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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]

We present spatially resolved VLT/SINFONI spectroscopy with adaptive optics of type-2 active galactic nuclei (AGN) from the SINFONI Survey for Unveiling the Physics and Effect of Radiative feedback (SUPER), which targeted X-ray bright (L2 − 10 keV ≳ 1042 erg s−1) AGN at cosmic noon (z ∼ 2). Our analysis of the rest-frame optical spectra unveils ionised outflows in all seven examined targets, as traced via [O III]λ5007 line emission, moving at v ≳ 600 km s−1. These outflows are clearly spatially resolved in six objects and extend on 2–4 kpc scales, but they are marginally resolved in the remaining one object. Interestingly, these SUPER type-2 AGN are all heavily obscured sources (NH ≳ 1023 cm−2) and host faster ionised outflows than their type-1 counterparts within the same range of bolometric luminosity (Lbol ∼ 1044.8 − 46.5 erg s−1). SUPER has hence provided observational evidence that the dichotomy of type-1 to type-2 at z ∼ 2 might not be driven simply by projection effects, but might reflect two distinct obscuring life stages of active galaxies, as predicted by evolutionary models. Within this picture, SUPER type-2 AGN might be undergoing the blow-out phase, where the large amount of obscuring material efficiently accelerates large-scale outflows via radiation pressure on dust, eventually unveiling the central active nucleus and signaling the start of the bright, unobscured type-1 AGN phase. Moreover, the velocities of the overall population of ionised outflows detected in SUPER are comparable with the escape speed of their dark matter haloes, and they are in general high enough to reach distances of 30–50 kpc from the centre. These outflows are hence likely to sweep away the gas (at least) out of the baryonic disk and/or to heat the host gas reservoir, thus reducing and possibly quenching star formation. [ABSTRACT FROM AUTHOR]

Small-scale winds driven from accretion discs surrounding active galactic nuclei (AGN) are expected to launch kpc-scale outflows into their host galaxies. However, the ways in which the structure of the interstellar medium (ISM) affects the multiphase content and impact of the outflow remain uncertain. We present a series of numerical experiments featuring a realistic small-scale AGN wind with velocity |$5\times 10^3 \!-\! 10^4\rm {\ km\ s^{-1}}$| interacting with an isolated galaxy disc with a manually controlled clumpy ISM, followed at sub-pc resolution. Our simulations are performed with arepo and probe a wide range of AGN luminosities (⁠|$L_{\rm {AGN}}{=} 10^{43-47}\rm {\ erg\ s^{-1}}$|⁠) and ISM substructures. In homogeneous discs, the AGN wind sweeps up an outflowing, cooling shell, where the emerging cold phase dominates the mass and kinetic energy budgets, reaching a momentum flux |$\dot{p} \approx 7\ L/c$|⁠. However, when the ISM is clumpy, outflow properties are profoundly different. They contain small, long-lived (⁠|$\gtrsim 5\ \rm {Myr}$|⁠), cold (⁠|$T{\lesssim }10^{4.5}{\rm {\ K}}$|⁠) cloudlets entrained in the faster, hot outflow phase, which are only present in the outflow if radiative cooling is included in the simulation. While the cold phase dominates the mass of the outflow, most of the kinetic luminosity is now carried by a tenuous, hot phase with |$T \gtrsim 10^7 \, \rm K$|⁠. While the hot phases reach momentum fluxes |$\dot{p} \approx (1 - 5)\ L/c$|⁠ , energy-driven bubbles couple to the cold phase inefficiently, producing modest momentum fluxes |$\dot{p} \lesssim L/c$| in the fast-outflowing cold gas. These low momentum fluxes could lead to the outflows being misclassified as momentum-driven using common observational diagnostics. We also show predictions for scaling relations between outflow properties and AGN luminosity and discuss the challenges in constraining outflow driving mechanisms and kinetic coupling efficiencies using observed quantities. [ABSTRACT FROM AUTHOR]

