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Broad absorption line (BAL) quasars are characterized by gas clouds that absorb flux at the wavelength of common quasar spectral features, although blueshifted by velocities that can exceed 0.1c. BAL features are interesting as signatures of significant feedback, yet they can also compromise cosmological studies with quasars by distorting the shape of the most prominent quasar emission lines, impacting redshift accuracy and measurements of the matter density distribution traced by the Lyman α forest. We present a catalogue of BAL quasars discovered in the Dark Energy Spectroscopic Instrument (DESI) survey Early Data Release, which were observed as part of DESI Survey Validation, as well as the first two months of the main survey. We describe our method to automatically identify BAL quasars in DESI data, the quantities we measure for each BAL, and investigate the completeness and purity of this method with mock DESI observations. We mask the wavelengths of the BAL features and re-evaluate each BAL quasar redshift, finding new redshifts which are 243 km s−1 smaller on average for the BAL quasar sample. These new, more accurate redshifts are important to obtain the best measurements of quasar clustering, especially at small scales. Finally, we present some spectra of rarer classes of BALs that illustrate the potential of DESI data to identify such populations for further study.

We use the Hubble Space Telescope to analyse the extended [O  iii ] 5007 Å emission in seven bright radio-quiet type 1 quasars (QSO1s), focusing on the morphology and physical conditions of their extended Narrow-Line Regions (NLRs). We find NLRs extending 3–9 kpc, with four quasars showing roughly symmetrical structures (⁠|$b/a$| =1.2–1.5) and three displaying asymmetric NLRs (⁠|$b/a$| =2.4–5.6). When included with type 1 and type 2 AGNs from previous studies, the sizes of the extended [O  iii ] regions scale with luminosity as |$R_{\rm [O\,{\rm {\small III}}]}\sim L_{\rm [O\,{\rm {\small III}}]}^{0.5}$|⁠ , consistent with photoionization. However, when analysed separately, type 1s exhibit a steeper slope (⁠|$\gamma _{1}$| = 0.57 |$\pm$| 0.05) compared to type 2 AGNs (⁠|$\gamma _{2}$| = 0.48 |$\pm$| 0.02). We use photoionization modelling to estimate the maximum NLRs sizes, assuming a minimum ionization parameter of log |$(U)=-3$|⁠ , an ionizing luminosity based on the |$L_{\rm [O\,{\rm {\small III}}]}$| -derived bolometric luminosity, and a minimum gas number density |$n_{\rm H}\sim 100$|  cm |$^{-3}$|⁠ , assuming that molecular clouds provide a reservoir for the ionized gas. The derived sizes agree well with direct measurements for a sample of type 2 quasars, but are underestimated for the current sample of QSO1s. A better agreement is obtained for the QSO1s using bolometric luminosities derived from the 5100 Å continuum luminosity. Radial mass profiles for the QSO1s show significant extended mass in all cases, but with less [O  iii ]-emitting gas near the central AGN compared to QSO2s. This may suggest that the QSO1s are in a later evolutionary stage than QSO2s, further past the blow-out stage. [ABSTRACT FROM AUTHOR]

To investigate how the radio-identified active galactic nuclei (AGN) fraction varies with cluster-centric radius, we present the projected and de-projected distributions of a large sample of Low-Frequency Array-identified radio AGN out to |$30R_{500}$| around galaxy clusters. The AGN fraction experiences a |${\sim} 25~{{\ \rm per\ cent}}$| increase above the field fraction in the cluster outskirts at around |$10R_{500}$|⁠ , a |${\sim} 20~{{\ \rm per\ cent}}$| decrease around |${\sim} 0.5R_{500}$|⁠ , and an increase of over three times the field fraction value in the very cluster core. We label these three radial windows the outer, intermediate , and inner regions respectively, and investigate how these radial trends might arise due to intrinsic properties of the AGN population. The only difference seen in host galaxy stellar mass is in the inner region, where there is a much higher fraction of massive host galaxies. Analysing AGN radio luminosity, regions with a higher AGN fraction tend to have more radio luminous AGN, and vice versa. We discuss the physical mechanisms that might be responsible for these results with reference to the literature. [ABSTRACT FROM AUTHOR]

High-ionization iron coronal lines (CLs) are a rare phenomenon observed in galaxy and quasi-stellar object spectra that are thought to be created by high-energy emission from active galactic nuclei and certain types of transients. In cases known as extreme coronal line emitting galaxies (ECLEs), these CLs are strong and fade away on a time-scale of years. The most likely progenitors of these variable CLs are tidal disruption events (TDEs), which produce sufficient high-energy emission to create and sustain the CLs over these time-scales. To test the possible connection between ECLEs and TDEs, we present the most complete variable ECLE rate calculation to date and compare the results to TDE rates from the literature. To achieve this, we search for ECLEs in the Sloan Digital Sky Survey (SDSS). We detect sufficiently strong CLs in 16 galaxies, more than doubling the number previously found in SDSS. Using follow-up spectra from the Dark Energy Spectroscopic Instrument and Gemini Multi-Object Spectrograph, Wide-field Infrared Survey Explorer mid-infrared observations, and Liverpool Telescope optical photometry, we find that none of the nine new ECLEs evolve in a manner consistent with that of the five previously discovered variable ECLEs. Using this sample of five variable ECLEs, we calculate the galaxy-normalized rate of variable ECLEs in SDSS to be |$R_\mathrm{G}=3.6~^{+2.6}_{-1.8}~(\mathrm{statistical})~^{+5.1}_{-0.0}~(\mathrm{systematic})\times 10^{-6}~\mathrm{galaxy}^{-1}~\mathrm{yr}^{-1}$|⁠. The mass-normalized rate is |$R_\mathrm{M}=3.1~^{+2.3}_{-1.5}~(\mathrm{statistical})~^{+4.4}_{-0.0}~(\mathrm{systematic})\times 10^{-17}~\mathrm{M_\odot ^{-1}}~\mathrm{yr}^{-1}$| and the volumetric rate is |$R_\mathrm{V}=7~^{+20}_{-5}~(\mathrm{statistical})~^{+10}_{-0.0}~(\mathrm{systematic})\times 10^{-9}~\mathrm{Mpc}^{-3}~\mathrm{yr}^{-1}$|⁠. Our rates are one to two orders of magnitude lower than TDE rates from the literature, which suggests that only 10–40 per cent of all TDEs produce variable ECLEs. Additional uncertainties in the rates arising from the structure of the interstellar medium have yet to be included. [ABSTRACT FROM AUTHOR]

The influence of Active Galactic Nuclei (AGN) on star formation within their host galaxies remains a topic of intense debate. One of the primary challenges in quantifying the star formation rate (SFR) within AGN hosts arises from the prevalent assumption in most methodologies, which attribute gas excitation to young stars alone. However, this assumption does not consider the contribution of the AGN to the ionization of the gas in their environment. To address this issue, we evaluate the use of strong optical emission lines to obtain the SFR surface density (⁠|$\Sigma {{\rm SFR_{AGN}}}$|⁠) in regions predominantly ionized by an AGN, using a sample of 293 AGN hosts from the MaNGA survey, with SFR measurements available through stellar population fitting. We propose calibrations involving the H |$\alpha$| and [O  iii ] |$\lambda$| 5007 emission lines, which can be used to determine |$\Sigma {{\rm SFR_{AGN}}}$|⁠ , resulting in values consistent with those estimated through stellar population fitting. [ABSTRACT FROM AUTHOR]

We report the chemical abundance pattern of GS_3073, a galaxy hosting an overmassive active black hole at |$z=5.55$|⁠ , by leveraging observations from JWST/NIRSpec and Very Large Telescope/VIsible Multi-Object Spectrograph. Based on the rest-frame ultraviolet (UV) emission lines, which trace high-density (⁠|$\sim 10^5~{\rm cm^{-3}}$|⁠) and highly ionized gas, we derive |$\rm \log (N/O) = 0.42^{+0.13}_{-0.10}$|⁠. At an estimated metallicity of |$0.2~Z_{\odot }$|⁠ , this is the most extreme nitrogen-rich object found by JWST thus far. In comparison, the relative carbon abundance derived is |$\rm \log (C/O) = -0.38^{+0.13}_{-0.11}$|⁠ , which is not significantly higher than those in local galaxies and stars with similar metallicities. We also found potential detection of [Fe  vii ] |$\lambda 6087$| and [Fe  xiv ] |$\lambda 5303$|⁠ , both blended with [Ca  v ]. We inferred a range of Fe abundances compatible with those in local stars and galaxies. Overall, the chemical abundance pattern of GS_3073 is compatible with enrichment by supermassive stars with |$M_* \gtrsim 1000~M_\odot$|⁠ , asymptotic giant branch stars, or Wolf–Rayet stars. Interestingly, when using optical emission lines that trace lower density (⁠|$\sim 10^3~{\rm cm}^{-3}$|⁠) and lower ionization gas, we found a sub-solar N/O ratio, consistent with local galaxies at the same metallicity. We interpret the difference in N/O derived from UV lines and optical lines as evidence for a stratified system, where the inner and denser region is both more chemically enriched and more ionized. Our results suggest that nitrogen loudness in high- z galaxies might be confined to the central, dense, and highly ionized regions of the galaxies, while the bulk of the galaxies evolves more normally. [ABSTRACT FROM AUTHOR]

