Tracing the outflow kinematics in Type 2 active galactic nuclei

Aims. We perform clustering measurements of 800 X-ray selected Chandra COSMOS Legacy (CCL) Type 2 active galactic nuclei (AGN) with known spectroscopic redshift to probe the halo mass dependence on AGN host galaxy properties, such as galaxy stellar mass Mstar, star formation rate (SFR), and specific black hole accretion rate (BHAR; λBHAR) in the redshift range z = [0−3]. Methods. We split the sample of AGN with known spectroscopic redshits according to Mstar, SFR and λBHAR, while matching the distributions in terms of the other parameters, including redshift. We measured the projected two-point correlation function wp(rp) and modeled the clustering signal, for the different subsamples, with the two-halo term to derive the large-scale bias b and corresponding typical mass of the hosting halo. Results. We find no significant dependence of the large-scale bias and typical halo mass on galaxy stellar mass and specific BHAR for CCL Type 2 AGN at mean z ∼ 1, while a negative dependence on SFR is observed, i.e. lower SFR AGN reside in richer environment. Mock catalogs of AGN, matched to have the same X-ray luminosity, stellar mass, λBHAR, and SFR of CCL Type 2 AGN, almost reproduce the observed Mstar − Mh, λBHAR − Mh and SFR–Mh relations, when assuming a fraction of satellite AGN fAGNsat ∼ 0.15. This corresponds to a ratio of the probabilities of satellite to central AGN of being active Q ∼ 2. Mock matched normal galaxies follow a slightly steeper Mstar − Mh relation, in which low mass mock galaxies reside in less massive halos than mock AGN of similar mass. Moreover, matched mock normal galaxies are less biased than mock AGN with similar specific BHAR and SFR, at least for Q > 1.

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Examining supernova events in Type 1 active galactic nuclei

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa1329 ◽

2020 ◽

Vol 495 (4) ◽

pp. 4419-4429

Author(s):

Beatriz Villarroel ◽

Iñigo Imaz ◽

Elisabeta Lusso ◽

Sébastien Comerón ◽

M Almudena Prieto ◽

...

Keyword(s):

Active Galactic Nuclei ◽

Detection Rate ◽

Statistical Study ◽

Galactic Nuclei ◽

Core Collapse ◽

Late Type ◽

Host Galaxies ◽

Specific Kind

ABSTRACT A statistical study of intermediate Palomar Transient Factory supernovae (SNe) in Type 1 active galactic nuclei (AGNs) has shown a major deficit of supernovae around Type 1 AGN host galaxies, with respect to Type 2 AGN hosts. The aim of this work is to test whether there is any preference for Type 1 AGNs to host SN of a specific kind. Through the analysis of SN occurrence and their type (thermonuclear versus core-collapse), we can directly link the type of stars producing the SN events, thus this is an indirect way to study host galaxies in Type 1 AGNs. We examine the detection fractions of SNe, the host galaxies and compare the sample properties to typical host galaxies in the Open Supernova Catalog (OSC). The majority of the host galaxies in the AGN sample are late type, similar to typical galaxies hosting SN within the OSC. The findings are supportive of a deficiency of SNe near Type 1 AGNs, although we cannot with certainty assess the overall detection fractions of SNe in Type 1 AGNs relative to other SN host galaxies. We can state that Type 1 AGN has equal detection fractions of thermonuclear versus core-collapse SNe. However, we note the possibility of a higher detection rate of core-collapse supernovae in Type 1 AGN with insecure AGN classifications.

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Powerful Water Masers in Active Galactic Nuclei

Publications of the Astronomical Society of Australia ◽

10.1071/as01100 ◽

2002 ◽

Vol 19 (4) ◽

pp. 401-421 ◽

Cited By ~ 29

Author(s):

Philip R. Maloney

Keyword(s):

Active Galactic Nuclei ◽

Galactic Nuclei ◽

Rotating Disk ◽

Future Prospects ◽

Maser Emission ◽

X Ray ◽

Central Engine ◽

Water Masers ◽

Water Maser

AbstractLuminous water maser emission in the 616–523 line at 22GHz has been detected from two dozen galaxies. In all cases the emission is confined to the nucleus and has been found only in AGN, in particular, in Type 2 Seyferts and LINERs. I argue that most of the observed megamaser sources are powered by X-ray irradiation of dense gas by the central engine. After briefly reviewing the physics of these X-Ray Dissociation Regions, I discuss in detail the observations of the maser disk in NGC 4258, its implications, and compare alternative models for the maser emission. I then discuss the observations of the other sources that have been imaged with VLBI to date, and how they do or do not fit into the framework of a thin, rotating disk, as in NGC 4258. Finally, I briefly discuss future prospects, especially the possibility of detecting other water maser transitions.

