Types Of Active Galactic Nuclei Research Articles

Spectral similarities in galaxies through an unsupervised classification of spaxels

We present the first unsupervised classification of spaxels in hyperspectral images of individual galaxies. Classes identify regions by spectral similarity and thus take all the information into account that is contained in the data cubes (spatial and spectral). We used Gaussian mixture models in a latent discriminant subspace to find clusters of spaxels. The spectra were corrected for small-scale motions within the galaxy based on emission lines with an automatic algorithm. Our data consist of two MUSE/VLT data cubes of JKB 18 and NGC 1068 and one NIRSpec/JWST data cube of NGC 4151. Our classes identify many regions that are most often easily interpreted. Most of the 11 classes that we find for JKB 18 are identified as photoionised by stars. Some of them are known regions, but we mapped them as extended, with gradients of ionisation intensities. One compact structure has not been reported before, and according to diagnostic diagrams, it might be a planetary nebula or a denser region. For NGC 1068, our 16 classes are of active galactic nucleus-type (AGN) or star-forming regions. Their spatial distribution corresponds perfectly to well-known structures such as spiral arms and a ring with giant molecular clouds. A subclassification in the nuclear region reveals several structures and gradients in the AGN spectra. Our unsupervised classification of the MUSE data of NGC 1068 helps visualise the complex interaction of the AGN and the jet with the interstellar medium in a single map. The centre of NGC 4151 is very complex, but our classes can easily be related to ionisation cones, the jet, or H$_2$ emission. We find a new elongated structure that is ionised by the AGN along the N-S axis perpendicular to the jet direction. It is rotated counterclockwise with respect to the axis of the H$_2$ emission. Our work shows that the unsupervised classification of spaxels takes full advantage of the richness of the information in the data cubes by presenting the spectral and spatial information in a combined and synthetic way.

EPOCHS Paper – VIII. An insight into MIRI-selected galaxies in SMACS-0723 and the benefits of deep MIRI photometry in revealing AGN and the dusty universe

ABSTRACT We present the analysis of the stellar population and star formation history of 181 MIRI selected galaxies at z = 0 − 3.5 in the massive galaxy cluster field SMACS J0723.3–7327, commonly referred to as SMACS0723, using the JWST Mid-Infrared Instrument (MIRI). We combine the data with the JWST Near Infrared Camera (NIRCam) catalogue, in conjunction with the Hubble Space Telescope (HST) WFC3/IR and ACS imaging. We find that the MIRI bands capture PAH features and dust emission, significantly enhancing the accuracy of photometric redshift and measurements of the physical properties of these galaxies. The median photo-z’s of galaxies with MIRI data are found to have a small 0.1 per cent difference from spectroscopic redshifts and reducing the error by 20 per cent. With MIRI data included in SED fits, we find that the measured stellar masses are unchanged, while the star formation rate is slightly lower by 0.1 dex. We also fit the median SED of active galactic nuclei (AGNs) and star-forming galaxies (SFG) separately. MIRI data provides tighter constraints on the AGN contribution, reducing the typical AGN contributions by ∼15 per cent. In addition, we also compare the median SED obtained with and without MIRI, and we find that including MIRI data yields steeper optical and UV slopes, indicating bluer colours, lower dust attenuation, and younger stellar populations. In the future, MIRI/MRS will enhance our understanding by providing more detailed spectral information and allowing for the study of specific emission features and diagnostics associated with AGN.