JWST has discovered a large population of active galactic nuclei (AGN) at high redshift, which are weak in the X-rays. Here we present the NIRSpec spectrum of the most extreme of these objects, GN-28074, an AGN at |$z=2.26$| with prominent hydrogen and He  i  broad lines, and with the highest limit on the bolometric to X-ray luminosity ratio among all spectroscopically confirmed AGN in GOODS. This source is also characterized by a mid-IR excess, likely associated with the AGN torus' hot dust. The high bolometric luminosity and moderate redshift of this AGN allow us to explore its properties more in depth relative to other JWST -discovered AGN. The NIRSpec spectrum reveals prominent, slightly blueshifted absorption of H |$\alpha$|⁠ , H |$\beta$|⁠ , and He  i   |$\lambda$| 10830. The Balmer absorption lines require gas with densities of |$n_{\rm H}\gt 10^8~{\rm cm}^{-3}$|⁠ , consistent with clouds in the broad-line region (BLR). This finding suggests that part of the X-ray weakness is due to high (Compton-thick) X-ray absorption by clouds in the BLR, or in its outer regions. GN-28074 is also extremely radio-weak. The radio weakness can also be explained in terms of absorption, as the inferred density of the BLR clouds makes them attenuate the radio emission through free–free absorption. Alternatively, the nuclear magnetic field may be underdeveloped, resulting both in intrinsically weak radio emission and lack of hot corona, hence intrinsic X-ray weakness. Finally, we show that recently proposed scenarios, invoking hyper-dense outflows or Raman scattering to explain the broad H |$\alpha$|⁠ , are ruled out. [ABSTRACT FROM AUTHOR]

Dual active galactic nuclei (AGNs) offer a unique opportunity to probe the relationship between supermassive black holes (SMBH) and their host galaxies as well as the role of major mergers in triggering AGN activity. The confirmed dual AGN Mrk 266 has been studied extensively with multiwavelength imaging. Now, high-spatial-resolution IFU spectroscopy of Mrk 266 provides an opportunity to probe the kinematics of both the merger event and AGN feedback. We present for the first time high-spatial-resolution kinematic maps for both nuclei of Mrk 266 obtained with the Keck OSIRIS IFU spectrograph, utilizing adaptive optics to achieve a resolution of |$0.31$| and |$0.20\,\mathrm{ arcsec}$| for the NE and SW nuclei, respectively. Using the |$M_\text{BH} \!-\! \sigma _*$| relation for mergers, we infer an SMBH mass of approximately |$7 \times 10^{7}\, \mathrm{M}_{\odot }$| for the south-western nucleus. Additionally, we report that the molecular gas kinematics of the south-western nucleus are dominated by rotation rather than large-scale chaotic motions. The south-west nucleus also contains both a circumnuclear ring of star formation from which an inflow of molecular gas is likely fuelling the AGN and a compact, AGN-dominated outflow of highly ionized gas with a time-scale of approximately 2 Myr, significantly shorter than the time-scale of the merger. The north-eastern nucleus, on the other hand, exhibits complex kinematics related to the merger, including molecular gas that appears to have decoupled from the rotation of the stars. Our results suggest that while the AGN activity in Mrk 266 was likely triggered during the merger, AGN feeding is currently the result of processes internal to each host galaxy, thus resulting in a strong asymmetry between the two nuclei. [ABSTRACT FROM AUTHOR]

Over the past decades, there has been significant progress in our understanding of accreting supermassive black holes (SMBHs) that drive active galactic nuclei (AGNs), both from observational and theoretical perspectives. As an iconic target for this area of study, the nearby giant elliptical galaxy M 87 has received special attention thanks to its proximity, large mass of the central black hole and bright emission across the entire electromagnetic spectrum from radio to very-high-energy γ -rays. In particular, recent global millimeter-very-long-baseline-interferometer observations towards this nucleus have provided the first-ever opportunity to image the event-horizon-scale structure of an AGN, opening a new era of black hole astrophysics. On large scales, M 87 exhibits a spectacular jet propagating far beyond the host galaxy, maintaining its narrowly collimated shape over seven orders of magnitude in distance. Elucidating the generation and propagation, as well as the internal structure, of powerful relativistic jets remains a longstanding challenge in radio-loud AGNs. M 87 offers a privileged opportunity to examine such a jet with unprecedented detail. In this review, we provide a comprehensive overview of the observational knowledge accumulated about the M 87 black hole across various wavelengths. We cover both accretion and ejection processes at spatial scales ranging from outside the Bondi radius down to the event horizon. By compiling these observations and relevant theoretical studies, we aim to highlight our current understanding of accretion and jet physics for this specific object. [ABSTRACT FROM AUTHOR]

Using the cosmological simulations IllustrisTNG, we perform a comprehensive analysis of quiescent, massive galaxies at |$z \gtrsim 3$|⁠. The goal is to understand what suppresses their star formation so early in cosmic time, and how other similar mass galaxies remain highly star forming. As a first-order result, the simulations are able to produce massive, quiescent galaxies in this high-redshift regime. We find that active galactic nucleus (AGN) feedback is the primary cause of halting star formation in early, massive galaxies. Not only do the central, supermassive black holes (SMBHs) of the quenched galaxies have earlier seed times, but they also grow faster than in star-forming galaxies. As a result, the quenched galaxies are exposed to AGN feedback for longer, and experience the kinetic, jet mode of the AGN feedback earlier than the star-forming galaxies. The release of kinetic energy reduces inflows of gas while likely maintaining outflows, which keeps a low cold gas fraction and decreases the star formation of the galaxies down to a state of quiescence. In addition to AGN feedback, we also investigate the influence of the large-scale environment. While mergers do not play a significant role in the quenching process, the quenched galaxies tend to reside in more massive haloes and denser regions during their evolution. As this provides a greater initial amount of infalling gas to the galaxies, the large-scale environment can mildly affect the fate of the central SMBH growth and, via AGN feedback, contribute to star formation quenching. [ABSTRACT FROM AUTHOR]

We derive the nitrogen and oxygen abundances in the narrow line regions (NLRs) of a sample of 38 local (⁠|$z \: \lt \: 0.4$|⁠) Seyfert 2 nuclei. For that, we consider narrow optical emission line intensities and direct estimates of the electron temperatures (⁠|$T_{\rm e}$| -method). We obtain a new theoretical expression for the nitrogen ionization correction factor [ICF(⁠|$\rm N^{+}$|⁠)] for NLRs. Applying this new ICF, we unexpectedly find that NLRs and disc H  ii regions exhibit similar ICF distributions. We find nitrogen abundances in the range |$7.6 \: \lt \: \rm 12+log(N/H) \: \lt \: 8.6$| (mean value |$8.06\pm 0.22$|⁠) or |$\rm 0.4 \: \lt \: (N/N_{\odot }) \: \lt 4.7$|⁠ , in the metallicity regime |$8.3 \: \lt \: \rm 12+log(O/H) \: \lt \: 9.0$|⁠. Our results indicate that the dispersion in N/H abundance for a fixed O/H value in AGNs of |$\sim 0.2$| dex agrees with that for disc H  ii regions with similar metallicity. We show that Seyfert 2 nuclei follow a similar (N/O)–(O/H) relation to the one followed by star-forming objects. Finally, we find that active galaxies called as ..nitrogen-loud.. observed at very high redshift (⁠|$z \: \gt \: 5$|⁠) show N/O values in consonance with those derived for local NLRs. This result indicates that the main star-formation event is completed in the early evolution stages of active galaxies. [ABSTRACT FROM AUTHOR]

We present a kinematic analysis based on the large integral field spectroscopy (IFS) dataset of SDSS-IV MaNGA (Sloan Digital Sky Survey/Mapping Nearby Galaxies at Apache Point Observatory; ∼10 000 galaxies). We have compiled a diverse sample of 594 unique active galactic nuclei (AGNs), identified through a variety of independent selection techniques, encompassing radio (1.4 GHz) observations, optical emission-line diagnostics (BPT), broad Balmer emission lines, mid-infrared colors, and hard X-ray emission. We investigated how ionized gas kinematics behave in these different AGN populations through stacked radial profiles of the [O III] 5007 emission-line width across each AGN population. We contrasted AGN populations against each other (and non-AGN galaxies) by matching samples by stellar mass, [O III] 5007 luminosity, morphology, and redshift. We find similar kinematics between AGNs selected by BPT diagnostics compared to broad-line-selected AGNs. We also identify a population of non-AGNs with similar radial profiles as AGNs, indicative of the presence of remnant outflows (or fossil outflows) of past AGN activity. We find that purely radio-selected AGNs display enhanced ionized gas line widths across all radii. This suggests that our radio-selection technique is sensitive to a population in which AGN-driven kinematic perturbations have been active for longer durations (potentially due to recurrent activity) than in purely optically selected AGNs. This connection between radio activity and extended ionized gas outflow signatures is consistent with recent evidence that suggests radio emission (expected to be diffuse) originated due to shocks from outflows. We conclude that different selection techniques can trace different AGN populations not only in terms of energetics but also in terms of AGN evolutionary stages. Our results are important in the context of the AGN duty cycle and highlight integral field unit data's potential to deepen our knowledge of AGNs and galaxy evolution. [ABSTRACT FROM AUTHOR]

