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This study analyses JWST MIRI/MRS observations of the infrared (IR) polycyclic aromatic hydrocarbon (PAH) bands in the nuclear (∼0.4″ at 11 μm; ∼75 pc) and circumnuclear regions (inner ∼kpc) of local active galactic nuclei (AGNs) from the Galactic Activity, Torus, and Outflow Survey (GATOS). We examine the PAH properties in the circumnuclear regions of AGNs and the projected direction of AGN-outflows and compare them to those in star-forming regions and the innermost regions of AGNs. This study employs 4.9–28.1 μm sub-arcsecond angular resolution data to investigate the properties of PAHs in three nearby sources (DL ∼ 30 − 40 Mpc). Our findings are aligned with previous JWST studies, demonstrating that the central regions of AGNs display a larger fraction of neutral PAH molecules (i.e. elevated 11.3/6.2 and 11.3/7.7 μm PAH ratios) in comparison to star-forming galaxies. We find that AGNs might affect not only the PAH population in the innermost region, but also in the extended regions up to ∼kpc scales. By comparing our observations to PAH diagnostic diagrams, we find that, in general, regions located in the projected direction of the AGN-outflow occupy similar positions on the PAH diagnostic diagrams as those of the innermost regions of AGNs. Star-forming regions that are not affected by the AGNs in these galaxies share the same part of the diagram as star-forming galaxies. We also examined the potential of the PAH-H2 diagram to disentangle AGN-versus-star-forming activity. Our results suggest that in Seyfert-like AGNs, the illumination and feedback from the AGN might affect the PAH population at nuclear and kpc scales, particularly with respect to the ionisation state of the PAH grains. However, PAH molecular sizes are rather similar. The carriers of the ionised PAH bands (6.2 and 7.7 μm) are less resilient than those of neutral PAH bands (11.3 μm), which might be particularly important for strongly AGN-host coupled systems. Therefore, caution must be applied when using PAH bands as star-formation rate indicators in these systems even at kpc scales, with the effects of the AGN being more important for ionised ones. [ABSTRACT FROM AUTHOR]

We present the analysis of archival XMM–Newton and Chandra observations of CH Cyg, one of the most studied symbiotic stars (SySts). The combination of the high-resolution XMM–Newton RGS and Chandra HETG X-ray spectra allowed us to obtain reliable estimates of the chemical abundances and to corroborate the presence of multitemperature X-ray-emitting gas. Spectral fitting of the medium-resolution XMM–Newton MOS (MOS1+MOS2) spectrum required the use of an additional component not seen in previous studies in order to fit the 2.0–4.0 keV energy range. Detailed spectral modelling of the XMM–Newton MOS data suggests the presence of a reflection component, very similar to that found in active galactic nuclei. The reflection component is very likely produced by an ionized disc (the accretion disc around the white dwarf) and naturally explains the presence of the fluorescent Fe emission line at 6.4 keV while also contributing to the soft and medium energy ranges. The variability of the global X-ray properties of CH Cyg are discussed as well as the variation of the three Fe lines around the 6–7 keV energy range. We conclude that reflection components are needed to model the hard X-ray emission and may be present in most β/δ-type SySt. [ABSTRACT FROM AUTHOR]

According to theory, the torus of active galactic nuclei (AGN) is sustained from a wind coming off the accretion disc, and for low efficient AGN, it has been proposed that such structure disappears. However, the exact conditions for its disappearance remain unclear. This can be studied throughout the reflection component at X-rays, which is associated with distant and neutral material at the inner walls of the torus in obscured AGN. We select a sample of 81 AGNs observed with NuSTAR with a distance limit of D< 200 Mpc and Eddington rate |$\rm {\lambda _{Edd} \equiv L_{bol}/L_{Edd}\lt 10^{-3}}$|⁠. We fit the 3–70 keV spectra using a model accounting for a partial-covering absorber plus a reflection component from neutral material. We find that the existence of the reflection component spans in a wide range of black hole mass and bolometric luminosities, with only ∼13 per cent of our sample (11 sources) lacking of any reflection signatures. These sources fall in the region in which the torus may be lacking in the L-MBH diagram. For the sources with a detected reflection component, we find that the vast majority of them are highly obscured (⁠|$\rm {\log \ N_H \gt 23}$|⁠), with |$\rm {\sim 20{{\ \rm per\ cent}}}$| being Compton-thick. We also find an increase in the number of unobscured sources and a tentative increase on the ratio between |$\rm {FeK\alpha }$| emission line and Compton-hump luminosities toward |$\rm {\lambda _{Edd}=10^{-5}}$|⁠ , suggesting that the contribution of the |$\rm {FeK\alpha }$| line changes with Eddington ratio. [ABSTRACT FROM AUTHOR]

