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In our previous study, we identified a shift in the synchrotron peak frequency of the blazar B2 1308+326 from 1012.9 to 1014.8 Hz during a flare, suggesting it could be a changing-look blazar (CLB). In this work, we investigate the changing-look behaviour of B2 1308+326 by analysing a newly acquired optical spectrum and comparing it with an archival spectrum. We find that between the two epochs, the continuum flux increased by a factor of ~4.4, while the Mg ii emission line flux decreased by a factor of 1.4 ± 0.2. Additionally, the equivalent width of the Mg ii line reduced from ~20 to ~3 Å, indicating an apparent shift from a flat-spectrum radio quasar (FSRQ) class to a BL Lacertae (BL Lac) class. Despite this apparent change, the ratio of accretion disk luminosity to Eddington luminosity remains >10−2 during both epochs, indicating efficient accretion persists in B2 1308+326. The measured black hole mass remains consistent with an average log M BH = 8.44 M ⊙. Our findings suggest that B2 1308+326 is not a genuine CLB but rather an intrinsic FSRQ that emerges as a BL Lac during high-flux states due to enhanced nonthermal emission. [ABSTRACT FROM AUTHOR]

We examine lengthy radio light curves of the flat spectrum radio galaxy 3C 454.3 for possible quasiperiodic oscillations (QPOs). The data used in this work were collected at five radio frequencies, 4.8, 8.0, 14.5, 22.0, and 37.0 GHz between 1979 and 2013 as observed at the University of Michigan Radio Astronomical Observatory, Crimean Astrophysical Observatory, and Aalto University Metsähovi Radio Observatory. We employ generalized Lomb–Scargle periodogram and weighted wavelet transform analyses to search for periodicities in these light curves. We confirm a QPO period of ∼2000 days to be at least 4 σ significant using both methods at all five radio frequencies between 1979 and 2007, after which a strong flare changed the character of the light curve. We also find a ∼600 day period, which is at least 4 σ significant, but only in the 22.0 and 37.0 GHz light curves. We briefly discuss physical mechanisms capable of producing such variations. [ABSTRACT FROM AUTHOR]

Active galactic nuclei (AGN) are the signposts of black hole growth, and likely play an important role in galaxy evolution. An outstanding question is whether AGN of different spectral types indicate different evolutionary stages in the coevolution of black holes and galaxies. We present the angular correlation function between an AGN sample selected from Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP) optical photometry and Wide-field Infrared Survey Explorer mid-IR photometry and a luminous red galaxy (LRG) sample from HSC-SSP. We investigate AGN clustering strength as a function of luminosity and spectral features across three independent HSC fields totaling ∼600 deg2, for z ∈ 0.6 −1.2 and AGN with L 6 μ m > 3 × 1044 erg s−1. There are ∼28,500 AGN and ∼1.5 million LRGs in our primary analysis. We determine the average halo mass for the full AGN sample (M h ≈ 1012.9 h −1 M ⊙), and note that it does not evolve significantly as a function of redshift (over this narrow range) or luminosity. We find that, on average, unobscured AGN (M h ≈ 1013.3 h −1 M ⊙) occupy ∼4.5× more massive halos than obscured AGN (M h ≈ 1012.6 h −1 M ⊙), at 5 σ statistical significance using 1D uncertainties, and at 3 σ using the full covariance matrix, suggesting a physical difference between unobscured and obscured AGN, beyond the line-of-sight viewing angle. Furthermore, we find evidence for a halo mass dependence on reddening level within the Type I AGN population, which could support the existence of a dust-obscured phase. However, we also find that quite small systematic shifts in the redshift distributions of the AGN sample could explain current and previously observed differences in M h . [ABSTRACT FROM AUTHOR]

A detailed broadband spectral and temporal study of a radio-loud active galactic nucleus, 3C 380, is carried out using 14.5 yr of Fermi-LAT data, available Swift observations, and data from other observatories, including AstroSat (2020 August). The source exhibited a GeV outburst on 2020 September 5. Given the sparsity of Swift observations, no useful correlations could be established between γ -ray, X-ray, and UV/optical bands. The source is also a part of the Monitoring of Jets in Active Galactic Nuclei with VLBA Experiments survey and has been monitored at 15 GHz for over a decade. The correlation studies show that radio emission lags γ -rays by ∼150 days. We constrain the location of γ -ray emission by the core shift measurements from the literature and the observed time delays. Using this localization, we constructed and modeled the broadband spectral energy distribution (SED) of the source during its high γ -ray activity states and for the long-term averaged state. The SEDs during the high γ -ray activity states are modeled with two zones: one corresponding to the "steady" or the emission from the source averaged over more than a decade and another corresponding to the "flare" emission. We conclude that the high-energy emission originates within the parsec-scale jet, and moving shocks in the region drive the observed γ -flux variations. [ABSTRACT FROM AUTHOR]

The interband lags among the optical broad-band continua of active galactic nuclei (AGNs) have been intensively explored over the past decade. However, the nature of the lags remains under debate. Here, utilizing two distinct scenarios for AGN variability, i.e., the thermal fluctuation of accretion disk and the reprocessing of both the accretion disk and clouds in the broad line region, we show that, owing to the random nature of AGN variability, the interband lags of an individual AGN would vary from one campaign with a finite baseline to another. Specifically, the thermal fluctuation scenario implies larger variations in the lags than the reprocessing scenario. Moreover, the former predicts a positive correlation between the lag and variation amplitude, while the latter does not result in such a correlation. For both scenarios, averaging the lags of an individual AGN measured with repeated and nonoverlapping campaigns would give rise to a stable lag, which is larger for a longer baseline and gets to saturation for a sufficiently long baseline. However, obtaining the stable lag for an individual AGN is very time-consuming. Alternatively, it can be equivalently inferred by averaging the lags of a sample of AGNs with similar physical properties, and thus can be properly compared with predictions of AGN models. In addition, several new observational tests suggested by our simulations are discussed, as well as the role of the deep high-cadence surveys of the Wide Field Survey Telescope in enriching our knowledge of the lags. [ABSTRACT FROM AUTHOR]

Objective: To examine prevalence of partial and complete HPV vaccination among middle‐aged adults and factors associated with vaccination status. Study Design: Nationally representative cross‐sectional survey. Setting: United States. Methods: Cohort includes adults aged 30 to 44 years from 2018 to 2022 Behavioral Risk Factor Surveillance System (BRFSS) survey who completed questions about HPV vaccination status. Survey‐weighted multivariable logistic regression was utilized to explore factors associated with partial and complete HPV vaccination status. Results: In this nationally representative cohort of 26,470 US middle‐aged adults, 15.8% [95% confidence interval [CI]: 15.1%‐16.6%] reported any HPV vaccination, and 6.5% [95% CI: 6.0%‐7.0%] reported complete HPV vaccination. On multivariable regression, younger age, female sex, residence in the West or Northeast, higher educational attainment, unmarried status, having a personal healthcare provider, and gay or lesbian sexual orientation were associated with increased likelihood of vaccination. Race was variably associated with vaccination status. Annual income, insurance status, cancer history, head and neck cancer history, and time of last physician checkup were not associated with HPV vaccination status. Conclusion: HPV vaccination among middle‐aged adults who were not previously vaccinated should be based on risk for new HPV infection and possible benefits of vaccination. While our analysis shows that consideration of personal factors likely plays a role in HPV vaccination in this cohort, we also find that gaps in vaccination may exist due to other socioeconomic disparities between sexes, educational attainment levels, racial/ethnic groups, geographic regions, and access to a personal healthcare provider. These factors' influence suggests potential room for improved public health measures. [ABSTRACT FROM AUTHOR]