We report on the second observing program of the active galactic nucleus NGC 4151 with simultaneous Imaging X-ray Polarimetry Explorer (IXPE; 750 ks), NuSTAR (∼60 ks), XMM-Newton (∼75 ks), and NICER (∼65 ks) pointings. NGC 4151 is the first Type-1 radio-quiet Seyfert galaxy with constrained polarization properties for the X-ray corona. Despite the lower flux state in which the source was re-observed and the resulting higher contribution of the constant reflection component in the IXPE energy band, our results are in agreement with the first detection. From polarimetric analysis, a polarization degree Π = 4.7 ± 1.3% and polarization angle Ψ = 77° ± 8° east of north (68% c.l.) were derived in the 2.0–8.0 keV energy range. Combining the two observations leads to polarization properties that are more constrained than those of the individual detections, showing Π = 4.5 ± 0.9% and Ψ = 81° ± 6° (with a detection significance of ∼4.6σ). The observed polarization angle aligns very well with the radio emission in this source, supporting, together with the significant polarization degree, a slab or wedge geometry for the X-ray corona. However, a switch in the polarization angle at low energies (37° ±7° in the 2–3.5 keV bin) suggests the presence of another component. When it is included in the spectro-polarimetric fit, a high polarization degree disfavors an interpretation in terms of a leakage through the absorbers, instead pointing to scattering from some kind of mirror. [ABSTRACT FROM AUTHOR]

Context. PKS 0903−57 is a little-studied γ-ray blazar that has recently attracted considerable interest due to the strong flaring episodes observed since 2020 in high energy (HE; 100 MeV ≤ E ≤ 100 GeV) and very high-energy (VHE; 100 GeV ≤ E ≤ 10 TeV) γ-rays. Its nature and properties are still not well determined. In particular, it is unclear whether PKS 0903−57 is a BL Lac or a flat-spectrum radio quasar (FSRQ), while its redshift estimation relies on a possibly misassociated low signal-to-noise ratio spectrum. Aims. Our aims were to reliably measure the redshift of the blazar, and to determine its spectral type and luminosity in the optical range. Methods. We performed spectroscopy of the optical counterpart of the blazar using the South African Large Telescope (SALT) and the Very Large Telescope (VLT), and monitored it photometrically with the Rapid Eye Mount (REM) telescope. Results. We firmly measured the redshift of the blazar as z = 0.2621 ± 0.0006 thanks to the detection of five narrow optical lines. The detection of a symmetric broad Hα line with full width at half maximum (FWHM) of 4020 ± 30 km/s together with a jet-dominated continuum leads us to classify it as a FSRQ. Finally, we detected with high significance a redshift offset (∼1500 km/s) between the broad line and the host. This is the first time that such an offset has been unequivocally detected in a VHE blazar, possibly pointing to a very peculiar accretion configuration, a merging system, or a recoiling black hole. [ABSTRACT FROM AUTHOR]

Context. The appearance of the jets and lobes of some radio galaxies makes it difficult to assign them to a known class of objects. This is often due to the activity of the central engine and/or interactions with the environment, as well as projection effects. Aims. We analyse the radio data for an apparently asymmetric radio source 4C 70.19, which is associated with the giant elliptical galaxy NGC 6048. The source shows distorted radio jets and lobes, one of which bends by 180°. The aim of our study is to explain the nature of the observed distortions. Methods. We used LOFAR, Effelsberg, and VLA radio data in a wide range of frequencies. At high frequencies, we also used radio polarimetry to study the properties of the magnetic fields. Additionally, we made use of optical, infra-red, and X-ray data. Results. Polarisation data suggest shearing of the magnetic fields at points where the jets bend. The low-frequency LOFAR map at 145 MHz, as well as the sensitive single-dish Effelsberg map at 8.35 GHz, reveal previously undetected diffuse emission around the source. The rotation measure (RM) derived from the polarimetric data allowed us to estimate the density of the medium surrounding the source, which agrees with typical densities of the intergalactic medium or the outer parts of insterstellar halos. Conclusions. We propose that the southern jet is bent in the same manner as the northern one, but that it is inclined to the sky plane. Both these bends are likely caused by the orbital motion within the galaxy group, as well as interactions with the intergalactic medium. Our analyses suggest that, despite its complex morphology, 4C 70.19 seems to be intrinsically symmetric with a physical extent of up to 600 kpc, and that the diffuse emission detected in our high-sensitivity maps is related to radio plumes that are expanding behind the source. [ABSTRACT FROM AUTHOR]

Context. Accretion onto supermassive black holes at close to the Eddington rate is expected to drive powerful winds, which have the potential to majorly influence the properties of the host galaxy. Theoretical models of such winds can simultaneously explain observational correlations between supermassive black holes and their host galaxies, such as the M − σ relation, and the powerful multi-phase outflows that are observed in a number of active galaxies. Analytic models developed to understand these processes usually assume simple galaxy properties, namely spherical symmetry and a smooth gas distribution with an adiabatic equation of state. However, the interstellar medium in real galaxies is clumpy and cooling is important, complicating the analysis. Aims. We wish to determine how gas turbulence, uneven density distribution, and cooling influence the development of active galactic nucleus (AGN) wind-driven outflows and their global properties on kiloparsec scales. Methods. We calculated a suite of idealised hydrodynamical simulations of AGN outflows designed to isolate the effects of turbulence and cooling, both separately and in combination. All simulations initially consisted of a 1 kpc gas shell with an AGN in the centre. We measured the main outflow parameters – the velocity, the mass outflow rate (Ṁout), and the momentum (ṗoutc/LAGN) and energy (Ėout/LAGN) loading factors – as the system evolves over 1.2 Myr and estimated plausible observationally derived values. Results. We find that adiabatic simulations approximately reproduce the analytical estimates of outflow properties independently of the presence or absence of turbulence and clumpiness. Cooling, on the other hand, has a significant effect, reducing the outflow energy rate by one to two orders of magnitude in the smooth simulations and by up to one order of magnitude in the turbulent ones. The interplay between cooling and turbulence depends on AGN luminosity: in Eddington-limited AGN, turbulence enhances the coupling between the AGN wind and the gas, while in lower-luminosity simulations, the opposite is true. This mainly occurs because dense gas clumps are resilient to low-luminosity AGN feedback but get driven away by high-luminosity AGN feedback. The overall properties of multi-phase outflowing gas in our simulations qualitatively agree with observations of multi-phase outflows, although there are some quantitative differences. We also find that using 'observable' outflow properties leads to their parameters being underestimated by a factor of a few compared with real values. Conclusions. We conclude that the AGN wind-driven outflow model is capable of reproducing realistic outflow properties in close-to-realistic galaxy setups and that the M − σ relation can be established without efficient cooling of the shocked AGN wind. Furthermore, we suggest ways to improve large-scale numerical simulations by accounting for the effects of AGN wind. [ABSTRACT FROM AUTHOR]

Context. We investigate active galactic nuclei (AGN) feeding through the molecular gas (CO(2−1) emission) properties of the local Seyfert 1 galaxy NGC 4593, using Atacama Large Millimeter Array (ALMA) observations and other multi-wavelength data. Aims. Our study aims to understand the interplay between the AGN and the interstellar medium (ISM) in this galaxy, examining the role of the AGN in steering gas dynamics within its host galaxy, evaluating the energy injected into the ISM, and determining whether gas is inflowing or outflowing from the galaxy. Methods. After reducing the ALMA CO(2−1) images, we employed two models, 3D-BAROLO and DISCFIT, to construct a disc model and fit its emission to the ALMA data. Additionally, we used photometric data to build a spectral energy distribution (SED) and apply the CIGALE code to derive key physical properties of the AGN and its host. Results. Our analysis reveals a complex interplay within NGC 4593, including a clear rotational pattern, the influence of a non-axisymmetric bar potential, and a central molecular zone (CMZ)-like ring. We observe an outflow of CO(2−1) gas along the minor axis, at a distance of ∼220 pc from the nucleus. The total molecular gas mass is estimated to be 1 − 5 × 108 M⊙, with non-circular motions contributing 10%. Our SED analysis indicates an AGN fraction of 0.88 and a star formation rate (SFR) of 0.42 M⊙ yr−1. Conclusions. These findings highlight the complex dynamics in the centre of NGC 4593, which are significantly influenced by the presence of the AGN. The overall physical properties of this system suggest that the AGN has a substantial impact on the evolution of NGC 4593. [ABSTRACT FROM AUTHOR]