One distinctive feature of low-luminosity active galactic nuclei (LLAGNs) is the relatively weak reflection features they may display in the X-ray spectrum, which can result from the disappearance of the torus with decreasing accretion rates. Some material, however, must surround the active nucleus, i.e. the accretion flow itself and, possibly, a flattened-out or thinned torus. In this work, we study whether reflection is indeed absent or undetectable due to its intrinsically weak features together with the low statistics inherent to LLAGNs. Here, we focus on NGC 3718 (L / L Edd ∼ 10−5) combining observations from XMM–Newton and the deepest to date NuSTAR (0.5–79 keV) spectrum of a LLAGNs, to constrain potential reflectors, and analyse how the fitted coronal parameters depend on the reflection model. We test models representing both an accretion disc (Relxill) and a torus-like (MYTorus and Borus) neutral reflector. From a statistical point of view, reflection is not required, but its inclusion allows to place strong constraints on the geometry and physical features of the surroundings: both neutral reflectors (torus) tested should be Compton thin (N H < 1023.2cm−2) and preferentially cover a large fraction of the sky. If the reflected light instead arises from an ionized reflector, a highly ionized case is preferred. These models produce an intrinsic power-law spectral index in the range [1.81–1.87], where the torus models result in steeper slopes. The cut-off energy of the power-law emission also changes with the inclusion of reflection models, resulting in constrained values for the disc reflectors and unconstrained values for torus reflectors. [ABSTRACT FROM AUTHOR]

In this paper, we present a multi-epoch analysis of NGC 1052, a prototypical low-luminisity active galactic nucleus, using XMM –Newton, Suzaku and NuSTAR observations taken from 2001 to 2017. This is the first time that results from NuSTAR observations have been reported for NGC 1052. Regarding technical aspects, we found a wavelength-dependent calibration issue between simultaneous XMM –Newton and NuSTAR spectra, characterized by a change in the photon index of |$\rm { \Gamma _{NuSTAR}- \Gamma _{XMM-Newton}=0.17\pm 0.04}$|⁠. We use ancillary Chandra data to decontaminate the nuclear spectrum from circumnuclear contributors. We find that two baseline models can fit the broad (0.5–50 keV) X-ray spectrum of the source. One consists of a power-law-like continuum that is absorbed by a uniform absorber, and is reflected by neutral material, and a separate power-law component in the soft band. The second model consists of a clumpy absorber. The reflection component is still present, but not the soft-band power law. Instead, absorption by a warm absorber is necessary to fit the spectra. This is the first time that a reflection component has been established in this object, thanks to high-energy data from NuSTAR. This component is constant in flux and shape, supporting the idea that it is produced away from the central source (probably in the torus). We find flux, spectral slope and absorption variations on time-scales of months to years. We also find that a patchy absorber can explain the behaviour of this source better, as it is ∼200 times more likely than the uniform absorber and yields smaller intrinsic variations. [ABSTRACT FROM AUTHOR]