The accretion disks of supermassive black holes (SMBHs) harboring in active galactic nuclei (AGN) are considered to be an ideal site for producing different types of gamma-ray bursts (GRBs). The detectability of these GRB phenomena hidden in AGN disks is highly dependent on the dynamical evolution of the GRB relativistic jets. By investigating the reverse- and forward-shock dynamics due to the interaction between the jets and AGN disk material, we find that the relativistic jets can successfully break out from the disks only for a sufficiently high luminosity and a long enough duration. In comparison, relatively normal GRB jets are inclined to be choked in the disks unless the GRBs occur near an SMBH with relatively low mass (e.g., ∼106 M ⊙). For the choked jets, unlike normal GRB prompt and afterglow emission, we can only expect to detect emission from the forward shock when the shock is very close to the edge of the disks, i.e., at the shock breakout emission and subsequent cooling of the shock. [ABSTRACT FROM AUTHOR]

The local (z = 0.0315) active galactic nucleus (AGN) Mrk 817 was monitored over more than 500 days with space-borne and ground-based instruments as part of a large international campaign, AGN STORM 2. Here, we present a comprehensive analysis of the broadband continuum variations using detailed modeling of the broad line region (BLR), several types of disk winds classified by their optical depth, and new numerical simulations. We find that diffuse continuum (DC) emission, with additional contributions from strong and broad emission lines, can explain the continuum lags observed in this source during high- and low-luminosity phases. Disk illumination by the variable X-ray corona contributes only a small fraction of the observed continuum lags. Our BLR models assume radiation-pressure-confined clouds distributed over a distance of 2–122 light days. We present calculated mean emissivity radii of many emission lines, and DC emission, and suggest a simple, transfer-function-dependent method that ties them to cross-correlation lag determinations. We do not find clear indications for large-optical-depth winds, but identify the signature of lower-column-density winds. In particular, we associate the shortest observed continuum lags with a combination of τ (1 Ryd) ≈ 2 wind and a partly shielded BLR. Even smaller optical depth winds may be associated with X-ray absorption features and with noticeable variations in the widths and lags of several high-ionization lines like He ii and C iv. Finally, we demonstrate the effect of torus dust emission on the observed lags in the i and z bands. [ABSTRACT FROM AUTHOR]

While there has been an increase in interest in the possibility of quasiperiodic oscillations (QPOs) in blazars, the search has hitherto been restricted to sources with well-sampled light curves. Objects with light curves that include gaps have been, to our knowledge, overlooked. Here, we study two such curves, which have the interesting feature of pertaining to relatively high-redshift blazars—FSRQs, PKS 2155-83, and PKS 2255-282—observed by the Fermi Large Area Telescope. Their redshifts border the "cosmic noon" era of galaxy formation and merging, and their light curves exhibit a distinctive pattern of repetitive high and low (gap dominant) states for 15.6 yr. To accommodate for the gaps in the curves, data are integrated over extended time intervals of 1 month and 2 months. The resulting curves were also examined using methods suitable for sparsely sampled data. This investigation of PKS 2155-83 and PKS 2255-282 suggests QPOs with periods of 4.69 ± 0.79 yr (3 σ) and 6.82 ± 2.25 yr (2.8 σ), respectively. The probability density functions of the blazars' fluxes, along with the correlation between their flux and spectral index, were also analyzed. Given the epochs in which the objects are observed, the plausibility of a binary black hole scenario as an origin of the apparent periodicity was examined. We estimated the prospective parameters of such a system using a simple geometric model. The total masses were estimated and found to be consistent, in principle, with independent (dynamical) measurements of the central black hole masses in the two host galaxies. [ABSTRACT FROM AUTHOR]

Blazars, the peculiar class of active galactic nuclei, are known to show flux variations across the accessible electromagnetic spectrum. Though they have been studied extensively for their flux variability characteristics across wavelengths, information on their ultraviolet (UV) flux variations on timescales of hours is very limited. Here, we present the first UV flux variability study on intraday timescales of a sample of ten blazars comprising two flat-spectrum radio quasars (FSRQs) and eight BL Lacertae objects (BL Lacs). These objects, spanning a redshift (z) range of 0.034 ≤ z ≤ 1.003, were observed in the far-UV (1300−1800 Å) and near-UV (2000−3000 Å) wavebands using the ultraviolet imaging telescope on board AstroSat. UV flux variations on timescales of hours were detected in nine sources out of the observed ten blazars. The spectral variability analysis showed a bluer-when-brighter trend with no difference in the UV spectral variability behavior between the studied sample of FSRQs and BL Lacs. The observed UV flux and spectral variability in our sample of both FSRQs and BL Lacs revealed that the observed UV emission in them is dominated by jet synchrotron process. [ABSTRACT FROM AUTHOR]

We present an enhanced version of the publicly available Stripe 82X catalog (S82-XL), featuring a comprehensive set of 22,737 unique X-ray point sources identified with a significance ≳4 σ. This catalog is four times larger than the original Stripe 82X catalog, by including additional archival data from the Chandra and XMM-Newton telescopes. Now covering ∼54.8 deg2 of nonoverlapping sky area, the S82-XL catalog roughly doubles the area and depth of the original catalog, with limiting fluxes (half-area fluxes) of 3.4 × 10−16 (2.4 × 10−15), 2.9 × 10−15 (1.5 × 10−14), and 1.4 × 10−15 (9.5 × 10−15) erg s−1 cm−2 across the soft (0.5–2 keV), hard (2–10 keV), and full (0.5–10 keV) bands, respectively. S82-XL occupies a unique region of flux-area parameter space compared to other X-ray surveys, identifying sources with rest-frame luminosities from 1.2 × 1038 to 1.6 × 1047 erg s−1 in the 2–10 keV band (median X-ray luminosity, 7.2 × 1043 erg s−1), and spectroscopic redshifts up to z ∼ 6. By using hardness ratios, we derived the obscuration of active galactic nuclei (AGNs), obtaining a median value of log (N H / cm − 2) = 21.6 − 1.6 + 1.0 and an overall, obscured fraction ( log (N H / cm − 2) > 22 ) of ∼36.9%. S82-XL serves as a benchmark in X-ray surveys and, with its extensive multiwavelength data, is especially valuable for comprehensive studies of luminous AGNs. [ABSTRACT FROM AUTHOR]

We report on the discovery of a dual supermassive black hole system in the radio galaxy J1543−0757, with a projected separation between the two black holes of ∼46 mas. The result is based on recent multifrequency observations using the Very Long Baseline Array and European VLBI Network, which reveal two compact, variable, flat-spectrum, active nuclei within the elliptical host galaxy of J1543−0757. Multiepoch observations from the Very Long Baseline Array also provide constraints on the spectral index and proper motions of all components. The flat spectra of both N and S at both frequencies strongly support the hypothesis that these radio components are associated with two separate, accreting supermassive black holes. The two nuclei appear stationary, while the jets emanating from the weaker of the two nuclei appear to move out and terminate in bright hotspots. The discovery of this system has implications for the number of close dual black holes that might be sources of gravitational radiation. [ABSTRACT FROM AUTHOR]

We introduce an improved method for decomposing the emission of active galactic nuclei (AGN) and their host galaxies using templates from principal component analysis (PCA). This approach integrates prior information from PCA with a penalized pixel fitting mechanism that improves the precision and effectiveness of the decomposition process. Specifically, we have reduced the degeneracy and overfitting in AGN host decomposition, particularly for those with low signal-to-noise ratios (SNRs), where traditional methods tend to fail. By applying our method to 76,565 Sloan Digital Sky Survey Data Release 16 quasars with z < 0.8, we achieve a success rate of ≈94%, thus establishing the largest host-decomposed spectral catalog of quasars to date. Our fitting results consider the impact of the host galaxy on the overestimation of the AGN luminosity and black hole mass (M BH). Furthermore, we obtained stellar velocity dispersion (σ ⋆) measurements for 4137 quasars. The slope of the M BH− σ ⋆ relation in this subsample is generally consistent with previous quasar studies beyond the local Universe. Our method provides a robust and efficient approach to disentangle the AGN and host galaxy components across a wide range of SNRs and redshifts. [ABSTRACT FROM AUTHOR]