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Changing-look active galactic nuclei: close binaries of supermassive black holes in action

Astronomy and Astrophysics ◽

10.1051/0004-6361/202039368 ◽

2020 ◽

Vol 643 ◽

pp. L9

Author(s):

Jian-Min Wang ◽

Edi Bon

Keyword(s):

Black Holes ◽

Angular Momentum ◽

Active Galactic Nuclei ◽

Galactic Nuclei ◽

Extreme Case ◽

Supermassive Black Holes ◽

Close Binaries ◽

Orbital Periods

Changing-look active galactic nuclei (CL-AGNs) as a new subpopulation challenge some fundamental physics of AGNs because the timescales of the phenomenon can hardly be reconciled with accretion disk models. In this Letter, we demonstrate the extreme case: close binaries of supermassive black holes (CB-SMBHs) with high eccentricities are able to trigger the CL transition through one orbit. In this scenario, binary black holes build up their own mini-disks by peeling gas off the inner edges of the circumbinary disk during the apastron phase, after which they tidally interact with the disks during the periastron phase to efficiently exchange angular momentum within one orbital period. For mini-disks rotating retrograde to the orbit, the tidal torque rapidly squeezes the tidal parts of the mini-disks into a much smaller radius, which rapidly results in higher accretion and short flares before the disks decline into type-2 AGNs. Prograde-rotation mini-disks gain angular momentum from the binary and rotate outward, which causes a rapid turn-off from type-1 to type-2. Turn-on occurs around the apastron phase. CB-SMBHs control cycle transitions between type-1 and type-2 with orbital periods but allow diverse properties in CL-AGN light curves.

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The relationship between X-ray and optical absorbers in active galactic nuclei

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa262 ◽

2020 ◽

Vol 493 (1) ◽

pp. 930-939 ◽

Cited By ~ 3

Author(s):

Gunnar W Jaffarian ◽

C Martin Gaskell

Keyword(s):

Active Galactic Nuclei ◽

Column Density ◽

Scattered Light ◽

Galactic Nuclei ◽

Broad Line ◽

Large Scatter ◽

Standard Type ◽

X Ray

ABSTRACT We present a large compilation of reddening estimates from broad-line Balmer decrements for active galactic nuclei (AGNs) with measured X-ray column densities. The median reddening is E(B − V) ≈ 0.77 ± 0.10 for type-1 to type-1.9 AGNs with reported column densities. This is notably higher than the median reddening of AGNs from the SDSS. We attribute this to the selection bias of the SDSS towards blue AGNs. For other AGNs, we find evidence of a publication bias against reporting low column densities. We find a significant correlation between NH and E(B − V) but with a large scatter of ±1 dex. On average, the X-ray columns are consistent with those predicted from E(B − V) for a solar neighbourhood dust-to-gas ratio. We argue that the large scatter of column densities and reddenings can be explained by X-ray column density variability. For AGNs with detectable broad-line regions (BLRs) that have undergone significant changes of Seyfert type (‘changing-look’ AGNs), we do not find any statistically significant differences in NH or E(B − V) compared to standard type-1 to type-1.9 AGNs. There is no evidence for any type-1 AGNs being Compton thick. We also analyse type-2 AGNs and find no significant correlation between NH and narrow-line region reddening. We find no evidence for a previously claimed anticorrelation. The median column density of LINERs is 22.68 ± 0.75 compared to a column density of 22.90 ± 0.28 for type-2 AGNs. We find the majority of low column density type-2 AGNs are LINERs, but NH is probably underestimated because of scattered light.