A detailed multiwavelength study of the properties of the triple-peaked active galactic nucleus (AGN) Mrk 622 showing different aspects of the nuclear emission region is presented. Radio, near- and mid-infrared, optical, and X-ray data have been considered for the analysis. In the optical, the WHAN diagnostic diagrams show that the three nuclear peaks are strong active galactic nuclei since the equivalent width of H α is > 6 Å  and log  [N  ii ] λ6584/H α  ratio is > −0.4. Optical variability of both the continuum flux and intensity of the narrow emission lines is detected in a time span of 13 yr. The size of the narrow-line region is found to be 2.7 pc, with a light-crossing time of 8.7 yr. Analysis done to an archival Hubble Space Telescope image at 1055.2 nm shows that the host galaxy has a 3.6 kpc inner bar with PA  =  74°, faint spiral arms, and a pseudobulge, evolving through secular processes. High-resolution mid-infrared images obtained with the Gran Telescopio Canarias (GTC) and the instrument CanariCam show that the nuclear emission at 11.6  |$\rm{\mu m}$| is not spatially resolved. Very Large Array archival observations at 10 GHz reveal a core source with a total flux density of 1.47 ± 0.03 mJy. The spectral index of the core between 8 and 12 GHz is −0.5 ± 0.2, characteristic of AGN. The core deconvolves into a source with dimensions of 82 ± 13 mas |$\, \times \,$| 41 ± 20 mas, and a PA = 70  ±  18 deg, which suggests that the core is elongated or that it is constituted by multiple components distributed along a ∼65° axis. [ABSTRACT FROM AUTHOR]

The Balmer emission originated in the broad-line region (BLR) of active galactic nuclei (AGNs) could be either weak and difficult to detect, or even absent, for low-luminosity AGNs, as low-ionization nuclear emission-line regions (LINERs). Our goals in this paper are threefold. First, we want to explore the AGN nature of nearby type-1 LINERs. Secondly, we aim at deriving a reliable interpretation for the different components of emission lines by studying their kinematics and ionization mechanism. Thirdly, we intend to probe the neutral gas in the nuclei of these LINERs. We study the 22 local ($$z$$  < 0.025) type-1 LINERs from the Palomar survey, on the basis of optical ground- and space-based long-slit spectroscopic observations taken with the TWIN spectrograph at Calar Alto Observatory (CAHA) and ALFOSC/NOT (Andalucia Faint Object Spectrograph and Camera/2.6 m North Optical Telescope). Kinematics and fluxes of a set of emission lines, from H $$\beta \, \lambda$$ 4861 to [S  ii ] λλ6716, 6731, and the NaD λλ5890, 5896 doublet in absorption have been modelled and measured, after the subtraction of the underlying starlight. We also use ancillary spectroscopic data from HST /STIS (Hubble Space Telescope /Space Telescope Imaging Spectrograph). We found that the broad H α component is sometimes elusive in our ground-based spectroscopy, whereas it is ubiquitous for space-based data. By combining optical diagnostic diagrams, theoretical models [for AGNs, post-asymptotic giant branch (pAGB) stars, and shocks] and the weak/strong-[O  i ] classification, we exclude the pAGB star scenario in favour of the AGN as the dominant mechanism of ionization in these LINERs, being shocks however relevant. The kinematical properties of the emission lines may indicate the presence of ionized outflows, preferentially seen in [O  i ]. However, the neutral gas outflows, diagnosed by NaD, would appear to be less frequent. [ABSTRACT FROM AUTHOR]