The central region of M87 has been observed by the Atacama Large Millimeter/submillimeter Array (ALMA) several times to resolve its molecular cloud distribution. We present the ALMA CO(1–0), CO(2–1), and CO(3–2) observations of the M87 circumnuclear region. The CO(1–0) shows emission as well as molecular absorption features toward its nucleus, indicating the existence of cold molecular clouds/gas. ALMA imaging of the CO(1–0) observations show the distribution of molecular clouds toward the nucleus of M87 with a radius of ∼105 pc. The clouds seen in the CO(1–0) are moving with very high velocity and have an apparent motion in the range of −1000 to 3600 km s−1 relative to the central supermassive black hole, which has a systemic velocity of ∼1266 km s−1. The molecular gas mass was estimated to be about 1.08 ± 0.64 × 107 M ⊙ in the central 210 pc of M87. We calculated the optical depths using the absorption lines of the CO(1–0) and CO(2–1). The excitation temperature was estimated to be ∼7.133 ± 0.03 K using the optical depth ratio of the CO(2-1) to CO(1-0). We also found the line-of-sight column density to be ∼2.25 × 1015 cm−2, which corresponds to a hydrogen column density of ∼0.28 × 1020 cm−2. [ABSTRACT FROM AUTHOR]

The ability to accurately discern active massive black holes (BHs) in nearby dwarf galaxies is paramount to understanding the origins and processes of "seed" BHs in the early Universe. We present Chandra X-ray Observatory observations of a sample of three local dwarf galaxies (M * ≤ 3 × 109 M ⊙, z ≤ 0.15) previously identified as candidates for hosting active galactic nuclei (AGN). The galaxies were selected from the NASA-Sloan Atlas with spatially coincident X-ray detections in the eROSITA Final Equatorial Depth Survey. Our new Chandra data reveal three X-ray point sources in two of the target galaxies with luminosities between log(L 2−10 keV [erg s−1]) = 39.1 and 40.4. Our results support the presence of an AGN in these two galaxies and an ultraluminous X-ray source (ULX) in one of them. For the AGNs, we estimate BH masses of M BH ∼ 105−6 M ⊙ and Eddington ratios on the order of ∼10−3. [ABSTRACT FROM AUTHOR]

We present a study of high-cadence, high-precision optical light curves from the TESS satellite of 67 blazars in the southern sky. We provide descriptive flux statistics, power spectral density (PSD) model parameters, and characteristic variability timescales. We find that only 15 BL Lacertae objects (BLLs) and 18 flat spectrum radio quasars (FSRQs) from the initial 26 and 41, respectively, exhibit statistically significant variability. We employ an adapted power spectral response method to test the goodness of fit for the PSD function to three power-law variant models. From our best-fitting description of the PSD, we extract the high-frequency power-spectral slopes, and if present, determine the significant bend or break in the model to identify characteristic timescales. We find no significant difference in the excess variance or rms scatter between blazar subpopulations. We identify a linear rms–flux relation in ∼69% of our sample, in which ∼20% show a strong correlation. We find that both subpopulations of blazars show power spectral slopes of α ∼ 2 in which a broken power-law best fits five BLLs and six FSRQs and a bending power-law best fits one BLL and five FSRQs. The shortest timescales of variability in each light-curve range widely from minutes to weeks. Additionally, these objects' characteristic timescales range from ∼0.8 to 8 days, consistent with optical variability originating in the jet. [ABSTRACT FROM AUTHOR]

We observed the Seyfert 1 galaxy Mrk 817 during an intensive multiwavelength reverberation mapping campaign for 16 months. Here, we examine the behavior of narrow UV absorption lines seen in the Hubble Space Telescope/Cosmic Origins Spectrograph spectra, both during the campaign and in other epochs extending over 14 yr. We conclude that, while the narrow absorption outflow system (at −3750 km s−1 with FWHM = 177 km s−1) responds to the variations of the UV continuum as modified by the X-ray obscurer, its total column density (log N H = 19.5 − 0.13 + 0.61 cm−2) did not change across all epochs. The adjusted ionization parameter (scaled with respect to the variations in the hydrogen-ionizing continuum flux) is log U H = −1.0 − 0.3 + 0.1 . The outflow is located at a distance smaller than 38 pc from the central source, which implies a hydrogen density of n H > 3000 cm−3. The absorption outflow system only covers the continuum emission source and not the broad emission line region, which suggests that its transverse size is small (< 1016 cm), with potential cloud geometries ranging from spherical to elongated along the line of sight. [ABSTRACT FROM AUTHOR]

The complexity of the energy levels in Fe ii has made it difficult to theoretically interpret its observational emission spectrum. However, addressing this challenge could provide valuable insights into the main sequence of QSOs using "eigenvector 1" and the chemical evolution of the Universe. Although the templates based on I Zw 1 are widely used, their universality remains unexplained. To address this, we utilized the CLOUDY spectral synthesis code to generate theoretical blends of Fe ii optical emission near the H β region. Our results indicate that the optimal cloud density and photon flux align with previous studies at gas density 1011 cm−3 and photon flux 1020.5 cm−2 s−1. We discovered a broad parameter region that fits the data well, encompassing a diverse range of densities and photon fluxes. This helps to explain the general applicability of optical templates. Additionally, we investigated the effects of different spectral energy distributions (SEDs), Eddington ratios, turbulence, and cloud column densities and found that they provided a sufficiently broad range for typical emitting clouds. We found different SEDs had a negligible impact on the template shape, further expanding the usability of empirical templates. However, they significantly affected the absolute intensity of Fe ii emission, consistent with previous research. Furthermore, we determined that a turbulence of approximately 100 km s−1 is necessary to produce sufficiently strong optical Fe ii, and either a column density greater than 1024 cm−2, which is typical for Fe ii UV emission, or an abundance higher than solar is preferred. [ABSTRACT FROM AUTHOR]

We have characterized the ionized, neutral, and warm molecular gas kinematics in the Seyfert 1 galaxy NGC 3227 using observations from the Hubble Space Telescope Space Telescope Imaging Spectrograph, Apache Point Observatory's Kitt Peak Ohio State Multi-Object Spectrograph, Gemini-North's Near-Infrared Integral Field Spectrometer, and the Atacama Large Millimeter/submillimeter Array. We fit multiple Gaussians to several spatially resolved emission lines observed with long-slit and integral-field spectroscopy and isolate the kinematics based on apparent rotational and outflowing motions. We use the kinematics to determine an orientation for the bicone along which the outflows travel and find that the biconical structure has an inclination of 40 − 4 + 5 ° from our line of sight and a half-opening angle with an inner and outer boundary of 47 − 2 + 6 ° and 68 − 1 + 1 °, respectively. We observe ionized outflows traveling 500 km s−1 at distances up to 7″ (800 pc) from the supermassive black hole (SMBH) and disturbed ionized gas up to a distance of 15″ (1.7 kpc). Our analysis reveals that the ionized outflows are launched from within 20 pc of the SMBH, at the same location as a bridge of cold gas across the nucleus detected in Atacama Large Millimeter/submillimeter Array CO(2–1) observations. We measure a turnover radius where the gas starts decelerating at a distance of 26 ± 6 pc from the active galactic nucleus. Compared to a turnover radius in the range of 31−63 pc from a radiative driving model, we confirm that radiative driving is the dominant acceleration mechanism for the narrow-line region outflows in NGC 3227. [ABSTRACT FROM AUTHOR]

