Optical Emission-Line Spectroscopy of Galaxies in the Distant Sample
observed at McDonald Observatory (2.7 m):
Harriet Dinerstein & Christine Pulliam, Univ. Texas at Austin
Galaxies observed:
NGC 278, NGC 693, NGC 1156, NGC 6821, NGC 7218, and NGC 7771.
The galaxies were observed with two setups, a blue setting covering [O II] 3727/29 to [O III] 5007 and a red setting from [O III] 4959/5007 to beyond the 7300 A [O II] lines, however fringing at the red end may limit the useful coverage to the region shortward of ~6750 A. We used a Cassegrain CCD spectrometer on the McDonald 2.7 m with a resolution element of ~ 8 Angstroms for the red setup for maximum wavelength coverage and a resolution element of ~ 4 A for the blue, since this did not compromise the coverage much. This is a long-slit instrument with a slit length of 150".
Summary of Results:
The major emission lines needed for crude estimates of extinction and O/H, N/H ratios were detected in all of the galaxies except NGC 7771. These include the lines [O II] 3727, [O III] 4959, 5007, [N II] 6584, and at least two H lines, H-alpha and H-beta. In NGC 7771, the oxygen lines seemed extremely weak or undetected, but we dohave H-alpha and H-beta, and should be able to set some limits on the possible value of O/H.