Search

We present a composite machine learning framework to estimate posterior probability distributions of bulge-to-total light ratio, half-light radius, and flux for active galactic nucleus (AGN) host galaxies within z < 1.4 and m < 23 in the Hyper Supreme-Cam (HSC) Wide survey. We divide the data into five redshift bins: low (0 < z < 0.25), mid (0.25 < z < 0.5), high (0.5 < z < 0.9), extra (0.9 < z < 1.1), and extreme (1.1 < z < 1.4), and train our models independently in each bin. We use PSFGAN to decompose the AGN point-source light from its host galaxy, and invoke the Galaxy Morphology Posterior Estimation Network (GaMPEN) to estimate morphological parameters of the recovered host galaxy. We first trained our models on simulated data, and then fine-tuned our algorithm via transfer learning using labeled real data. To create training labels for transfer learning, we used GALFIT to fit ∼20,000 real HSC galaxies in each redshift bin. We comprehensively examined that the predicted values from our final models agree well with the GALFIT values for the vast majority of cases. Our PSFGAN + GaMPEN framework runs at least three orders of magnitude faster than traditional light-profile fitting methods, and can be easily retrained for other morphological parameters or on other data sets with diverse ranges of resolutions, seeing conditions, and signal-to-noise ratios, making it an ideal tool for analyzing AGN host galaxies from large surveys coming soon from the Rubin-LSST, Euclid, and Roman telescopes. [ABSTRACT FROM AUTHOR]

JWST is revealing a remarkable new population of high-redshift (z ≳ 4), low-luminosity active galactic nuclei in deep surveys and detecting the host galaxy's stellar light in the most luminous and massive quasars at z ∼ 6 for the first time. Recent findings claim that supermassive black holes (SMBHs) in these systems are significantly more massive than predicted by the local black hole (BH) mass–stellar mass ( M BH - M ⋆ ) relation and that this is not due to sample selection effects. Through detailed statistical modeling, we demonstrate that the coupled effects of selection biases (i.e., finite detection limit and requirements for detecting broad lines) and measurement uncertainties can largely explain the reported offset and flattening in the observed M BH - M ⋆ relation toward the upper envelope of the local relation, even for those at M BH < 1 0 8 M ⊙ . We further investigate the possible evolution of the M BH - M ⋆ relation at z ≳ 4 with careful treatment of observational biases and consideration of the degeneracy between intrinsic evolution and dispersion in this relation. The bias-corrected intrinsic M BH - M ⋆ relation in the low-mass regime ( M ⋆ ≲ 1 0 10 M ⊙ ) suggests a large population of low-mass BHs ( M BH ≲ 1 0 5 M ⊙ ), possibly originating from lighter seeds, may remain undetected or unidentified. These results underscore the importance of forward modeling observational biases to better understand BH seeding and SMBH–galaxy coevolution mechanisms in the early universe, even with the deepest JWST surveys. [ABSTRACT FROM AUTHOR]

We present a search for luminous long-duration ambiguous nuclear transients (ANTs) similar to the unprecedented discovery of the extreme ambiguous event AT2021lwx with a |$\gt 150$|  d rise time and luminosity |$10^{45.7}$|  erg s |$^{-1}$|⁠. We use the Lasair transient broker to search Zwicky Transient Facility (ZTF) data for transients lasting more than one year and exhibiting smooth declines. Our search returns 59 events, 7 of which we classify as ANTs assumed to be driven by accretion onto supermassive black holes. We propose the remaining 52 are stochastic variability from regular supermassive black hole accretion rather than distinct transients. We supplement the seven ANTs with three nuclear transients in ZTF that fail the light curve selection but have clear single flares and spectra that do not resemble typical active galactic nucleus. All of these 11 ANTs have a mid-infrared flare from an assumed dust echo, implying the ubiquity of dust around the black holes giving rise to ANTs. No events are more luminous than AT2021lwx, but one (ZTF19aamrjar) has twice the duration and a higher integrated energy release. On the other extreme, ZTF20abodaps reaches a luminosity close to AT2021lwx with a rise time |$\lt 20$|  d and that fades smoothly in |$\gt 600$|  d. We define a portion of rise-time versus flare amplitude space that selects ANTs with |$\sim 50$|  per cent purity against variable AGNs. We calculate a volumetric rate of |$\gtrsim 3\times 10^{-11}$|  Mpc |$^{-1}$|  yr |$^{-1}$|⁠ , consistent with the events being caused by tidal disruptions of intermediate and high-mass stars. [ABSTRACT FROM AUTHOR]

The torus in active galactic nuclei (AGNs) is a complex dynamical structure of gas and dust. It is thought to be composed of an equatorial dusty disc and a polar dusty wind launched by radiation pressure. However, this picture is based on studies of moderately accreting AGN. Models suggest that the disc/wind structure will change with specific accretion rate. Here we examine the wind launching region in two high accretion rate objects, I Zw 1 (super-Eddington) and H0557-385 (high-Eddington), using high spatial resolution interferometric observations in the K -band from VLTI/GRAVITY and |$LM$| bands from VLTI/MATISSE. We recover wavelength-dependent sizes of the dust emission using a Gaussian and power-law fit to the visibilities. Both objects are partially resolved and have radial sizes in the |$KLM$| bands between 0.3 and 1.5 mas, with no signs of elongation. Combining our measurements with VLTI/MIDI N -band data gives a full multiwavelength picture of the dust structure. We find that in H0557-385, the dust sizes between 3.5 and 8  |$\mu\rm m$| are independent of the wavelength, roughly constant at |$3-10$| sublimation radii. We argue that this indicates a direct view of the wind launching region and, together with an absence of polar elongation, this implies that any wind would be launched in a preferentially equatorial direction or blown out by strong radiation pressure. The size–wavelength relation for both objects shows a preferentially discy equatorial dust distribution. We conclude that there is strong evidence that the Eddington ratio shapes the inner dust structure, most notably the wind-launching region and wind direction. [ABSTRACT FROM AUTHOR]

Recent studies have found a striking positive correlation between the amount of dust obscuration and enhanced radio emission in quasi-stellar objects (QSOs). However, what causes this connection remains unclear. In this paper we analyse uGMRT Band-3 (400 MHz) and Band-4 (650 MHz) data of a sample of 38 1.0  <   z   <  1.5 QSOs with existing high-resolution |$0{_{.}^{\prime\prime}} 2$| e-MERLIN 1.4 GHz imaging. In combination with archival radio data, we have constructed sensitive 4–5 band radio spectral energy distributions (SEDs) across 0.144–3 GHz to further characterize the radio emission in dusty QSOs. We find that the dusty QSOs [those with |$E(B-V)$|   >  0.1 mag] are more likely to exhibit steep spectral slopes (⁠|$\alpha$|   <   |$-0.5$|⁠ ; S   |$\propto$|   |$\nu ^{\alpha }$|⁠) than the non-dusty QSOs [ |$E(B-V)$|   <  0.1 mag], with fractions of 46 |$\pm$| 12 and 12 |$\pm$| 4 per cent, respectively. A higher fraction of the non-dusty QSOs have peaked radio SEDs (48 |$\pm$| 9 per cent) compared to the dusty QSOs (23 |$\pm$| 8 per cent). We discuss the origin of the radio emission, finding that the majority of the peaked, predominantly non-dusty, QSOs have consistent sizes and luminosities with compact jetted radio galaxies. However, the connection between steepness and dust obscuration implies an outflow-driven shock origin for the enhanced radio more commonly found in dusty QSOs. These results add to the emerging picture whereby dusty QSOs are in an earlier blow-out phase, with shocks that heat and destroy the surrounding dust, eventually revealing a typical non-dusty QSO. [ABSTRACT FROM AUTHOR]

We search for reflection-dominated Compton-thick active galactic nuclei (CT AGN) candidates in the Lockman Hole (LH) region using the data of SRG/eROSITA LH survey. We selected sources with anomalously hard photon indices in the 0.3–8.0 keV band, untypical for Type I AGN. In particular, we required that the upper end of the 90 per cent error interval did not exceed a fiducial boundary of |$\Gamma =1.3$|⁠. We found 291 sources which constitute a rare sub-population among extragalactic X-ray sources detected by eROSITA in the LH field, |$\approx 5~{{\ \rm per\ cent}}$|⁠. These sources constitute the eROSITA sample of CT AGN candidates in the LH field. We further divide the sources into three categories depending on the availability of reliable redshift and statistically significant detection of intrinsic absorption. We present two catalogues: the bright sample (37 sources) and the faint one (254). We estimate the fraction and sky density of reflection-dominated CT AGN candidates. We show examples of individual spectra and use stacking analysis to search for possible redshift evolution of their properties with redshift. We analyse combined eROSITA spectra of bright sources of different categories with a physically motivated spectral model UXCLUMPY and find them fully consistent with the fits to the |$\sim 1$|  Ms XMM–Newton data for one of our reflection-dominated CT candidates, Type 2 galaxy SRGe J105348.6+573032. The catalogues of CT AGN candidates could be a good starting point for planning future studies and follow-ups at all wavelengths. [ABSTRACT FROM AUTHOR]

