EMISSION LINES

Identifications

• Line No. 1. No accurate wavelength for this line is available. There are four possible candidates: N II 4241.8 (mult. 47), N II 4241.8 (mult. 48), S III 4253.6 (mult. 4), and C II 4267 (mult. 6).
• Line No. 2. This is the strongest line in these quasars. The best value for the wavelengths appears to be 5013 Å. The spectrum given in Atwood et al. (1985) also supports this value. There are two very good candidates for identification of this line : He I 5015.7 (mult. 4) and C IV 5018, 5017 (mult. 3). Laser action in either of these lines can give rise to the observed line. An emission line at about 5018 Å has been known for many years in Wolf-Rayet spectra. We may note here one point concerning laser action in He I 5015.7. The lower level for the transition giving rise to this line is metastable. While population inversion, when the lower level is metastable, is not very common, it can occur.
• Line No. 3. It appears as a hump on the long wavelength shoulder of line No. 2, and there may be considerable uncertainty in its wavelength. A good candidate for its identification is C II 5121.7 (mult. 12).
• Line No. 4. We identify this line with C IV 5801, 5812 (mult. 1), which is a well-known line in Wolf-Rayet spectra.
• Line No. 5 . The uncertainty in the wavelength is simply too large to attempt an identification.