We present a study of the H α line emission from a sample of 1482 optically selected, morphologically classified bright galaxies (median redshift of 0.05) derived from the Sloan Digital Sky Survey. The luminosity function is calculated for each morphological class and for the total sample. The luminosity function fitted with the Schechter form gives a slope α = -1.43 ± 0.10 for the total sample, and the Ha luminosity density is 103 39.31±0.04±-0.07+0.10h ergs s -1 Mpc -3, where the first error is statistical and the second is systematic. This value is consistent with that derived by Gallego et al. in 1995, but this agreement is caused by a fortuitous cancellation of their neglect of stellar absorption that affects the estimate of extinction corrections and a significant sample incompleteness of emission-line galaxies. The fraction of Ha emitters monotonically increases from early (a few percent for elliptical galaxies) to late types (100% for irregular galaxies), whereas strong emitters exist in all classes of morphological types. We find that 83% of the luminosity density comes from spiral galaxies, 5% from irregular galaxies, and 9% from early-type galaxies; a small number of morphologically disturbed galaxies contribute by 3%.
All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science