We introduce a novel galaxy classification methodology based on the visible spectra of a sample of over 68 000 nearby (⁠|$z\le 0.1$|⁠) Sloan Digital Sky Survey lenticular (S0) galaxies. Unlike traditional diagnostic diagrams, which rely on a limited set of emission lines and class dividers to identify ionizing sources, our approach provides a comprehensive framework for characterizing galaxies regardless of their activity level. By projecting galaxies into the 2D latent space defined by the first three principal components (PCs) of their entire visible spectra, our method remains robust even when data from individual emission lines are missing. We employ Gaussian kernel density estimates of the classical Baldwin–Phillips–Terlevich (BPT) activity classes in the new classification subspace, adjusted according to their relative abundance in our S0 sample, to generate probability maps for star-forming, Seyfert, composite, and low-ionization nuclear emission-line region (LINER) galaxies. These maps closely mirror the canonical distribution of BPT classes shown by the entire galaxy population, demonstrating that our PC-based taxonomy effectively predicts the dominant ionizing mechanisms through a probabilistic approach that provides a realistic reflection of galaxy activity and allows for refined class membership. Our analysis further reveals that flux-limited BPT-like diagrams are inherently biased against composite and star-forming galaxies due to their weaker [O  iii ] emission. Besides, it suggests that although most low-activity galaxies excluded from these diagnostics exhibit visual spectra with LINER-like characteristics, their remaining activity is likely driven by mechanisms unrelated to either star formation or supermassive black hole accretion. A machine-readable catalogue listing BPT-class probabilities for the galaxies analysed is publicly released with this article. [ABSTRACT FROM AUTHOR]

We used a supervised machine learning algorithm (probabilistic random forest) to classify |$\sim$| 130 million sources in the VISTA Survey of the Magellanic Clouds (VMC). We used multiwavelength photometry from optical to far-infrared as features to be trained on, and spectra of active galactic nuclei (AGNs), galaxies and a range of stellar classes including from new observations with the Southern African Large Telescope (SALT) and South African Astronomical Observatory (SAAO) 1.9-m telescope. We also retain a label for sources that remain unknown. This yielded average classifier accuracies of |$\sim$| 79 per cent [Small Magellanic Cloud (SMC)] and |$\sim$| 87 per cent [Large Magellanic Cloud (LMC)]. Restricting to the 56 696 719 sources with class probabilities (P |$_{\rm class}$|⁠) > 80 per cent yields accuracies of |$\sim$| 90 per cent (SMC) and |$\sim$| 98 per cent (LMC). After removing sources classed as 'Unknown', we classify a total of 707 939 (SMC) and 397 899 (LMC) sources, including > 77 600 extragalactic sources behind the Magellanic Clouds. The extragalactic sources are distributed evenly across the field, whereas the Magellanic sources concentrate at the centres of the Clouds, and both concentrate in optical/IR colour–colour/magnitude diagrams as expected. We also test these classifications using independent data sets, finding that, as expected, the majority of X-ray sources are classified as AGN (554/883) and the majority of radio sources are classed as AGN (1756/2694) or galaxies (659/2694), where the relative AGN–galaxy proportions vary substantially with radio flux density. We have found > 49 500 hitherto unknown AGN candidates, likely including more AGN dust dominated sources which are in a critical phase of their evolution; > 26 500 new galaxy candidates and > 2800 new young stellar object (YSO) candidates. [ABSTRACT FROM AUTHOR]

Whether the mass of supermassive black hole (⁠|$M_\mathrm{BH}$|⁠) is directly linked to the quasar radio luminosity remains a long-debated issue, and understanding the role of |$M_\mathrm{BH}$| in the evolution of quasars is pivotal to unveiling the mechanism of active galactic nucleus (AGN) feedback. In this work, based on a two-component Bayesian model, we examine how |$M_\mathrm{BH}$| affects the radio emission from quasars, separating the contributions from host galaxy star formation (SF) and AGN activity. By modelling the radio flux density distribution of Sloan Digital Sky Survey quasars from the LOFAR Two-metre Sky Survey Data Release 2, we find no correlation between |$M_\mathrm{BH}$| and star formation rate (SFR) at any mass for quasars at a given redshift and bolometric luminosity. The same holds for AGN activity across most |$M_\mathrm{BH}$| values; however, quasars with the top 20 per cent most massive supermassive black holes (SMBHs) are two to three times more likely to host strong radio jets than those with lower mass SMBHs at similar redshift and luminosity. We suggest defining radio quasar populations by their AGN and SF contributions instead of radio loudness; our new definition unifies previously divergent observational results on the role of |$M_\mathrm{BH}$| in quasar radio emissions. We further demonstrate that this radio enhancement in quasars with the 20 per cent most massive SMBHs affects only the |$\sim 5~{{\rm per\ cent}}$| most radio bright quasars at a given redshift and bolometric luminosity. We discuss possible physical origins of this radio excess in the most massive and radio-bright quasar population, which remains an interest for future study. [ABSTRACT FROM AUTHOR]

We present 6 GHz e -MERLIN observations of 42 |$z\lt 0.2$| type 1 and type 2 mostly radio-quiet quasars (⁠|$L_{\rm [O\,{\small III}]}\gtrsim 10^{42}$|  erg s |$^{-1}$|⁠ ; |$L_{\rm AGN}\gtrsim 10^{45}$|  erg s |$^{-1}$|⁠) from the Quasar Feedback Survey. The nature and origin of radio emission in these types of sources is typically ambiguous based on all-sky, low-resolution surveys. With e -MERLIN, we investigate radio emission on sub-kiloparsec scales (⁠|$\sim$| 10s–100s pc). We find 37/42 quasars are detected, with a diversity of radio morphologies, including compact cores, knots, and extended jet-like structures, with sizes of 30–540 pc. Based on morphology and brightness temperature, we classify 76 per cent of the quasars as radio-AGN, compared to the |$\sim$| 57 per cent identified as radio-AGN at the |$\sim$| 1–60 kpc scales probed in prior studies. Combining results from e -MERLIN and the Very Large Array, 86 per cent reveal a radio-AGN. On average, |$\sim$| 60 per cent of the total radio flux is resolved away in the e -MERLIN maps, and is likely dominated by jet-driven lobes and outflow-driven shocks. We find no significant differences in measured radio properties between type 1 and type 2 quasars, and estimate sub-relativistic jet speeds of |$\sim$| 0.2–0.3c and modest jet powers of |$P_\mathrm{jet} \approx \times 10^{43}$|  erg s |$^{-1}$| for the few targets, where these measurements were possible. These quasars share characteristics with compact radio-selected populations, and the global radio emission likely traces strong interactions between the AGN (jets/outflows) and their host galaxy ISM from 10s parsec to 10s kiloparsec scales. [ABSTRACT FROM AUTHOR]

Variable |$\gamma$| -ray flares up to minute time-scales reflect extreme particle acceleration sites. However, for high-redshift blazars, the detection of such rapid variations remains limited by current telescope sensitivities. Gravitationally lensed blazars serve as powerful tools to probe |$\gamma$| -ray production zones in distant sources, with time delays between lensed signals providing crucial insights into the spatial distribution of emission regions relative to the lens's mass-weighted centre. We have utilized 15 yr of Fermi– LAT |$\gamma$| -ray data from direction of PKS 1830–211 to understand the origin of flaring high-energy production zone at varying flux states. To efficiently estimate the (lensed) time delay, we used a machine learning-based tool – the Gaussian Process regression algorithm, in addition to – Autocorrelation function and Double power spectrum. We found a consistent time delay across all flaring activity states, indicating a similar location for the |$\gamma$| -ray emission zone, possibly within the radio core. The estimated time delay of approximately 20 d for the five flaring epochs was significantly shorter than previously estimated radio delays. This suggests that the |$\gamma$| -ray emission zone is closer to the central engine, in contrast to the radio emission zone, which is expected to be much farther away. A linear relationship between lag and magnification has been observed in the identified source and echo flares. Our results suggest that the |$\gamma$| -ray emission zone originates from similar regions away from the site of radio dissipation. [ABSTRACT FROM AUTHOR]

