Compton-thick AGN in the NuSTAR Era VI: The Observed Compton-thick Fraction in the Local Universe

Abstract We present the analysis of simultaneous Nuclear Spectroscopic Telescope Array (NuSTAR) and XMM-Newton data of eight Compton-thick active galactic nuclei (CT-AGN) candidates selected in the Swift-BAT 100 month catalog. This work is part of an ongoing effort to find and characterize all CT-AGN in the Local (z ≤ 0.05) Universe. We used two physically motivated models, MYTorus and borus02, to characterize the sources in the sample, finding five of them to be confirmed CT-AGN. These results represent an increase of ∼19% over the previous NuSTAR-confirmed, BAT-selected CT-AGN at z ≤ 0.05, bringing the total number to 32. This corresponds to an observed fraction of ∼8% of all AGN within this volume-limited sample, although it increases to 20% ± 5% when limiting the sample to z ≤ 0.01. Out of a sample of 48 CT-AGN candidates, selected using BAT and soft (0.3−10 keV) X-ray data, only 24 are confirmed as CT-AGN with the addition of the NuSTAR data. This highlights the importance of NuSTAR when classifying local obscured AGN. We also note that most of the sources in our full sample of 48 Seyfert 2 galaxies with NuSTAR data have significantly different lines of sight and average torus column densities, favoring a patchy torus scenario.

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Host galaxy properties of X-ray active galactic nuclei in the local Universe

Astronomy and Astrophysics ◽

10.1051/0004-6361/202142466 ◽

2021 ◽

Author(s):

L. Koutoulidis ◽

G. Mountrichas ◽

I. Georgantopoulos ◽

E. Pouliasis ◽

M. Plionis

Keyword(s):

Active Galactic Nuclei ◽

Galactic Nuclei ◽

Host Galaxy ◽

Local Universe ◽

X Ray

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BAT AGN Spectroscopic Survey – XIII. The nature of the most luminous obscured AGN in the low-redshift universe

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz2309 ◽

2019 ◽

Vol 489 (3) ◽

pp. 3073-3092 ◽

Cited By ~ 2

Author(s):

Rudolf E Bär ◽

Benny Trakhtenbrot ◽

Kyuseok Oh ◽

Michael J Koss ◽

O Ivy Wong ◽

...

Keyword(s):

Active Galactic Nuclei ◽

Galactic Nuclei ◽

Local Universe ◽

X Ray ◽

Massive Galaxies ◽

Optical Images ◽

Sky Survey ◽

Large Spread ◽

Black Hole Masses ◽

Lower Luminosity

ABSTRACT We present a multiwavelength analysis of 28 of the most luminous low-redshift narrow-line, ultra-hard X-ray-selected active galactic nuclei (AGN) drawn from the 70-month Swift/BAT all-sky survey, with bolometric luminosities of $\log (L_{\rm bol} /{\rm erg\, s}^{-1}) \gtrsim 45.25$. The broad goal of our study is to determine whether these objects have any distinctive properties, potentially setting them aside from lower luminosity obscured AGN in the local Universe. Our analysis relies on the first data release of the BAT AGN Spectroscopic Survey (BASS/DR1) and on dedicated observations with the VLT, Palomar, and Keck observatories. We find that the vast majority of our sources agree with commonly used AGN selection criteria which are based on emission line ratios and on mid-infrared colours. Our AGN are pre-dominantly hosted in massive galaxies (9.8 ≲ log (M*/M⊙) ≲ 11.7); based on visual inspection of archival optical images, they appear to be mostly ellipticals. Otherwise, they do not have distinctive properties. Their radio luminosities, determined from publicly available survey data, show a large spread of almost four orders of magnitude – much broader than what is found for lower X-ray luminosity obscured AGN in BASS. Moreover, our sample shows no preferred combination of black hole masses (MBH) and/or Eddington ratio (λEdd), covering 7.5 ≲ log (MBH/M⊙) ≲ 10.3 and 0.01 ≲ λEdd ≲ 1. Based on the distribution of our sources in the λEdd−NH plane, we conclude that our sample is consistent with a scenario where the amount of obscuring material along the line of sight is determined by radiation pressure exerted by the AGN on the dusty circumnuclear gas.

