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Universe
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Panchromatic View of the Life-Cycle of AGN
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Panchromatic View of the Life-Cycle of AGN

A special issue of Universe (ISSN 2218-1997). This special issue belongs to the section "Galaxies and Clusters".

Deadline for manuscript submissions: closed (15 September 2021) | Viewed by 13941

Special Issue Editor

Dr. Marco Berton

E-Mail Website
Guest Editor
European Southern Observatory (ESO), Alónso de Cordova 3107, Casilla 19, Santiago 19001, Chile
Interests: active galactic nuclei; AGN feedback; relativistic jets; radio astronomy; physics of ionized gas

Special Issue Information

Dear Colleagues,

In the last two decades, the unified models of active galactic nuclei (AGN) have been able to explain several of their observational properties. Whereas the simple orientation-based unification model works as a first-degree approximation, the reality is more complicated, and there is a host of different parameters at play. Statistical methods, aimed at simplifying multidimensional data, and in particular the so-called eigenvector 1 (EV1), have proven to be a useful tool in studying AGN grand unification. The position of a source on the EV1 is believed to be a combination of observational (mainly inclination) and physical properties, with the Eddington ratio acting as the main driver. However, different stages of AGN evolution can also appear as different classes of sources. Indeed, mounting evidence shows that the AGN life-cycle, that is, how AGN are born, how they grow, and how they interact with their closest environment, likely plays an essential role in this grand-unification scenario.

The main purpose of this Special Issue is to gather different points of view on these fundamental aspects, in order to better clarify what the role played by evolution in the grand-unification of active galaxies is.

Dr. Marco Berton
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Universe is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • active galactic nuclei
  • supermassive black holes
  • accretion disk
  • relativistic jets
  • AGN feedback
  • AGN evolution
  • AGN unification
  • changing-look AGN

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Published Papers (5 papers)

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Research

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23 pages, 2091 KiB  
Article
Optical Singly-Ionized Iron Emission in Radio-Quiet and Relativistically Jetted Active Galactic Nuclei
by Paola Marziani, Marco Berton, Swayamtrupta Panda and Edi Bon
Universe 2021, 7(12), 484; https://doi.org/10.3390/universe7120484 - 8 Dec 2021
Cited by 11 | Viewed by 2227
Abstract
The issue of the difference between optical and UV properties of radio-quiet and radio-loud (relativistically “jetted”) active galactic nuclei (AGN) is a long standing one, related to the fundamental question of why a minority of powerful AGN possess strong radio emission due to [...] Read more.
The issue of the difference between optical and UV properties of radio-quiet and radio-loud (relativistically “jetted”) active galactic nuclei (AGN) is a long standing one, related to the fundamental question of why a minority of powerful AGN possess strong radio emission due to relativistic ejections. This paper examines a particular aspect: the singly-ionized iron emission in the spectral range 4400–5600 Å, where the prominent HI Hβ and [Oiii]λλ4959,5007 lines are also observed. We present a detailed comparison of the relative intensity of Feii multiplets in the spectral types of the quasar main sequence where most jetted sources are found, and afterwards discuss radio-loud narrow-line Seyfert 1 (NLSy1) nuclei with γ-ray detection and with prominent Feii emission. An Feii template based on I Zw 1 provides an accurate representation of the optical Feii emission for RQ and, with some caveats, also for RL sources. CLOUDY photoionization simulations indicate that the observed spectral energy distribution can account for the modest Feii emission observed in composite radio-loud spectra. However, spectral energy differences alone cannot account for the stronger Feii emission observed in radio-quiet sources, for similar physical parameters. As for RL NLSy1s, they do not seem to behave like other RL sources, likely because of their different physical properties, that could be ultimately associated with a higher Eddington ratio. Full article
(This article belongs to the Special Issue Panchromatic View of the Life-Cycle of AGN)
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111 pages, 1556 KiB  
Article
A New Sample of Gamma-Ray Emitting Jetted Active Galactic Nuclei—Preliminary Results
by Luigi Foschini, Matthew L. Lister, Sonia Antón, Marco Berton, Stefano Ciroi, Maria J. M. Marchã, Merja Tornikoski, Emilia Järvelä, Patrizia Romano, Stefano Vercellone and Elena Dalla Bontà
Universe 2021, 7(10), 372; https://doi.org/10.3390/universe7100372 - 5 Oct 2021
Cited by 17 | Viewed by 3500
Abstract
We are compiling a new list of gamma-ray jetted active galactic nuclei (AGN), starting from the fourth catalog of point sources of the Fermi Large Area Telescope (LAT). Our aim is to prepare a list of jetted AGN with known redshifts and classifications [...] Read more.
We are compiling a new list of gamma-ray jetted active galactic nuclei (AGN), starting from the fourth catalog of point sources of the Fermi Large Area Telescope (LAT). Our aim is to prepare a list of jetted AGN with known redshifts and classifications to be used to calibrate jet power. We searched in the available literature for all the published optical spectra and multiwavelength studies useful to characterize the sources. We found new, missed, or even forgotten information leading to a substantial change in the redshift values and classification of many sources. We present here the preliminary results of this analysis and some statistics based on the gamma-ray sources with right ascension within the interval 0h--12h (J2000). Although flat-spectrum radio quasars and BL Lac objects are still the dominant populations, there is a significant increase in the number of other objects, such as misaligned AGN, narrow-line Seyfert 1 galaxies, and Seyfert galaxies. We also introduced two new classes of objects: changing-look AGN and ambiguous sources. About one third of the sources remain unclassified. Full article
(This article belongs to the Special Issue Panchromatic View of the Life-Cycle of AGN)
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29 pages, 659 KiB  
Article
Jet-Induced Feedback in the [O III] Lines of Early Evolution Stage Active Galactic Nuclei
by Marco Berton and Emilia Järvelä
Universe 2021, 7(6), 188; https://doi.org/10.3390/universe7060188 - 6 Jun 2021
Cited by 7 | Viewed by 2362
Abstract
It is well known that active galactic nuclei (AGN) show various forms of interaction with their host galaxy, in a number of phenomena generally called AGN feedback. In particular, the relativistic plasma jets launched by a fraction of AGN can strongly affect their [...] Read more.
It is well known that active galactic nuclei (AGN) show various forms of interaction with their host galaxy, in a number of phenomena generally called AGN feedback. In particular, the relativistic plasma jets launched by a fraction of AGN can strongly affect their environment. We present here a study of the [O III] λλ4959,5007 lines in a diverse sample of early evolution stage AGN–specifically narrow-line Seyfert 1 galaxies. Radio imaging observations of all of the sources enable a division to jetted and non-jetted sources, and exploiting this we show that the ionized gas properties are significantly influenced by the presence of the jets, as we often find the [O III] lines (blue-)shifted with respect to their restframe wavelength. We also show how the radio morphology and the radio spectral index do not seem to play a role in the origin of the [O III] shifts, thus suggesting that the source inclination is not relevant to the lines displacement. We do not find a strong relation between the [O III] line properties and the bolometric luminosity, suggesting that within our sample radiatively driven outflows do not seem to have a significant contribution to the [O III] line kinematics. We finally suggest that [O III] shifts may be a good proxy to identify the presence of relativistic jets. Additional studies, especially with integral-field spectroscopy, will provide a deeper insight into the relation between jets and their environment in early evolution stage AGN. Full article
(This article belongs to the Special Issue Panchromatic View of the Life-Cycle of AGN)
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8 pages, 256 KiB  
Communication
On the Heating of AGN Magnetospheres
by Zaza Osmanov and Swadesh Mahajan
Universe 2021, 7(4), 83; https://doi.org/10.3390/universe7040083 - 31 Mar 2021
Cited by 2 | Viewed by 1583
Abstract
The Langmuir–Landau-Centrifugal Drive (LLCD), which can effectively “convert” gravitational energy into particles, is explored as a driving mechanism responsible for the extreme thermal luminosity acquired by some active galactic nuclei (AGN). For this purpose, we consider equations governing the process of heating of [...] Read more.
The Langmuir–Landau-Centrifugal Drive (LLCD), which can effectively “convert” gravitational energy into particles, is explored as a driving mechanism responsible for the extreme thermal luminosity acquired by some active galactic nuclei (AGN). For this purpose, we consider equations governing the process of heating of AGN magnetospheres. In particular, we examine the Fourier components of the momentum equation, the continuity equation and the Poisson equation in the linear approximation and estimate the growth rate of the centrifugally excited electrostatic waves and the increment of the Langmuir collapse. It is shown that the process of energy pumping is composed of three stages: in the first stage the energy is efficiently transferred from rotation to the electrostatic modes. In due course of time, the second regime-the Langmuir collapse-occurs, when energy pumping is even more efficient. This process is terminated by the Landau damping, when enormous energy is released in the form of heat. We show that the magnetospheres of the supermassive black holes with luminosities of the order of 1045−46 erg/s can be heated up to 106−10 K. Full article
(This article belongs to the Special Issue Panchromatic View of the Life-Cycle of AGN)
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Review