The energy coupling efficiency of active galactic nucleus (AGN) outbursts is known to vary significantly with factors including the jet kinetic power, duration of the outburst, and properties of the host galaxy group or cluster. As such, constraints on their jet power and lifetime functions are crucial to quantify the role of kinetic-mode AGN feedback on the evolution of galaxies since |$z \sim 1$|⁠. In this work, we address this issue by measuring the energetics of a sample of 79 low-redshift (0.02 |$\lt z \lt $| 0.2) remnant radio galaxies compiled from large-sky radio surveys – remnants uniquely probe the full duration of an AGN outburst. The jet kinetic power and outburst duration of each remnant are determined using the raise dynamical model based on the surface brightness distribution observed in multifrequency radio images. We compare the energetics constrained for this sample to those predicted for mock radio source populations – with various intrinsic functions for jet power and lifetime distributions – to correct for sample selection biases imposed on our sample. The intrinsic jet power and lifetime functions that yield a selection-biased mock population most similar to our observed sample are determined using Bayesian inference. Our analysis places robust constraints on assumed power-law indices for the intrinsic jet power and lifetime functions: |$p(Q)\propto Q^{-1.49\pm 0.07}$| and |$p(t_{\mathrm{on}})\propto t_{\mathrm{on}}^{-0.97\pm 0.12}$|⁠ , respectively. We discuss the implications of these findings for feedback-regulated accretion and the self-regulating nature of jet activity. The methodology proposed in this work can be extended to active radio galaxies in future studies. [ABSTRACT FROM AUTHOR]

It is generally thought that active galactic nucleus (AGN) optical variability is produced, at least in part, by reprocessing of central X-rays by a surrounding accretion disc, resulting in wavelength-dependent lags between bands. Any good model of AGN optical variability should explain not only these lags, but also the overall pattern of variability as quantified by the power spectral density (PSD). Here, we present |$\sim$| daily g ′-band monitoring of the low-mass AGN NGC 4395 over 3 yr. Together with previous Transiting Exoplanet Survey Satellite (TESS) and Gran Telescopio Canarias (GTC)/HiPERCAM observations, we produce an optical PSD covering an unprecedented frequency range of ∼seven decades allowing excellent determination of PSD parameters. The PSD is well fitted by a bending power law with low-frequency slope |$\alpha _{L} = 1.0 \pm 0.2$|⁠ , high-frequency slope |$2.1^{+0.2}_{-0.4}$|⁠ , and bend time-scale |$3.0^{+6.6}_{-1.7}\,$|  d. This time-scale is close to that derived previously from a damped random walk (DRW) model fitted to just the TESS observations, although |$\alpha _{L}$| is too steep to be consistent with a DRW. We compare the observed PSD with one made from light curves synthesized assuming reprocessing of X-rays, as observed by XMM–Newton and Swift , in a disc defined by the observed lags. The simulated PSD is also well described by a bending power law but with a bend two decades higher in frequency. We conclude that the large-amplitude optical variations seen on long time-scales are not due to disc reprocessing but require a second source of variability whose origin is unknown but could be propagating disc accretion rate variations. [ABSTRACT FROM AUTHOR]

Compact Symmetric Objects (CSOs) are a distinct category of jetted active galactic nuclei whose high-energy emission is not well understood. We examined the X-ray characteristics of 17 bona fide CSOs using observations from Chandra, XMM – Newton , and NuSTAR. Among the sources with XMM – Newton observations, we found two sources, J0713+4349 and J1326+3154 to show clear evidence of variations in the soft (0.3–2 keV), the hard (2–10 keV), and the total energy (0.3–10 keV) bands with the normalized excess variance (F |$_{\mathrm{ var}}$|⁠) as large as 1.17 |$\pm$| 0.27. Also, the F |$_{\mathrm{ var}}$| is found to be larger in the hard band relative to the soft band for J1326+3154. From the analysis of the hardness ratio (HR) with count rate, we found both sources to show a harder when brighter (HWB) trend. Similarly, in the Chandra observations, we found one source, J0131+5545, to show flux variations in the total energy band (0.5–7 keV). We discuss possible reasons for about 82 per cent of the CSOs being non-variable. From spectral analysis, carried out in a homogeneous manner, we found the existence of obscured as well as unobscured CSOs. Three CSOs, J0111+3906, J1407+2827, and J2022+6136, were found to have the intrinsic neutral hydrogen column density N |$_{\rm H,z} \gt 10^{23}$|  cm |$^{-2}$|⁠ , consistent with earlier analyses. For the majority of the CSOs, the observed hard X-ray emission is expected to be dominated by their mildly relativistic jet emission. For the sources, J0713+4349, J1347+1217, J1407+2827, J1511+0518, and J2022+6136, the confirmed detection of Fe K  |$\alpha$| emission line suggests a significant contribution from the disc/corona. Our results point to diverse X-ray characteristics of CSOs. [ABSTRACT FROM AUTHOR]

In this study we report the spatially resolved, wideband spectral properties of three giant radio galaxies (GRGs) in the COSMOS field: MGTC J095959.63+024608.6, MGTC J100016.84+015133.0, and MGTC J100022.85+031520.4. One of these galaxies, MGTC J100022.85+031520.4, is reported here for the first time, with a projected linear size of 1.29 Mpc at a redshift of 0.1034. Unlike the other two, it is associated with a brightest cluster galaxy (BCG), making it one of the few GRGs known to inhabit cluster environments. We examine the spectral age distributions of the three GRGs using new MeerKAT UHF-band (544–1088 MHz) observations, and L -band (900–1670 MHz) data from the MeerKAT International GHz Tiered Extragalactic Exploration (MIGHTEE) survey. We test two models of spectral ageing, the Jaffe–Perola and Tribble models, using the Broadband Radio Astronomy Tools (brats) software, and find that they agree well with each other. We estimate the Tribble spectral age for MGTC J095959.63+024608.6 as 68 Myr, for MGTC J100016.84+015133.0 as 47 Myr, and for MGTC J100022.85+031520.4 as 67 Myr. We find significant disagreements between these spectral age estimates and the estimates of the dynamical ages of these GRGs, modelled in cluster and group environments. Our results highlight the need for additional processes that are not accounted for in either the dynamic age or the spectral age estimations. [ABSTRACT FROM AUTHOR]

The radio source J0028+0035 is a recently discovered double–double radio galaxy at redshift z = 0.398 . Its relic outer lobes are separated by about 3 ′ in the sky, corresponding to ∼1 Mpc projected linear size. Inside this large-scale structure, the inner pair of collinear lobes span about 100 kpc. In the arcsec-resolution radio images of J0028+0035, there is a central radio feature that offers the intriguing possibility of being resolved into a pc-scale, third pair of innermost lobes. This would make this radio galaxy a rare triple–double source where traces of three distinct episodes of radio activity could be observed. To reveal the compact radio structure of the central component, we conducted observation with the European Very Long Baseline Interferometer Network and the enhanced Multi Element Remotely Linked Interferometer Network. Our 1.66 GHz image with high (∼5 milliarcsec) resolution shows a compact central radio core with no indication of a third, innermost double feature. The observation performed in multi-phase-centre mode also revealed that the physically unrelated but in projection closely separated background source 5BZU J0028+0035 has a single weak, somewhat resolved radio feature, at odds with its blazar classification. [ABSTRACT FROM AUTHOR]

The extremely luminous infrared galaxy (ELIRG), WISE J090924.01 |$+$| 000211.1 (hereafter WISE J0909 |$+$| 0002, |$z=1.87$|⁠) is an extraordinary object with a quasar aspect. This study performed monitoring observations of WISE J0909 |$+$| 0002 with the 105 |$\:$| cm Murikabushi telescope, Okayama and Akeno 50 |$\:$| cm telescopes/MITSuME (⁠|$g^{\,\prime}$|⁠ , |$R_{\rm c}$|⁠ , and |$I_{\rm c}$| bands), and the SaCRA 55 |$\:$| cm telescope/MuSaSHI (r, i , and z bands) for three years. We obtain the following results by combining the UV/optical light curves of the CRTS, Pan-STARRS, and ZTF archive data, and our observational data: (1) the light curves of WISE J0909 |$+$| 0002 present quasi-periodic (sinusoidal) oscillations with the rest-frame period of |$\sim \!660$| – |$689\:$| d; (2) the structure functions of WISE J0909 |$+$| 0002 do not show a damped random walk (DRW) trend; (3) the mock DRW light curves present periodic-like trend on rare occasions in 10000 simulations; (4) the relativistic boost scenario is favored, since the relation between variability amplitude and power-law slope ratio is consistent with the theoretical prediction of this scenario, and a substantial parameter space exists between the inclination angles and the black hole mass; (5) the circumbinary disk model is insufficient to explain the spectral energy distribution of our target; (6) the significant radio flux density of WISE J0909+0002 is not detected from the VLA FIRST Survey, thus the radio jet precession scenario is ruled out. The Doppler boost scenario is, from our results, likely as a cause of the periodic variability; consequently the quasi-periodic oscillations in WISE J0909 |$+$| 0002 is possibly interpreted by a supermassive black hole binary. Additional observations to investigate the continuity of the periodic trend would bring new insights into mechanisms of the quasi-periodic oscillations and/or ELIRGs. [ABSTRACT FROM AUTHOR]

