Dusty plasma in active galactic nuclei

Naddaf, Mohammad-Hassan; Śniegowska, Marzena; Panda, Swayamtrupta; Różáńska, A.; Adhikari, T. P.; Pandey, A. K.; Jaiswal, Vikram Kumar; Karas, Vladimír; Borkar, A.; Martínez-Aldama, Mary Loli; Prince, Raj

doi:10.1140/epjd/s10053-023-00630-8

“…This can be interpreted to be predominantly the intrinsic color excess expected for the majority of type I QSOs (Richards et al 2003). This extinction originates in the circumnuclear medium, e.g., in an obscuring torus, a warped disk-like structure, or an outflowing clumpy wind within ∼1 pc from the supermassive black hole Gohil & Ballantyne 2017;Gaskell & Harrington 2018;Gaskell et al 2023), and the host galaxy interstellar medium, also see Stolc et al (2023) and Czerny et al (2023c) for discussions. Dust can also be present on the scales of a few thousand gravitational radii, i.e., on subparsec scales, within the BLR clouds (Pandey et al 2023).…”

Section: Relation To the Extinction Curve And E B − Vmentioning

confidence: 95%

Effect of Extinction on Quasar Luminosity Distances Determined from UV and X-Ray Flux Measurements

Zajaček,

Czerny,

Khadka

et al. 2024

ApJ

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In Khadka et al., a sample of X-ray-detected reverberation-mapped quasars was presented and applied for the comparison of cosmological constraints inferred using two well-established relations in active galactic nuclei—the X-ray/UV luminosity (L X –L UV) relation and the broad-line region radius–luminosity (R–L) relation. L X –L UV and R–L luminosity distances to the same quasars exhibit a distribution of their differences that is generally asymmetric and positively shifted for the six cosmological models we consider. We demonstrate that this behavior can be interpreted qualitatively as arising as a result of the dust extinction of UV/X-ray quasar emission. We show that the extinction always contributes to the nonzero difference between L X –L UV-based and R–L-based luminosity distances and we derive a linear relationship between the X-ray/UV color index E X−UV and the luminosity-distance difference, which also depends on the value of the L X –L UV relation slope. Taking into account the median and the peak values of the luminosity-distance difference distributions, the average X-ray/UV color index falls in the range of E ¯ X − UV = 0.03 – 0.28 mag for the current sample of 58 sources. This amount of extinction is typical for the majority of quasars and can be attributed to the circumnuclear and interstellar media of host galaxies. After applying the standard hard X-ray and far-UV extinction cuts, heavily extincted sources are removed but overall the shift toward positive values persists. The effect of extinction on luminosity distances is more pronounced for the L X –L UV relation since the extinction of UV and X-ray emissions both contribute.

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“…We are still far from fully understanding the physical processes of the plasma in the broad-line region (BLR), such as what the densities and temperatures are (Popović 2003;Marziani et al 2020), how to predict the observed emission line ratios (e.g., Ilić et al 2012;Netzer 2020), understand the production of diffuse BLR continuum emission (Chelouche et al 2019), the presence and role of dust (Baron et al 2016;Czerny et al 2023), or determine the location and origin of the Fe II emission (e.g., Baldwin et al 2004;Gaskell et al 2022). For sure, a promising approach for these investigations is to exploit large spectral data sets and provide catalogs of their spectral properties, as has been done for more than half a million of quasars from the Sloan Digital Sky Survey (SDSS; Rakshit et al 2020).…”

Section: Introductionmentioning

confidence: 99%

Fantastic Fits with fantasy of Active Galactic Nuclei Spectra: Exploring the Fe ii Emission near the Hα Line

Ilić

¹

,

Rakić

²

,

Popovic

³

2023

ApJS

4

0

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In this study, a refined approach for multicomponent fitting of active galactic nuclei (AGNs) spectra is presented utilizing the newly developed Python code Fully Automated pythoN Tool for AGN Spectra analYsis (fantasy). AGN spectra are modeled by simultaneously considering the underlying broken power-law continuum, predefined emission line lists, and an Fe ii model, which is here extended to cover the wavelength range 3700–11000 Å. The Fe ii model, founded solely on atomic data, effectively describes the extensive emission of the complex iron ion in the vicinity of the Hγ and Hβ lines, as well as near the Hα line, which was previously rarely studied. The proposed spectral fitting approach is tested on a sample of high-quality AGN spectra from the Sloan Digital Sky Survey Data Release 17. The results indicate that when Fe ii emission is present near Hβ, it is also detected redward from Hα, potentially contaminating the broad Hα line wings and thus affecting the measurements of its flux and width. The production of Fe ii emission is found to be strongly correlated with Eddington luminosity and appears to be controlled by a similar mechanism as the hydrogen Balmer lines. The study highlights the benefits of fitting type 1 AGN spectra with the fantasy code, pointing that it may be used as a robust tool for analyzing a large number of AGN spectra in the coming spectral surveys.

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Science with a Small Two-Band UV-Photometry Mission III: Active Galactic Nuclei and Nuclear Transients

Zajaček,

Czerny,

Jaiswal

et al. 2024

Space Sci Rev

1

0

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In this review, the third one in the series focused on a small two-band UV-photometry mission, we assess possibilities for a small UV two-band photometry mission in studying accreting supermassive black holes (SMBHs; mass range $\sim 10^{6}$ ∼ 10 6 –$10^{10}\,M_{\odot }$ 10 10 M ⊙ ). We focus on the following observational concepts: (i) dedicated monitoring of selected type-I Active Galactic Nuclei (AGN) in order to measure the time delay between the far-UV, the near-UV, and other wavebands (X-ray and optical), (ii) nuclear transients including (partial) tidal disruption events and repetitive nuclear transients, and (iii) the study of peculiar sources, such as changing-look AGN, hollows and gaps in accretion disks, low-luminosity AGN, and candidates for Intermediate-Mass Black Holes (IMBHs; mass range $\sim 10^{2}$ ∼ 10 2 –$10^{5}\,M_{\odot }$ 10 5 M ⊙ ) in galactic nuclei. The importance of a small UV mission for the observing program (i) is to provide intense, high-cadence monitoring of selected sources, which will be beneficial for, e.g. reverberation-mapping of accretion disks and subsequently confronting accretion-disk models with observations. For program (ii), a relatively small UV space telescope is versatile enough to start monitoring a transient event within ≲ 20 minutes after receiving the trigger; such a moderately fast repointing capability will be highly beneficial. Peculiar sources within the program (iii) will be of interest to a wider community and will create an environment for competitive observing proposals. For tidal disruption events (TDEs), high-cadence UV monitoring is crucial for distinguishing among different scenarios for the origin of the UV emission. The small two-band UV space telescope will also provide information about the near- and far-UV continuum variability for rare transients, such as repetitive partial TDEs and jetted TDEs. We also discuss the possibilities to study and analyze sources with non-standard accretion flows, such as AGN with gappy disks, low-luminosity active galactic nuclei with intermittent accretion, and SMBH binaries potentially involving intermediate-mass black holes.

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Dusty plasma in active galactic nuclei

Cited by 9 publications

References 242 publications

Effect of Extinction on Quasar Luminosity Distances Determined from UV and X-Ray Flux Measurements

Effect of Extinction on Quasar Luminosity Distances Determined from UV and X-Ray Flux Measurements

Fantastic Fits with fantasy of Active Galactic Nuclei Spectra: Exploring the Fe ii Emission near the Hα Line

Science with a Small Two-Band UV-Photometry Mission III: Active Galactic Nuclei and Nuclear Transients

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