AGN Feedback Signatures in UV Emission

Supermassive black holes (SMBH) are believed to influence galaxy evolution through AGN (active galactic nuclei) feedback. Galaxy mergers are key processes of galaxy formation that lead to AGN activity and star formation. The relative contribution of AGN feedback and mergers to star formation is not yet well understood. In radio-loud objects, AGN outflows are dominated by large jets. However, in radio-quiet objects, outflows are more complex and involve jet, wind, and radiation. In this review, we discuss the signatures of AGN feedback through the alignment of radio and UV emissions. Current research on AGN feedback is discussed, along with a few examples of studies such as the galaxy merger system MRK 212, the radio-quiet AGN NGC 2639, and the radio-loud system Centaurus A. Multi-frequency observations of MRK 212 indicate the presence of dual AGN, as well as feedback-induced star-forming UV clumps. The fourth episode of AGN activity was detected in radio observations of the Seyfert galaxy NGC 2639, which also showed a central cavity of 6 kpc radius in CO and UV maps. This indicates that multi-epoch jets of radio-quiet AGN can blow out cold molecular gas, which can further reduce star formation in the center of the galaxies. Recent UV observations of Cen A have revealed two sets of stellar population in the northern star-forming region, which may have two different origins. Recent studies have shown that there is evidence that both positive and negative feedback can be present in galaxies at different scales and times. High-resolution, multi-band observations of large samples of different types of AGN and their host galaxies are important for understanding the two types of AGN feedback and their effect on the host galaxies. Future instruments like INSIST and UVEX will be able to help achieve some of these goals.

Observational properties of active galactic nucleus obscuration during the peak of accretion growth

ABSTRACT We investigated the gas obscuration and host galaxy properties of active galactic nuclei (AGNs) during the peak of cosmic accretion growth of supermassive black holes at redshift 0.8–1.8 using X-ray-detected AGNs with mid-infrared and far-infrared detection. The sample was classified as type-1 and type-2 AGNs using optical spectral and morphological classification while the host galaxy properties were estimated with multiwavelength spectral energy distribution fitting. For type-1 AGNs, the black hole mass was determined from MgII emission lines while the black hole mass of type-2 AGNs was inferred from the host galaxy’s stellar mass. Based on the derived parameters, the distribution of the sample in the absorption hydrogen column density (NH) versus Eddington ratio diagram is examined. Among the type-2 AGNs, 28 ± 5 per cent are in the forbidden zone, where the obscuration by dust torus cannot be maintained due to radiation pressure on dusty material. The fraction is higher than that observed in the local universe from the Burst Alert Telescope AGN Spectroscopic Survey data release 2 (BASS DR2) (11 ± 3 per cent). The higher fraction implies that the obscuration of the majority of AGNs is consistent with the radiation pressure regulated unified model but with an increased incidence of interstellar matter (ISM)-obscured AGNs. We discuss the possibility of dust-free absorption in type-1 AGNs and heavy ISM absorption in type-2 AGNs. We also find no statistical difference in the star-formation activity between type-1 and type-2 AGNs which may suggest that obscuration triggered by a gas-rich merging is not common among X-ray detected AGNs in this epoch.

To test RNLRs−LO3 relation for narrow emission line regions of AGNs through low-redshift Type-2 AGNs in SDSS

ABSTRACT Sizes of narrow emission line regions (NLRs) of active galactic nuclei (AGNs) could be estimated by [O iii] line luminosity LO3 through the known RNLRs−LO3 empirical relations. Unfortunately, it is not convenient to test the RNLRs− LO3 empirical relations through structure properties of spatially resolved NLRs of large samples of AGNs. In this manuscript, a method is proposed to test the $R_{\mathrm{ NLRs}}\!\!-\!\!L_{\mathrm{ O3}}^{\sim 0.25}$ empirical relations for AGN NLRs through Sloan Digital Sky Survey (SDSS) Type-2 AGNs having few orientation effects on NLR sizes expected by the AGN unified model, after considering sizes Rfib of SDSS fibre-covered regions. Comparing Rfib and RNLRs estimated by LO3, Type-2 AGNs with Rfib > RNLRs (Sample-II) and with Rfib < RNLRs (Sample-I) should have different physical properties of NLRs. Accepting electron density gradients in AGN NLRs, statistically higher electron densities (traced by lower flux ratio RS2 of [S ii] λ6717 Å to [S ii] λ6731 Å) could be expected for the Type-2 AGNs in the Sample-I. Then, through the collected 1062 SDSS Type-2 AGNs in the Sample-I and 3658 SDSS Type-2 AGNs in the Sample-II, statistically lower RS2 for the Type-2 AGNs in the Sample-I can be confirmed with confidence level higher than 5σ, even after considering necessary effects. Therefore, the results in this manuscript can provide strong clues to support that the reported $R_{\mathrm{ NLRs}}~\propto ~L_{\mathrm{ O3}}^{0.25}$ empirical relation is preferred to estimate NLR sizes of SDSS AGNs through SDSS fibre spectroscopic results, and also to support the commonly expected electron density gradients in AGN NLRs.