We report the highest-redshift detection of [O  i ] 63  |$\mu$| m from a luminous quasar, J2054 |$-$| 0005, at |$z=6.04$| based on the Atacama Large Millimeter/sub-millimeter Array (ALMA) Band 9 observations. The [O  i ] 63  |$\mu$| m line luminosity is |$(4.5\pm 1.5) \times 10^{9} L_{\odot }$|⁠ , corresponding to the [O  i ] 63  |$\mu$| m-to-far-infrared luminosity ratio of |$\approx$| 6.7 |$\times 10^{-4}$|⁠ , which is consistent with the value obtained in the local Universe. Remarkably, [O  i ] 63  |$\mu$| m is as bright as [C  ii ] 158  |$\mu$| m, resulting in the [O  i ]-to-[C  ii ] line luminosity ratio of |$1.3\pm 0.5$|⁠. Based on a careful comparison of the luminosity ratios of [O  i ] 63  |$\mu$| m, [C  ii ] 158  |$\mu$| m, and dust continuum emission to models of photodissociation regions, we find that J2054 |$-$| 0005 has a gas density |$\log (n_{\rm H}/{\rm cm}^{-3}) = 3.7\pm 0.3$| and an incident far-ultraviolet radiation field of |$\log (G/G_{\rm 0}) = 3.0\pm 0.1$|⁠ , showing that [O  i ] 63  |$\mu$| m serves as an important coolant of the dense and warm gas in J2054 |$-$| 0005. A close examination of the [O  i ] and [C  ii ] line profiles suggests that the [O  i ] line may be partially self-absorbed; however, deeper observations are needed to verify this conclusion. Regardless, the gas density and incident radiation field are in broad agreement with the values obtained in nearby star-forming galaxies and objects with [O  i ] 63  |$\mu$| m observations at |$z=1$| –3 with the Herschel Space Observatory. These results demonstrate the power of ALMA high-frequency observations targeting [O  i ] 63  |$\mu$| m to examine the properties of photodissociation regions in high-redshift galaxies. [ABSTRACT FROM AUTHOR]

The Six-degree Field Galaxy Survey (6dFGS) is a spectroscopic redshift survey of the Southern hemisphere completed in 2006. While it provides 136 304 spectra of mostly low-redshift galaxies, a large and reliable catalogue of active galactic nuclei (AGNs) that are selected based on spectral signatures is still lacking. In this work, we present an extensive list of verified broad emission-line AGNs in the 6dFGS sample. We visually confirm the AGN nature of all spectra, and disentangle fibre cross-talk to remove bogus AGNs. The final catalogue contains 2513 unique broad-line AGNs with a median redshift of 0.207, of which 891 are identified for the first time. A flux-limited subsample contains 665 AGNs to a K -band magnitude of 13. This new sample adds to the list of known low-luminosity AGNs in the Southern hemisphere and thus provides a basis for investigations of low-redshift AGNs with the upcoming Vera C. Rubin Observatory. [ABSTRACT FROM AUTHOR]

Active galactic nuclei (AGNs) feedback from supermassive black holes (SMBHs) at the centres of galaxy clusters plays a key role in regulating star formation and shaping the intracluster medium, often manifesting through prominent X-ray cavities embedded in the cluster's hot atmosphere. Here we show that X-ray cavities arise naturally due to AGN feedback in TNG-Cluster. This is a new suite of magnetohydrodynamic cosmological simulations of galaxy formation and evolution, and hence of galaxy clusters, whereby cold dark matter, baryon dynamics, galactic astrophysics, and magnetic fields are evolved together consistently. We construct mock Chandra X-ray observations of the central regions of the 352 simulated clusters at z = 0 and find that |$\sim$| 39 per cent contain X-ray cavities. Identified X-ray cavities vary in configuration with some still attached to their SMBH, while others have buoyantly risen. Their size ranges from a few to several tens of kpc. TNG-Cluster X-ray cavities are underdense compared to the surrounding halo and filled with hot gas (⁠|$\sim 10^8$|  K); 25 per cent of them are surrounded by an X-ray bright and compressed rim associated with a weak shock (Mach number |$\sim$| 1.5). Clusters exhibiting X-ray cavities are preferentially strong or weak cool-cores, are dynamically relaxed, and host SMBHs accreting at low Eddington rates. We show that TNG-Cluster X-ray cavities originate from episodic, wind-like energy injections from central AGN. Our results illustrate the existence and diversity of X-ray cavities simulated in state-of-the-art models within realistic cosmological environments and show that these can form without necessarily invoking bipolar, collimated, or relativistic jets. [ABSTRACT FROM AUTHOR]

Radio galaxies can extend far beyond the stellar component of their originating host galaxies, and their radio emission can consist of multiple discrete components. Furthermore, the apparent source structure will depend on survey sensitivity, resolution and the observing frequency. Associated discrete radio components and their originating host galaxy are typically identified through a visual comparison of radio and mid-infrared survey images. We present the first data release of Radio Galaxy Zoo, an online citizen science project that enlists the help of citizen scientists to cross-match extended radio sources from the Faint Images of the Radio Sky at Twenty Centimeters (FIRST) and the Australia Telescope Large Area Survey (ATLAS) surveys, often with complex structure, to host galaxies in 3.6  |$\mu$| m infrared images from the Wide-field Infrared Survey Explorer (WISE) and the SpitzerSpace Telescope. This first data release consists of 100 185 classifications for 99 146 radio sources from the FIRST survey and 583 radio sources from the ATLAS survey. We include two tables for each of the FIRST and ATLAS surveys: (1) the identification of all components making up each radio source and (2) the cross-matched host galaxies. These classifications have an average reliability of 0.83 based on the weighted consensus levels of our citizen scientists. The reliability of the DR1 catalogue has been further demonstrated through several parallel studies which used the pre-release versions of this catalogue to train and prototype machine learning-based classifiers. We also include a brief description of the radio source populations catalogued by RGZ DR1. [ABSTRACT FROM AUTHOR]

We report the analysis of ∼1 Ms of XMM-Newton observations of the rapidly accreting active galactic nucleus RE J1034+396. The 0.3–9 keV EPIC-pn spectra are well described by a model consisting of steep continuum emission from the corona accompanied by relativistically blurred reflection from a highly ionized accretion disk. The source is known to exhibit strong excess soft X-ray emission, which we show is well represented by thermal disk photons Comptonized by a warm plasma spanning the inner accretion flow. Additionally, the EPIC-pn data provide compelling evidence (Δ C ∼ 60 for four additional parameters) for the presence of an ultrafast outflow (UFO) with a line-of-sight velocity v / c = 0.30 7 − 0.005 + 0.001 , and an emission signature consistent with reflection of the corona from modestly ionized, outflowing gas. The simultaneous 0.5–2.5 keV RGS spectra show clear absorption lines. Modelling of these data confirms the presence of the UFO and constrains its equivalent hydrogen column density, log N H/(atom cm−2) = 21.7 − 0.2 + 0.1 . The RGS data also reveal at least two warm absorber components with a modest outflow velocity ( 168 0 − 50 + 40 km s−1). The measured properties and time evolution of the UFO in RE J1034+396 suggest that it is formed from collisionally ionized plasma, launched from the disk surface and accelerated by radiation pressure. The high terminal velocity and substantial absorbing column density imply that the outflow carries sufficient momentum and energy to transform its environment, being capable of driving out essentially all dust and gas it interacts with along the line of sight, even if the AGN were initially surrounded by a Compton-thick absorber. [ABSTRACT FROM AUTHOR]

The high angular resolution and sensitivity of Very Long Baseline Interferometry (VLBI) offer a unique tool to identify and study active galactic nuclei and star-formation activity over cosmic time. However, despite recent technical advances, such as multiple phase centre correlation, VLBI surveys have thus far been limited to either a few well-studied deep-fields or wide-areas to a relatively shallow depth. To enter the era of extensive statistical studies at high angular resolution, a significantly larger area of the sky must be observed to much better sensitivity with VLBI. The Synoptic Wide-field EVN– e -MERLIN Public Survey (SWEEPS) is a proposed commensal observing mode for the EVN and e -MERLIN, where single-target principle investigator-led observations are re-correlated at the position of known radio sources within 12 arcmin of the pointing centre. Here, we demonstrate a proof-of-concept of this methodology by detecting a 5.6 mJy core-jet object at 1.7 GHz that would have otherwise been lost from the parent data set. This is the first object to be recovered as part of the SWEEPS pilot programme, which highlights the potential for increasing sample sizes of VLBI-detected radio sources with commensal observing modes in the near future. [ABSTRACT FROM AUTHOR]