Context. Double-double radio galaxies are characterized by intermittent jet-formation activity. The exact reasons for this behavior are not yet fully understood. Studying these objects and their environment allows us to find common characteristics and compare them with the general population of radio galaxies. 3C 219 is a well-known and thoroughly studied radio galaxy. Among the many explanations for its unusual "partial jet" structure, intermittent activity seems to be the leading one. However, this hypothesis has never been tested using aging analysis. Aims. The aim of this paper is to put constraints on the active galactic nucleus duty cycle and dynamics of radio lobe expansion in 3C 219, in both the inner and outer double. This will provide us with information on the behavior of the central engine and the interaction of the radio lobes with the ambient medium, allowing us to verify whether the structure of 3C 219 is the result of intermittent activity and to search for its possible causes. Methods. We performed a spectral aging analysis of the 3C 219 double-double radio galaxy using archival Karl G. Jansky Very Large Array and Low Frequency Array data. We present detailed spectral age maps and constructed a spectral age profile. We compared ratios of linear sizes and luminosities in individual phases of activity with lobe expansion velocities in the plane of the sky derived from the age profile to infer hot-spot advance velocities through the surrounding medium and the orientation of the jet axes. Results. The galaxy shows a general asymmetry in the distribution of plasma with respect to the inferred jet axis in the original phase of activity, suggesting an influence of the intracluster medium on the formation of the radio structure. The advance speed of hot spots in the outer double is typical of classical FRII sources expanding into an ambient thermal medium, while for the inner double, the lower limit is estimated to be ∼0.28 c. The radio galaxy has experienced a very short quiescent period of no more than 2 Myr, which is ≲7% of its total lifetime. Conclusions. The most plausible explanation for the double-double radio structure in 3C 219 is a rapid jet reorientation along the line of sight, which may be the result of a minor merger. Further study of the 3C 219 inner double is needed. High-resolution maps are required to probe its structure in sufficient detail, while high-frequency observations are necessary to better constrain the durations of the quiescent and restarted phases. [ABSTRACT FROM AUTHOR]

This study presents the detection of a high-frequency quasi-periodic oscillation (QPO) in the Seyfert galaxy NGC 1365 based on observational data obtained by XMM-Newton in January 2004. Utilizing the weighted wavelet Z-transform (WWZ) and Lomb-Scargle periodogram (LSP) methods, a QPO signal is identified at a frequency of 2.19 × 10−4 Hz (4566 s), with a confidence level of 3.6σ. The signal is notably absent in the lower 0.2–1.0 keV energy band, with the primary contribution emerging from the 2.0–10.0 keV band, where the confidence level reaches 3.9σ. Spectral analysis shows that there are multiple absorption and emission lines in the high-energy band (> 6 keV). The correlation between the QPO frequency (fQPO) and the mass of the central black hole (MBH) of NGC 1365 aligns with the established logarithmic trend observed across black holes, indicating the QPO is of high frequency. This discovery provides new clues for studying the generation mechanism of QPOs in Seyfert galaxies, which helps us understand the accretion process around supermassive black holes and the characteristics of strong gravitational fields in active galactic nuclei. [ABSTRACT FROM AUTHOR]

We present one of the largest multiwavelength studies of simultaneous optical-to-X-ray spectral energy distributions (SEDs) of unobscured (NH < 1022 cm−2) active galactic nuclei (AGN) in the local Universe. Using a representative sample of hard-X-ray-selected AGN from the 70-month Swift/BAT catalog, with optical/UV photometric data from Swift/UVOT and X-ray spectral data from Swift/XRT, we constructed broadband SEDs of 236 nearby AGN (0.001 < z < 0.3). We employed GALFIT to estimate host galaxy contamination in the optical/UV and determine the intrinsic AGN fluxes. We used an absorbed power law with a reflection component to model the X-ray spectra and a dust-reddened multi-temperature blackbody to fit the optical/UV SED. We calculated intrinsic luminosities at multiple wavelengths, total bolometric luminosities (Lbol), optical-to-X-ray spectral indices (αox), and multiple bolometric corrections (κλ) in the optical, UV, and X-rays. We used black hole masses obtained by reverberation mapping and the virial method to estimate Eddington ratios (λEdd) for all our AGN. We confirm the tight correlation (scatter = 0.45 dex) between UV (2500 Å) and X-ray (2 keV) luminosity for our sample. We observe a significant decrease in αox with Lbol and λEdd, suggesting that brighter sources emit more UV photons per X-rays. We report a second-order regression relation (scatter = 0.15 dex) between the 2–10 keV bolometric correction (κ2 − 10) and αox, which is useful to compute Lbol in the absence of multiband SEDs. We also investigate the dependence of optical/UV bolometric corrections on the physical properties of AGN and obtain a significant increase in the UV bolometric corrections (κW2 and κM2) with Lbol and λEdd, unlike those in the optical (κV and κB), which are constant across five orders of Lbol and λEdd. We obtain significant dispersions (∼0.1–1 dex) in all bolometric corrections, and hence recommend using appropriate relations with observed quantities while including the reported scatter, instead of their median values. [ABSTRACT FROM AUTHOR]

The Euclid space mission will cover over 14 000 deg2 with two optical and near-infrared spectro-photometric instruments, and is expected to detect around ten million active galactic nuclei (AGN). This unique data set will make a considerable impact on our understanding of galaxy evolution in general, and AGN in particular. For this work we identified the best colour selection criteria for AGN, based only on Euclid photometry or including ancillary photometric observations, such as the data that will be available with the Rubin Legacy Survey of Space and Time (LSST) and observations already available from Spitzer/IRAC. The analysis was performed for unobscured AGN, obscured AGN, and composite (AGN and star-forming) objects. We made use of the spectro-photometric realisations of infrared-selected targets at all-z (SPRITZ) to create mock catalogues mimicking both the Euclid Wide Survey (EWS) and the Euclid Deep Survey (EDS). Using these mock catalogues, we estimated the best colour selection, maximising the harmonic mean (F1) of: (a) completeness, that is, the fraction of AGN correctly selected with respect to the total AGN sample; and (b) purity, that is, the fraction of AGN inside the selection with respect to the selected sample. The selection of unobscured AGN in both Euclid surveys (Wide and Deep) is possible with Euclid photometry alone with F1 = 0.22–0.23 (Wide and Deep), which can increase to F1 = 0.43–0.38 (Wide and Deep) if we limit out study to objects at z > 0.7. Such a selection is improved once the Rubin/LSST filters, that is, a combination of the u, g, r, or z filters, are considered, reaching an F1 score of 0.84 and 0.86 for the EDS and EWS, respectively. The combination of a Euclid colour with the [3.6]−[4.5] colour, which is possible only in the EDS, results in an F1 score of 0.59, improving the results using only Euclid filters, but worse than the selection combining Euclid and LSST colours. The selection of composite (fAGN = 0.05–0.65 at 8–40 μm) and obscured AGN is challenging, with F1 ≤ 0.3 even when including Rubin/LSST or IRAC filters. This is unsurprising since it is driven by the similarities between the broad-band spectral energy distribution of these AGN and star-forming galaxies in the wavelength range 0.3–5 μm. [ABSTRACT FROM AUTHOR]

The energy released by active galactic nuclei (AGN) has the potential to heat or remove the gas of the ISM, thus likely impacting the cold molecular gas reservoir of host galaxies at first, with star formation following as a consequence on longer timescales. Previous works on high-z galaxies, which compared the gas content of those without identified AGN, have yielded conflicting results, possibly due to selection biases and other systematics. To provide a reliable benchmark for galaxy evolution models at cosmic noon (z = 1 − 3), two surveys were conceived: SUPER and KASHz, both targeting unbiased X-ray-selected AGN at z > 1 that span a wide bolometric luminosity range. In this paper we assess the effects of AGN feedback on the molecular gas content of host galaxies in a statistically robust, uniformly selected, coherently analyzed sample of AGN at z = 1 − 2.6, drawn from the KASHz and SUPER surveys. By using targeted and archival ALMA data in combination with dedicated SED modeling, we retrieve CO and far-infrared (FIR) luminosity as well as M* of SUPER and KASHz host galaxies. We selected non-active galaxies from PHIBBS, ASPECS, and multiple ALMA/NOEMA surveys of submillimeter galaxies in the COSMOS, UDS, and ECDF fields. By matching the samples in redshift, stellar mass, and FIR luminosity, we compared the properties of AGN and non-active galaxies within a Bayesian framework. We find that AGN hosts at given FIR luminosity are on average CO depleted compared to non-active galaxies, thus confirming what was previously found in the SUPER survey. Moreover, the molecular gas fraction distributions of AGN and non-active galaxies are statistically different, with the distribution of AGN being skewed to lower values. Our results indicate that AGN can indeed reduce the total cold molecular gas reservoir of their host galaxies. Lastly, by comparing our results with predictions from three cosmological simulations (TNG, Eagle, and Simba) filtered to match the properties of observed AGN, AGN hosts, and non-active galaxies, we confirm already known discrepancies and highlight new discrepancies between observations and simulations. [ABSTRACT FROM AUTHOR]

Aims. The direct redshift determination of BL Lac objects is highly challenging as the emission in the optical and near-infrared bands is largely dominated by the non-thermal emission from the relativistic jet, which points very close to our line of sight. Therefore, the optical spectra of BL Lac objects often show no spectral lines from the host galaxy. In this work, we aim to overcome this difficulty by attempting to detect the host galaxy and derive redshift constraints based on assumptions on the galaxy magnitude ('imaging redshifts'). Methods. Imaging redshifts were derived by obtaining deep optical images under good seeing conditions, making it possible to detect the host galaxy as a weak extension of the point-like source. We then derived the imaging redshift by using the host galaxy as a standard candle, employing two different methods. Results. We determine the imaging redshift for 9 out of 17 blazars that we observed as part of this programme. The redshift range of these targets is 0.28–0.60, and the two methods used to derive the redshift give very consistent results within the uncertainties. We also performed a detailed comparison of the imaging redshifts with those obtained using other methods, such as direct spectroscopic constraints or looking for groups of galaxies close to the blazar. We show that the constraints from the different methods are consistent and that combining the three constraints narrows down the redshift. For example, in the case of J2156.0+1818, which is the most distant source for which we detect the host galaxy, the redshift range is narrowed to 0.63 < z < 0.71. This makes the source interesting for future studies of extragalactic background light in the Cherenkov Telescope Array Observatory era. [ABSTRACT FROM AUTHOR]