High energy gamma-ray sources in the VVV survey - II. The AGN counterparts

ABSTRACT We identified Active Galactic Nuclei (AGN) candidates as counterparts to unidentified gamma-ray sources (UGS) from the Fermi-LAT Fourth Source Catalogue at lower Galactic latitudes. Our methodology is based on the use of near- and mid-infrared photometric data from the VISTA Variables in the Vía Láctea (VVV) and Wide-field Infrared Survey Explorer (WISE) surveys. The AGN candidates associated with the UGS occupy very different regions from the stars and extragalactic sources in the colour space defined by the VVV and WISE infrared colours. We found 27 near-infrared AGN candidates possibly associated with 14 Fermi-LAT sources using the VVV survey. We also found 2 blazar candidates in the regions of 2 Fermi-LAT sources using WISE data. There is no match between VVV and WISE candidates. We have also examined the Ks light curves of the VVV candidates and applied the fractional variability amplitude (σrms) and the slope of variation in the Ks passband to characterise the near-infrared variability. This analysis shows that more than 85 per cent of the candidates have slopes in the Ks passband >10−4 mag/day and present σrms values consistent with a moderate variability. This is in good agreement with typical results seen from type-1 AGN. The combination of YJHKs colours and Ks variability criteria was useful for AGN selection, including its use in identifying counterparts to Fermi γ-ray sources.

The properties of supermassive black holes and their host galaxies for type 1 and 2 active galactic nuclei in the eFEDS and COSMOS fields

In this study, our primary objective is to compare the properties of supermassive black holes (SMBHs) and their host galaxies between type 1 and type 2 active galactic nuclei (AGNs). In our analysis, we use X-ray detected sources in two fields, namely the eFEDS and the COSMOS-Legacy. To classify the X-ray sources, we performed a spectral energy distribution (SED) fitting analysis, using the CIGALE code. The robustness of our analysis was paramount so, to ensure this, we imposed stringent selection criteria. Thus, only sources with extensive photometric data across the optical, near- and mid-infrared part of the spectrum and reliable host galaxy properties and classifications were included. The final sample consists of 3312 AGNs, of which 3049 are classified as type 1 and 263 as type 2. The sources span a redshift range of 0.5 < z < 3.5 and encompass a wide range of X-ray luminosities, falling within 42 < log,[LX,2−10 keV(erg s−1)] < 46. Our results show that type 2 AGNs exhibit a tendency to inhabit more massive galaxies, by 0.2 − 0.3 dex (on a logarithmic scale), compared to type 1 sources. Type 2 AGNs also display, on average, lower specific black hole accretion rates, a proxy of the Eddington ratio, compared to type 1 AGNs. These differences persist across all redshifts and LX considered within our dataset. Moreover, our analysis uncovers that type 2 sources tend to have lower star formation rates compared to type 1 AGNs at z < 1. This picture reverses at z > 2 and log,[LX,2−10 keV(erg s−1)] > 44. Similar patterns emerge when we categorize AGNs based on their X-ray obscuration levels (NH). However, in this case, the observed differences are pronounced only for low-to-intermediate LX AGNs and are also sensitive to the NH threshold applied for the AGN classification. These comprehensive findings enhance our understanding of the intricate relationships governing AGN types and their host galaxy properties across diverse cosmic epochs and luminosity regimes.