Jetted active galactic nuclei (AGN) hosting extended photoionized nebulae provide us with a unique view of the timescales associated with AGN activity. Here, we present a new green bean galaxy at z = 0.304458 ± 0.000007 with large-scale jet-induced radio emission. The spectral energy distributions of the radio components show steep spectral indices (α = −0.85 to −0.92 for the extended regions, and α = −1.02 for the faint radio core), and spectral age modeling of the extended radio emission indicates that the lobes are >6 Myr old. It is unclear whether the jet is active, or is a remnant with an off-time of 2–3 Myr. Several detached clouds lie around the host galaxy up to 37.8 kpc away from the nucleus, and their ionization profile indicates a decline (∼2 dex) in the AGN ionizing photon production over the past ∼0.15 Myr. Furthermore, we measure a blueshift for one of the clouds that is spatially coincident with the path of the radio jet. The cloud is likely illuminated by the photoionizing AGN, and potentially underwent an interaction with the relativistic jet. Our multiwavelength analysis suggests that RGB1 was in a phase of jet production prior to the radiatively efficient accretion phase traced by the detached cloud emission. It is unclear whether RGB1 transitioned into a low-excitation radio galaxy or an inactive galaxy over the past ∼0.15 Myr, or whether the extended radio and optical emission trace distinct accretion phases that occurred in succession. [ABSTRACT FROM AUTHOR]

Previous X-ray works on Mrk 1239 have revealed a complex narrow-line Seyfert 1 that exhibits substantial absorption and strong emission from both collisionally ionized and photoionized plasmas. Here, we report on deep-pointed observations with XMM-Newton and NuSTAR, along with Swift monitoring, to understand the 0.3–30 keV continuum emission and the central engine geometry. A strong X-ray flare, where the AGN brightens by a factor of 5 in ∼30 ks, is captured between 4 and 30 keV and can be attributed to a brightening of the primary continuum. However, the lack of any variability below ∼3 keV on long or short timescales requires complete absorption of the AGN continuum with a neutral medium of column density ∼1023.5 cm−2. The timing and spectral properties are consistent with a blurred reflection interpretation for the primary emission. The variability and presence of a Compton hump disfavors ionized partial covering. The neutral absorber, if outflowing, could be crashing into the surrounding medium and interstellar medium to produce the low-energy continuum and collisionally ionized emission. Scattered emission off the inner torus could produce the photoionized emission. The intricate scenario is demanded by the data and highlights the complexity of the environment that is normally invisible when overwhelmed by the AGN continuum. Objects like Mrk 1239 serve as important sources for unveiling the interface between the AGN and host galaxy environments. [ABSTRACT FROM AUTHOR]

Binary black holes (BBHs) embedded within the accretion disks that fuel active galactic nuclei (AGN) are promising progenitors for the source of gravitational wave (GW) events detected by LIGO/VIRGO. Several recent studies have shown that when these binaries form, they are likely to be highly eccentric and retrograde. However, many uncertainties remain concerning the orbital evolution of these binaries as they either inspiral toward merger or disassociate. Previous hydrodynamical simulations exploring their orbital evolution have been predominantly two-dimensional or have been restricted to binaries on nearly circular orbits. We present the first high-resolution, three-dimensional local shearing-box simulations of both prograde and retrograde eccentric BBHs embedded in AGN disks. We find that retrograde binaries shrink several times faster than their prograde counterparts and exhibit significant orbital eccentricity growth, the rate of which monotonically increases with binary eccentricity. Our results suggest that retrograde binaries may experience runaway orbital eccentricity growth, which may bring them close enough together at pericenter for GW emission to drive them to coalescence. Although their eccentricity is damped, prograde binaries shrink much faster than their orbital eccentricity decays, suggesting they should remain modestly eccentric as they contract toward merger. Finally, binary precession driven by the AGN disk may dominate over precession induced by the supermassive black hole depending on the binary accretion rate and its location in the AGN disk, which can subdue the evection resonance and von Ziepel–Lidov–Kozai cycles. [ABSTRACT FROM AUTHOR]

We present a morphological analysis of the 16 μ m flux-density-limited galaxy sample at 0.8 < z < 1.3 from Huang et al. (2021). At the targeted redshift, the 16 μ m emission corresponds to the polycyclic aromatic hydrocarbon feature from intense star formation, or dust heated by active galactic nuclei (AGN). Our sample of 479 galaxies are dominated by luminous infrared galaxies (LIRGs; 67%) in three CANDLES fields (Extended Groth Strip, ​​​​Great Observatories Origins Deep Survey North and South fields), and are further divided into AGN-dominated, star-forming dominated, composite, and blue compact galaxies by their spectral energy distribution types. The majority of our sample (71%) have disk morphologies, with the few AGN-dominated galaxies being more bulge-dominated than the star-forming-dominated and composite galaxies. The distribution of our sample on the Gini versus M 20 plane is consistent with previous studies, where the Sérsic index n shows an increasing trend toward the smaller M 20 and higher Gini region below the dividing line for mergers. The subsample of ultraluminous infrared galaxies (ULIRGs) follows a steep size–mass relation that is closer to the early-type galaxies. In addition, as the 4.5 μ m luminosity excess ( L 4.5 exc , proxy for AGN strength) increases, our sample appears to be more bulge dominated (i.e., higher n). Based on the specific star formation rate and compactness ( log 10 Σ 1.5 , Σ 1.5 = M * / R e 1.5 ) diagram, the majority of our LIRG-dominated galaxy sample follows a secular evolution track, and their distribution can be explained without involving any merging activities. Out of the 16 ULIRGs in our sample, six are compact with strong AGN contributions, likely evolving along the fast track from more violent activities. [ABSTRACT FROM AUTHOR]

The variability of active galactic nuclei (AGNs) has long been servicing as an essential avenue of exploring the accretion physics of a black hole (BH). There are two commonly used methods for analyzing AGN variability. First, the AGN variability, characterized by the structure function (SF) of a single band, can be well described by a damped random walk (DRW) process on timescales longer than ∼weeks, shorter than which departures have been reported. Second, the color variation (CV) between two bands behaves timescale dependent, raising challenges to the widely accepted reprocessing scenario. However, both the departure from the DRW process and the timescale-dependent CV are hitherto limited to AGNs, mainly quasars, at the supermassive scale. Here, utilizing the high-cadence multiwavelength monitoring on NGC 4395 harboring an intermediate-mass BH, we unveil at the intermediate-mass scale for the first time, prominent departures from the DRW process at timescales shorter than ∼hours in all three nights and bands, and plausible timescale-dependent CVs in the two longest nights of observation. Furthermore, comparing SFs of NGC 4395 to four AGNs at the supermassive scale, we suggest a new scaling relation between the timescale (τ ; across nearly 3 orders of magnitude) and the BH mass (M BH): τ ∝ M BH γ where the exponent γ is likely ≃0.6–0.8. This exponent differs from most previous measurements, but confirms a few, and is consistent with a recent theoretical prediction, suggesting a similar accretion process in AGNs across different mass scales. [ABSTRACT FROM AUTHOR]

Henize 2–10 is a dwarf galaxy experiencing positive black hole (BH) feedback from a radio-detected low-luminosity active galactic nucleus. Previous Green Bank Telescope (GBT) observations detected a H2O "kilomaser" in Henize 2–10, but the low angular resolution (33″) left the location and origin of the maser ambiguous. We present new Karl G. Jansky Very Large Array observations of the H2O maser line at 22.23508 GHz in Henize 2–10 with ∼2″ resolution. These observations reveal two maser sources distinct in position and velocity. The first maser source is spatially coincident with the known BH outflow and the region of triggered star formation ∼70 pc to the east. Combined with the broad width of the maser (W 50 ∼ 66 km s−1), this confirms our hypothesis that part of the maser detected with the GBT is produced by the impact of the BH outflow shocking the dense molecular gas along the flow and at the interface of the eastern star-forming region. The second maser source lies to the southeast, far from the central BH, and has a narrow width (W 50 ∼ 8 km s−1), suggesting a star formation–related origin. This work has revealed the nature of the H2O kilomaser in Henize 2–10 and illustrates the first known connection between outflow-driven H2O masers and positive BH feedback. [ABSTRACT FROM AUTHOR]