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

Context. Extreme continuum variability in extragalactic nuclear sources can indicate extreme changes in accretion flows onto supermassive black holes. Aims. We explore the multiwavelength nature of a continuum flare in the Seyfert LCRS B040659.9−385922. The all-sky X-ray surveys conducted by the Spectrum Roentgen Gamma (SRG)/extended ROentgen Survey with an Imaging Telescope Array (eROSITA) showed that its X-ray flux increased by a factor of roughly five over six months, and concurrent optical photometric monitoring with the Asteroid Terrestrial-impact Last Alert System (ATLAS) showed a simultaneous increase. Methods. We complemented the eROSITA and ATLAS data by triggering a multiwavelength follow-up monitoring program (X-ray Multi-Mirror Mission: XMM-Newton, Neutron star Interior Composition Explorer: NICER; optical spectroscopy) to study the evolution of the accretion disk, broad-line region, and X-ray corona. During the campaign, X-ray and optical continuum flux subsided over roughly six months. Our campaign includes two XMM-Newton observations, one taken near the peak of this flare and the other taken when the flare had subsided. Results. The soft X-ray excess in both XMM-Newton observations was power law-like (distinctly nonthermal). Using a simple power law, we observed that the photon index of the soft excess varies from a steep value of Γ ∼ 2.7 at the flare peak to a relatively flatter value of Γ ∼ 2.2 as the flare subsided. We successfully modeled the broadband optical/UV/X-ray spectral energy distribution at both the flare peak and post-flare times with the AGNSED model, incorporating thermal disk emission into the optical/UV and warm thermal Comptonization in the soft X-rays. The accretion rate falls by roughly 2.5, and the radius of the hot Comptonizing region increases from the flaring state to the post-flare state. Additionally, from the optical spectral observations, we find that the broad He IIλ4686 emission line fades significantly as the optical/UV/X-ray continuum fades, which could indicate a substantial flare of disk emission above 54 eV. We also observed a redshifted broad component in the Hβ emission line that is present during the high flux state of the source and disappears in subsequent observations. Conclusions. A sudden strong increase in the local accretion rate in this source manifested itself via an increase in accretion disk emission and in thermal Comptonized emission in the soft X-rays, which subsequently faded. The redshifted broad Balmer component could be associated with a transient kinematic component distinct from that comprising the rest of the broad-line region. [ABSTRACT FROM AUTHOR]

We present a comprehensive study of the physical origin of radio emission in optical quasars at redshifts z < 2.5. We focus particularly on the associations between compact radio emission, dust reddening, and outflows identified in our earlier work. Leveraging the deepest low-frequency radio data available to date (LoTSS Deep DR1), we achieve radio detection fractions of up to 94%, demonstrating the virtual ubiquity of radio emission in quasars, and a continuous distribution in radio loudness. Through our analysis of radio properties, combined with spectral energy distribution modelling of deep multiwavelength photometry, we establish that the primary source of radio emission in quasars is the active galactic nucleus (AGN), rather than star formation. Modelling the dust reddening of the accretion disc emission shows a continuous increase in radio detection in quasars as a function of the reddening parameter E(B − V), suggesting a causal link between radio emission and dust reddening. Confirming previous findings, we observe that the radio excess in red quasars is most pronounced for sources with compact radio morphologies and intermediate radio loudness. We find a significant increase in [O III] and C IV outflow velocities for red quasars not seen in our control sample, with particularly powerful [O III] winds in those around the threshold from radio-quiet to radio-loud. Based on the combined characterisation of radio, reddening, and outflow properties in our sample, we favour a model in which the compact radio emission observed in quasars originates in compact radio jets and their interaction with a dusty, circumnuclear environment. In particular, our results align with the theory that jet-induced winds and shocks resulting from this interaction are the origin of the enhanced radio emission in red quasars. Further investigation of this model is crucial for advancing our understanding of quasar feedback mechanisms and their role in galaxy evolution. [ABSTRACT FROM AUTHOR]

JWST has revealed a class of numerous, extremely compact sources with rest-frame red optical/near-infrared (NIR) and blue ultraviolet (UV) colours nicknamed 'little red dots'. We present one of the highest signal-to-noise ratio JWST NIRSpec prism spectra of a little red dot, J0647_1045 at z = 4.5319 ± 0.0001, and examine its NIRCam morphology to differentiate the origin of the UV and optical/NIR emission and elucidate the nature of the little red dot phenomenon. J0647_1045 is unresolved (re ≲ 0.17 kpc) in the three NIRCam long-wavelength filters but significantly extended (re = 0.45 ± 0.06 kpc) in the three short-wavelength filters, indicating a red compact source in a blue star-forming galaxy. The spectral continuum shows a clear change in slope, from blue in the optical/UV to red in the rest-frame optical/NIR, which is consistent with two distinct components fit by power laws with different attenuations: AV = 0.38 ± 0.01 (UV) and AV = 5.61 ± 0.04 (optical/NIR). Fitting the Hα line requires both broad (full width at half maximum of ∼4300 ± 100 km s−1) and narrow components, but none of the other emission lines, including Hβ, show evidence of broadness. We calculated AV = 0.9 ± 0.4 from the Balmer decrement using narrow Hα and Hβ and AV > 4.1 ± 0.1 from broad Hα and an upper limit on broad Hβ, which is consistent with blue and red continuum attenuation, respectively. Based on a single-epoch Hα line width, the mass of the central black hole is 8−0.4+0.5 × 108 M⊙. Our findings are consistent with a multi-component model, in which the optical/NIR and broad lines arise from a highly obscured, spatially unresolved region, likely a relatively massive active galactic nucleus, while the less obscured UV continuum and narrow lines arise, at least partly, from a small but spatially resolved star-forming host galaxy. [ABSTRACT FROM AUTHOR]

Context. Active galactic nuclei (AGNs) are known to be variable across all wavelengths. Significant observational efforts have been invested in the last decade in studying their ultraviolet (UV) and optical variability. Long and densely sampled, multi-wavelength monitoring campaigns of numerous Seyfert galaxies have been conducted with the aim of determining the X-ray/UV/optical continuum time lags. Time-lag studies can be used to constrain theoretical models. The observed time lags can be explained by thermal reprocessing of the X-rays illuminating the accretion disc (known as the X-ray reverberation model). However, the observed light curves contain more information that can be used to further constrain physical models. Aims. Our primary objective is to investigate whether, in addition to time lags, the X-ray reverberation model can also explain the UV/optical variability amplitude of nearby Seyferts. Methods. We measured the excess variance of four sources (namely Mrk 509, NGC 4151, NGC 2617, and Mrk 142) as a function of wavelength using data from archival long, multi-wavelength campaigns with Swift, and ground-based telescopes. We also computed the model excess variance in the case of the X-ray reverberation model by determining the disc's transfer function and assuming a bending power law for the X-ray power spectrum. We tested the validity of the model by comparing the measured and model variances for a range of accretion rates and X-ray source heights. Results. Our main result is that the X-ray thermal reverberation model can fit both the continuum, UV/optical time lags, as well as the variance (i.e. the variability amplitude) in these AGNs, for the same physical parameters. Our results suggest that the accretion disc is constant and that all the observed UV/optical variations, on timescales of days and up to a few weeks, can be fully explained by the variable X-rays as they illuminate the accretion disc. [ABSTRACT FROM AUTHOR]

We analyzed Multi Unit Spectroscopic Explorer observations of 42 local z ≲ 0.1 type 1 active galactic nucleus (AGN) host galaxies taken from the Palomar-Green quasar sample and the close AGN reference survey. Our goal was to study the relation between the black hole mass (M•) and bulge stellar velocity dispersion (σe) for type 1 active galaxies. The sample spans black hole masses of 106.0 − 109.2 M⊙, bolometric luminosities of 1042.9 − 1046.0 erg s−1, and Eddington ratios of 0.006 − 1.2. We avoided AGN emission by extracting the spectra over annular apertures. We modeled the calcium triplet stellar features and measured stellar velocity dispersions of σ* = 60 − 230 km s−1 for the host galaxies. We find stellar velocity dispersion values in agreement with previous measurements for local (z ≲ 0.1) AGN host galaxies, but slightly lower compared with those reported for nearby X-ray-selected type 2 quasars. Using a novel annular aperture correction recipe to estimate σe from σ* that considers the bulge morphology and observation beam-smearing, we estimate flux-weighted σe = 60 − 250 km s−1. If we consider the bulge type when estimating M•, we find no statistical difference between the distributions of AGN hosts and the inactive galaxies on the M•–σe plane for M• ≲ 108 M⊙. Conversely, if we do not consider the bulge type when computing M•, we find that both distributions disagree. We find no correlation between the degree of offset from the M•–σe relation and Eddington ratio for M• ≲ 108 M⊙. The current statistics preclude firm conclusions from being drawn for the high-mass range. We argue these observations support notions that a significant fraction of the local type 1 AGNs and quasars have undermassive black holes compared with their host galaxy bulge properties. [ABSTRACT FROM AUTHOR]