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Correlation between relativistic reflection fraction and photon index in NuSTAR sample of Seyfert 1 AGN

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa1288 ◽

2020 ◽

Vol 495 (3) ◽

pp. 3373-3386

Author(s):

Savithri H Ezhikode ◽

Gulab C Dewangan ◽

Ranjeev Misra ◽

Ninan Sajeeth Philip

Keyword(s):

Black Hole ◽

Active Galactic Nuclei ◽

Galactic Nuclei ◽

Relativistic Effects ◽

Accretion Disc ◽

Telescope Array ◽

X Ray ◽

Photon Index ◽

The Relationship ◽

Reflection Component

ABSTRACT The primary X-ray emission from active galactic nuclei (AGNs), described by a power-law, irradiates the accretion disc producing reflection features in the spectrum. The reflection features arising from the inner regions of the disc can be significantly modified by the relativistic effects near the black hole. We investigate the relationship between the relativistic reflection fraction Rf, defined as the ratio of the coronal intensity that illuminates the accretion disc to the coronal intensity observed directly, and the hard X-ray photon index Γ of a Nuclear Spectroscopic Telescope Array (NuSTAR) sample of Seyfert 1 galaxies. The X-ray spectra are modelled using relxill code that helps to directly obtain the reflection fraction of a relativistically smeared reflection component. The parameter Rf depends on the amount of Comptonized X-ray emission intercepted by the inner accretion disc. We found a positive correlation between Γ and Rf in our sample. Seed photons from a larger area of an accretion disc entering the corona will result in increased cooling of the coronal plasma, giving rise to steeper X-ray spectrum. The corona irradiating the larger area of the disc will result in higher reflection fraction. Thus, the observed Rf –Γ relation is most likely related to the variations in the disc–corona geometry of AGNs.

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Comprehensive Broadband X-Ray and Multiwavelength Study of Active Galactic Nuclei in 57 Local Luminous and Ultraluminous Infrared Galaxies Observed with NuSTAR and/or Swift/BAT

The Astrophysical Journal Supplement Series ◽

10.3847/1538-4365/ac17f5 ◽

2021 ◽

Vol 257 (2) ◽

pp. 61

Author(s):

Satoshi Yamada ◽

Yoshihiro Ueda ◽

Atsushi Tanimoto ◽

Masatoshi Imanishi ◽

Yoshiki Toba ◽

...

Keyword(s):

Active Galactic Nuclei ◽

Galactic Nuclei ◽

Infrared Galaxies ◽

Telescope Array ◽

X Ray ◽

Bolometric Luminosity ◽

Small Column ◽

Ultraluminous Infrared Galaxy ◽

Ultraluminous Infrared Galaxies ◽

Infrared Data

Abstract We perform a systematic X-ray spectroscopic analysis of 57 local luminous and ultraluminous infrared galaxy systems (containing 84 individual galaxies) observed with the Nuclear Spectroscopic Telescope Array and/or Swift/BAT. Combining soft X-ray data obtained with Chandra, XMM-Newton, Suzaku, and/or Swift/XRT, we identify 40 hard (>10 keV) X-ray–detected active galactic nuclei (AGNs) and constrain their torus parameters with the X-ray clumpy torus model XCLUMPY. Among the AGNs at z < 0.03, for which sample biases are minimized, the fraction of Compton-thick (N H ≥ 1024 cm−2) AGNs reaches 64 − 15 + 14 % (6/9 sources) in late mergers, while it is 24 − 10 + 12 % (3/14 sources) in early mergers, consistent with the tendency reported by Ricci et al. We find that the bolometric AGN luminosities derived from the infrared data increase but the X-ray to bolometric luminosity ratios decrease with merger stage. The X-ray-weak AGNs in late mergers ubiquitously show massive outflows at subparsec to kiloparsec scales. Among them, the most luminous AGNs (L bol,AGN ∼ 1046 erg s−1) have relatively small column densities of ≲1023 cm−2 and almost super-Eddington ratios (λ Edd ∼ 1.0). Their torus covering factors (C T (22) ∼ 0.6) are larger than those of Swift/BAT-selected AGNs with similarly high Eddington ratios. These results suggest a scenario where, in the final stage of mergers, multiphase strong outflows are produced due to chaotic quasi-spherical inflows, and the AGN becomes extremely X-ray weak and deeply buried due to obscuration by inflowing and/or outflowing material.

