Related papers: Metallicities and Abundance Ratios from Quasar Bro…
We measured the metallicity Z in the broad emission line regions (BELRs) of 43 SDSS quasars with the strongest N IV] and N III] emission lines. These N-Loud QSOs have unusually low black hole masses. We used the intensity ratio of N lines…
We study the degree of chemical enrichment in the Broad Emission Line Regions (BELRs) of two QSOs with unusually strong nitrogen emission lines. The N V 1240/ C IV 1549 intensity ratio is often used as a metallicity indicator for QSOs. The…
We present an analysis of UV spectra of quasars at intermediate redshifts believed to belong to the extreme Population A (xA), aimed to estimate the chemical abundances of the broad line emitting gas. We follow the approach described in a…
We present an analysis of UV spectra of 13 quasars believed to belong to extreme Population A (xA) quasars, aimed at the estimation of the chemical abundances of the broad line emitting gas. Metallicity estimates for the broad line emitting…
The intensity of the strong N V 1240 line relative to C IV 1549 or to He II 1640 has been proposed as an indicator of the metallicity of QSO broad emission line regions, allowing abundance measurements in a large number of QSOs out to the…
Active galactic nuclei (AGNs) are characterized by a clear correlation between luminosity and metallicity (L_AGN-Z_AGN relation). The origin of this correlation is not clear. It may result from a relation between the black hole mass (M_BH)…
We present a correlation between the presence of luminous extended emission-line regions (EELRs) and the metallicity of the broad-line regions (BLRs) of low-redshift quasars. The result is based on ground-based [O III] 5007 narrow-band…
We compare the metallicities in high-redshift quasars to the star formation rates (SFR) in their host galaxies using measurements of broad emission lines and far-infrared (FIR) luminosities. The FIR emission indicates the level of ongoing…
Metallicity ($Z$) estimates based on ultraviolet (UV) emission lines from the narrow-line regions (NLRs) of active galactic nuclei (AGNs) have been found to differ from those derived from optical lines. However, the origin of this…
The flux ratios of high-ionization lines are commonly assumed to indicate the metallicity of the broad emission line region in luminous quasars. When accounting for the variation in their kinematic profiles, we show that the NV/CIV,…
The 4D eigenvector 1 (E1) sequence has emerged as a powerful tool for organizing the observational and physical characteristics of type-1 active galactic nuclei (AGNs). In this study, we present a comprehensive analysis of the metallicity…
We present rest-frame optical spectra of 12 nitrogen-loud quasars at z ~ 2.2, whose rest-frame ultraviolet (UV) spectra show strong nitrogen broad emission lines. To investigate their narrow-line region (NLR) metallicities, we measure the…
Broad line regions (BLRs) in high-redshift quasars provide crucial information of chemical enrichment in the early universe. Here we present a study of BLR metallicities in 33 quasars at redshift $5.7<z<6.4$. Using the near-IR spectra of…
The determination of the bulk metallicity and the abundance mixture of various elements is very difficult in quasars and AGNs because only a few lines are observed and the ionization correction is unknown. Most abundance studies of AGNs…
We derive metal abundance estimates for a large sample of starbursting emission-line galaxies (ELGs). Our sample is drawn from the KPNO International Spectroscopic Survey (KISS) which has discovered over 2000 ELG candidates to date.…
We investigate the metallicity of the broad line region (BLR) of a sample of 30 quasars in the redshift range 4<z<6.4, by using near-IR and optical spectra. We focus on the ratio of the broad lines (SiIV1397+OIV]1402)/CIV1549, which is a…
The 4D Eigenvector 1 sequence has proven to be a highly effective tool for organizing observational and physical properties of type 1 active galactic nuclei (AGN). In this paper, we present multiple measurements of metallicity for the broad…
We present new near infrared spectroscopic measurements of the H_beta region for a sample of 29 luminous high redshift quasars. We have measured the width of H_beta in those sources, and added archival H_beta width measurements, to create a…
We present high S/N spectroscopy of 15 emission-line galaxies (ELGs) cataloged in the KPNO International Spectroscopic Survey (KISS), selected for their possession of high equivalent width [O III] lines. The primary goal of this study was…
The elemental abundances in the broad-line regions of high-redshift quasars trace the chemical evolution in the nuclear regions of massive galaxies in the early universe. In this work, we study metallicity-sensitive broad emission-line flux…