In Panda et al.2018a, we constructed a refined sample from the original Shen et al.(2011) QSO catalog. Based on our hypothesis — the main driver of the Quasar Main Sequence is the maximum of the accretion disk temperature (TBBB) defined by the Big Blue Bump on the Spectral Energy Distribution (Panda et al.2017; Panda et al.2018b). We select the four extreme sources that have RFeII ⩾ 4.0 and use {CIGALE (Boquien et al.2018) to fit their multi—band photometric data. We also perform detailed spectral fitting including the Fe II pseudo—continuum (based on Śniegowska et al.2018)) to estimate and compare the value of RFEII. We show the dependence of FeII strength on changing metallicity.

We address the effect of orientation of the accretion disk plane and the geometry of the broad line region (BLR) in the context of understanding the distribution of quasars along their Main Sequence. We utilize the photoionization code CLOUDY to model the BLR, incorporating the ‘un-constant’ virial factor. We show the preliminary results of the analysis to highlight the co-dependence of the Eigenvector 1 parameter, RFeII on the broad HβFWHM (i.e. the line dispersion) and the inclination angle (θ), assuming fixed values for the Eddington ratio (Lbol/ LEdd), black hole mass (MBH), spectral energy distribution (SED) shape, cloud density (nH) and composition.†

The interpretation of the main sequence of quasars has become a frontier subject in the last years. This considers the effect of a highly flattened, axially symmetric geometry for the broad line region (BLR) on the parameters related to the distribution of quasars along their main sequence. We utilize the photoionization code CLOUDY to model the BLR, assuming ‘un-constant’ virial factor with a strong dependence on the viewing angle. We show the preliminary results of the analysis to highlight the co-dependence of the Eigenvector 1 parameter, RFeii on the broad Hβ FWHM (i.e. the line dispersion) and the inclination angle (θ), assuming fixed values for the Eddington ratio (Lbo1/LEdd), black hole mass (MBH) and spectral energy distribution (SED) shape. We consider four cases with changing cloud density (nH) and composition. Understanding the emitting region is crucial as this knowledge can be extended to the use of quasars as distance indicators for Cosmology.‡

This article presents an up-dated analysis of synthetic optical and UV emission lines of simulated galaxies over cosmic time. The strong emission lines are derived from self-consistently coupling novel spectral models accounting for nebular emission from young stars, AGN and Post-AGB stars to cosmological zoom-in as well as large-scale simulations. Investigating the evolution of optical line-ratios in the BPT diagrams, the simulations can successfully reproduce the observed trend of [OIII]/Hβ ratio increasing from low to high redshifts, due to evolving star formation rate and gas metallicity. Standard selection criteria in the BPT diagrams can appropriately distinguish the main ionising source(s) of galaxies at low redshifts, but they are less reliable for metal-poor galaxies, dominating the early Universe. To robustly classify the ionising radiation of such metal-poor galaxies, diagnostic diagrams based on luminosity ratios of UV lines are discussed. The novel interface between simulations and observations is potentially important for the interpretation of high-quality spectra of very distant galaxies to be gathered by next-generation telescopes, such as the James Webb Space Telescope.

In this proceeding I will summarize our on-going observational campaign to characterize Active Galactic Nuclei (AGN) driven ionized gas outflows at z ˜ 2 and assess their impact on galaxy evolution. The results are mostly derived from a recently completed SINFONI/VLT Large Programme named SUPER, conducted with Adaptive Optics to reach a spatial resolution of ˜2 kpc at z ˜ 2.

When galaxies merge, gas accretes onto both central supermassive black holes. Thus, one expects to see dual active galactic nuclei (AGNs) in a fraction of galaxy mergers. Candidates for galaxies containing dual AGNs have been identified by the presence of double-peaked narrow [O III] emission lines and by high spatial resolution images of close galaxy pairs. 30% of double-peaked narrow [OIII] emission line SDSS AGNs have two spatial components within a 3″ radius. However, spatially resolved spectroscopy is needed to confirm these galaxy pairs as systems with double AGNs. With the Keck 2 Laser Guide Star Adaptive Optics system and the OSIRIS near-infrared integral field spectrograph, we obtained spatially resolved spectra for SDSS J095207.62+255257.2, confirming that it contains a Type 1 and a Type 2 AGN separated by 4.8 kpc (=1.0″). We performed similar integral field and long-slit spectroscopy observations of more spatially separated candidate dual AGNs and will report on the varied results. By assessing what fraction of radio-quiet double-peaked emission line SDSS AGNs are true dual AGNs, we can better constrain the statistics of dual AGNs and characterize physical conditions throughout these interacting AGNs.

We present results from infrared spectroscopic projects that aim to test the relation between the mass of a black hole MBH and the velocity dispersion of the stars in its host-galaxy bulge. We demonstrate that near-infrared, high-resolution spectroscopy assisted by adaptive optics is key in populating the high-luminosity end of the relation. We show that the velocity dispersions of mid-infrared, high-ionization lines originating from gas in the narrow-line region of the active galactic nucleus follow the same relation. This result provides a way of inferring MBH estimates for the cosmologically significant population of obscured, type 2 AGN that can be applicable to data from spectrographs on next-generation infrared telescopes.

We present two ongoing studies of gas phase abundances around high redshift quasars. First, we examine broad emission line (BEL) metallicities for 29 quasars with 2.3 < z < 4.6 and far-infrared (far-IR) luminosities (LFIR) from 1013.4 to ≤ 1012.2 L⊙, corresponding to star formation rates (SFRs) of 6740 to ≤ 1360 M⊙ yr−1. Quasar samples sorted by LFIR might represent an evolutionary sequence if SFRs in quasar hosts generally diminish across quasar lifetimes. We create three composite spectra from rest-frame ultra-violet Sloan Digital Sky Survey spectra with increasing far-IR luminosity. We measure the N V(λ1240)/C IV(λ1550) and Si IV(λ1397)+O IV](λ1402)/C IV(λ1550) emission line flux ratios for each composite and find uniformly high (~5-10 times solar) metallicities for the three composites, and no evidence for changes in metal enrichment with changes in ongoing SFR. Second, we present preliminary results from the largest ever survey of high resolution associated absorption line (AAL) region metallicities and physical properties in a sample of high redshift (z > 3) quasars. This includes five quasars with previously known AALs at z > 4 and two well measured z ~3 quasars with unusually rich absorption spectra. We determine well-constrained metallicities of about twice solar for five AAL systems. We find a range of lower limits for AAL metallicities in the z > 4 quasars from 1/100ths solar to 3 times solar. Overall, these results for typically super-solar gas-phase metallicities near quasars are consistent with evolutionary schemes where the major episodes of star formation in the host galaxies occur before the visibly luminous quasar phase. High SFRs (comparable to ULIRGs) in the host galaxies are not clearly linked to younger or chemically less mature quasar environments.