We present the study on the relationship between supermassive black holes (SMBHs) and their host galaxies using our variability-selected active galactic nuclei (AGNs) sample (i AB ≤ 25.9 and z ≤ 4.5) constructed from the Hyper Suprime-Cam Subaru Strategic Program Ultradeep survey in the COSMOS field. We estimated the black hole (BH) mass (M BH = 105.5−10 M ⊙) based on the single-epoch virial method and the total stellar mass (M star = 1010−12 M ⊙) by separating the AGN component with spectral energy distribution fitting. We found that the redshift evolution of the BH–stellar mass ratio (M BH/ M star) depends on the M BH, which is caused by no significant correlation between M BH and M star. Variable AGNs with massive SMBHs (M BH > 109 M ⊙) at 1.5 < z < 3 show considerably higher BH–stellar mass ratios (> ∼1%) than the BH–bulge ratios (M BH/ M bulge) observed in the local Universe for the same BH range. This implies that there is a typical growth path of massive SMBHs, which is faster than the formation of the bulge component as final products seen in the present day. For the low-mass SMBHs (M BH < 108 M ⊙) at 0.5 < z < 3, on the other hand, variable AGNs show similar BH–stellar mass ratios with the local objects (∼0.1%), but smaller than those observed at z > 4. We interpret that host galaxies harboring less massive SMBHs at intermediate redshift have already acquired sufficient stellar mass, although high- z galaxies are still in the early stage of galaxy formation relative to those at the intermediate/local Universe. [ABSTRACT FROM AUTHOR]

Flows driven by photons have been studied for almost a century, and a quantitative description of the radiative forces on atoms and ions is important for understanding a wide variety of systems with outflows and accretion disks, such as active galactic nuclei (AGN). Quantifying the associated forces is crucial to determining how these outflows enable interactive mechanisms within these environments, such as AGN feedback. The total number of spectral lines in any given ion of the outflow material must be tabulated in order to give a complete characterization of this force. Here, we provide calculations of the dimensionless line force multiplier for AGN environments. For a wide array of representative AGN sources, we explicitly calculate the photoionization balance at the proposed wind-launching region above the accretion disk, compute the strength of the line-driving force on the gas, and revisit and formalize the role of the commonly used ionization parameter ξ in ultimately determining the line-driving force. We perform these computations and analyses for a variety of AGN central source properties, such as black hole mass, initial wind velocity, and number density. We find that, while useful, the ionization parameter provides an incomplete description of the overall ionization state of the outflow material. We use these findings to provide an updated method for calculating the strength of the radiative line-driving using both the X-ray spectral index Γ X and the ionization parameter. [ABSTRACT FROM AUTHOR]

We investigate the torus size–luminosity relation of Type 1 active galactic nuclei (AGNs) based on the reverberation-mapping analysis using the light curves of the optical continuum and the IR continuum obtained with the W1 and W2 bands of the Wide-field Infrared Survey Explorer survey. The final sample consists of 446 and 416 AGNs, respectively, for W1- and W2-band light curves, covering a large dynamic range of bolometric luminosity from 1043.4 to 1047.6 erg s−1, which show reliable lag measurements based on our quality assessment analysis. After correcting for the accretion disk contamination in the observed IR flux, we constrain the torus size (R dust) and AGN bolometric luminosity (L bol) relationship with the best-fit slope of 0.39 (0.33) for the W1 (W2) band, which is shallower than expected from the dust radiation equilibrium model. By combining the previous K -band lag measurements, we find that the measured torus size depends on the observed wavelength of the dust radiation, as R dust, K : R dust,W1: R dust,W2 = 1.0:1.5:1.8 (R dust ∝ λ 0.80) at L bol = 1046 erg s−1, confirming a stratified structure of the torus, where wavelength-dependent emissions originate from distinct regions of the torus. By investigating the deviation from the best-fit torus size–luminosity relation, we find a moderate correlation between the offset from the R dust– L bol relation and Eddington ratio. This suggests a possible influence of the Eddington ratio on the observed flattening of the R dust– L bol relationship. [ABSTRACT FROM AUTHOR]

We present the results of an investigation of a highly variable C iv broad absorption line (BAL) feature in spectra of the quasar SBS 1408+544 (z = 2.337) that shows a significant shift in velocity over time. This source was observed as a part of the Sloan Digital Sky Survey (SDSS) Reverberation Mapping project and the SDSS-V Black Hole Mapper Reverberation Mapping project, and has been included in two previous studies, both of which identified significant variability in a high-velocity C iv BAL on timescales of just a few days in the quasar rest frame. Using ∼130 spectra acquired over 8 yr of spectroscopic monitoring with SDSS, we have determined that this BAL is not only varying in strength, but is also systematically shifting to higher velocities. Using cross-correlation methods, we measure the velocity shifts (and corresponding acceleration) of the BAL over a wide range of timescales, measuring an overall velocity shift of Δ v = − 683 − 84 + 89 km s−1 over the 8 yr monitoring period. This corresponds to an average rest-frame acceleration of a = 1.04 − 0.13 + 0.14 cm s−2, though the magnitude of the acceleration on shorter timescales is not constant throughout. We place our measurements in the context of BAL-acceleration models and examine various possible causes of the observed velocity shift. [ABSTRACT FROM AUTHOR]

Gravitational instability in the outskirts of active galactic nuclei (AGN) disks leads to disk fragmentation and formation of ∼300 M ⊙ supermassive stars with potentially long lifetimes. Alternatively, stars can be captured ex situ and grow from gas accretion in the AGN disk. However, the number density distribution throughout the disk is limited by thermal feedback as their luminosities provide the dominant heating source. We derive equilibrium stellar surface density profiles under two limiting contexts: in the case where the stellar lifetimes are prolonged, due to the recycling of hydrogen-rich disk gas, only the fraction of gas converted into heat is removed from the disk accretion flow. Alternatively, if stellar composition recycling is inefficient and stars can evolve off the main sequence, the disk accretion rate is quenched toward smaller radii resembling a classical starburst disk, albeit the effective removal rate depends not only on the stellar lifetime, but also the mass of stellar remnants. For AGNs with central supermassive black hole masses of ∼106–108 M ⊙ accreting at ∼0.1 Eddington efficiency, we estimate a total number of 103–105 massive stars and the rate of stellar mergers to be 10−3 to 1 yr−1. We initiate the detailed study of the interaction between a swarm of massive stars through hydro and N -body simulations to provide better prescriptions of dynamical processes in AGN disks, and to constrain more accurate estimates of the stellar population. [ABSTRACT FROM AUTHOR]

The interaction between supermassive black hole (SMBH) feedback and the circumgalactic medium (CGM) continues to be an open question in galaxy evolution. In our study, we use smoothed particle hydrodynamics simulations to explore the impact of SMBH feedback on galactic metal retention and the motion of metals and gas into and through the CGM of L* galaxies. We examine 140 galaxies from the 25 Mpc cosmological volume Romulus25, with stellar masses between log(M */ M ⊙) = 9.5–11.5. We measure the fraction of metals remaining in the interstellar medium (ISM) and CGM of each galaxy and calculate the expected mass of each SMBH based on the M BH– σ relation (Kormendy & Ho 2013). The deviation of each SMBH from its expected mass, Δ M BH, is compared to the potential of its host via σ. We find that SMBHs with accreted mass above M BH– σ are more effective at removing metals from the ISM than undermassive SMBHs in star-forming galaxies. Overall, overmassive SMBHs suppress the total star formation of their host galaxies and more effectively move metals from the ISM into the CGM. However, we see little to no evacuation of gas from the CGM out of their halos, in contrast with other simulations. Finally, we predict that C iv column densities in the CGM of L* galaxies are unlikely to depend on host galaxy SMBH mass. Our results show that the scatter in the low-mass end of the M BH– σ relation may indicate how effective an SMBH is in the local redistribution of mass in its host galaxy. [ABSTRACT FROM AUTHOR]