From Sub-Solar to Super-Solar Chemical Abundances along the Quasar Main Sequence

The 4D (four-dimensional) eigenvector 1 (E1) sequence has proven to be a highly effective tool for organizing observational and physical properties of type-1 active galactic nuclei (AGNs). In this paper, we present multiple measurements of metallicity for the broad line region gas, from new and previously-published data. We demonstrate a consistent trend along the optical plane of the E1 (also known as the quasar main sequence), defined by the line width of Balmer hydrogen Hβ profile and by a parameter measuring the prominence of singly-ionized iron emission. The trend involves an increase from sub-solar metallicity in correspondence with extreme Population B (weak Feii emission, large Hβ FWHM (full width at half maximum)) to metallicity several tens the solar value in correspondence with extreme Population A (strongest Feii optical emission, narrower Hβ profiles). The data establish the metallicity as a correlate of the 4DE1/main sequence. If the considerably high metallicity (Z≳10Z⊙, solar metallicity) gas is expelled from the sphere of influence of the central black hole, as indicated by the widespread evidence of nuclear outflows and disk wind in the case of sources radiating at a high Eddington ratio, then it is possible that the outflows from quasars played a role in chemically enriching the host galaxy.

The Application of Machine Learning to Quasar and Seyfert Classification

Machine learning can be utilized to classify spectra flagged as Active Galactic Nuclei (AGNs) belonging to Seyferts or Quasars, expediting data collection and aiding in analyzing the AGN types. While many properties of Seyferts and Quasars can be used as feature points in training a machine learning model, one relatively available property with high information density is the spectra of the AGN types. This paper aims to describe the training and results of a K-Nearest Neighbors and a Dense Neural Network machine learning model built to classify AGNs as Seyfert type 1s, Seyfert type 2s, or Quasars.

Fierce Feedback in an Obscured, Sub-Eddington State of the Seyfert 1.2 Markarian 817

Mrk 817 is a bright and variable Seyfert 1.2 active galactic nucleus (AGN). X-ray monitoring of Mrk 817 with the Neil Gehrels Swift Observatory in 2022 revealed that the source flux had declined to a lower level than recorded at any prior point in the then 19 yr mission. We present an analysis of deep XMM-Newton and NuSTAR observations obtained in this low flux state. The spectra reveal a complex X-ray wind consisting of neutral and ionized absorption zones. Three separate velocity components are detected as part of a structured ultrafast outflow (UFO), with v/c=0.043−0.003+0.007 , v/c=0.079−0.0008+0.003 , and v/c=0.074−0.005+0.004 . These projected velocities suggest that the wind likely arises at radii that are much smaller than the optical broad-line region. In order for each component of the outflow to contribute significant feedback, the volume filling factors must be greater than f ≃ 0.009, f ≃ 0.003, and f ≃ 0.3, respectively. For plausible, data-driven volume filling factors, these limits are passed, and the total outflow likely delivers the fierce feedback required to reshape its host environment, despite a modest radiative Eddington fraction of λ ≃ 0.008–0.016 (this range reflects plausible masses). UFOs are often detected at or above the Eddington limit; this result signals that black hole accretion has the potential to shape host galaxies even at modest Eddington fractions and over a larger fraction of a typical AGN lifetime. We discuss our findings in terms of models for disk winds and black hole feedback in this and other AGN.

Morphological Study of Active Galaxies based on SDSS Images. Preliminary Results

Activity in galaxies has mainly two major forms: Active Galactic Nuclei (AGN) and Starburst (SB). Moreover, different types of AGN have different morphology. However, this question has not yet been properly investigated and due to old low-quality images, the morphology of many galaxies is not well described. SDSS images give a good possibility to homogeneously classify galaxies and investigate differences by the activity types. The concentration of the central part and the ratio between the central bulge and the total flux is a subject for detailed study. We use SDSS images to classify different types of active galaxies (both AGN and Starburst) and understand differences between QSOs, Seyferts 1 and 2, LINERS and Composites, as well as Starburst galaxies. The best expectation from our study will be the preliminary classification of active galaxies into activity types based on the images and before having their spectral types.

Are There Higher Electron Densities in Narrow Emission Line Regions of Type-1 AGNs than in Type-2 AGNs?