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19 pages, 3528 KiB  
Review
Project MOMO: Multiwavelength Observations and Modeling of OJ 287
by S. Komossa, D. Grupe, A. Kraus, L. C. Gallo, A. G. Gonzalez, M. L. Parker, M. J. Valtonen, A. R. Hollett, U. Bach, J. L. Gómez, I. Myserlis and S. Ciprini
Universe 2021, 7(8), 261; https://doi.org/10.3390/universe7080261 - 23 Jul 2021
Cited by 17 | Viewed by 2786
Abstract
Our project MOMO (Multiwavelength observations and modeling of OJ 287) consists of dedicated, dense, long-term flux and spectroscopic monitoring, and deep follow-up observations of the blazar OJ 287 at >13 frequencies from the radio to the X-ray band since late 2015. In particular, [...] Read more.
Our project MOMO (Multiwavelength observations and modeling of OJ 287) consists of dedicated, dense, long-term flux and spectroscopic monitoring, and deep follow-up observations of the blazar OJ 287 at >13 frequencies from the radio to the X-ray band since late 2015. In particular, we are using Swift to obtain optical-UV-X-ray spectral energy distributions (SEDs) and the Effelsberg telescope to obtain radio measurements between 2 and 40 GHz. MOMO is the densest long-term monitoring of OJ 287 involving X-rays and broad-band SEDs. The theoretical part of the project aims at understanding jet and accretion physics of the blazar central engine in general and the supermassive binary black hole scenario in particular. Results are presented in a sequence of publications and so far included: detection and detailed analysis of the bright 2016/17 and 2020 outbursts and the long-term light curve; Swift, XMM, and NuSTAR spectroscopy of the 2020 outburst around maximum; and interpretation of selected events in the context of the binary black hole scenario of OJ 287 (papers I–IV). Here, we provide a description of the project MOMO, a summary of previous results, the latest results, and we discuss future prospects. Full article
(This article belongs to the Special Issue Panchromatic View of the Life-Cycle of AGN)
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