Circumbinary accretion occurs throughout the universe, from the formation of stars and planets to the aftermath of major galactic mergers. We present an extensive investigation of circumbinary accretion disks, studying circular binaries with mass ratios (q ≡ M 2/ M 1) from 0.01 to 1 and at each mass ratio probing the effects of disk thickness and viscosity. We study disks with aspect ratios H / r ∈ {0.1, 0.05, 0.03} and vary both the magnitude and spatial dependence of viscosity. Although thin accretion disks have previously been found to promote rapid inspirals of equal-mass binaries, we find that gravitational torques become weaker at lower mass ratios and most binaries with 0.01 ≤ q ≤ 0.04 outspiral, which may delay the coalescence of black hole binaries formed from minor mergers and cause high-mass exoplanets to migrate outward. However, in a number of cases, the disks accreting onto binaries with mass ratios ∼0.07 fail to develop eccentric modes, leading to extremely rapid inspirals. Variability in black hole accretion correlates with disk eccentricity, and we observe variability above the ∼10% level even for mass ratios of 0.01. We demonstrate that the spatial dependence of the viscosity (e.g., α vs. constant ν) significantly affects the degree of preferential accretion onto the secondary, resolving discrepancies between previous studies. Colder circumbinary disks remain eccentric even at q ∼ 0.01 and sustain deep, asymmetric cavities. [ABSTRACT FROM AUTHOR]

Accretion of black holes at near-Eddington or super-Eddington rates represents the most powerful episode driving black hole growth, potentially occurring across various types of objects. However, the physics governing accretion and jet–disk coupling in such states remains unclear, primarily due to the difficulty in detecting associated jets, which may emit extremely weakly or exhibit episodic behavior. Only a few near/super-Eddington systems have demonstrated radio activity, and it remains uncertain whether jets exist and what their properties are in super-Eddington active galactic nuclei (AGNs) and ultraluminous X-ray sources. This uncertainty stems mainly from the complex radio emission mix, which includes contributions from jets, star formation activity, photoionized gas, accretion disk wind, and coronal activity. In this work, we conducted high-resolution, very long baseline interferometry observations to investigate jets in the highly accreting narrow-line Seyfert I system I Zw 1. Our observations successfully revealed small-scale jets (with a linear size of ∼45 pc) at both 1.5 and 5 GHz, based on the high radio brightness temperature, radio morphology, and spectral index distribution. Additionally, the parsec-scale jet observed in I Zw 1 displays a knotted morphology reminiscent of other sources accreting at similar rates. In summary, the high accretion rates and jet properties observed in the AGN I Zw 1 may support the AGN/X-ray binary analogy in this extreme state. [ABSTRACT FROM AUTHOR]

Continuum reverberation mapping is widely used in studying the accretion disks of active galactic nuclei (AGNs). Some indirect evidence and simulations have indicated that the diffuse continuum, especially the strong Balmer continuum from the broad-line region, may contribute to the continuum in the u / U band. Here, we present direct evidence for this contribution. In this work, we apply the ICCF-Cut method to continuum reverberation mapping to extract the possible diffuse continuum light curves of six AGNs, using high-cadence, high-quality, and multiband observations. We find the existence of an outer component out of the accretion disk for each of the six AGNs in the Swift U band. Meanwhile, similar results can be derived with the JAVELIN Photometric Reverberation Mapping Model for four of them. The lags of the outer components are consistent with the predicted Balmer continuum lags, which are about half of the H β lag values. Our result directly reinforces the understanding that an outer component, especially the Balmer continuum in the rest-frame u / U band, can contribute significantly to the continuum reverberation lags of AGNs. [ABSTRACT FROM AUTHOR]

Blazars are characterized by largely aperiodic variability on timescales ranging from minutes to decades across the electromagnetic spectrum. The Transiting Exoplanet Survey Satellite (TESS) mission provides continuous sampling of blazar variability on timescales ranging from tens of minutes to 27 days for a single sector observation. Proper removal of the background, thermal ramping, and onboard systematic effects are crucial to the extraction of a reliable blazar light curve. Multiple publicly available procedures have been created to correct for these effects. Using ground-based observations from the Zwicky Transit Facility (ZTF) and the Asteroid Terrestrial-impact Last Alert System (ATLAS) as "ground truth" observations, we compare six different methods (regression, cotrending basis vectors, pixel-level decorrelation, eleanor, quaver, and simple differential photometry) to each other, and to our "ground truth" observations, to identify which methods properly correct light curves of a sample of 11 bright blazars, including the suspected neutrino source TXS 0506+056. In addition to comparing the resulting light curves, we compare the slopes of the power spectral densities, perform least-square fitting to simultaneous ZTF data, and quantify other statistical qualities generated from the light curves of each method. We find that only three of the six methods compared (simple differential photometry, eleanor, and quaver) produce TESS light curves consistent with the ground-based ZTF and ATLAS observations. [ABSTRACT FROM AUTHOR]

The UV/optical light curves of Active Galactic Nuclei (AGNs) are commonly described by the Damped Random Walk (DRW) model. However, the physical interpretation of the damping timescale, a key parameter in the DRW model, remains unclear. Particularly, recent observations indicate a weak dependence of the damping timescale upon both wavelength and accretion rate, clearly being inconsistent with the accretion-disk theory. In this study, we investigate the damping timescale in the framework of the Corona Heated Accretion disk Reprocessing (CHAR) model, a physical model that describes AGN variability. We find that while the CHAR model can reproduce the observed power spectral densities of the 20 yr light curves for 190 sources from Stone et al., the observed damping timescale, as well as its weak dependence on wavelength, can also be well recovered through fitting the mock light curves with DRW. We further demonstrate that such weak dependence is artificial due to the effect of inadequate durations of light curves, which leads to best-fitting damping timescales lower than the intrinsic ones. After eliminating this effect, the CHAR model indeed yields a strong dependence of the intrinsic damping timescale on the bolometric luminosity and rest-frame wavelength. Our results highlight the demand for sufficiently long light curves in AGN variability studies and important applications of the CHAR model in such studies. [ABSTRACT FROM AUTHOR]

In our previous work on broadband photometric reverberation mapping (PRM), we proposed the interpolated cross-correlation function (ICCF)-Cut process to obtain the time lags of the H α emission line from two broadband lightcurves via subtracting the continuum emission from the line band. Extending the work, we enlarge our sample to the Zwicky Transient Facility (ZTF) database. We adopt two criteria to select 123 type 1 active galactic nuclei (AGNs) with sufficient variability and smooth light curves from 3537 AGNs at z < 0.09 with more than 100 epoch observations in the g and r bands from the ZTF database. We calculate the H α time lags for 23 of them that have previous spectroscopic reverberation mapping (SRM) results using the ICCF-Cut, Just Another Vehicle for Estimating Lags In Nuclei (JAVELIN), and χ 2 methods. Our obtained H α time lags are slightly larger than the H β time lags, which is consistent with the previous SRM results and the theoretical model of the AGN broad-line region. The comparisons between the SRM and PRM lag distributions and between the subtracted emission line light curves indicate that after selecting AGNs with the two criteria, combining the ICCF-Cut, JAVELIN, and χ 2 methods provides an efficient way to get the reliable H α lags from the broadband PRM. Such techniques can be used to estimate the black hole masses of a large sample of AGNs in large multiepoch photometric sky surveys such as the Legacy Survey of Space and Time and the survey from the Wide Field Survey Telescope in the near future. [ABSTRACT FROM AUTHOR]