In the manuscript, we check properties of electron densities n e traced by flux ratio R sii of [S ii]λ6716 Å to [S ii]λ6731 Å in narrow emission line regions (NLRs) between Type-1 active galactic nucleus (AGN) and Type-2 AGN in SDSS Data Release 12 (DR12). Under the framework of unified model considering kiloparsec-scale structures, similar n e in NLRs should be expected between Type-1 AGN and Type-2 AGN. Based on reliable measurements of the [S ii] doublet with measured parameters at least 5 times larger than corresponding uncertainties, there are 6039 Type-1 AGN and 8725 Type-2 AGN (excluding the Type-2 LINERs and the composite galaxies) collected from SDSS DR12. Then, lower R sii (higher n e ) in NLRs can be well confirmed in Type-1 AGN than in Type-2 AGN, with the confidence level higher than 5σ, even after considering the necessary effects including effects of electron temperatures traced by [O iii]λ4364,4959,5007 Å on estimating n e in NLRs. Two probable methods are proposed to explain the higher n e in NLRs in Type-1 AGN. First, the higher n e in NLRs of Type-1 AGN could indicate longer time durations of AGN activities in Type-1 AGN than in Type-2 AGN, if AGN activities triggering galactic-scale outflows leading to more electrons injecting into NLRs were accepted to explain the higher n e in NLRs of Type-2 AGN than H ii galaxies. Second, the lower n e in NLRs of Type-2 AGN could be explained by stronger star-forming contributions in Type-2 AGN, considering lower n e in H ii regions. The results provide interesting challenges to the commonly and widely accepted unified model of AGN.

WISDOM Project - XVI. The link between circumnuclear molecular gas reservoirs and active galactic nucleus fuelling

ABSTRACT We use high-resolution data from the millimetre-Wave Interferometric Survey of Dark Object Masses (WISDOM) project to investigate the connection between circumnuclear gas reservoirs and nuclear activity in a sample of nearby galaxies. Our sample spans a wide range of nuclear activity types including radio galaxies, Seyfert galaxies, low-luminosity active galactic nuclei (AGN) and inactive galaxies. We use measurements of nuclear millimetre continuum emission along with other archival tracers of AGN accretion/activity to investigate previous claims that at, circumnuclear scales (<100 pc), these should correlate with the mass of the cold molecular gas. We find that the molecular gas mass does not correlate with any tracer of nuclear activity. This suggests the level of nuclear activity cannot solely be regulated by the amount of cold gas around the supermassive black hole (SMBH). This indicates that AGN fuelling, that drives gas from the large-scale galaxy to the nuclear regions, is not a ubiquitous process and may vary between AGN type, with time-scale variations likely to be very important. By studying the structure of the central molecular gas reservoirs, we find our galaxies have a range of nuclear molecular gas concentrations. This could indicate that some of our galaxies may have had their circumnuclear regions impacted by AGN feedback, even though they currently have low nuclear activity. Alternatively, the nuclear molecular gas concentrations in our galaxies could instead be set by secular processes.

X-ray polarization from parsec-scale components of active galactic nuclei: observational prospects

ABSTRACT We present a broad analysis of X-ray polarimetric observational prospects for radio-quiet active galactic nuclei (AGN), focusing on the role of parsec-scale components. We provide a revision of self-consistent type-1 and type-2 generic AGN radiative transfer models that were obtained with a Monte Carlo code stokes, evaluating the effects of absorption and scattering. Our model consists of a central disc–corona emission obtained with the kynstokes code in the lamp-post geometry, an equatorial wedge-shaped dusty torus and two symmetric conical polar outflows. We argue that the information on the mutual orientation, shape, relative size, and composition of such components, usually obtained from spectroscopy or polarimetry in other wavelengths, is essential for the X-ray polarization analysis of the obscured type-2 AGNs. We provide general detectability prospects for AGNs with 2–8 keV polarimeters onboard of the currently flying Imaging X-ray Polarimetry Explorer (IXPE) satellite and the forthcoming enhanced X-ray Timing and Polarimetry mission. Finally, we assess the role of contemporary X-ray polarimetry in our understandings of the unified AGN model after the first year and a half of IXPE operation.

SDSS J1619 with blueshifted broad components in H α and in [O iii] having similar line width and velocity shifts: a recoiling SMBH candidate?