We present mid-infrared (MIR; 7.5-13.5 μm) imaging and spectroscopy observations obtained with the CanariCam (CC) instrument on the 10.4-m Gran Telescopio CANARIAS for a sample of 20 nearby,MIR bright and X-ray luminous quasi-stellar objects (QSOs).We find that for the majority of QSOs the MIR emission is unresolved at angular scales∼0.3 arcsec, corresponding to physical scales ≲600 pc. We find that the higher-spatial resolution CC spectra have similar shapes to those obtained with Spitzer/IRS, and hence we can assume that the spectra are not heavily contaminated by extended emission in the host galaxy. We thus take advantage of the higher signal-to-noise ratio Spitzer/IRS spectra, as a fair representation of the nuclear emission, to decompose it into a combination of active galactic nuclei (AGN), polycyclic aromatic hydrocarbon (PAH) and stellar components. In most cases, the AGN is the dominant component, with a median contribution of 85 per cent of the continuum light at MIR (5-15 μm) within the IRS slit. This IR AGN emission is well reproduced by CLUMPY torus models. We find evidence for significant differences in the parameters that describe the dusty tori of QSOs when compared with the same parameters of Seyfert 1 and 2 nuclei. In particular, we find a lower number of clouds (N0 ≲ 12), steeper radial distribution of clouds (q ∼ 1.5-3.0) and clouds that are less optically thick (τV ≲ 100) than in Seyfert 1, which could be attributed to dusty structures that have been partially evaporated and piled up by the higher radiation field in QSOs. We find that the combination of the angular width σtorus, viewing angle i, and number of clouds along the equatorial line, N0, produces large escape probabilities (Pesc > 2 per cent) and low geometrical covering factors (f2 ≲ 0.6), as expected for AGN with broad lines in their optical spectra. [ABSTRACT FROM AUTHOR]

We present 31.5 µm imaging photometry of 11 nearby Seyfert galaxies observed from the Stratospheric Observatory For Infrared Astronomy (SOFIA) using the Faint Object infraRed CAmera for the SOFIA Telescope (FORCAST). We tentatively detect extended 31 µm emission for the first time in our sample. In combination with this new data set, subarcsecond resolution 1-18 µm imaging and 7.5-13 µm spectroscopic observations were used to compute the nuclear spectral energy distribution (SED) of each galaxy.We found that the turnover of the torus emission does not occur at wavelengths ≤31.5 µm, which we interpret as a lower-limit for the wavelength of peak emission. We used CLUMPY torus models to fit the nuclear infrared (IR) SED and infer trends in the physical parameters of the AGN torus for the galaxies in the sample. Including the 31.5 µm nuclear flux in the SED (1) reduces the number of clumpy torus models compatible with the data, and (2) modifies the model output for the outer radial extent of the torus for 10 of the 11 objects. Specifically, six (60 per cent) objects show a decrease in radial extent while four (40 per cent) show an increase.We find torus outer radii ranging from <1 to 8.4 pc. [ABSTRACT FROM AUTHOR]

The origin of the unification model for Active Galactic Nuclei (AGN) was the detection of broad hydrogen recombination lines in the optical polarized spectrum of the Seyfert 2 galaxy (Sy2) NGC 1068. Since then, a search for the hidden broad-line region (HBLR) of nearby Sy2s started, but polarized broad lines have only been detected in ~30-40% of the nearby Sy2s observed to date. Here we present new VLT/FORS2 optical spectropolarimetry of a sample of 15 Sy2s, including Compton-thin and Compton-thick sources. The sample includes six galaxies without previously published spectropolarimetry, some of them normally treated as non-hidden BLR (NHBLR) objects in the literature, four classified as NHBLR, and five as HBLR based on previous data. We report ≥4σ detections of a HBLR in 11 of these galaxies (73% of the sample) and a tentative detection in NGC 5793, which is Compton-thick according to the analysis of X-ray data performed here. Our results confirm that at least some NHBLRs are misclassified, bringing previous publications reporting differences between HBLR and NHBLR objects into question. We detect broad Ha and Hβ components in polarized light for 10 targets, and just broad Hα for NGC 5793 and NGC 6300, with line widths ranging between 2100 and 9600 km s-1. High bolometric luminosities and low column densities are associated with higher polarization degrees, but not necessarily with the detection of the scattered broad components. [ABSTRACT FROM AUTHOR]