We present a study of molecular gas, traced via CO (3–2) from Atacama Large Millimeter/submillimeter Array data, of four z < 0.2, 'radio quiet', type 2 quasars (Lbol ∼ 1045.3–1046.2 erg s−1; L |$_{\mathrm{1.4\, GHz}}\sim 10^{23.7}\!-\!10^{24.3}$|   W  Hz−1). Targets were selected to have extended radio lobes (≥ 10 kpc), and compact, moderate-power jets (1–10 kpc; P jet ∼ 1043.2–1043.7 erg s−1). All targets show evidence of central molecular outflows, or injected turbulence, within the gas discs (traced via high-velocity wing components in CO emission-line profiles). The inferred velocities (V out = 250–440 km s−1) and spatial scales (0.6–1.6 kpc), are consistent with those of other samples of luminous low-redshift active galactic nuclei. In two targets, we observe extended molecular gas structures beyond the central discs, containing 9–53  per cent of the total molecular gas mass. These structures tend to be elongated, extending from the core, and wrap-around (or along) the radio lobes. Their properties are similar to the molecular gas filaments observed around radio lobes of, mostly 'radio loud', brightest cluster galaxies. They have the following: projected distances of 5–13 kpc; bulk velocities of 100–340 km s−1; velocity dispersion of 30–130 km s−1; inferred mass outflow rates of 4–20 M⊙ yr−1; and estimated kinetic powers of 1040.3–1041.7 erg s−1. Our observations are consistent with simulations that suggest moderate-power jets can have a direct (but modest) impact on molecular gas on small scales, through direct jet–cloud interactions. Then, on larger scales, jet-cocoons can push gas aside. Both processes could contribute to the long-term regulation of star formation. [ABSTRACT FROM AUTHOR]

We present a comprehensive study of the molecular gas properties of 17 Type 2 quasars at z < 0.2 from the Quasar Feedback Survey (L |$_{\rm [O~{\small III}]}$| > 1042.1  |$\rm ergs^{-1}$|⁠), selected by their high [O  iii ] luminosities and displaying a large diversity of radio jet properties, but dominated by LIRG-like galaxies. With these data, we are able to investigate the impact of AGN and AGN feedback mechanisms on the global molecular interstellar medium. Using Atacama Pathfinder EXperiment and ALMA ACA observations, we measure the total molecular gas content using the CO(1-0) emission and homogeneously sample the carbon monoxide (CO) spectral line energy distributions, observing CO transitions (J up  = 1, 2, 3, 6, 7). We observe high r 21 ratios (r 21  =  L 'CO(2-1)/ L 'CO(1-0)) with a median r 21  = 1.06, similar to local (U)LIRGs (with r 21 ∼ 1) and higher than normal star-forming galaxies (with r 21 ∼ 0.65). Despite the high r 21 values, for the seven targets with the required data, we find low excitation in CO(6-5) & CO(7-6) (r 61 and r 62 < 0.6 in all but one target), unlike high-redshift quasars in the literature, which are far more luminous and show higher line ratios. The ionized gas traced by [O  iii ] exhibits systematically higher velocities than the molecular gas traced by CO. We conclude that any effects of quasar feedback (e.g. via outflows and radio jets) do not have a significant instantaneous impact on the global molecular gas content and excitation and we suggest that it only occurs on more localized scales. [ABSTRACT FROM AUTHOR]

Observations of the nearby universe reveal an increasing fraction of active galactic nuclei (AGNs) with decreasing projected separation for close galaxy pairs, relative to control galaxies. This implies galaxy interactions play a role in enhancing AGN activity. However, the picture at higher redshift is less established, partly due to limited spectroscopic redshifts. We combine spectroscopic surveys with photometric redshift probability distribution functions for galaxies in the CANDELS and COSMOS surveys, to produce the largest ever sample of galaxy pairs used in an AGN fraction calculation for cosmic noon (0.5 < z < 3). We present a new technique for assessing galaxy pair probability (based on line-of-sight velocities ±1000 km s−1) from photometric redshift posterior convolutions and use these to produce weighted AGN fractions. Over projected separations 5–100 kpc, we find no evidence for enhancement, relative to isolated control galaxies, of X-ray (LX > 1042 erg s−1) or infrared-selected AGN in major (mass ratios up to 4:1) or minor (4:1 to 10:1) galaxy pairs. However, defining the most obscured AGN as those detected in the infrared but not in X-rays, we observe a trend of increasing obscured AGN enhancement at decreasing separations. The peak enhancement, relative to isolated controls, is a factor of 2.08 ± 0.61 for separations <25 kpc. Our simulations with mock data, indicates this could be a lower limit of the true enhancement. If confirmed with improved infrared imaging (e.g. with JWST) and redshifts (e.g. with forthcoming multi-object spectrograph surveys), this would suggest that galaxy interactions play a role in enhancing the most obscured black hole growth at cosmic noon. [ABSTRACT FROM AUTHOR]