Ultraviolet Fe ii emission in<i>z</i>∼ 2 quasars

Sameshima, Hiroaki; Maza, J.; Matsuoka, Yoshiki; Oyabu, Shinki; Kawara, Kimiaki; Yoshii, Yuzuru; Asami, Naoko; Ienaka, N.; Tsuzuki, Y.

doi:10.1111/j.1365-2966.2009.14605.x

Cited by 15 publications

(12 citation statements)

References 25 publications

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“…According to models of cosmological nucleosynthesis, Fe enrichment trails behind α-element enrichment until ∼ 1−2 Gyr after the initial star-formation burst; consequently, many groups are actively trying to find such a point of inflexion (e.g. Kurk et al 2007;Sameshima et al 2009). However, most of these efforts have been inconclusive due to the large scatter in the Fe/Mg ratio.…”

Section: Introductionmentioning

confidence: 99%

ATOMIC DATA AND SPECTRAL MODEL FOR Fe II

Bautista

Fivet

Ballance

et al. 2015

ApJ

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We present extensive calculations of radiative transition rates and electron impact collision strengths for Fe II. The data sets involve 52 levels from the 3d 7 , 3d 6 4s, and 3d 5 4s 2 configurations. Computations of A-values are carried out with a combination of state-of-the-art multiconfiguration approaches, namely the relativistic Hartree-Fock, Thomas-Fermi-Dirac potential, and Dirac-Fock methods;while the R-matrix plus intermediate coupling frame transformation, Breit-Pauli R-matrix and Dirac R-matrix packages are used to obtain collision strengths. We examine the advantages and shortcomings of each of these methods, and estimate rate uncertainties from the resulting data dispersion. We proceed to construct excitation balance spectral models, and compare the predictions from each data set with observed spectra from various astronomical objects. We are thus able to establish benchmarks in the spectral modeling of [Fe II] emission in the IR and optical regions as well as in the UV Fe II absorption spectra. Finally, we provide diagnostic line ratios and line emissivities for emission spectroscopy as well as column densities for absorption spectroscopy. All atomic data and models are available online and through the AtomPy atomic data curation environment. Subject headings: atomic data -quasars: absorption lines -quasars: individual (QSO 2359-1241) -ISM: individual objects (HH 202) -ISM: individual objects (Orion) -ISM: individual objects (ESO-Hα 574, Par-Lup 3-4) -ISM: jets and outflows -ISM: lines and bands -stars: pre-main sequence reliable scattering calculations. For this work we use a combination of numerical methods: the pseudo-relativistic Hartree-Fock (hfr) code of Cowan (1981); the Multiconfiguration Dirac-Fock (mcdf) code (Dyall et al. 1989), and the scaled Thomas-Fermi-Dirac central-field potential as implemented in autostructure (Badnell 1997). hfr calculationshfr uses a superposition of configurations approach to account for configuration interactions. The code solves the Hartree-Fock equations for each electronic configuration.Relativistic corrections are also included in this set of equations. The radial parts of the multi-electron Hamiltonian can be adjusted empirically to reproduce the spectroscopic energy levels in a least-squares fit procedure. These semi-empirical corrections are used to account for the contributions from higher order correlations in the atomic state functions.The following configurations were explicitly included in the physical model: 3d 6 4s, 3d 7 , 3d 5 4s 2 , 3d 6 5s, 3d 6 4d, 3d 6 5d, 3d 5 4p 2 , 3d 5 4d 2 , 3d 5 4s4d, 3s3p 6 3d 7 4s, 3s3p 6 3d 8 , and 3s3p 6 3d 6 4s 2 . This configuration expansion extends the one used in the previous hfr calculation by Quinet et al. (1996) by including 3d 5 4d 2 and 3s3p 6 3d 6 4s 2 . In order to minimize the discrepancies between computed and experimental energy levels, the hfr technique was used in combination with a well-known least-squares optimization of the radial parameters. The fitting procedure was applied to 3d 6 4s, 3d 7 , ...