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Polarization Variability of Active Galactic Nuclei and X‐Ray Binaries

The Astrophysical Journal ◽

10.1086/304575 ◽

1997 ◽

Vol 487 (1) ◽

pp. 142-152 ◽

Cited By ~ 9

Author(s):

Gang Bao ◽

Petr Hadrava ◽

Paul J. Wiita ◽

Ying Xiong

Keyword(s):

Active Galactic Nuclei ◽

Galactic Nuclei ◽

X Ray ◽

X Ray Binaries

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Gamma-Ray and Neutrino Signals from Accretion Disk Coronae of Active Galactic Nuclei

Galaxies ◽

10.3390/galaxies9020036 ◽

2021 ◽

Vol 9 (2) ◽

pp. 36

Author(s):

Yoshiyuki Inoue ◽

Dmitry Khangulyan ◽

Akihiro Doi

Keyword(s):

Active Galactic Nuclei ◽

Gamma Ray ◽

Galactic Nuclei ◽

High Energy ◽

Thermal Activity ◽

X Ray ◽

Cascade Models ◽

Coronal Activity ◽

Ngc 1068 ◽

High Energy Particles

To explain the X-ray spectra of active galactic nuclei (AGN), non-thermal activity in AGN coronae such as pair cascade models has been extensively discussed in the past literature. Although X-ray and gamma-ray observations in the 1990s disfavored such pair cascade models, recent millimeter-wave observations of nearby Seyferts have established the existence of weak non-thermal coronal activity. In addition, the IceCube collaboration reported NGC 1068, a nearby Seyfert, as the hottest spot in their 10 yr survey. These pieces of evidence are enough to investigate the non-thermal perspective of AGN coronae in depth again. This article summarizes our current observational understanding of AGN coronae and describes how AGN coronae generate high-energy particles. We also provide ways to test the AGN corona model with radio, X-ray, MeV gamma ray, and high-energy neutrino observations.

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Hot gaseous atmospheres of rotating galaxies observed with XMM–Newton

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa3182 ◽

2020 ◽

Vol 499 (4) ◽

pp. 5163-5174

Author(s):

A Juráňová ◽

N Werner ◽

P E J Nulsen ◽

M Gaspari ◽

K Lakhchaura ◽

...

Keyword(s):

Angular Momentum ◽

Active Galactic Nuclei ◽

Spiral Galaxy ◽

Galactic Nuclei ◽

X Ray ◽

Hot Gas ◽

Heating And Cooling ◽

Theoretical Predictions ◽

Central Regions ◽

Gaseous Atmospheres

ABSTRACT X-ray emitting atmospheres of non-rotating early-type galaxies and their connection to central active galactic nuclei have been thoroughly studied over the years. However, in systems with significant angular momentum, processes of heating and cooling are likely to proceed differently. We present an analysis of the hot atmospheres of six lenticulars and a spiral galaxy to study the effects of angular momentum on the hot gas properties. We find an alignment between the hot gas and the stellar distribution, with the ellipticity of the X-ray emission generally lower than that of the optical stellar emission, consistent with theoretical predictions for rotationally supported hot atmospheres. The entropy profiles of NGC 4382 and the massive spiral galaxy NGC 1961 are significantly shallower than the entropy distribution in other galaxies, suggesting the presence of strong heating (via outflows or compressional) in the central regions of these systems. Finally, we investigate the thermal (in)stability of the hot atmospheres via criteria such as the TI- and C-ratio, and discuss the possibility that the discs of cold gas present in these objects have condensed out of the hot atmospheres.

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