Sub/millimeter galaxies are a key population for the study of galaxy evolution because the majority of star formation at high redshifts occurred in galaxies deeply embedded in dust. To search for this population, we have performed an extensive survey with Atacama Large Millimeter/submillimeter Array (ALMA), called the ALMA Lensing Cluster Survey (ALCS). This survey covers 133 arcmin2 area and securely detects 180 sources at z ∼ 0.5–6 with a flux limit of ∼0.2 mJy at 1.2 mm. Here, we report the results of multiwavelength spectral energy distribution analysis of the whole ALCS sample, utilizing the observed-frame UV to millimeter photometry. We find that the majority of the ALCS sources lie on the star-forming main sequence, with a smaller fraction showing intense starburst activities. The ALCS sample contains high infrared-excess sources ( IRX = log (L dust / L UV) > 1 ), including two extremely dust-obscured galaxies (IRX > 5). We also confirm that the ALCS sample probes a broader range in lower dust mass than conventional submillimeter galaxy samples in the same redshift range. We identify six heavily obscured active galactic nucleus (AGN) candidates that are not detected in the archival Chandra data in addition to the three X-ray AGNs reported by Uematsu et al. (2023). The inferred AGN luminosity density shows a possible excess at z = 2–3 compared with that determined from X-ray surveys below 10 keV. [ABSTRACT FROM AUTHOR]

Quasars are bright and unobscured active galactic nuclei (AGN) thought to be powered by the accretion of matter around supermassive black holes at the centers of galaxies. The temporal variability of a quasar's brightness contains valuable information about its physical properties. The UV/optical variability is thought to be a stochastic process, often represented as a damped random walk described by a stochastic differential equation (SDE). Upcoming wide-field telescopes such as the Rubin Observatory Legacy Survey of Space and Time (LSST) are expected to observe tens of millions of AGN in multiple filters over a ten year period, so there is a need for efficient and automated modeling techniques that can handle the large volume of data. Latent SDEs are machine learning models well suited for modeling quasar variability, as they can explicitly capture the underlying stochastic dynamics. In this work, we adapt latent SDEs to jointly reconstruct multivariate quasar light curves and infer their physical properties such as the black hole mass, inclination angle, and temperature slope. Our model is trained on realistic simulations of LSST ten year quasar light curves, and we demonstrate its ability to reconstruct quasar light curves even in the presence of long seasonal gaps and irregular sampling across different bands, outperforming a multioutput Gaussian process regression baseline. Our method has the potential to provide a deeper understanding of the physical properties of quasars and is applicable to a wide range of other multivariate time series with missing data and irregular sampling. [ABSTRACT FROM AUTHOR]

We present new JWST NIRSpec integral field spectroscopy (IFS) data for the luminous infrared galaxy NGC 7469, a nearby (70.6 Mpc) active galaxy with a Seyfert 1.5 nucleus that drives a highly ionized gas outflow and a prominent nuclear star-forming ring. Using the superb sensitivity and high spatial resolution of the JWST instrument NIRSpec IFS, we investigate the role of the Seyfert nucleus in the excitation and dynamics of the circumnuclear gas. Our analysis focuses on the [Fe ii ], H2, and hydrogen recombination lines that trace the radiation/shocked-excited molecular and ionized interstellar medium around the active galactic nucleus (AGN). We investigate gas excitation through H2/Br γ and [Fe ii ]/Pa β emission line ratios and find that photoionization by the AGN dominates within the central 300 pc of the galaxy except in a small region that shows signatures of shock-heated gas; these shock-heated regions are likely associated with a compact radio jet. In addition, the velocity field and velocity dispersion maps reveal complex gas kinematics. Rotation is the dominant feature, but we also identify noncircular motions consistent with gas inflows as traced by the velocity residuals and the spiral pattern in the Pa α velocity dispersion map. The inflow is 2 orders of magnitude higher than the AGN accretion rate. The compact nuclear radio jet has enough power to drive the highly ionized outflow. This scenario suggests that the inflow and outflow are in a self-regulating feeding–feedback process, with a contribution from the radio jet helping to drive the outflow. [ABSTRACT FROM AUTHOR]

We present multiband follow-up observations of the supermassive binary black hole (BBH) candidate and misaligned double–double radio galaxy, J1328+2752. To investigate its parsec-scale structure, we have carried out observations with the Very Long Baseline Array (VLBA) and the European Very Long Baseline Interferometry (VLBI) Network. Additionally, we have obtained optical spectroscopic observations with the 3.6 m Devasthal Optical Telescope. Within 3.5 yr of our previous VLBI observations, the central parsec-scale radio structure of J1328+2752 has changed from a double component to a single central component and its flux density has increased by a factor of 3 in the 5 GHz VLBA observations. The new radio component is largely unresolved at 3, 5, and 8 GHz. The multifrequency radio data shows a convex-shaped spectrum for this unresolved component. The turnover frequency is at ∼3 GHz. While the total intensity image does not reveal any details, a super-resolved VLBA 5 and 8 GHz spectral index image does indicate the presence of two components at a separation of ∼4.2 pc with spectral indices −0.5 ± 0.3 and −0.9 ± 0.3. We have not observed a simultaneous change in the optical line profiles or intensities over the past few years. The radio structure, the variation of the flux density, and spectral shape can potentially be consistent both with the signature of a young radio source or a BBH at the center of J1328+2752. [ABSTRACT FROM AUTHOR]

We present the first systematic search for UV signatures from radio source-driven active galactic nuclei (AGN) feedback in Compact Steep Spectrum (CSS) radio galaxies. Owing to their characteristic sub-galactic jets (1–20 kpc projected linear sizes), CSS hosts are excellent laboratories for probing galaxy scale feedback via jet-triggered star formation. The sample consists of seven powerful CSS galaxies, and two galaxies host to radio sources >20 kpc as the control, at low to intermediate redshifts (z < 0.6). Our new Hubble Space Telescope images show extended UV continuum emission in six out of seven CSS galaxies, with five CSS hosts exhibiting UV knots cospatial and aligned along the radio-jet axis. Young (≲ 10 Myr), massive (≳ 5 M ⊙) stellar populations are likely to be the dominant source of the blue excess emission in radio galaxies at these redshifts. Hence, the radio-aligned UV regions could be attributed to jet-induced starbursts. Lower near-UV star formation rates compared to other indicators suggest low scattered AGN light contribution to the observed UV. Dust attenuation of UV emission appears unlikely from high internal extinction correction estimates in most sources. Comparison with evolutionary synthesis models shows that our observations are consistent with recent (∼1−8 Myr old) star-forming activity likely triggered by current or an earlier episode of radio emission, or by a confined radio source that has frustrated growth, due to a dense environment. While follow-up spectroscopic and polarized light observations are needed to constrain the activity-related components in the observed UV, the detection of jet-induced star formation is a confirmation of an important prediction of the jet feedback paradigm. [ABSTRACT FROM AUTHOR]

