The CaFe Project: Optical Fe II and Near-infrared Ca II Triplet Emission in Active Galaxies. II. The Driver(s) of the Ca II and Fe II and Its Potential Use as a Chemical Clock

Martínez-Aldama, Mary Loli; Panda, Swayamtrupta; Marinello, Murilo; Marziani, Paola; Dultzin, D.

doi:10.3847/1538-4357/ac03b6

Cited by 14 publications

(14 citation statements)

References 107 publications

(161 reference statements)

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“…The similarity in the location of the line production of these species suggests a common origin of these LILs, especially between the strengths of the Fe ii and the CaT 5 . This has been confirmed both from observational and photoionization studies in our recent works (Martínez-Aldama et al, 2015;Panda et al, 2020;Martínez-Aldama et al, 2021b).…”

Section: Introductionsupporting

confidence: 80%

“…These smaller 𝑅 BLR values show a marked deviation from the expected 𝑅 H𝛽 − 𝐿 5100 relation, and addressing this problem is key to our understanding of how these systems evolve and if viable corrections to the classical relation can be made to utilize AGNs as "standardizable" cosmological candles. In addition to this issue, we find in Martínez-Aldama et al (2021b) that the ratio of the CaT to Fe ii (justifying the project name -CaFe) is an effective tracer of the chemical evolution of AGNs and can help us probe the co-evolution of the AGN and its host galaxy in more detail.…”

Section: Introductionmentioning

confidence: 84%

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Revisiting the spectral energy distribution of I Zw 1 under the CaFe Project

Panda¹,

Santos²

2021

Acta Astrophys. Tau.

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The CaFe Project involves the study of the properties of the low ionization emission lines (LILs) pertaining to the broad-line region (BLR) in active galaxies. These emission lines, especially the singly-ionized iron (Fe II) in the optical and the corresponding singly-ionized calcium (Ca II) in the near-infrared (NIR) are found to show a strong correlation in their emission strengths, i.e. with respect to the broad H$\beta$ emission line, the latter also belonging to the same category of LILs. The origin of this correlation is attributed to the similarity in the physical conditions necessary to emit these lines - especially in terms of the strength of the ionization from the central continuum source and the local number density of available matter in these regions. In this paper, we focus on the issue of the spectral energy distribution (SED) characteristic to a prototypical Type-1 Narrow-line Seyfert galaxy (NLS1) - I Zw 1. We extract the continuum from quasi-simultaneous spectroscopic measurements ranging from the near-UV (~1200A) to the near-infrared (~24000A) to construct the SED and supplement it with archival X-ray measurements available for this source. Using photoionization code CLOUDY, we assess and compare the contribution of the prominent "Big Blue Bump" seen in our SED versus the SED used in our previous work, wherein the latter was constructed from archival, multi-epoch photometric measurements. Following the prescription from our previous work, we constrain the physical parameter space to optimize the emission from these LILs and discuss the implication of the use of a "better" SED.

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Section: Introductionsupporting

confidence: 80%

Section: Introductionmentioning

confidence: 84%

Revisiting the spectral energy distribution of I Zw 1 under the CaFe Project

Panda¹,

Santos²

2021

Acta Astrophys. Tau.

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“…In addition, we show the change in the line EWs in Figure 5, wherein we can notice that for the location in the log U − log n H plane with the optimal values for EWs, i.e. ∼40Å for Fe ii and ∼100Å for Hβ (see Table A1 in Martínez-Aldama et al, 2021b), which corresponds to a log U -3.0 around BLR densities log n H ∼ 10 12 cm −3 , we have a ∆Fe ii around 10-20Å, while for Hβ this difference rises to be around 30-50Å. This leads to the slump in the R FeII that we notice in Figure 4.…”

Section: Resultsmentioning

confidence: 94%

“…These smaller R BLR values show a marked deviation from the expected R Hβ − L 5100 relation, and addressing this problem is key to our understanding of how these systems evolve and if viable corrections to the classical relation can be made to utilize AGNs as "standardizable" cosmological candles. In addition to this issue, we find in Martínez-Aldama et al (2021b) that the ratio of the CaT to Fe ii (justifying the project name -CaFe) is an effective tracer of the chemical evolution of AGNs and can help us probe the co-evolution of the AGN and its host galaxy in more detail.…”