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Erratum: “Host Galaxies of Hard X‐Ray–Selected Type 2 Active Galactic Nuclei at Intermediate Redshifts” (ApJ, 647, 892 [2006])

The Astrophysical Journal ◽

10.1086/509803 ◽

2006 ◽

Vol 653 (2) ◽

pp. 1583-1583

Author(s):

Gaku Kiuchi ◽

Kouji Ohta ◽

Masayuki Akiyama ◽

Kentaro Aoki ◽

Yoshihiro Ueda

Keyword(s):

Active Galactic Nuclei ◽

Galactic Nuclei ◽

Host Galaxies ◽

X Ray ◽

Intermediate Redshifts

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Black hole mass estimation for active galactic nuclei from a new angle

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz1546 ◽

2019 ◽

Vol 487 (3) ◽

pp. 3404-3418 ◽

Cited By ~ 9

Author(s):

Dalya Baron ◽

Brice Ménard

Keyword(s):

Black Hole ◽

Active Galactic Nuclei ◽

Cosmic Time ◽

Galactic Nuclei ◽

Host Galaxy ◽

Black Hole Mass ◽

Mass Estimation ◽

Line Region

Abstract The scaling relations between supermassive black holes and their host galaxy properties are of fundamental importance in the context black hole-host galaxy co-evolution throughout cosmic time. In this work, we use a novel algorithm that identifies smooth trends in complex data sets and apply it to a sample of 2000 type 1 active galactic nuclei (AGNs) spectra. We detect a sequence in emission line shapes and strengths which reveals a correlation between the narrow L([O iii])/L(H β) line ratio and the width of the broad H α. This scaling relation ties the kinematics of the gas clouds in the broad line region to the ionization state of the narrow line region, connecting the properties of gas clouds kiloparsecs away from the black hole to material gravitationally bound to it on sub-parsec scales. This relation can be used to estimate black hole masses from narrow emission lines only. It therefore enables black hole mass estimation for obscured type 2 AGNs and allows us to explore the connection between black holes and host galaxy properties for thousands of objects, well beyond the local Universe. Using this technique, we present the MBH–σ and MBH–M* scaling relations for a sample of about 10 000 type 2 AGNs from Sloan Digital Sky Survey. These relations are remarkably consistent with those observed for type 1 AGNs, suggesting that this new method may perform as reliably as the classical estimate used in non-obscured type 1 AGNs. These findings open a new window for studies of black hole-host galaxy co-evolution throughout cosmic time.

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The Host-galaxy Properties of Type 1 versus Type 2 Active Galactic Nuclei

The Astrophysical Journal ◽

10.3847/1538-4357/ab1eb1 ◽

2019 ◽

Vol 878 (1) ◽

pp. 11 ◽

Cited By ~ 11

Author(s):

Fan Zou ◽

Guang Yang ◽

William N. Brandt ◽

Yongquan Xue

Keyword(s):

Active Galactic Nuclei ◽

Galactic Nuclei ◽

Host Galaxy

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The different neighbours around Type-1 and Type-2 active galactic nuclei

Nature Physics ◽

10.1038/nphys2951 ◽

2014 ◽

Vol 10 (6) ◽

pp. 417-420 ◽

Cited By ~ 23

Author(s):

Beatriz Villarroel ◽

Andreas J. Korn

Keyword(s):

Active Galactic Nuclei ◽

Galactic Nuclei

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AGN Obscuration and the Unified Model

Advances in Astronomy ◽

10.1155/2012/782030 ◽

2012 ◽

Vol 2012 ◽

pp. 1-17 ◽

Cited By ~ 59

Author(s):

Stefano Bianchi ◽

Roberto Maiolino ◽

Guido Risaliti

Keyword(s):

Black Hole ◽

Active Galactic Nuclei ◽

Galactic Nuclei ◽

Line Of Sight ◽

Host Galaxy ◽

Geometrical Distribution ◽

Orientation Effects ◽

Open Issues

Unification Models of Active Galactic Nuclei postulate that all the observed differences between type 1 and type 2 objects are due to orientation effects with respect to the line of sight to the observer. The key ingredient of these models is the obscuring medium, historically envisaged as a toroidal structure on a parsec scale. However, many results obtained in the last few years are clearly showing the need for a more complex geometrical distribution of the absorbing media. In this paper, we review the various pieces of evidence for obscuring media on different scales, from the vicinity of the black hole to the host galaxy, in order to picture an updated unification scenario explaining the complex observed phenomenology. We conclude by mentioning some of the open issues.

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