We measure the bolometric luminosity of a complete and unbiased 12 μ m-selected sample of active galactic nuclei (AGN) in the local Universe. For each galaxy, we used a 10-band radio-to-X-ray spectral energy distribution (SED) to isolate the genuine AGN continuum in each band, including subarcsecond measurements where available, and correcting those contaminated by the host galaxy. We derive the median SED of Seyfert type 1 AGN, Seyferts with hidden broad lines (HBLs), Seyferts of type 2, and LINER nuclei in our sample. The median Seyfert 1 SED shows the characteristic blue bump feature in the UV, but nevertheless, the largest contribution to the bolometric luminosity comes from the IR and X-ray continua. The median SEDs of both HBL and type 2 AGN are affected by starlight contamination in the optical/UV. The median SED of HBL AGN is consistent with that of Seyfert 1s, when an extinction of A V ∼ 1.2 mag is applied. The comprehensive SEDs allowed us to measure accurate bolometric luminosities and derive robust bolometric corrections for the different tracers. The 12 μ m and K -band nuclear luminosities have good linear correlations with the bolometric luminosity, similar to those in the X-rays. We derive bolometric corrections for either continuum bands (K band, 12 μ m, 2–10 keV, and 14–195 keV) or narrow emission lines (mid-IR high-ionization lines of [O iv ] and [Ne v ] and optical [O iii ] 5007 Å) as well as for combinations of IR continuum and line emission. A combination of continuum plus line emission accurately predicts the bolometric luminosity up to quasar luminosities (∼1046 erg s−1). [ABSTRACT FROM AUTHOR]

While supermassive black holes are ubiquitous features of galactic nuclei, only a small minority are observed during episodes of luminous accretion. The physical mechanism(s) driving the onset of fueling and ignition in these active galactic nuclei (AGN) are still largely unknown for many galaxies and AGN-selection criteria. Attention has focused on AGN triggering by means of major galaxy mergers gravitationally funneling gas toward the galactic center, with evidence both for and against this scenario. However, several recent studies have found that radio-loud AGN overwhelmingly reside in ongoing or recent major galaxy mergers. In this study, we test the hypothesis that major galaxy mergers are important triggers for radio-loud AGN activity in powerful quasars during cosmic noon (1 ≲ z ≲ 2). To this end, we compare Hubble Space Telescope WFC3/IR observations of the z > 1 3CR radio-loud broad-lined quasars to three matched radio-quiet quasar control samples. We find strong evidence for major-merger activity in nearly all radio-loud AGN, in contrast to the much lower merger fraction in the radio-quiet AGN. These results suggest major galaxy mergers are key ingredients in launching powerful radio jets. Given many of our radio-loud quasars are blue, our results present a possible challenge to the "blowout" paradigm of galaxy evolution models in which blue quasars are the quiescent end result following a period of red quasar feedback initiated by a galaxy merger. Finally, we find a tight correlation between black hole mass and host galaxy luminosity for these different high-redshift AGN samples that is inconsistent with those observed for local elliptical galaxies. [ABSTRACT FROM AUTHOR]

We previously built a sample of 14,012 extremely variable quasars (EVQs) based on Sloan Digital Sky Survey (SDSS) and Pan-STARRS1 photometric observations. In this work we present the spectral fitting to their SDSS spectra and study the spectral variation in 1259 EVQs with multiepoch SDSS spectra (after prudently excluding spectra with potentially unreliable spectroscopic photometry). We find a clear "bluer-when-brighter" trend in EVQs, consistent with previous findings of normal quasars and active galactic nuclei. We detect significant intrinsic Baldwin effect (iBeff, i.e., smaller line equivalent width at higher continuum flux in individual active galactic nuclei) in the broad Mg ii and C iv lines of EVQs. Meanwhile, no systematical iBeff is found for the broad H β line, which could be attributed to strong host contamination at longer wavelengths. Remarkably, by comparing the iBeff slope of EVQs with archived changing-look quasars, we show that the changing-look quasars identified in the literature are most likely a biased (due to its definition) subpopulation of EVQs, rather than a distinct population of quasars. We also found no significant broad line breathing of H β, Mg ii, or C iv, suggesting the broad line breathing in quasars may disappear at longer timescales (∼3000 days). [ABSTRACT FROM AUTHOR]

With two central galaxies engaged in a major merger and a remarkable chain of 19 young stellar superclusters wound around them in projection, the galaxy cluster SDSS J1531+3414 (z = 0.335) offers an excellent laboratory to study the interplay between mergers, active galactic nucleus (AGN) feedback, and star formation. New Chandra X-ray imaging reveals rapidly cooling hot (T ∼ 106 K) intracluster gas, with two "wings" forming a concave density discontinuity near the edge of the cool core. LOFAR 144 MHz observations uncover diffuse radio emission strikingly aligned with the "wings," suggesting that the "wings" are actually the opening to a giant X-ray supercavity. The steep radio emission is likely an ancient relic of one of the most energetic AGN outbursts observed, with 4 pV > 1061 erg. To the north of the supercavity, GMOS detects warm (T ∼ 104 K) ionized gas that enshrouds the stellar superclusters but is redshifted up to +800 km s−1 with respect to the southern central galaxy. The Atacama Large Millimeter/submillimeter Array detects a similarly redshifted ∼1010 M ⊙ reservoir of cold (T ∼ 102 K) molecular gas, but it is offset from the young stars by ∼1–3 kpc. We propose that the multiphase gas originated from low-entropy gas entrained by the X-ray supercavity, attribute the offset between the young stars and the molecular gas to turbulent intracluster gas motions, and suggest that tidal interactions stimulated the "beads-on-a-string" star formation morphology. [ABSTRACT FROM AUTHOR]

We select a sample of 1437 active galactic nuclei (AGN) from the catalog of the Sloan Digital Sky Survey galaxy properties from the Portsmouth group by detection of the high-ionization [Ne v ] 3426 Å emission line. We compare the fluxes of [Ne III ] 3869 Å, [O III ] 5007 Å, [O II ] 3726, 3728 Å, and [O i ] 6300 Å to that of [Ne v]. All four lines show a strong linear correlation with [Ne v], although lines from ions with lower ionization potentials have a lower correlation coefficient. We investigate the use of two forbidden line ratio diagnostic diagrams that do not rely on H α in order to classify high-redshift galaxies. These use the [Ne III ]/[O II ] line ratio plotted against [O III ]/[O i ] and [O III ]/[O II ], respectively. We use photoionization modeling to characterize the behavior of the narrow-line region in AGN and star-forming regions and test the validity of our diagnostic diagrams. We also use a luminosity cutoff of log L [O III ] [erg s−1] = 42, which lowers the contamination of the AGN region by star-forming galaxies down to 10% but does not remove green pea and purple grape galaxies from the AGN region. We also investigate the OHNO diagram, which uses [Ne III ]/[O II ] plotted against [O III ]/H β. Using our new diagnostic diagrams, we are able to reliably classify AGN up to a redshift of z ≤ 1.06 and add more than 822 new AGN to the [Ne v]-selected AGN sample. [ABSTRACT FROM AUTHOR]

Close encounters between stellar-mass black holes (BHs) and stars occur frequently in dense star clusters and in the disks of active galactic nuclei. Recent studies have shown that in highly eccentric close encounters, the star can be tidally disrupted by the BH in a microtidal disruption event (microTDE), resulting in rapid mass accretion and possibly bright electromagnetic signatures. Here we consider a scenario in which the star might approach the stellar-mass BH in a gradual, nearly circular inspiral, under the influence of dynamical friction in a circum-binary gas disk or three-body interactions in a star cluster. We perform hydrodynamics simulations of this scenario using the smoothed particle hydrodynamics code PHANTOM. We find that under certain circumstances (for initial eccentricity e 0 ≳ 0.4 and penetration factor β = 1, or e 0 < 0.4 and β ≲ 0.67), the mass of the star is slowly stripped away by the BH. We call this gradual tidal disruption a "tidal-peeling event." Additionally, we discover that some low-eccentricity microTDEs (e 0 < 0.4 and β = 1) are a new form of fast luminous transients similar to parabolic microTDEs. Depending on the initial distance and eccentricity of the encounter, these low-eccentricity microTDEs might exhibit significant accretion rates and orbital evolution distinct from those of a typical (eccentric) microTDE. [ABSTRACT FROM AUTHOR]