Context. Obscured active galactic nuclei (AGNs) are thought to be very common in the Universe. Observations and surveys have shown that the number of sources increases for near galaxies and at the low-luminosity regime (the so-called LLAGNs). Furthermore, many AGNs show changes in their obscuration properties at X-rays that may suggest a configuration of clouds very close to the accretion disk. However, these variations could also be due to changes in the intrinsic continuum of the source. It is therefore important to study nearby AGN to better understand the locus and distribution of clouds in the neighbourhood of the nucleus. Aims. We aim to study the nuclear obscuration of LLAGN NGC835 and its extended emission using mid-infrared observations. Methods. We present sub-arcsecond-resolution mid-infrared 11.5 µm imaging of the LLAGN galaxy NGC835 obtained with the instrument CanariCam in the Gran Telescopio CANARIAS (GTC), archival Spitzer/IRS spectroscopy, and archival Chandra data observed in 2000, 2008, and 2013. Results. The GTC/CanariCam 11.5 µm image reveals faint extended emission out to ~6 arcsec. We obtained a nuclear flux of F(11:5 µm) ~ 18 mJy; whereas the extended emission accounts for 90% of the total flux within the 6 arcsec. This means that the low angular resolution (~4 arcsec) IRS spectrum is dominated by this extended emission and not by the AGN. This is clearly seen in the Spitzer/IRS spectrum, which resembles that of star-forming galaxies. Although the extended soft X-ray emission shows some resemblance with that of the mid-infrared, the knots seen at X-rays are mostly located in the inner side of this mid-infrared emission. The nuclear X-ray spectrum of the source has undergone a spectral change between 2000/2008 and 2013. We argue that this variation is most probably due to changes in the hydrogen column density from ~8 × 1023 cm–2 to ~3 × 1023 cm–2. NGC835 therefore is one of the few LLAGN, together with NGC1052, in which changes in the absorber can be claimed. [ABSTRACT FROM AUTHOR]

We present an analysis of the nuclear infrared (IR, 1.6-18 µm) emission of the ultraluminous IR galaxy UGC 5101 to derive the properties of its active galactic nucleus (AGN) and its obscuring material. We use new mid-IR high angular resolution (0.3-0.5 arcsec) imaging using the Si-2 filter (λC = 8.7µm) and 7.5-13 µm spectroscopy taken with CanariCam (CC) on the 10.4 m Gran Telescopio CANARIAS. We also use archival Hubble Space Telescope/NICMOS and Subaru/COMICS imaging and Spitzer/IRS spectroscopy. We estimate the near- and mid-IR unresolved nuclear emission by modelling the imaging data with galfit. We decompose the Spitzer/IRS and CC spectra using a power-law component, which represents the emission due to dust heated by the AGN, and a starburst component, both affected by foreground extinction. We model the resulting unresolved near- and mid-IR, and the starburst subtracted CC spectrum with the CLUMPY torus models of Nenkova et al. The derived geometrical properties of the torus, including the large covering factor and the high foreground extinction needed to reproduce the deep 9.7µm silicate feature, are consistent with the lack of strong AGN signatures in the optical. We derive an AGN bolometric luminosity Lbol ~ 1.9 × 1045 erg s-1 that is in good agreement with other estimates in the literature. [ABSTRACT FROM AUTHOR]

Context. Variability across the electromagnetic spectrum is a property of active galactic nuclei (AGN) that can help constrain the physical properties of these galaxies. Nonetheless, the way in which the changes happen and whether they occur in the same way in every AGN are still open questions. Aims. This is the third in a series of papers with the aim of studying the X-ray variability of different families of AGN. The main purpose of this work is to investigate the variability pattern(s) in a sample of optically selected Seyfert 2 galaxies. Methods. We use the 26 Seyfert 2s in the Véron-Cetty and Véron catalog with data available from Chandra and/or XMM-Newton public archives at different epochs, with timescales ranging from a few hours to years. All the spectra of the same source were simultaneously fitted, and we let different parameters vary in the model. Whenever possible, short-term variations from the analysis of the light curves and/or long-term UV flux variations were studied. We divided the sample into Compton-thick and Compton-thin candidates to account for the degree of obscuration. When transitions between Compton-thick and thin were obtained for different observations of the same source, we classified it as a changing-look candidate. Results. Short-term variability at X-rays was studied in ten cases, but variations are not found. From the 25 analyzed sources, 11 show long-term variations. Eight (out of 11) are Compton-thin, one (out of 12) is Compton-thick, and the two changing-look candidates are also variable. The main driver for the X-ray changes is related to the nuclear power (nine cases), while variations at soft energies or related to absorbers at hard X-rays are less common, and in many cases these variations are accompanied by variations in the nuclear continuum. At UV frequencies, only NGC5194 (out of six sources) is variable, but the changes are not related to the nucleus. We report two changing-look candidates, MARK273 and NGC7319. Conclusions. A constant reflection component located far away from the nucleus plus a variable nuclear continuum are able to explain most of our results. Within this scenario, the Compton-thick candidates are dominated by reflection, which suppresses their continuum, making them seem fainter, and they do not show variations (except MARK3), while the Compton-thin and changing-look candidates do. [ABSTRACT FROM AUTHOR]