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Section: Introductionmentioning

confidence: 99%

ATOMIC DATA AND SPECTRAL MODEL FOR Fe II

Bautista

Fivet

Ballance

et al. 2015

ApJ

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“…Under the assumption that the Fe ii /Mg ii flux ratio reflects [Fe/Mg], various groups have measured Fe ii /Mg ii in high‐redshift quasars hoping to discover such a break (e.g. Elston, Thompson & Hill 1994; Kawara et al 1996; Dietrich et al 2002, 2003; Iwamuro et al 2002, 2004; Freudling, Corbin & Korista 2003; Maiolino et al 2003; Kurk et al 2007; Sameshima et al 2009). However, these efforts have ended up with finding a large scatter of Fe ii /Mg ii showing little evolution.…”

Section: Introductionmentioning

confidence: 99%

Implications from the optical to ultraviolet flux ratio of Fe ii emission in quasars

Sameshima¹,

Kawara²,

Matsuoka³

et al. 2010

Monthly Notices of the Royal Astronomical Society

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We investigate Fe II emission in the broad-line region (BLR) of active galactic nuclei by analysing the Fe II(UV), Fe II(λ4570) and Mg II emission lines in 884 quasars in the Sloan Digital Sky Survey Quasar catalogue in a redshift range of 0.727 < z < 0.804. Fe II(λ4570)/Fe II(UV) is used to infer the column density of Fe II-emitting clouds and explore the excitation mechanism of Fe II emission lines. As suggested before in various works, the classical photoionization models fail to account for Fe II(λ4570)/Fe II(UV) by a factor of 10, which may suggest anisotropy of UV Fe II emission, or an alternative mechanism like shocks. The column density distribution derived from Fe II(λ4570)/Fe II(UV) indicates that radiation pressure plays an important role in BLR gas dynamics. We find a positive correlation between Fe II(λ4570)/Fe II(UV) and the Eddington ratio. We also find that the ionizing photon fraction must be much smaller than that previously suggested unless Fe II-emitting clouds are super-Eddington. Finally, we propose a physical interpretation of a striking set of correlations between various emission-line properties, known as 'Eigenvector 1'.

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“…Many studies in the literature investigate the Mg II/Fe II ratio in the BLR of quasars, by estimating the ratio of the Fe II and Mg II fluxes (F F Fe Mg II II ), considered a first-order proxy of the abundance ratio (e.g., Iwamuro et al 2002Iwamuro et al , 2004Barth et al 2003;Maiolino et al 2003;Jiang et al 2007;Kurk et al 2007;Sameshima et al 2009;De Rosa et al 2011 , and bolometric luminosities (right panel) for one of the 1000 bolometric luminosity-matched subsamples drawn from low-redshift SDSS quasars (gray histograms; Shen et al 2011 andPâris et al 2017; see text for details), and for the z 6.5  quasars presented here (red histograms). The gray circles represent the mean of black hole masses, Eddington ratios, and bolometric luminosities in each bin, resulting from all the 1000 trials at z 1 .…”

Section: Fe Ii/ Mg IImentioning

confidence: 99%

Physical Properties of 15 Quasars at z ≳ 6.5

Mazzucchelli

Bañados

Venemans

et al. 2017

ApJ

328

444

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Quasars are galaxies hosting accreting supermassive black holes; due to their brightness, they are unique probes of the early universe. To date, only a few quasars have been reported at (<800 Myr after the big bang). In this work, we present six additional quasars discovered using the Pan-STARRS1 survey. We use a sample of 15 quasars to perform a homogeneous and comprehensive analysis of this highest-redshift quasar population. We report four main results: (1) the majority of quasars show large blueshifts of the broad C iv λ1549 emission line compared to the systemic redshift of the quasars, with a median value ∼3× higher than a quasar sample at ; (2) we estimate the quasars’ black hole masses ( (0.3–5) × 109 M ⊙) via modeling of the Mg ii λ2798 emission line and rest-frame UV continuum and find that quasars at high redshift accrete their material (with ) at a rate comparable to a luminosity-matched sample at lower redshift, albeit with significant scatter (0.4 dex); (3) we recover no evolution of the Fe ii/Mg ii abundance ratio with cosmic time; and (4) we derive near-zone sizes and, together with measurements for quasars from recent work, confirm a shallow evolution of the decreasing quasar near-zone sizes with redshift. Finally, we present new millimeter observations of the [C ii] 158 μm emission line and underlying dust continuum from NOEMA for four quasars and provide new accurate redshifts and [C ii]/infrared luminosity estimates. The analysis presented here shows the large range of properties of the most distant quasars.

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Ultraviolet Fe ii emission inz∼ 2 quasars

Cited by 15 publications

References 25 publications

ATOMIC DATA AND SPECTRAL MODEL FOR Fe II

ATOMIC DATA AND SPECTRAL MODEL FOR Fe II

Implications from the optical to ultraviolet flux ratio of Fe ii emission in quasars

Physical Properties of 15 Quasars at z ≳ 6.5

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