The primary formation channel for the stellar-mass Binary Black Holes which have been detected merging by the LIGO–Virgo–KAGRA (LVK) collaboration is yet to be discerned. One of the main reason is that the detection of an Electromagnetic counterpart to such Gravitational Wave (GW) events, which could signpost their formation site, has so far been elusive. Recently, 20 Active Galactic Nuclei flaring activities detected by the Zwicky Transient Facility have been investigated as potential counterparts of GW events by Graham et al. We present the results of a spatial correlation analysis that involves such events and uses the up-to-date posterior samples of 78 mergers, detected during the third observing run of the LVK collaboration. We apply a likelihood method which takes into account the exact position of the flares within the 3D sky map of the GW events. We place an upper limit of 0.155 at a 90 per cent credibility level on the fraction of the detected coalescences that are physically related to an observed flare, whose posterior probability distribution peaks at a null value. Finally, we show that the typically larger values of the masses of the GW-events, which host at least one flare in their localization volume, are also consistent with the no-connection hypothesis. This is because of a positive correlation between binary masses and the size of the localization uncertainties. [ABSTRACT FROM AUTHOR]

We investigate the kinematical and dynamical properties of cluster galaxy populations classified according to their dominant source of gas ionization, namely: star-forming (SF) galaxies, optical active galactic nuclei (AGNs), mixed SF plus AGN ionization (transition objects, T), and quiescent (Q) galaxies. We stack 8892 member galaxies from 336 relaxed galaxy clusters to build an ensemble cluster and estimate the observed projected profiles of numerical density and velocity dispersion, |$\sigma _P(R)$|⁠ , of each galaxy population. The MAMPOSSt code and the Jeans equations inversion technique are used to constrain the velocity anisotropy profiles of the galaxy populations in both parametric and non-parametric ways. We find that Q (SF) galaxies display the lowest (highest) typical cluster-centric distances and velocity dispersion values. Transition galaxies are more concentrated and tend to exhibit lower velocity dispersion values than SF galaxies. Galaxies that host an optical AGN are as concentrated as Q galaxies but display velocity dispersion values similar to those of the SF population. MAMPOSSt is able to find equilibrium solutions that successfully recover the observed |$\sigma _P(R)$| profile only for the Q, T, and AGN populations. We find that the orbits of all populations are consistent with isotropy in the inner regions, becoming increasingly radial with the distance from the cluster centre. These results suggest that Q galaxies are in equilibrium within their clusters, while SF galaxies have more recently arrived in the cluster environment. Finally, the T and AGN populations appear to be in an intermediate dynamical state between those of the SF and Q populations. [ABSTRACT FROM AUTHOR]

We develop a simple method to search for changing-look (CL) active galactic nucleus (AGN) candidates, and conduct a test run. In this method, optical variations of AGNs are monitored and CL-AGNs may appear to have a pattern of being bluer when in brightening flare-like events. Applying this method, previously classified type 2 AGNs that show the bluer-when-brighter (BWB) pattern are selected. Among more than ten thousands type 2 AGNs classified in the Sloan Digital Sky Survey (SDSS), we find 73 candidates with possibly the strongest BWB pattern. We note that 13 of them have previously been reported as CL-AGNs. We have observed nine candidates, and found that five among them showed the CL transition from type 2 to type 1. In addition, we also test extending the selection to previously classified type 1 AGNs in the SDSS by finding sources with a possible redder-when-brighter pattern, but none of the three sources observed by us is found to show the transition from type 1 to type 2. We discuss the variation properties in both the success and failure cases, and plan to observe more candidates selected with the method. From the observational results, a detailed comparison between the CL-AGNs and none CL-AGNs will help quantitatively refine the selection criteria and in turn allow us to configure the general properties of CLAGNs. [ABSTRACT FROM AUTHOR]

In this work, we use gas phase metallicities calculated from the Sloan Digital Sky Survey (SDSS) Mapping Nearby Galaxies at Apache Point (MaNGA) Data Release 17 (DR17) to assess the extent of potential biases in spaxels which are spatially adjacent to spaxels identified as non-star forming (non-SF) on a BPT diagram. We identify a sample of |$\sim 21\,000$| such spaxels with calculable metallicities from the full metallicity catalogue (⁠|$\sim$| 1.57 million), representing a small fraction (⁠|$\sim 1.3$|  per cent) of the full metallicity sample. |$\sim$| 23 per cent of all galaxies with at least one spaxel with a calculable metallicity also contain at least one spaxel with a calculated metallicity adjacent to a non-SF spaxel, with a typical galaxy hosting 9 non-SF-adjacent spaxels. From our suite of 6 different metallicity calibrations, we find that only the metallicity calibrations based entirely on the [N  ii ] |$_{6584}$| /H  |$\alpha$| ratio are affected, showing systematic offsets to higher metallicities by up to |$\sim$| 0.04 dex if they are located adjacent to a non-SF flagged spaxel, relative to a radially matched control sample. The inclusion of additional diagnostic diagrams (based on [O  i ] |$_{6300}$|  and/or [S  ii ] |$_{6717+6731}$|⁠) is insufficient to remove the observed offset in the [N  ii ] |$_{6584}$| /H  |$\alpha$| based calibrations. Using a stricter diagnostic line on the BPT diagram removes |$\sim$| 94 per cent of identified bordering spaxels with metallicities for all metallicity calibrations, and removes the residual offset to higher metallicity values seen in [N  ii ] |$_{6584}$| /H  |$\alpha$| calibrations. If science cases demand an exceptionally clean metallicity sample, we recommend either a stricter BPT cut, and/or a non-[N  ii ] |$_{6584}$| /H  |$\alpha$| based metallicity calibration. [ABSTRACT FROM AUTHOR]

We present a qualitative comparison between the host and black hole properties of radio galaxies in the MeerKAT International GHz Tiered Extragalactic Exploration (MIGHTEE) survey with the radio galaxy population in the simba suite of cosmological hydrodynamical simulations. The MIGHTEE data include a |$\sim$| 1 deg |$^{2}$| pointing of the COSMOS field observed at 1.28 GHz with the MeerKAT radio telescope and cross-matched with multiwavelength counterparts to provide classifications of high- and low-excitation radio galaxies (HERGs and LERGs) along with their corresponding host properties. We compare the properties of the MIGHTEE HERGs and LERGs with that predicted by the simba simulations where HERGs and LERGs are defined as radio galaxies dominated by cold or hot mode accretion, respectively. We consider stellar masses |$\,\,{M}_{*}$|⁠ , star formation rates SFR, AGN bolometric luminosity |$L_{\rm bol}$|⁠ , and Eddington fraction |$f_{\rm Edd}$|⁠ , as a function of 1.4 GHz radio luminosity and redshift. In both MIGHTEE and simba , the properties of HERGs and LERGs are similar across all properties apart from SFRs due to differences in host cold gas content in simba. We predict a population of HERGs with low |$f_{\rm Edd}$| in simba that are confirmed in the MIGHTEE observations and tied to the faint population at low z. The predictions from simba with the MIGHTEE observations describe a regime where our understanding of the radio galaxy dichotomy breaks down, challenging our understanding of the role of AGN accretion and feedback in the faint population of radio galaxies. [ABSTRACT FROM AUTHOR]

Estimating physical quantities such as the star formation rate, stellar mass, and active galactic nucleus (AGN) fraction of galaxies is a key step in understanding galaxy formation and evolution. In order to estimate the uncertainties in the predicted values for these quantities, in this paper we explore the impact of adopting four different AGN torus models in fitting the multiwavelength spectral energy distributions (SED) of galaxies. We also explore the impact of adopting two different geometries for the host, a spheroidal geometry, more appropriate for late-stage mergers, and a disc geometry, more appropriate for galaxies forming stars with secular processes. We use optical to submillimetre photometry from the Herschel Extragalactic Legacy Project (HELP) and utilize a Markov chain Monte Carlo SED-fitting code. We use exclusively radiative transfer models for the AGN torus as well as for the starburst and host galaxy. We concentrate on a sample of 200 galaxies at |$z\approx 2$|⁠ , selected in the ELAIS-N1 field. All galaxies have a detection at 250  |$\mu \mathrm{ m}$| which ensures the presence of a starburst. We find that the stellar mass and star formation rate of the galaxies can be robustly estimated by the SED fitting but the AGN fraction depends very much on the adopted torus model. We also find that the vast majority of the galaxies in our sample are better fitted by a spheroidal geometry and lie above the main sequence. Our method predicts systematically higher SFR and lower stellar mass than the popular energy balance method cigale. [ABSTRACT FROM AUTHOR]

