A Search for Nitrogen-Rich Quasars in the Sloan EDR Misty C. Bentz and Patrick S. Osmer

1. A Search for Nitrogen-Rich Quasars in the Sloan EDR Misty C. Bentz and Patrick S. Osmer The Ohio State University I. Prototype and Motivation II. Results III. Emission Line Data The quasar Q0353-383 has long been known to have strong nitrogen inter-combination lines (Osmer 1980) and a recent, detailed analysis (Baldwin et al. 2003) indicates a metallicity ~15  solar. But it is the only quasar of its kind known. SDSS offers a vast resource of high-quality quasar spectra in which to search for more members of the population of nitrogen-rich quasars. As nitrogen enrichment is believed to be a result of chemical evolution within the nucleus of a galaxy, better constraints on the population of nitrogen-rich quasars could lead to a better understanding of quasar lifecycles. The spectrum of Q0353-383 was used as a template for cross-correlation with the spectra of all Sloan EDR quasars with redshifts of 1.8 < z < 4.1 (a sample size of 1082 objects). The N IV] λ1486 and N III] λ1750 emission lines are visible in this redshift range. Sixteen nitrogen-rich quasar candidates were found. Four are relatively strong (see below), although not as strong as Q0353-383. A preliminary search using an emission line criterion of 0 < C IV/(Ly α + N V) < 0.1 (another distinctive feature of Q0353-383) yielded a sample of 24 unusual objects. Among these unusual objects are two quasars with strong P-Cygni (narrow BAL) line profiles, a z2.5 starburst galaxy, and an assortment of quasars with unusual emission or absorption-line properties. Rest frame spectrum of Q0353-383 (Baldwin, private communication). II-a. Nitrogen-Rich Quasars II-b. Unusual Objects Four previously unknown quasars with strong nitrogen emission. All spectra have been averaged over five pixels. (blue line: N III] λ1750; red line: N IV] λ1486) Four previously unknown peculiar objects: (e) & (f) show evidence for extremely strong, narrow outflows; (g) high-z starburst galaxy; (h) narrow, strong Ly α emission line with a well separated N V line We give guideline measurements of the equivalent widths of the emission lines found in IRAF using a simple summing method and two-point continuum interpolation. The error in each measurement is approximately 0.5-1.0 Å. Objects in red are the best candidates for future study. IV. Future Work Further observations are necessary to attain better S/N and more accurate measurements of the strengths of the emission lines, especially taking blending into account. With better measurements, metallicities could be estimated through a variety of line ratios, ie. N III]/O III], N III]/C III], and N V/He II. Subsequent SDSS data releases should be searched for additional objects and, with a homogeneous sample, the percentage of quasars like Q0353-383 may be determined, which may help to increase our understanding of quasar evolution. V. References Baldwin, J. A., et al. 2003, ApJ, 583, 649 Osmer, P. S. 1980, ApJ, 237, 666