We present mid-infrared (MIR) imaging and spectroscopic data of the Seyfert 2 galaxy Mrk 1066 obtained with CanariCam (CC) on the 10.4-m Gran Telescopio CANARIAS (GTC). The galaxy was observed in imaging mode with an angular resolution of 0.24 arcsec (54 pc) in the Si-2 filter (8.7 μm). The image reveals a series of star-forming knots within the central ∼400 pc, after subtracting the dominant active galactic nucleus (AGN) component. We also subtracted this AGN unresolved component from the 8-13 μm spectra of the knots and the nucleus, and measured equivalent widths (EWs) of the 11.3 μm polycyclic aromatic hydrocarbon (PAH) feature which are typical of pure starburst galaxies. This EW is larger in the nucleus than in the knots, confirming that, at least in the case of Mrk 1066, the AGN dilutes, rather than destroys, the molecules responsible for the 11.3 μm PAH emission. By comparing the nuclear GTC/CC spectrum with the Spitzer/Infrared Spectrograph (IRS) spectrum of the galaxy, we find that the AGN component that dominates the continuum emission at λ < 15 μm on scales of ∼60 pc (90-100 per cent) decreases to 35-50 per cent when the emission of the central ∼830 pc is considered. On the other hand, the AGN contribution dominates the 15-25 μm emission (75 per cent) on the scales probed by Spitzer/IRS. We reproduced the nuclear infrared emission of the galaxy with clumpy torus models, and derived a torus gas mass of 2 × 105 M⊙, contained in a clumpy structure of ∼2 pc radius and with a column density compatible with Mrk 1066 being a Compton-thick candidate, in agreement with X-ray observations. We find a good match between the MIR morphology of Mrk 1066 and the extended Paβ, Brγ and [O III] λ5007 emission. This coincidence implies that the 8.7 μm emission is probing star formation, dust in the narrow-line region and the oval structure previously detected in the near-infrared. On the other hand, the Chandra soft X-ray morphology does not match any of the previous, contrary to what it is generally assumed for Seyfert galaxies. A thermal origin for the soft X-ray emission, rather than AGN photoionization, is suggested by the different data analysed here. [ABSTRACT FROM AUTHOR]

We present Gran Telescopio CANARIAS CanariCam 8.7 μm imaging and 7.5–13 μm spectroscopy of six local systems known to host an active galactic nucleus (AGN) and have nuclear star formation. Our main goal is to investigate whether the molecules responsible for the 11.3 μm polycyclic aromatic hydrocarbon (PAH) feature are destroyed in the close vicinity of an AGN. We detect 11.3 μm PAH feature emission in the nuclear regions of the galaxies as well as extended PAH emission over a few hundred parsecs. The equivalent width (EW) of the feature shows a minimum at the nucleus but increases with increasing radial distances, reaching typical star-forming values a few hundred parsecs away from the nucleus. The reduced nuclear EWs are interpreted as due to increased dilution from the AGN continuum rather than destruction of the PAH molecules. We conclude that at least those molecules responsible for the 11.3 μm PAH feature survive in the nuclear environments as close as 10 pc from the AGN and for Seyfert-like AGN luminosities. We propose that material in the dusty tori, nuclear gas discs, and/or host galaxies of AGN is likely to provide the column densities necessary to protect the PAH molecules from the AGN radiation field. [ABSTRACT FROM PUBLISHER]