Spectroscopy with the James Webb Space Telescope has opened the possibility of identifying moderate-luminosity active galactic nuclei (AGNs) in the early Universe, at and beyond the epoch of re-ionisation, complementing previous surveys of much more luminous (and much rarer) quasars. We present 12 new AGNs at 4 < z < 7 in the JADES survey (in addition to the previously identified AGN in GN-z11 at z = 10.6) revealed through the detection of a broad-line region (BLR) seen in the Balmer emission lines. The depth of JADES, together with the use of three different spectral resolutions, enables us to probe a lower-mass regime relative to previous studies. In a few cases, we find evidence for two broad components of Hα, which suggests that these could be candidate merging black holes (BHs), although a complex BLR geometry cannot be excluded. The inferred BH masses range from 8 × 107 M⊙ down to 4 × 105 M⊙, interestingly probing the regime expected for direct collapse BHs. The inferred AGN bolometric luminosities (∼1044 − 1045 erg/s) imply accretion rates that are < 0.5 times the Eddington rate in most cases. However, small BHs, with MBH ∼ 106 M⊙, tend to accrete at Eddington or super-Eddington rates. These BHs at z ∼ 4–11 are over-massive relative to their host galaxies' stellar masses when compared to the local MBH − Mstar relation, even approaching MBH ∼ Mstar, as was expected from heavy BH seeds and/or super-Eddington accretion scenarios. However, we find that these early BHs tend to be more consistent with the local relation between MBH and velocity dispersion, as well as between MBH and dynamical mass, suggesting that these are more fundamental and universal relations. On the classical, optical narrow-line excitation-diagnostic diagrams, these AGNs are located in the region that is locally occupied by star-forming galaxies, implying that they would be missed by the standard classification techniques if they did not display broad lines. Their location on the diagram is consistent with what is expected for AGNs hosted in metal-poor galaxies (Z ∼ 0.1 − 0.2 Z⊙). The fraction of broad-line AGNs with LAGN > 1044 erg/s among galaxies in the redshift range of 4 < z < 6 is about 10%, suggesting that the contribution of AGNs and their hosts to the re-ionisation of the Universe is > 10%. [ABSTRACT FROM AUTHOR]

Aims. A new method of determining the parameters of close binary systems of supermassive black holes (SMBHs) and the level of gravitational waves (GWs) on the Earth's surface are proposed. Methods. Data are presented from long-term monitoring of possibly the most powerful emitter in the Universe, S 0528+134, at five frequencies in the radio range from 4.8 GHz to 37 GHz, obtained by the RT-22 radio telescope of the Radio Astronomy Laboratory CrAO in Simeiz, the RT-26 radio telescope at Michigan Observatory, and the 40 m radio telescope of the Owens Valley Radio Observatory. Results. The dynamics of powerful flares that have occurred in the object since its discovery in a sky survey in 1970 were considered. The main physical characteristics of binary SMBHs located in the central regions of the system were obtained. These data were used to find the masses of the SMBH companions, the parameters of their orbits, the energy reserve of the system, and the lifetime of the object before the SMBHs' merger. The level of GWs on the Earth's surface was determined and the possibility of their detection by International Pulsar Timing Array (IPTA) GW detectors was considered. [ABSTRACT FROM AUTHOR]

Supermassive black holes (SMBHs) at the centers of active galaxies are fed by accretion disks that radiate from the infrared or optical to the X-ray bands. Several types of objects can orbit SMBHs, including massive stars, neutron stars, clouds from the broad- and narrow-line regions, and X-ray binaries. Isolated black holes with a stellar origin (BHs of ∼10 M⊙) should also be present in large numbers within the central parsec of the galaxies. These BHs are expected to form a cluster around the SMBH as a result of the enhanced star formation rate in the inner galactic region and the BH migration caused by gravitational dynamical friction. However, except for occasional microlensing effects on background stars or gravitational waves from binary BH mergers, the presence of a BH population is hard to verify. In this paper, we explore the possibility of detecting electromagnetic signatures of a central cluster of BHs when the accretion rate onto the central SMBH is greater than the Eddington rate. In these supercritical systems, the accretion disk launches powerful winds that interact with the objects orbiting the SMBH. Isolated BHs can capture matter from this dense wind, leading to the formation of small accretion disks around them. If jets are produced in these single microquasars, they could be sites of particle acceleration to relativistic energies. These particles in turn are expected to cool by various radiative processes. Therefore, the wind of the SMBH might illuminate the BHs through the production of both thermal and nonthermal radiation. [ABSTRACT FROM AUTHOR]

The structure of the accretion flow on to supermassive black holes is not well understood. Standard disc models match to zeroth-order in predicting substantial energy dissipation within optically thick material producing a characteristic strong blue/ultraviolet continuum. However, they fail at reproducing more detailed comparisons to the observed spectral shapes along with their observed variability. Based on stellar mass black holes within our Galaxy, accretion discs should undergo a transition into an X-ray hot, radiatively inefficient flow, below a (mass scaled) luminosity of |$\sim 0.02\, L_{\rm {Edd}}$|⁠. While this has been seen in limited samples of nearby low-luminosity active galactic nuclei (AGN) and few rare changing-look AGN, it is not at all clear whether this transition is present in the wider AGN population across cosmic time. A key issue is the difficulty in disentangling a change in spectral state from increased dust obscuration and/or host galaxy contamination, effectively drowning out the AGN emission. Here, we use the new eROSITA eFEDS Survey to identify unobscured AGN from their X-ray emission, matched to excellent optical imaging from Subaru's Hyper Suprime-Cam; allowing the subtraction of the host galaxy contamination. The resulting, uncontaminated, AGN spectra reveal a smooth transition from a strongly disc-dominated state in bright AGN, to the collapse of the disc into an inefficient X-ray plasma in the low-luminosity AGN, with the transition occurring at |$\sim 0.02\, L_{\rm {Edd}}$|⁠ ; revealing fundamental aspects of accretion physics in AGN. [ABSTRACT FROM AUTHOR]

We explore the relations between the gas-phase metallicity radial profiles (few hundred inner parsec) and multiple galaxy properties for 15 Seyfert galaxies from the active galactic nuclei integral field spectroscopy sample using optical integral field unit observations from Gemini Multi-Object Spectrograph (GMOS) and Multi Unit Spectroscopic Explorer (MUSE) processed archival data. The data were selected at |$z \lesssim 0.013$| within black hole mass range |$\left[6\lt \log \left(M_{\rm BH}/{\rm M_\odot } \right)\lt 9\right]$| with moderate 14–150-keV X-ray luminosities |$\left[42\, \lesssim \, \log L_X (\rm erg\, s^{-1})\, \lesssim \, 44\right]$|⁠. We estimated the gas-phase metallicity using the strong-line methods and found mean values for the oxygen-dependent (⁠|$Z \sim 0.75\, \mathrm{Z}_\odot$|⁠) and nitrogen-dependent (⁠|$Z \sim 1.14\, \mathrm{Z}_\odot$|⁠) calibrations. These estimates show excellent agreement with |$\Delta Z \approx 0.19$| and 0.18 dex between the mean values from the two strong-line calibrations for GMOS and MUSE, respectively, consistent with the order of metallicity uncertainty via the strong-line methods. We contend that our findings align with a scenario wherein local Seyferts have undergone seamless gas accretion histories, resulting in positive metallicity profiles over an extended period of time, thereby providing insights into galaxy evolution and the chemical enrichment or depletion of the universe. Additionally, we argue that metal-poor gas inflow from the local interstellar medium and accreted through the circumgalactic medium on to the galaxy systems regulates the star formation processes by diluting their central metallicity and inverting their gas-phase metallicity radial gradients, producing a more prominent anticorrelation between gas-phase metallicity and Eddington ratio. [ABSTRACT FROM AUTHOR]

Molecular gas is the key probe for the complex interaction between the accretion of black holes and star formation of the host galaxy of active galactic nuclei (AGN). The molecular gas discovered around the AGN indicates that this gas is providing fuel for the AGN. According to the theoretical model of the relativistic jet, the spin of a black hole enhances the relativistic jet of AGN. The spin of the black hole is used as an indicator of AGN activity. Therefore, we study the relationship between the activity of AGN and molecular gas. We find a significant strong correlation between molecular gas fraction and CO luminosity and black hole spin for the early-type galaxies. However, there is no correlation between molecular gas fraction and CO luminosity and black hole spin for the late-type galaxies. These results indicate that the spin of black holes mainly regulates the accretion of molecular gas in massive early-type galaxies. The activity of AGN depends on the amount of gas. [ABSTRACT FROM AUTHOR]

In this paper we explore the properties of the |$z=6.853$| obscured hyperluminous quasar COS-87259, discovered in the Cosmological Evolution Survey (COSMOS) field, with our recently developed Bayesian spectral energy distribution (SED) fitting code SMART (Spectral energy distributions Markov chain Analysis with Radiative Transfer models). SMART fits SEDs exclusively with multicomponent radiative transfer models that constitute four different types of pre-computed libraries for the active galactic nucleus (AGN) torus, the starburst, and the spheroidal or disc host. We explore two smooth radiative transfer models for the AGN torus and two two-phase models, in order to put constraints on the AGN fraction of the galaxy, the black hole mass, and its star formation rate (SFR). We find that either of the smooth tapered disc or the two-phase flared disc models provide a good fit to the SED of COS-87259. The best-fitting models predict an AGN fraction in the range |$86-92$| per cent, a bolometric AGN luminosity of |$5.8-10.3 \times 10^{13} L_\odot$|⁠ , a black hole mass of |$1.8-3.2 \times 10^{9} M_\odot$| (assuming the quasar is accreting at the Eddington limit), and an SFR in the range |$1985-2001~M_\odot \rm yr^{-1}$|⁠. The predicted space density of such objects in the redshift range |$4-7$| is |$\sim 20$| times more than that of co-eval unobscured quasars. [ABSTRACT FROM AUTHOR]

