The Main Sequence of quasars: the taming of the extremes

Marziani, P.; Bon, E.; Bon, N.; D'Onofrio, M.; Punsly, B.; Sniegowska, M.; Czerny, B.; Panda, S.; Aldama, M. L. Martinez; del Olmo, A.; Deconto-Machado, A.; Negrete, C. A.; Dultzin, D.; Buendia, T.; Garnica, K.

doi:10.48550/arxiv.2111.04140

Cited by 3 publications

(3 citation statements)

References 28 publications

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“…In the case of the high accretors there is a significant correlation between R Fe and 𝜂, reflecting the small influence of the orientation in high-accreting sources which mostly show a face-on orientation (Panda et al 2019;Marziani et al 2021). In the subset of low accretors the correlation is weak, which most likely reflects the difficulties of measuring weak Fe contribution to the spectrum and the effect caused by the large viewing angles (𝜃 ∼ 5 − 50 • ) found in the AGN population (Marziani et al 2021). On the other hand, the correlation between Δ𝜏 and R Fe is not significant in the low-and high-R Fe subsets according to Spearman's rank coefficient and the 𝑝−values (right panel of Fig.…”

Section: Datamentioning

confidence: 99%

Do reverberation-measured H$β$ quasars provide a useful test of cosmology?

Khadka,

Martínez-Aldama,

Zajaček

et al. 2021

Preprint

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We use 118 H𝛽 quasar (QSO) observations in the redshift range 0.0023 ≤ 𝑧 ≤ 0.89 to simultaneously constrain cosmological model parameters and QSO 2-parameter radius-luminosity (𝑅 − 𝐿) relation parameters in six different cosmological models. We find that the 𝑅 − 𝐿 relation parameters for these QSOs are independent of the assumed cosmology so these QSOs seem to be standardizable through the 𝑅 − 𝐿 relation (although there is a complication that might render this untrue). Cosmological constraints obtained using these QSOs are weak, more favor currently decelerated cosmological expansion, and are ∼ 2𝜎 inconsistent with those obtained from a joint analysis of baryon acoustic oscillation and Hubble parameter measurements. Extending the 𝑅 − 𝐿 relation to a 3-parameter one to try to correct for the accretion rate effect does not result in a reduction of the cosmological constraints discrepancy nor does it result in the hoped-for significant reduction of the intrinsic scatter of the 𝑅 − 𝐿 relation.

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Section: Datamentioning

confidence: 99%

Do reverberation-measured H$β$ quasars provide a useful test of cosmology?

Khadka,

Martínez-Aldama,

Zajaček

et al. 2021

Preprint

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show abstract

“…Most interesting along the MS are the spectral types at the extremes (Marziani et al 2021). At the high R FeII end, quasars are found to be radiating at a high Eddington ratio from a variety of theoretical and observational analyses (e.g., Marziani et al 2001;Sun & Shen 2015;Du et al 2016;Panda et al 2019).…”

Section: Introductionmentioning

confidence: 99%

High metal content of highly accreting quasars: Analysis of an extended sample

Garnica

Negrete²,

Marziani

et al. 2022

A&A

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Context. 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 previous work, extending the sample to 42 sources. Aims. Our aim is to test the robustness of the analysis carried out previously, as well as to confirm the two most intriguing results of this investigation: evidence of very high solar metallicities and a deviation of the relative abundance of elements with respect to solar values. Methods. The basis of our analysis are multicomponent fits in three regions of the spectra centered at 1900, 1550, and 1400 Å in order to deblend the broad components of Aliiiλ1860, Ciii]λ1909, Civλ1549, Heiiλ1640, and Siivλ1397 + Oiv]λ1402 and their blue excess. Results. By comparing the observed flux ratios of these components with the same ratios predicted by the photoionization code CLOUDY, we found that the virialized gas (broad components) presents a metallicity (Z) higher than 10Z . For nonvirialized clouds, we derived a lower limit to the metallicity around ∼ 5Z under the assumption of chemical composition proportional to the solar one, confirming the previous results. We especially relied on the ratios between metal lines and Heiiλ1640. This allowed us to confirm systematic differences in the solar-scaled metallicity derived from the lines of Aluminum and Silicon, and of Carbon, with the first being a factor ≈ 2 higher. Conclusions. For luminous quasars accreting at high rates, high Z values are likely, but Z-scaled values are affected by the possible pollution due to highly-enriched gas associated with the circumnuclear star formation. The high-Z values suggest a complex process involving nuclear and circumnuclear star formation and an interaction between nuclear compact objects and an accretion disk, possibly with the formation of accretion-modified stars.

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“…Most interesting along the MS are the spectral types at the extremes (Marziani et al 2021). At the high R FeII end, quasars are found to be radiating at high Eddington ratio from a variety of theoretical and observational analyses (e.g., Marziani et al 2001;Sun & Shen 2015;Du et al 2016;Panda et al 2019).…”

Section: Introductionmentioning

confidence: 99%

High Metal Content of Highly Accreting Quasars: Analysis of an Extended Sample

Garnica¹,

Negrete²,

Marziani³

et al. 2022

Preprint

View full text Add to dashboard Cite

Context. 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 previous work extending the sample to 42 sources. Aims. Our aim is to test the robustness of the analysis carried out previously, as well as to confirm the two most intriguing results of this investigation: evidence of very high solar metallicities, and deviation of the relative abundance of elements with respect to solar values. Methods. The basis of our analysis are multi-component fits in three regions of the spectra centered at 1900, 1550 and 1400 Å in order to deblend the broad components of Aliiiλ1860, Ciii]λ1909, Civλ1549, Heiiλ1640, and Siivλ1397 + Oiv]λ1402 and their blue excess. Results. By comparing the observed flux ratios of these components with the same ratios predicted by photoionization code CLOUDY we found that the virialized gas (broad components) presents a metallicity (Z) higher than 10Z . For non-virialized clouds we derive a lower limit to the metallicity around ∼ 5Z under the assumption of chemical composition proportional to the solar one, confirming the previous results. We especially rely on the ratios between metal lines and Heiiλ1640. This allowed us to confirm systematic differences in the solar-scaled metallicity derived from the lines of Aluminium and Silicon, and of Carbon, with the first being a factor ≈ 2 higher. Conclusions. For luminous quasars accreting at high rates, high Z values are likely, but that Z scaled-values are affected by the possible pollution due to highly-enriched gas associated with the circumnuclear star formation. The high-Z values suggest a complex process involving nuclear and circumnuclear star formation, interaction between nuclear compact objects and accretion disk, possibly with the formation of accretion-modified stars.

show abstract

The Main Sequence of quasars: the taming of the extremes

Cited by 3 publications

References 28 publications

Do reverberation-measured H$β$ quasars provide a useful test of cosmology?

Do reverberation-measured H$β$ quasars provide a useful test of cosmology?

High metal content of highly accreting quasars: Analysis of an extended sample

High Metal Content of Highly Accreting Quasars: Analysis of an Extended Sample

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