ABSTRACT In this letter, we report a potential candidate of recoiling supermassive black hole (rSMBH) in Sloan Digital Sky Survey (SDSS) J1619 based on similar velocity shifts and line widths of the blueshifted broad components in H α and [O iii] doublet. The measured line width ratio between blueshifted broad H α and broad [O iii] line is 1.06, if compared with common values around 5.12 for normal Type-1 active galactic nuclei, indicating different properties of the blueshifted broad components in SDSS J1619 from those of normal Quasi Stellar Objects (QSOs). The virial BH mass MBHr derived from the broad H α is consistent with the mass expected from the MBH–σ relation. The similar velocity shifts and line widths of the blueshifted broad components in H α and [O iii] and the virial BH mass derived from the H α broad line emissions that is consistent with the mass expected from the MBH–σ relation, can be explained by an rSMBH scenario. Besides the rSMBH scenario, either the similar line widths of the blueshifted broad components in H α and in [O iii] or the consistency between the virial BH mass and the mass expected from the MBH–σ relation cannot be explained by the other proposed models in SDSS J1619.

Accretion/Ejection Phenomena and Emission-Line Profile (A)symmetries in Type-1 Active Galactic Nuclei

The distinct behaviors of blue- and redshifted broad emission-line shifts, emitted by ionic species with varying ionization potentials in active galactic nuclei (AGN), can be elucidated by considering the balance between radiation and gravitational forces along the quasar main sequence. Blueshifts are attributed to outflowing motions of the line-emitting gas toward the observer, and they are most pronounced in AGN with high Eddington ratios (Population A) and high luminosities. Conversely, redshifts in the broad-line wings are observed in Balmer emission lines of sources radiating at low Eddington ratios (Population B), though the origin of these redshifts remains a subject of ongoing debate. A correlation linking the redward asymmetry as measured by the centroid shift of the Hβ line profile to the black hole mass lends support to the notion that these shifts arise from gravitational and transverse redshift effects, particularly for black hole masses MBH≳108.7 M⊙.

Testing Physical Scenarios for the Reflection Features of Type-1 AGNs using XMM-Newton and NuSTAR Simultaneous Observations

Above ∼3 keV, the X-ray spectrum of active galactic nuclei (AGNs) is characterized by the intrinsic continuum and Compton reflection features. For type-1 AGNs, several regions may contribute to the reflection. To investigate the nature of the reflecting medium, we perform a systematic analysis of the reflector using XMM-Newton and Nuclear Spectroscopic Telescope Array observations of a sample of 22 type-1 AGNs. We create a baseline model that includes Galactic absorption and an intrinsically absorbed power law, plus a reflection model. We test a set of nine reflection models in a subsample of five objects. Based on these results, we select three models to be tested on the entire sample, accounting for distinct physical scenarios: neutral/distant reflection, ionized/relativistic reflection, and neutral/distant+ionized/relativistic reflection, namely, a hybrid model. We find that 18 sources require the reflection component to fit their spectra. Among them, 67% prefer the hybrid model. Neutral and ionized models are equally preferred by three sources. We conclude that both the neutral/distant reflector most probably associated with the inner edges of the torus and the ionized/relativistic reflector associated with the accretion disk are required to describe the reflection in type-1 AGNs.

A complete catalogue of broad-line AGNs and double-peaked emission lines from MaNGA integral-field spectroscopy of 10K galaxies: stellar population of AGNs, supermassive black holes, and dual AGNs

