc³. Using the Kennicutt relation between the Hα luminosity and the star formation rate, the star formation rate density in the covered volume is estimated to be 0.036^+0.006_–0.012M_☉yr^–1 Mpc^–3. This value is higher by a factor of 3 than the local star formation rate density.