We present the results of a new X-ray to near-IR photometric and spectroscopic monitoring of the changing look active galactic nucleus NGC 2617 carried out from March 2022 to March 2024. We found significant variability at all wavelengths and in the intensities and profiles of the broad Balmer lines. Reverberation mapping was carried out for three observing seasons during 2021–2024. We obtained time delays of |$\sim$| 4 d for the response of the H  |${\beta }$| line to optical continuum variations. The X-ray variations correlate well with the UV and optical, with a few days lag for longer wavelengths. The K band lagged the B band by |$\sim$| 15 d during the last three seasons, which is significantly shorter than the delays reported previously by the 2016 and 2017–2019 campaigns. Near-IR variability arises from two different emission regions: the outer part of the accretion disc and a more distant dust component. The |$HK$| -band variability is governed primarily by dust. The H  |${\beta }$| /H  |${\alpha }$| ratio variations (for broad components only) correlate with the X-ray and UV fluxes. The spectral type changed from type 1.8 to type 1.9 during 2023 October–2024 January and then a more rapid change to type 1.5 occurred in 2024 February. We interpret these changes as a combination of two factors: changes in the accretion rate as a dominant cause but also the sublimation or recovery of dust along the line of sight. [ABSTRACT FROM AUTHOR]

S-shaped radio galaxy jets are prime sources for investigating the dynamic interplay between the central active galactic nucleus (AGN), the jets, and the ambient intergalactic medium. These sources are excellent candidates for studying jet precession, as their S-shaped inversion symmetry strongly indicates underlying precession. We present a multiwavelength analysis of the giant inversion-symmetric S-shaped radio galaxy PKS 2300 |$-$| 18, which spans 0.76 Mpc. The host is a quasar at a redshift of 0.128, displaying disturbed optical morphology due to an ongoing merger with a companion galaxy. We conducted a broad-band radio spectral study using multifrequency data ranging from 183 MHz to 6 GHz, incorporating dedicated observations with the upgraded Giant Metrewave Radio Telescope (uGMRT) and Karl G. Jansky Very Large Array (JVLA) alongside archival radio data. A particle injection model was fitted to the spectra of different regions of the source to perform ageing analysis, which was supplemented with a kinematic jet precession model. The ageing analysis revealed a maximum plasma age of |$\sim$| 40 Myr, while the jet precession model indicated a precession period of |$\sim$| 12 Myr. ROentgen SATellite (ROSAT) data revealed an X-ray halo of Mpc size, and from Chandra the AGN X-ray spectrum was modelled using thermal and power-law components. The optical spectrum displaying double-peaked broad emission lines was modelled, indicating complex broad-line region kinematics at the centre with the possibility of a binary SMBH. We present the results of our multiwavelength analysis of the source, spanning scales from a few light-days to a few Mpc, and discuss its potential evolutionary path. [ABSTRACT FROM AUTHOR]

We present multifrequency radio data for a sample of Narrow-Line type 1 Seyfert (NLS1) galaxies. We first focus on the sub-class of gamma-ray emitting NLS1 galaxies, studying the long-term radio variability of five sources and comparing it to their gamma-ray state. We then extend the observations of the southern NLS1 galaxy sample of Chen et al. by observing several candidate NLS1 sources for the first time, and re-observing several other gamma-ray-quiet sources to obtain a first indication of their radio variability. We find that the gamma-ray emitting NLS1 galaxies are highly variable radio emitters and that there are instances of contemporaneous flaring activity between the radio and gamma-ray bands (PKS 0440 |$-$| 00, PMN J0948+0022, and PKS 1244 |$-$| 255). However, there are also cases of significant radio outbursts without gamma-ray counterparts (PMN J0948+0022 and PKS 2004 |$-$| 447). The five gamma-ray NLS1s favour flat or inverted radio spectra, although the spectral indices vary significantly over time. For the gamma-ray-quiet sample, the difference between the previous observations at 5.5 GHz and new Australia Telescope Compact Array (ATCA) observations indicates that over half of the 14 sources exhibit apparent variability. In contrast to gamma-ray-loud sources, gamma-ray-quiet objects tend to have steep spectra, especially in the lower radio band (887.5–1367.5 MHz) of Australian Square Kilometre Array Pathfinder (ASKAP) data, with a number of the variable sources having flatter spectra at higher radio frequencies. [ABSTRACT FROM AUTHOR]

To test the scenario that outflows accelerated by active galactic nuclei (AGN) have a major impact on galaxy-wide scales, we have analysed deep Very Large Telescope/Multi Unit Spectroscopic Explorer (VLT/MUSE) data for the type-2 quasar/ultraluminous infrared galaxy F13451+1232 – an object that represents the major mergers considered in some models of galaxy evolution. After carefully accounting for the effects of atmospheric seeing that had smeared the emission from known compact nuclear outflows across the MUSE field of view, we find that the large-scale kinematics in F13451+1232 are consistent with gravitational motions that are expected in a galaxy merger. Therefore, the fast (⁠|$\mathrm{W_{80}}\gt 500$|  km s |$^{-1}$|⁠) warm-ionized AGN-driven outflows in this object are limited to the central |$\sim$| 100 pc of the galaxy, although we cannot rule out larger scale, lower velocity outflows. Moreover, we directly demonstrate that failure to account for the beam-smearing effects of atmospheric seeing would have led to the mass outflow rates and kinetic powers of spatially extended emission being overestimated by orders of magnitude. We also show that beam-smeared compact-outflow emission can be significant beyond radial distances of 3.5 arcsec (more than 8 times the radius of the seeing disc), and support the argument that some previous claims of large-scale outflows in active galaxies were likely the result of this effect rather than genuine galaxy-wide (⁠|$r\gt 5$|  kpc) outflows. Our study therefore provides further evidence that warm-ionized AGN-driven outflows are limited to the central kiloparsecs of galaxies and highlights the critical importance of accounting for atmospheric seeing in ground-based observational studies of active galaxies. [ABSTRACT FROM AUTHOR]

Some active galactic nuclei (AGN) host outflows which have the potential to alter the host galaxy's evolution (AGN feedback). These outflows have been linked to enhanced radio emission. Here, we investigate the connection between low-frequency radio emission using the international LOw Frequency ARray (LOFAR) telescope and [O  iii ] |$\lambda$| 5007 ionized gas outflows using the Sloan Digital Sky Survey. Using the LOFAR Two-metre Sky Survey (LoTSS) Deep Fields, we select 198 AGN with optical spectra, 115 of which are detected at 144 MHz, and investigate their low-frequency radio emission properties. The majority of our sample do not show a radio excess when considering radio luminosity – star formation rate relationship, and are therefore not driven by powerful jets. We extract the [O  iii ] |$\lambda$| 5007 kinematics and remove AGN luminosity dependencies by matching the radio detected and non-detected AGN in |$L_{\mathrm{6\, \mu m}}$| and redshift. Using both spectral fitting and |$W_{80}$| measurements, we find radio detected AGN have a higher outflow rate (67.2 |$\pm$| 3.4 per cent) than the radio non-detected AGN (44.6 |$\pm$| 2.7 per cent), indicating a connection between ionized outflows and the presence of radio emission. For spectra where there are two components of the [O  iii ] emission line present, we normalize all spectra by the narrow component and find that the average broad component in radio detected AGN is enhanced compared to the radio non-detected AGN. This could be a sign of higher gas content, which is suggestive of a spatial relationship between [O  iii ] outflows and radio emission in the form of either low-powered jets or shocks from AGN winds. [ABSTRACT FROM AUTHOR]

We combine X-ray data from the X-ray Multi-Mirror Mission 12th data release (4XMM DR12) and the extended ROentgen Survey with an Imaging Telescope Array (eROSITA) Final Equatorial-Depth Survey (eFEDS) early data release catalogues with the Galaxy and Mass Assembly spectroscopic galaxy survey to form a sample of 526 local (⁠|$0.05\le z \le 0.3$|⁠), moderately luminous active galactic nuclei (AGNs; |$L_{\rm X} \ge 10^{42}$| erg s-1). We compare the distribution of AGN hosts with that of the general galaxy population, finding no evidence of AGNs being preferentially hosted within over/underdense environments at a 7-Mpc scale. Next, we compare the distances to nearest-neighbour galaxies and find that AGN host galaxies are separated from their neighbours by the same distance as galaxies in a matched non-AGN sample. Finally, we consider mid-IR colour, provided by the All-WISE survey, the |$L_{\rm X}/L_{6\, \mu \mathrm{m}}$| ratio, and X-ray hardness as tracers of AGN obscuration, to explore whether there is a change in the galaxy environment for obscured AGNs. We find no evidence of increasing AGN obscuration with decreasing separation in close galaxy pairs. We conclude that close galaxy–galaxy interactions may not be sufficiently disruptive to cause any observable increase in AGN activity. [ABSTRACT FROM AUTHOR]