ABSTRACT We analyse the integral field spectroscopy data for the ≈10 000 galaxies in final data release of the MaNGA survey. We identify 188 galaxies for which the emission lines cannot be described by single Gaussian components. These galaxies can be classified into (1) 38 galaxies with broad $\rm H\alpha$ and [O iii] $\rm \lambda$5007 lines, (2) 101 galaxies with broad $\rm H\alpha$ lines but no broad [O iii] $\rm \lambda$5007 lines, and (3) 49 galaxies with double-peaked narrow emission lines. Most of the broad-line galaxies are classified as active galactic nuclei (AGNs) from their line ratios. The catalogue helps us further understand the AGN-galaxy coevolution through the stellar population of broad-line region host galaxies and the relation between broad lines’ properties and the host galaxies’ dynamical properties. The stellar population properties (including mass, age, and metallicity) of broad-line host galaxies suggest there is no significant difference between narrow-line Seyfert-2 galaxies and Type-1 AGNs with broad $\rm H\alpha$ lines. We use the broad-$\rm H\alpha$ line width and luminosity to estimate masses of black hole in these galaxies, and test the MBH–σe relation in Type-1 AGN host galaxies. Furthermore, we find three dual AGN candidates supported by radio images from the VLA FIRST survey. This sample may be useful for further studies on AGN activities and feedback processes.

Hydrodynamic simulations of the disc of gas around supermassive black holes (HDGAS) – I. Molecular gas dynamics

ABSTRACT We present hydrodynamic simulations of the interstellar medium (ISM) within the circumnuclear disc (CND) of a typical active galactic nucleus (AGN)-dominated galaxy influenced by mechanical feedback from an AGN. The simulations are coupled with the CHIMES non-equilibrium chemistry network to treat the radiative-cooling and AGN-heating. A focus is placed on the central 100 pc scale where AGN outflows are coupled to the ISM and constrained by observational Seyfert-2 galaxies. AGN-feedback models are implemented with different wind-velocity and mass-loading factors. We post-process the simulation snapshots with a radiative-transfer code to obtain the molecular emission lines. We find that the inclusion of an AGN promotes the formation of CO in clumpy and dense regions surrounding supermassive black holes (SMBHs). The CO(1-0) intensity maps (<6 Myr) in the CND seem to match well with observations of NGC 1068 with a best match for a model with 5000 km s−1 wind-velocity and a high mass-loading factor. We attempt to discern between competing explanations for the apparent counter-rotating gas disc in the NGC 1068 through an analysis of kinematic maps of the CO line emission. We suggest that mechanical AGN-feedback could explain the alignment-stability of position-angle across the different CND radii around the SMBH through momentum and energy loading of the wind. It is the wind-velocity that drives the disc out of alignment on a 100 pc scale for a long period of time. The position–velocity diagrams are in broad agreement with the predicted Keplerian rotation-curve in the model without AGN, but the AGN models exhibit a larger degree of scatter, in better agreement with NGC 1068 observations.

Cosmological-scale Lyα Forest Absorption around Galaxies and AGNs Probed with the HETDEX and SDSS Spectroscopic Data

We present cosmological-scale three-dimensional neutral hydrogen (H i) tomographic maps at z = 2–3 over a total of 837 deg2 in two blank fields that are developed with Lyα forest absorptions of 14,736 background Sloan Digital Sky Survey (SDSS) quasars at z = 2.08–3.67. Using the tomographic maps, we investigate the large-scale (≳10 h −1 cMpc) average H i radial profiles and two-direction profiles of the line-of-sight (LOS) and transverse directions around galaxies and active galactic nuclei (AGNs) at z = 2–3 identified by the Hobby–Eberly Telescope Dark Energy eXperiment survey and SDSS, respectively. The peak of the H i radial profile around galaxies is lower than the one around AGNs, suggesting that the dark matter halos of galaxies are less massive on average than those of AGNs. The LOS profile of AGNs is narrower than the transverse profile, indicating the Kaiser effect. There exist weak absorption outskirts at ≳30 h −1 cMpc beyond H i structures of galaxies and AGNs found in the LOS profiles that can be explained by the H i gas at ≳30 h −1 cMpc falling toward the source position. Our findings indicate that the H i radial profile of AGNs has transitions from proximity zones (≲a few h −1 cMpc) to the H i structures (∼1–30 h −1 cMpc) and the weak absorption outskirts (≳30 h −1 cMpc). Although there is no significant dependence of AGN types (type 1 vs. type 2) on the H i profiles, the peaks of the radial profiles anticorrelate with AGN luminosities, suggesting that AGNs’ ionization effects are stronger than the gas mass differences.