Q0353: 383: The best case yet for abundance anomalies in quasars

Q0353: 383, in many respects the most unusual quasar in the -400 zone of the Curtis Schmidt survey; has prominent emission lines of N III], N IV], and N V, and abnormally weak C III] and C IV lines. Lines of He II and O III] are also seen. Calibrated spectrophotometry of Q0353: 383 together with Shields's models shows that the best explanation of the spectrum is a factor of 10 enhancement in the N/C ratio. The large N/C ratio is primarily due to a low abundance of carbon rather than a high abundance of nitrogen, not in accord with the standard picture of chemical abundances in the nuclear regions of galaxies. A differential comparison of Q0353: 383 with the Baldwin-Netzer data for PHL 938, a normal quasar, leads to similar conclusions. Of the 80 quasars in the Curtis Schmidt sample with measured C IV/(Lα+N V) line ratios, Q0353: 383 has the lowest value; a crude estimate of the frequency of such quasars is of the order of 1%