Variation mechanism of blazar is still under debate. In this study, we investigate the correlation and spectral variation of the BL Lacertae and propose a scenario to explain various phenomena in a comprehensive manner. The local cross-correlation function analysis indicates a strong positive correlation between the |$\gamma$| -ray and optical fluxes, suggesting a common emission region for these emissions. Additionally, we found a hint of correlation between the X-ray and the radio emissions. The source shows a softer-when-brighter trend at a low flux level and a harder-when-brighter trend at a high flux level in the optical band. The long-term variability indicates that the BL Lacertae changes from an intermediate-synchrotron-peaked object to a high-synchrotron-peaked object in multiple epochs. This is further supported by modelling the broad-band spectral energy distributions of the source during these epochs using the log-parabolic model. The flux correlations and spectral behaviours at multiple bands could be explained by the shift of synchrotron peak frequency in the shock-in-jet model. At short-term time-scale, the variation on the |$qu$| planes suggests a polarized background component. There is no correlation between polarization degree and flux at long-term time-scales. Our study sheds light on the variation mechanism of BL Lacertae. [ABSTRACT FROM AUTHOR]

Astrophysical black holes (BHs) have two fundamental properties: mass and spin. While the mass-evolution of BHs has been extensively studied, much less work has been done on predicting the distribution of BH spins. In this paper, we present the spin evolution for a sample of intermediate-mass and massive BHs from the NewHorizon simulation, which evolved BH spin across cosmic time in a full cosmological context through gas accretion, BH–BH mergers and BH feedback including jet spindown. As BHs grow, their spin evolution alternates between being dominated by gas accretion and BH mergers. Massive BHs are generally highly spinning. Accounting for the spin energy extracted through the Blandford–Znajek mechanism increases the scatter in BH spins, especially in the mass range |$10^{5}{-}10^{7}\,\rm M_\odot$|⁠ , where BHs had previously been predicted to be almost universally maximally spinning. We find no evidence for spin-down through efficient chaotic accretion. As a result of their high spin values, massive BHs have an average radiative efficiency of |$\lt \varepsilon _{\rm r}^{\rm thin}\gt \approx 0.19$|⁠. As BHs spend much of their time at low redshift with a radiatively inefficient thick disc, BHs in our sample remain hard to observe. Different observational methods probe different sub-populations of BHs, significantly influencing the observed distribution of spins. Generally, X-ray-based methods and higher luminosity cuts increase the average observed BH spin. When taking BH spin evolution into account, BHs inject, on average, between three times (in quasar mode) and eight times (in radio mode) as much feedback energy into their host galaxy as previously assumed. [ABSTRACT FROM AUTHOR]

This paper presents a preliminary investigation into the influence of radial behavior of disk outflow on the structure and dynamics of the broad line region (BLR) in active galactic nuclei (AGNs), with an emphasis on how the mass ejection rate contributes to shaping the broad emission-line profiles. Specifically, we analyze how varying the radial efficiency of mass loss from accretion disks, driven by radiative dust-based mechanisms, contributes to the distribution of material in the BLR. By exploring different radial scenarios of disk mass loss behavior, we uncover connections between outflow radial efficiency and emission line profiles, particularly for lowly ionized lines. Our findings reveal that while the observed shape of broad emission lines is partially influenced by the radial behavior of the disk outflow, it ultimately depends more critically on the physical conditions of the clouds and the specific approach adopted regarding the emissivity for their contribution to the line formation. [ABSTRACT FROM AUTHOR]

To investigate the radio properties of the recently found high-redshift population, we collected a sample of 919 little red dots (LRDs) from the literature. By cross-matching their co-ordinates with the radio catalogues based on the first- and second-epoch observations of the Very Large Array Sky Survey (VLASS) and the Faint Images of the Radio Sky at Twenty-centimeters (FIRST) survey, we found no radio counterparts coinciding with any of the LRDs. To uncover possible sub-milli-Jansky-level weak radio emission, we performed mean and median image stacking analyses of empty-field 'quick look' VLASS and FIRST image cutouts centred on the LRD positions. We found no radio emission above 3σ noise levels (∼11 and ∼18 μJy beam−1 for the VLASS and FIRST maps, respectively) in either of the stacked images for the LRD sample, while the noise levels of the single-epoch images are comparable to those found earlier in the stacking of high-redshift radio-quiet active galactic nuclei (AGNs). The non-detection of radio emission in LRDs suggests that these sources host weaker (or no) radio AGNs. [ABSTRACT FROM AUTHOR]

We present a new iterative deblending method to separate the host galaxy (HG) and their Active Galactic Nuclei (AGNs) emission with the use of Integral Field spectroscopic (IFS) data. The method decomposes the resolved HG emission from the unresolved AGN emission by modelling the two-dimensional surface brightness (SB) profile of the point-spread function (PSF) and the two-dimensional SB HG continuum simultaneously per each monochromatic slide. Our method does not require any prior information about the observed SB profile or a detailed fitting of the PSF, making it ideal for the automatic analysis of large galaxy samples. In this work, we test the quality of our method, its advantages, and its disadvantages. We test our method by using a set of IFS mock data cubes to quantify the reliability of our deblending process and further compare our method with the qdblend3d analysis tool. Furthermore, we applied our method to three data cubes selected from the MaNGA survey according to the dominance of either its HG or its AGN. We show that our deblending method is capable of disengaging the bright, non-resolved AGN emission from the HG continuum and its narrow emission lines. However, the decoupling depends on how well the IFS spatially resolves the PSF, and on the relative flux intensity of the HG-AGN. Therefore, the method is ideal for disentangling the bright-flux contribution from AGN-dominated spectra. [ABSTRACT FROM AUTHOR]

Statistical analyses based on the spatial correlation between the sky maps of gravitational wave (GW) events and the positions of potential host environments are a powerful tool to infer the origin of the black hole binary mergers that have been detected by the LIGO, Virgo, and KAGRA instruments. In this paper, we tighten our previous constraints on the fraction of detected GW events that may have originated from active galactic nuclei (AGNs). We consider 159 mergers detected not later than 1st June, 2024, and the all-sky quasar catalogue Quaia. We increase by a factor of 5.3 and 114, the number of considered GW sources and AGN, respectively, also extending our analysis from redshift 0.3 to 1.5. This is possible thanks to the uniformity of the AGN catalogue and its high level of completeness, which we estimate as a function of redshift and luminosity. We find at a 95 per cent credibility level that un-obscured AGN with a bolometric luminosity higher than |$10^{44.5}\,{\rm erg\ s}^{-1}$| (⁠|$10^{45}\,{\rm erg\ s}^{-1}$|⁠) do not contribute to more than the 21 (11) per cent of the detected GW events. [ABSTRACT FROM AUTHOR]

We present NIRSpec/micro-shutter assembly observations from the JWST large-area survey WIDE, targeting the rest-frame UV–optical spectrum of Ulema, a radio-active galactic nucleus host at redshift |$z=4.6348$|⁠. The low-resolution prism spectrum displays high equivalent width nebular emission, with remarkably high ratios of low-ionization species of oxygen, nitrogen, and sulphur, relative to hydrogen; auroral O |$^+$| emission is clearly detected, possibly also C |$^+$|⁠. From the high-resolution grating spectrum, we measure a gas velocity dispersion of |$\sigma \sim 400$| |$\mathrm{km\, s^{-1}}$|⁠ , broad enough to rule out star-forming gas in equilibrium in the gravitational potential of the galaxy. Diagnostics based on emission-line ratios suggest that the nebular emission is due to a shock which ran out of pre-shock gas. To infer the physical properties of the system, we model simultaneously the galaxy spectral energy distribution and shock-driven line emission under a Bayesian framework. We find a relatively low-mass, star-forming system (⁠|$M_\star = 1.4 \times 10^{10}~{\rm M}_\odot$|⁠ , |$\mathrm{SFR} = 70~{\rm M}_\odot ~{\rm yr^{-1}}$|⁠), where shock-driven emission contributes 50 per cent to the total H β luminosity. The nebular metallicity is near solar – three times higher than that predicted by the mass–metallicity relation at |$z=4.6$|⁠ , possibly related to fast-paced chemical evolution near the galaxy nucleus. We find no evidence for a recent decline in the star-formation rate of the galaxy, meaning that, already at this early epoch, fast radio-mode active galactic nucleus feedback was poorly coupled with the bulk of the star-forming gas; therefore, most of the feedback energy must end up in the galaxy halo, setting the stage for future quenching. [ABSTRACT FROM AUTHOR]