Section: Introductionmentioning

confidence: 84%

Revisiting the spectral energy distribution of I Zw 1 under the CaFe Project

Panda¹,

Santos²

2021

Preprint

Self Cite

View full text Add to dashboard Cite

The CaFe Project involves the study of the properties of the low ionization emission lines (LILs) pertaining to the broad-line region (BLR) in active galaxies. These emission lines, especially the singly-ionized iron (Fe ii) in the optical and the corresponding singly-ionized calcium (Ca ii) in the near infrared (NIR) are found to show a strong correlation in their emission strengths, i.e. with respect to the broad Hβ emission line, the latter also belonging to the same category of LILs. The origin of this correlation is attributed to the similarity in the physical conditions necessary to emit these lines -especially in terms of the strength of the ionization from the central continuum source and the local number density of available matter in these regions. In this paper, we focus on the issue of the spectral energy distribution (SED) characteristic to a prototypical Type-1 Narrow-line Seyfert galaxy (NLS1) -I Zw 1. We extract the continuum from quasi-simultaneous spectroscopic measurements ranging from the near-UV (∼1200Å) to the near infrared (∼24000Å) to construct the SED and supplement it with archival X-ray measurements available for this source. Using the photoionization code CLOUDY, we assess and compare the contribution of the prominent "Big Blue Bump" seen in our SED versus the SED used in our previous work, wherein the latter was constructed from archival, multi-epoch photometric measurements. Following the prescription from our previous work, we constrain the physical parameter space to optimize the emission from these LILs and discuss the implication of the use of a "better" SED.

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“…Similar to Table 1, we report the estimates for all the cases accounting for the appropriate χ values for the two sources in the last two columns in Table 3. -Aldama et al, 2021b). The M BH is estimated using the spectral properties obtained from Persson (1988).…”

Section: Discussionmentioning

confidence: 99%

Parameterizing the AGN radius -- luminosity relation from the Eigenvector 1 viewpoint

Panda¹

2022

Preprint

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The study of the broad-line region (BLR) using reverberation mapping has allowed us to establish an empirical relation between the size of this line emitting region and the continuum luminosity that drives the line emission (i.e. the R Hβ − L 5100 relation). To realize its full potential, the intrinsic scatter in the R Hβ − L 5100 relation needs to be understood better. The mass accretion rate (or equivalently the Eddington ratio) plays a key role in addressing this problem. On the other hand, the Eigenvector 1 schema has helped to reveal an almost clear connection between the Eddington ratio and the strength of the optical Fe II emission that originates from the BLR. This paper aims to reveal the connection between theoretical entities, like, the ionization parameter (U) and cloud mean density (n H ) of the BLR, with physical observables obtained directly from the spectra, such as optical Fe II strength (R FeII ) that has shown immense potential to trace the accretion rate. We utilize the photoionization code CLOUDY and perform a suite of models to reveal the physical conditions in the low-ionization, dust-free, line emitting BLR. The key here is the focus on the recovery of the equivalent widths (EWs) for the two low-ionization emission lines -Hβ and the optical Fe II, in addition to the ratio of their EWs, i.e., R FeII . We compare the spectral energy distributions of prototypical Population A and Population B sources, I ZW 1 and NGC 5548, respectively, in this study. The results from the photoionization modelling are then combined with existing reverberation mapped sources with observed R FeII estimates taken from the literature, allowing us to assess our analytical formulation to tie together the aforementioned quantities. The recovery of the correct physical conditions in the BLR then suggests that -the BLR "sees" only a very small fraction (∼1-10%) of the original ionizing continuum.

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The CaFe Project: Optical Fe II and Near-infrared Ca II Triplet Emission in Active Galaxies. II. The Driver(s) of the Ca II and Fe II and Its Potential Use as a Chemical Clock

Cited by 14 publications

References 107 publications

Revisiting the spectral energy distribution of I Zw 1 under the CaFe Project

Revisiting the spectral energy distribution of I Zw 1 under the CaFe Project

Revisiting the spectral energy distribution of I Zw 1 under the CaFe Project

Parameterizing the AGN radius -- luminosity relation from the Eigenvector 1 viewpoint

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