We present a comprehensive analysis of the X-ray spectral properties of 198 newly identified active galactic nuclei (AGNs), leveraging archival data from the Chandra X-ray Observatory. All these AGNs exhibit a power-law spectral signature spanning a broad energy range of |$0.5{\!-\!}7.0$| keV, characterized by the photon index (⁠|$\Gamma$|⁠) values ranging from |$0.3^{+0.16}_{-0.14}$| to |$2.54^{+0.14}_{-0.13}$|⁠. Particularly, 76 of these AGNs display discernible levels of intrinsic absorption, after considering the Galactic absorption. The column densities associated with this local absorption (⁠|$n_{\rm H}^{\rm local}$|⁠) are within a range of |${\sim} 10^{19}{\!-\!}10^{22}\ {\rm cm^{-2}}$|⁠. We study the cosmological evolution of AGNs using the variation of |$n_{\rm H}^{\rm local}$| and |$\Gamma$| with their estimated redshift. The intrinsic spectral signature did not reveal any significant cosmological evolution; however, a deficit of hard sources at high redshift is possibly intrinsic. Our sample covers several orders of broad-band intrinsic luminosity (⁠|$L_{\rm B}^{\rm intr}$|⁠) ranging from |$4.59^{+0.41}_{-0.41} \times 10^{42}$| to |$2.4^{+0.12}_{-0.12} \times 10^{46}\, {\rm erg~s}^{-1}$| with peak at 1.84 redshift. We also investigate the hardness–luminosity diagram to further probe the AGNs. We conduct a sanity check by applying our findings to known AGNs, and the results are consistent with our observations. [ABSTRACT FROM AUTHOR]

A ringed accretion disc (RAD) models a cluster of axis-symmetric co-rotating and/or counter-rotating tori orbiting in the equatorial plane of a central Kerr supermassive black hole. We discuss the time evolution of such a ringed disc within the general relativity framework. Our analysis presents a study of the evolving RAD properties using a thin-disc scheme and solving a diffusion-like evolution equation for a RAD in the Kerr space–time. In the first stage of evolution, there is the inter–disc interaction where the individual rings spread inwardly and outwardly, levelling the structure and forming a single distribution with maximum density determined by the initial spread of the component rings. Time-scales are dependent on viscosity prescriptions. The early time luminosity, dominated by the dynamics of the inner ringed structure, shows a clear mark of the inner ringed structure. The RAD eventually reaches a single disc phase, building accretion to the inner edge regulated by the inner edge boundary conditions. The late-time luminosity associated with the ringed disc follows a power law decline for the final single disc. In the sideline of this analysis, we also considered a modified prescription mimicking an effective turbulent viscosity in the early phases of the rings evolutions. [ABSTRACT FROM AUTHOR]

We present an analysis of 152 355 radio sources identified in the second data release of the LOFAR Two Metre Sky Survey (LoTSS-DR2) with Sloan Digital Sky Survey (SDSS) spectroscopic redshifts in the range |$0.00 \lt z \lt 0.57$|⁠. Using Monte Carlo simulations, we determine the reliability of each source exhibiting an excess in radio luminosity relative to that predicted from their H |$\alpha$| emission, and, for a subset of 124 023 sources we combine this measurement with a full BPT analysis. Using these two independent diagnostics, we determine the reliability of each source hosting a supermassive black hole of high or low Eddington-scaled accretion rate, and combine the measurements to determine the reliability of sources belonging to each of four physical classes of objects: star-forming galaxies (SFGs), radio-quiet active galactic nuclei (RQAGN), and high- or low-excitation radio galaxies (HERGs or emission-line LERGs). The result is a catalogue that enables user-defined samples of radio sources with a reliability threshold suited to their science goal, for example prioritizing purity or completeness. Here, we select high-confidence samples of radio sources (>90 per cent reliability) to report: 38 588 radio-excess AGNs in the LoTSS-DR2 sample (362 HERGs, and 12 648 emission-line LERGs), together with 38 729 SFGs, and 18 726 RQAGN. We validate these results through comparison to literature using independent emission-line measurements, and to widely adopted WISE photometric selection techniques. While our use of SDSS spectroscopy limits our current analysis to |$\sim 4$|  per cent of the LoTSS-DR2 catalogue, our method is directly applicable to data from the forthcoming WEAVE-LOFAR survey, which will obtain over a million spectra of 144 MHz selected sources. [ABSTRACT FROM AUTHOR]

We present observations of mid- J (J = 4–3 or J = 5–4) carbon monoxide (CO) emission lines and continuum emission from a sample of ten of the most luminous (L bol |$\ge$| 10 |$^{14}$|  L |$\rm \odot$| ) Hot Dust-Obscured Galaxies (Hot DOGs) discovered by the Wide-field Infrared Survey Explorer (WISE) with redshifts up to 4.6. We uncover broad spectral lines (FWHM |$\ge$| 400 km s |$^{-1}$|⁠) in these objects, suggesting a turbulent molecular interstellar medium (ISM) may be ubiquitous in Hot DOGs. A halo of molecular gas, extending out to a radius of 5 kpc is observed in W2305–0039, likely supplied by 940 km s |$^{-1}$| molecular outflows. W0831+0140 is plausibly the host of a merger between at least two galaxies, consistent with observations made using ionized gas. These CO(4–3) observations contrast with previous CO(1–0) studies of the same sources: the CO(4–3) to CO(1–0) luminosity ratios exceed 300 in each source, suggesting that the lowest excited states of CO are underluminous. These findings show that the molecular gas in Hot DOGs is consistently turbulent, plausibly a consequence of AGN feedback, triggered by galactic mergers. [ABSTRACT FROM AUTHOR]

'Bare' active galactic nuclei (AGN) are a subclass of Type 1 AGN that show little or no intrinsic absorption. They offer an unobscured view of the central regions of the AGN and therefore serve as ideal targets to study the relativistic reflection features originating from the innermost regions of the accretion disc. We present a detailed broad-band spectral analysis (0.3–70 keV) of one of the most luminous bare AGN in the local Universe, RBS 1124 (⁠|$z= 0.208$|⁠) using a new, co-ordinated high signal-to-noise observation obtained by XMM – Newton and NuSTAR. The source exhibits a power-law continuum with |$\Gamma \sim$| 1.8 along with a soft excess below 2 keV, a weak neutral iron line and curvature at high energies (⁠|${\sim} 30$|  keV). The broad-band spectrum, including the soft excess and the high-energy continuum, is well fit by the relativistic reflection model when the accretion disc is allowed to have densities of log |$(n_{\rm e}$| /cm |$^{-3}$|⁠) |$\gtrsim 19.2$|⁠. Our analysis therefore suggests that when high-density effects are considered, relativistic reflection remains a viable explanation for the soft excess. [ABSTRACT FROM AUTHOR]

In the era of massive photometric surveys, we explore several approaches to estimate the masses of supermassive black holes (SMBHs) in active galactic nuclei (AGNs) from optical ground-based imaging, in each case comparing to the independent SMBH mass measurement obtained from spectroscopic data. We select a case-study sample of 28 type 1 AGN hosted by nearby galaxies from the Galaxy And Mass Assembly (GAMA) survey. We perform multicomponent spectral decomposition, extract the AGN component, and calculate the SMBH mass from the broad H |$\alpha$| emission line width and luminosity. The photometric g and i band data is decomposed into AGN+spheroid(+disc)(+bar) components with careful surface brightness fitting. From these, the SMBH mass is estimated using its relation with the spheroid Sérsic index or effective radius (both used for the first time on ground-based optical imaging of AGN); and the more widely used scaling relations based on bulge or galaxy stellar mass. We find no correlation between the H |$\alpha$| -derived SMBH masses and those based on the spheroid Sérsic index or effective radius, despite these being the most direct methods involving only one scaling relation. The bulge or galaxy stellar mass based methods both yield significant correlations, although with considerable scatter and, in the latter case, a systematic offset. We provide possible explanations for this and discuss the requirements, advantages, and drawbacks of each method. These considerations will be useful to optimize strategies for upcoming high quality ground-based and space-borne sky surveys to estimate SMBH masses in large numbers of AGN. [ABSTRACT FROM AUTHOR]