Context. One of the most distinctive features in active galactic nuclei (AGN) is the variability of their emission. Variability has been discovered at X-ray, UV, and radio frequencies on timescales from hours to years. Among the AGN family and according to theoretical studies, low-ionization nuclear emission line region (LINER) nuclei would be objects variable on long timescales. Aims. Our purpose is to investigate spectral X-ray variability in LINERs and to understand the nature of these types of objects, as well as their accretion mechanism. Methods. Chandra and XMM-Newton public archives were used to compile X-ray spectra of seven LINER nuclei at different epochs with timescales of years. To search for variability we fit all spectra from the same object with a set of models to identify the parameters responsible for the variability pattern. We also analyzed the light curves to search for short timescale (from hours to days) variability. Whenever possible, UV variability was also studied. Results. We found spectral variability in four objects (NGC1052, NGC3226, NGC4278, and NGC4552), with variations mostly related to hard energies (2-10 keV). These variations are generated by several possible changes that act either alone or in combination: changes in the soft excess or in the absorber. Added to this can be intrinsic variations of the source, which may also be responsible by themselves for the spectral variability. These variations occurred within years, the shortest timescale being found for NGC4278 (two months). Another two galaxies (NGC4261 and NGC 5846) apparently do not vary. No short timescale variations during individual observations were found. Our analysis confirms the previously reported anticorrelation between the X-ray spectral index, Γ, and the Eddington ratio, Lbol/LEdd, and also the correlation between the X-ray to UV flux ratio, αox, and the Eddington ratio, Lbol/LEdd. These results support an advection dominated accretion flow as the accretion mechanism in LINERs. [ABSTRACT FROM AUTHOR]

Context. Active galactic nuclei (AGN), powered by accretion onto supermassive black holes (SMBHs), are thought to be scaled up versions of Galactic black hole X-ray binaries (BH-XRBs). In the past few years evidence of such correspondence include similarities in the broadband shape of the X-ray variability power spectra, with characteristic bend times-scales scaling with mass. Aims. The aim of this project is to characterize the X-ray temporal properties of a sample of AGN to study the connection among different classes of AGN and their connection with BH-XRBs. Methods. We have performed a uniform analysis of the power spectrum densities (PSDs) of 104 nearby (z < 0.4) AGN using 209 XMM-Newton/pn observations. These PSDs span ≃ 3 decades in temporal frequencies, ranging from minutes to days. The PSDs have been estimated in three energy bands: 0.2-10 (total), 0.2-2 (soft), and 2-10 keV (hard). The sample comprises 61 Type-1 AGN, 21 Type-2 AGN, 15 NLSy1, and 7 BLLACS. We have fitted each PSD to two models: (1) a single power-law model and (2) a bending power-law model. Results. Among the entire sample, 72% show significant variability in at least one of the three bands tested. A high percentage of low-luminosity AGN do not show any significant variability (86% of LINERs). The PSD of the majority of the variable AGN was well described by a simple power-law with a mean index of α = 2.01 ?± 0.01. In 15 sources we found that the bending power law model was preferred with a mean slope of α = 3.08 ± 0.04 and a mean bend frequency of ? ?b ? ≃ 2 × 10-4 Hz. Only KUG?1031+398 (RE?J1034+396) shows evidence for quasi-periodic oscillations. The "fundamental plane" relating variability timescale, black hole mass, and luminosity is demonstrated using the new X-ray timing results presented here together with a compilation of the previously detected timescales from the literature. Conclusions. Both quantitative (i.e. scaling with BH mass) and qualitative (overall PSD shapes) found in this sample of AGN are in agreement with the expectations for the SMBHs and BH-XRBs being the same phenomenon scaled-up with the size of the BH. The steep PSD slopes above the high frequency bend bear a closer resemblance to those of the "soft/thermal dominated" BH-XRB states than other states. [ABSTRACT FROM AUTHOR]