We characterize the co-evolution of radio-loud active galactic nuclei (AGN) and their galaxies by mapping the dependence of radio-loud AGN activity on stellar mass and star formation rate (SFR) across cosmic time (out to |$z \sim 1.5$|⁠). Deep LOFAR radio observations are combined with large galaxy samples to study the incidence of radio-loud AGN across the galaxy population; the AGN are further split into low-excitation radio galaxies (LERGs) and high-excitation radio galaxies (HERGs). We find that LERG activity occurs over a wide range of SFRs, whereas HERGs are typically found in galaxies with ongoing star formation. The LERGs are then split based on their SFRs relative to the main sequence, across redshift. Within quiescent galaxies, LERG activity shows a steep stellar mass dependence with the same normalization across the past |$\sim$| 10 Gyr; this indicates that hot gas fuels LERGs in quiescent galaxies across cosmic time. In massive galaxies [ |$\log _{10}(M/\rm {{\rm M}_{\odot }}) \gtrsim 11$| ], the incidence of LERGs is roughly constant across the galaxy population, suggesting that LERGs in massive galaxies may be fuelled by hot gas regardless of the star formation activity. At lower masses, however, LERG activity is significantly more enhanced (by a factor of up to 10) in star-forming galaxies compared to quiescent galaxies; this suggests that an additional fuelling mechanism, likely associated with cold gas, may fuel the LERGs in galaxies with higher SFRs. We find that HERGs typically accrete above 1 per cent of the Eddington-scaled accretion rate, and the LERGs typically accrete below this level. [ABSTRACT FROM AUTHOR]

Supermassive black holes (BHs) are known to efficiently grow through gas accretion, but even sustained and intense mass build-up through this mechanism struggles to explain the assembly of the most massive BHs observed in the local Universe. Using the Chandra Deep-Wide Field Survey (CDFWS) in the Boötes field, we measure BH–galaxy assembly in massive galaxies (⁠|$M_\star \gtrsim 10^{10}\,\rm M_\odot$|⁠) through the active galactic nucleus (AGN) fraction and specific black hole accretion rate (sBHAR) distribution as a function of redshift and stellar mass. We determine stellar masses and star formation rates for a parent sample of optically selected galaxies as well as those with X-ray detections indicating the presence of an AGN through spectral energy distribution (SED) fitting. We derive a redshift-dependent mass completeness limit and extract X-ray information for every galaxy as to provide a comprehensive picture of the AGN population in massive galaxies. While X-ray AGN samples are dominated by moderately massive host galaxies of |$M_{\star } \geqslant 10^{10}\rm {\rm M}_{\odot }$|⁠ , we do not find a strong stellar mass dependence in AGN fraction (to limits in sBHAR), indicating a bias towards massive galaxies in the observed samples. We derive BH–galaxy growth tracks over time, which reveal that while most BH mass has been accumulated since |$z=4$| for lower mass BHs, the assembly of the most massive BHs is more complex, with little to no relative mass gain since |$z=4$|⁠ , implying that rapid and intense growth episodes prior to |$z=4$| were necessary to form these massive BHs. [ABSTRACT FROM AUTHOR]

The coevolution of supermassive black holes and their host galaxies represents a fundamental question in astrophysics. One approach to investigating this question involves comparing the star formation rates (SFRs) of active galactic nuclei (AGNs) with those of typical star-forming galaxies. At relatively low redshifts (z ≲ 1), radio AGNs manifest diminished SFRs, indicating suppressed star formation, but their behavior at higher redshifts is unclear. To examine this, we leveraged galaxy and radio-AGN data from the well-characterized W-CDF-S, ELAIS-S1, and XMM-LSS fields. We established two mass-complete reference star-forming galaxy samples and two radio-AGN samples, consisting of 1763 and 6766 radio AGNs, the former being higher in purity and the latter more complete. We subsequently computed star-forming fractions (f SF; the fraction of star-forming galaxies to all galaxies) for galaxies and radio-AGN host galaxies and conducted a robust comparison between them up to z ≈ 3. We found that the tendency for radio AGNs to reside in massive galaxies primarily accounts for their low f SF, which also shows a strong negative dependence upon M ⋆ and a strong positive evolution with z. To investigate further the star formation characteristics of those star-forming radio AGNs, we constructed the star-forming main sequence (MS) and investigated the behavior of the position of AGNs relative to the MS at z ≈ 0–3. Our results reveal that radio AGNs display lower SFRs than star-forming galaxies in the low- z and high- M ⋆ regime and, conversely, exhibit comparable or higher SFRs than MS star-forming galaxies at higher redshifts or lower M ⋆. [ABSTRACT FROM AUTHOR]

Gigahertz peaked spectrum (GPS) and compact steep spectrum (CSS) sources are compact radio galaxies (RGs), with jets extending up to 20 kpc and ages <103 yr. They are considered to evolve to Fanaroff–Riley RGs, but the real scenario to explain the compact sources remains unsolved. The young compact jets make GPS/CSS ideal for studying feedback in the nuclear region of active galactic nuclei because the jets are just starting to leave this region. Numerical simulations and jet power estimates suggest that compact sources can drive outflows on scales several times larger than the radio source itself, but the lack of suitable data limits comparisons between theory and observation. We carried out an optical spectroscopic study of 82 CSS/GPS with Sloan Digital Sky Survey-DR12 data to investigate the influence of compact jets in the gas. We found outflowing gas components in the [O iii ] λ 5007 emission lines in half of our sample. The kinetic energy of the outflowing gas in compact sources is comparable to that observed in extended RGs, indicating that the compact jets can drive powerful outflows similar to those in FR RGs. The observed anticorrelation between the kinetic power of the outflow and the radio luminosity suggests an interaction between the young jet and the interstellar medium (ISM). This finding provides significant observational support for previous simulations of jet–ISM interactions and supports the evolutionary scenario for RGs. However, the lack of sources with high kinetic efficiency indicates that some compact galaxies may be frustrated sources. [ABSTRACT FROM AUTHOR]

Both star formation (SF) and active galactic nuclei (AGNs) play an important role in galaxy evolution. Statistically quantifying their relative importance can be done using radio luminosity functions (RLFs). Until now these relied on galaxy classifications, where sources with a mixture of radio emission from SF and AGN are labelled as either a star-forming galaxy or an AGN. This can cause the misestimation of the relevance of AGN. Brightness temperature measurements at 144 MHz with the International LOw Frequency ARray telescope can separate radio emission from AGN and SF. We use the combination of sub-arcsec and arcsec resolution imaging of 7497 sources in the Lockman Hole and ELAIS-N1 fields to identify AGN components in the sub-arcsec resolution images and subtract them from the total flux density, leaving flux density from SF only. We construct, for the first time, RLFs by physical process, either SF or AGN activity, revealing a hidden AGN population at |$L_{\textrm {144 MHz}}$| |$\lt 10^{24}$| W Hz |$^{-1}$|⁠. This population is 1.56 |$\pm$| 0.06 more than expected for |$0.5\lt z\lt 2.0$| when comparing to RLFs by galaxy classification. The star-forming population has only 0.90 |$\pm$| 0.02 of the expected SF. These 'hidden' AGNs can have significant implications for the cosmic SF rate and kinetic luminosity densities. [ABSTRACT FROM AUTHOR]

Active galaxies hosting radio jets can exhibit distinct active phases marked by two sets of radio lobes. Typically, these episodic radio sources have been identified through morphological observations. In addition, spectral characteristics-based methods are also employed wherever multi-frequency deep radio observations are available. However, these methods are inefficient in detecting restarted radio sources that do not exhibit a clear morphology. To address this, a method of using the spectral curvature ( SPC = α 150 MHz 1400 MHz - α 74 MHz 150 MHz ) to identify restarted radio sources is presented. This is based on the fact that restarted radio sources with significant remnant emission are expected to have concave spectra in contrast to the convex or straight spectra observed in most radio sources. We use available wide area radio surveys in the range of frequencies from 74 MHz to 1.4 GHz to search for episodic radio sources and to shortlist 9,405 sources based on the criteria of SPC ≥ 0.5 . The candidates thus identified can be followed up for detailed morphological and spectral index studies. This method will find application in the automated identification of episodic radio sources in large radio sky surveys from telescopes like LOFAR and SKA. [ABSTRACT FROM AUTHOR]

We study the variability of the thermal (accretion disc) and non-thermal (jet) emission of thirteen flat spectrum radio quasars in the optical and near infrared (OIR) regime using light curves spanning years with an average sampling of three observations per week. We fit a combination of a blackbody and a power-law function to the OIR data, in the blazar rest frame, to extract the corresponding thermal (disc) and non-thermal (jet) components from the total flux. We carry out this analysis for the entire duration of the light curves to obtain the variation of the disc and jet components over years. Reliability of our fits have been affirmed by successfully retrieving accurate parameters by employing our method to simulated data and by comparing our results with published disc luminosity obtained by other methods for a few well-observed blazars. In blazars, the thermal (disc) emission is difficult to extract because the relativistically beamed radiation of the jet dominates at all wavelengths. By employing this method, the disc emission in blazars may be estimated directly from photometric data at OIR bands instead of indirect methods, such as, inferring it from the emission line luminosities. We find that the variability of the disc and jet emission obtained by the above method are strongly correlated in most cases. [ABSTRACT FROM AUTHOR]