The unified model of jetted active galactic nuclei (AGNs) based on intrinsic properties presumes that the blazar subtypes of BL Lacertae objects (BLs) and flat-spectrum radio quasars (FSRQs) are aligned equivalents of Fanaroff–Riley type I (FR I) and Fanaroff–Riley type II (FR II) radio galaxies (RGs) from where their parent sources are obtained. Using compiled radio, X-ray and γ -ray data of 397 Fermi Large Area Telescope (Fermi-LAT) blazars and 153 non-Fermi detected RGs, we computed the γ -ray core-dominance parameter (Rγ) and γ -ray emission components (beamed and unbeamed) to study the consequences of relativistic beaming and orientation effects on γ -ray properties of radio RGs, BLs and FSRQs. Data analysis shows that the distributions of RX and Rγ, on average, are consistent with the prediction of the unified scheme in which FSRQs and BLs are strongly beamed and inclined at smaller angles than RGs. Through statistical tests with chance probability, p < 0.05 , we find that the distributions of RX and Rγ for radio galaxies and the blazar subtypes are not significantly different. There is a regular positive trend (r > + 0.60 ) in the variation of radio core-dominance parameter – X-ray luminosity (R − L x ) data from radio galaxies to FSRQs through BLs, which suggests that radio galaxies could be relativistically less beamed population of jetted AGNs. The results are consistent with the unified model for radio galaxies and the conventional blazar subtypes. [ABSTRACT FROM AUTHOR]

We estimated values of spin, mass, and inclination angle for sample of 42 red quasars. Our estimations show that two objects: F2MS J1113+1244 and F2MS J1434+0935 with the highest Eddington ratios may have geometrically thick disk. Six objects: SDSS J0036‐0113, S82X 0040+0058, S82X 0118+0018, S82X 0303‐0115, FBQS J1227+3214, S82X 2328‐0028 may have "retrograde" rotation. Analysis of estimated spin values shows that red quasar population may contain Seyfert galaxies and NLS1. [ABSTRACT FROM AUTHOR]

The IceCube Collaboration has reported possible detections of high-energy neutrinos from nearby Seyfert galaxies. While central hot coronae are proposed as the primary neutrino production site, the exact coronal cosmic ray energy budget has been loosely constrained. In this study, we propose a new stringent upper bound on the coronal cosmic ray energy budget of Seyfert galaxies, considering both accretion dynamics and observed properties of radio-quiet Seyfert galaxies. Notably, even under the calorimetric condition where cosmic rays lose all their energy, our limit indicates that the coronal neutrino flux of NGC 1068 is about an order of magnitude fainter than the observed levels. This discrepancy suggests the need for further theoretical and observational investigations on the IceCube signals from Seyfert galaxies. [ABSTRACT FROM AUTHOR]

We conduct X-ray reverberation mapping and spectral analysis of the radio galaxy Centaurus A to uncover its central structure. We compare the light curve of the hard X-ray continuum from Swift Burst Alert Telescope observations with that of the Fe K |$\alpha$| fluorescence line, derived from the Nuclear Spectroscopic Telescope Array (NuSTAR), Suzaku, XMM–Newton, and Swift X-ray Telescope observations. The analysis of the light curves suggests that a top-hat transfer function, commonly employed in reverberation mapping studies, is improbable. Instead, the relation between these light curves can be described by a transfer function featuring two components: one with a lag of |$0.19_{- 0.02}^{+ 0.10} \,\, \mathrm{pc}/c$|⁠ , and another originating at |$r \\gt 1.7 \,\, \mathrm{pc}$| that produces an almost constant light curve. Further, we analyze the four-epoch NuSTAR and six-epoch Suzaku spectra, considering the time lag of the reflection component relative to the primary continuum. This spectral analysis supports that the reflecting material is Compton-thin, with |$N_{\mathrm{H}} = 3.14_{-0.74}^{+0.44} \times 10^{23} \,\, \mathrm{cm}^{-2}$|⁠. These results suggest that the Fe K |$\alpha$| emission may originate from Compton-thin circumnuclear material located at a sub-parsec scale, likely a dust torus, and materials at a greater distance. [ABSTRACT FROM AUTHOR]

In this manuscript, strong clues are reported to support the normal broad line AGN SDSS J1617+0638 as the host galaxy harbouring a central tidal disruption event (TDE). Through the optical flare in the CSS 8.5yr-long light curve and the none-variability in the up-to-date ASAS-SN light curves, the theoretical TDE model described by the mosfit code can be applied in SDSS J1617+0638. Meanwhile, considering the assumed central TDE expected continuum emissions not strong enough to describe the continuum emissions in the SDSS spectrum of SDSS J1617+0638, an additional power-law component from pre-existing AGN activity should be necessary in SDSS J1617+0638. Furthermore, considering the short time duration to the observed date for the SDSS spectrum from the starting time of the assumed central TDE in SDSS J1617+0638, TDE model expected accreting mass only about 0.03 |$\mathrm{ M}_\odot$| can lead to few effects of TDEs debris on the observed broad emission lines in the SDSS spectrum of SDSS J1617+0638, indicating the TDE model determined BH mass simply consistent with the virial BH mass by broad emission lines, as determined results in SDSS J1617+0638. Therefore, through both the photometric variability and the spectroscopic results, a central TDE can be preferred in the normal broad line AGN SDSS J1617+0638 with pre-existing central AGN activity and pre-existing broad emission line regions. [ABSTRACT FROM AUTHOR]

Broad absorption line (BAL) outflows are commonly detected in active galactic nuclei (AGNs), but their driving mechanism remains poorly constrained. Here, we investigate whether radiation pressure on dust can adequately explain the BAL phenomenon observed in quasars. In the framework of our AGN radiative dusty feedback scenario, we show that dust-driven outflows can reach BAL wind-like velocities (⁠|$v \sim 10^4$| km s |$^{-1}$|⁠) on galactic scales (⁠|$r \lesssim 1$| kpc). This is consistent with recent observations indicating that BAL acceleration typically occurs on scales of |$\sim 10$| pc, and that the majority of BAL outflows are located at galactocentric radii greater than |$\sim 100$| pc. We derive the outflow radial velocity profile and compute the associated outflow momentum rate and kinetic power, which are found to be in agreement with the outflow energetics measured in BAL quasars. Therefore, radiation pressure on dust may account for the observed BAL outflow dynamics and energetics. Furthermore, we consider BAL clouds/clumps (leading to a clumpy BAL flow characterized by a wide range of outflowing velocities), and we analyse how the resulting covering factors affect the shape of the absorption line profiles. We conclude that dust-driven BAL outflows may provide a significant contribution to AGN feedback on galactic scales. [ABSTRACT FROM AUTHOR]

We present rest-frame optical data of the |$z\sim 4$| submillimetre galaxy GN20 obtained with the JWST Near Infrared Spectrograph (NIRSpec) in integral field spectroscopy mode. The H |$\alpha$| emission is asymmetric and clumpy and extends over a projected distance of >15 kpc. To first order, the large-scale ionized gas kinematics are consistent with a turbulent (⁠|$\sigma \sim 90$| km s |$^{-1}$|⁠), rotating disc (⁠|$v_{\rm rot}\sim 500$| km s |$^{-1}$|⁠), congruent with previous studies of its molecular and ionized gas kinematics. However, we also find clear evidence for non-circular motions in the H |$\alpha$| kinematics. We discuss their possible connection with various scenarios, such as external perturbations, accretion, or radial flows. In the centre of GN20, we find broad-line emission (full width at half-maximum |$\sim 1000{-}2000$| km s |$^{-1}$|⁠) in the H |$\alpha$|  + [N  ii ] complex, suggestive of fast, active galactic nucleus-driven winds or, alternatively, of the broad-line region of an active black hole. Elevated values of [N  ii ]  |$\lambda 6583$| /H |$\alpha \ \gt\ 0.4$| and of the Hα equivalent width EW(H |$\alpha)\ \gt\ 6$| Å throughout large parts of GN20 suggest that feedback from the active black hole is able to photoionize the interstellar medium. Our data corroborate that GN20 offers a unique opportunity to observe key processes in the evolution of the most massive present-day galaxies acting in concert, over 12 billion years ago. [ABSTRACT FROM AUTHOR]

LSST will catalogue the light curves of up to 100 million quasars. Among these there can be |$\sim$| 100 ultra-compact massive black hole (MBH) binaries, whose gravitational waves (GWs) can be detected 5–15 yr later by LISA. Here, we assume such a LISA detection occurred, and assess whether or not its electromagnetic (EM) counterpart can be identified as a periodic quasar in archival LSST data. We use the binary's properties derived from the LISA waveform, including the evolution of its orbital frequency, its total mass, distance, and sky localization, to predict the redshift, magnitude, and historical periodicity of the quasar expected in the LSST data. We then use Monte Carlo simulations to compute the false alarm probability (FAP), i.e. the number of quasars in the LSST catalogue matching these properties by chance, based on the (extrapolated) quasar luminosity function, the cadence of LSST, and intrinsic 'damped random walk' quasar variability. We analyse four fiducial LISA binaries, with masses and redshifts of |$(M_{\rm bin}/{\rm M_{\odot }},z) = (3\times 10^5,0.3)$|⁠ , |$(3\times 10^6,0.3)$|⁠ , |$(10^7,0.3)$|⁠ , and |$(10^7,1)$|⁠. While noise and aliasing due to LSST's cadence produces false periodicities by chance, we find that the frequency chirp of the LISA source during the LSST observations washes out these noise peaks and allows the genuine source to stand out in appropriately scaled Lomb–Scargle periodograms. We find that all four fiducial binaries can be uniquely identified, with |${\rm FAP}\lt 10^{-5}$|⁠ , a week or more before merger. This should enable follow-up EM observations targeting individual EM counterparts during their inspiral stage. [ABSTRACT FROM AUTHOR]