LYMAN-ALPHA EMISSION FROM GALAXIES - THE CASE OF ABSORPTION-LINE SELECTED GALAXIES AT Z-SIMILAR-TO-0.3-0.4

Three galaxies, at moderate redshifts (z similar to 0.3-0.4) and ident ified as causing MgII absorption lines in the spectra of the quasars 0 229+131, 1127-145 and 1209+107, have been observed with the Faint Obje ct Spectrograph on-board the Hubble Space Telescope. The spectra have been obtained with the large aperture (4 ''.3 x 1 ''.4 effective), at a resolution (point-source ) of R approximate to 1300 and in the wavel ength range (observed frame) 1570 - 2320 Angstrom. A possible, weak Ly alpha emission is reported for G0229+131. A faint continuum may be pr esent in all three spectra at the longest wavelengths. Both the Ly alp ha detection and the Ly alpha upper limits derived for the other two o bjects, are lower than predicted from their respective H beta or [On] intensities. This result indicates a significant extinction at Ly alph a. In the case of 01209+107, enhanced extinction accompanying the Ly a lpha resonant multiple scattering is responsible for the Ly alpha depl etion. The results are consistent with both the weakness (or the lack) of Ly alpha emission from normal galaxies at high redshift, and the t rend of Ly alpha depletion as a function of metallicity observed in ne arby star-forming galaxies.