arXiv subjects

Francesco Salvestrini

Publications and source records attributed to Francesco Salvestrini.

At least 19 recordsLinked to original sources

arXiv2026

Resolving the Assembly of Disk Galaxies from the Epoch of Reionisation to Cosmic Noon

Most of the mass and angular momentum of today's disk galaxies assembled at $z>1$. Yet, it remains unclear how these galaxies acquired their gas, how their baryons and dark matter coevolved, and how feedback and radial gas transport shaped their disks. Addressing these gaps requires resolved observations of cold gas, which carries most of the mass and angular momentum involved in galaxy assembly. By resolving CO and [C II] at kpc scales, ALMA revealed a surprising population of rotation-dominated disks, even at $z>2$, exhibiting kinematic signatures consistent with spiral arms, bars, and tidal tails. Yet, these studies are limited to massive ($M_\star>10^{10.5}$ M$_\odot$) and highly star-forming (SFRs$\gtrsim 100$ M$_\odot$yr$^{-1}$) galaxies, the progenitors of today's most massive elliptical and disk galaxies. To understand how most present-day spirals (like the Milky Way) assembled, it is crucial to resolve their low-mass progenitors, which dominate the star-forming galaxy population by number at $z>1$. Achieving this goal demands a tenfold increase in line sensitivity and hence a next-generation sub-/millimetre facility: ALMA2040. This leap in sensitivity will enable routine resolved studies of hundreds of $M_\star>10^9$ M$_\odot$ galaxies, including those on and below the main sequence of star-forming galaxies, providing representative, statistical galaxy samples with sub-kpc constraints on the cold gas kinematics and morphology. By uniquely providing resolved CO, [C I], and [C II] observations across $z=1-6$, ALMA2040 will trace a much larger fraction of the cold-gas reservoir than is accessible today, extending resolved studies from rare massive and/or lensed systems to representative galaxy populations. In this way, ALMA2040 will transform our understanding of how galaxy disks formed and evolved.

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arXiv2026

Dust at cosmic dawn: unveiling the onset of dust and obscured star formation at $z\gtrsim8$

Although less than 1 percent of the baryonic mass budget of a galaxy, cosmic dust profoundly alters the multi-wavelength appearance of galaxies across cosmic time. The (sub)millimeter wavelength regime is uniquely capable of weighing these dust reservoirs, and revealing the total extent of galaxy evolution that remains hidden behind them. With current facilities, however, doing so at $z > 8$ is largely out of reach. ALMA2040, a next-generation (sub)millimeter interferometer, is set to change this. Through an order-of-magnitude increase in sensitivity compared to ALMA, ALMA2040 is a transformational facility that will be able to routinely detect dust emission from galaxies at $z > 8$ and, through simultaneous multi-band characterization, accurately measure their dust masses, temperatures, and infrared luminosities. Combined with ancillary metallicity measurements -- including from the far-infrared lines detected by ALMA2040 itself -- this will establish the relative roles of supernovae and grain growth in building up dust in the earliest galaxies. Simultaneously, ALMA2040 will measure the fraction of star formation that is obscured by dust at cosmic dawn, and thereby the extent to which rest-UV and optical surveys miss early galaxy build-up. Without a 10$\times$ upgrade to ALMA -- comparable to the leap from the VLT to the ELT -- we will not be able to capitalize on the momentous advances enabled by JWST, and will remain blind to the cold and obscured component of galaxy formation in the $z > 8$ Universe.

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arXiv2026

Direct measures of black hole masses through cosmic time

Supermassive black holes (BHs) are thought to reside in all massive galaxies. They play a fundamental role in shaping galaxy evolution by suppressing star formation and halting the stellar growth of the most massive galaxies via feedback mechanisms. However, to date, measuring even their most basic property, their mass, is still challenging. The mass of BHs carries information on the growth history and the mutual interplay with the host galaxy. Uncertain BH masses leave many key questions on galaxy evolution wide open. Here we show that a transformational facility such as ALMA2040 would open a new window to measure BH mass by directly observing the kinematics of cold gas in galaxy cores from the local Universe up to very high redshift, irrespective of BH activity. This would revolutionise our understanding of BH formation, growth, and their role within galaxy evolution.

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arXiv2026

Tracking the flow of interstellar gas across scales: from galaxies to star clusters

While the baryon cycle of the interstellar medium - and its ability to form stars - plays a key role in galaxy evolution, unravelling the physical processes driving its evolution remains a critical challenge, given that present-day observing facilities are unable to map entire galactic ecosystems down to the scales of individual star-forming clumps. Here, we outline the technical requirements that would enable, for the first time, to connect the small (pc) scale physics of star formation, to the large (tens-of-kpc) scales of galaxies, enabling an effective tracking of the flows of matter and energy across a vast range of environments, and answering the long-standing question of what regulates star formation across cosmic time.

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arXiv2026

Molecular atlas of nearby galaxies through sensitive high-resolution multi-band molecular line surveys

Star formation and associated feedback processes play a key role in galaxy evolution. Astrochemistry is a powerful tool for characterising the physical conditions of dense star-forming gas and understanding the reciprocal relation between stellar feedback and the interstellar medium (ISM): from the way feedback influences the ISM to how the ISM conditions regulate the formation of new stars. The advent of large spectral surveys of a few individual galaxy centres have demonstrated the potential of molecular gas inventories to reveal the physical conditions of star-forming gas in great detail. A next-generation (sub)mm facility in the 2040s would extend this science to the local star-forming galaxy population, providing for the first time a comprehensive view of the physical and chemical conditions of the molecular ISM in the local universe.

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arXiv2026

ALMA2040: The High-Redshift Circumgalactic Medium. Imaging the fueling and feedback of galaxies in the early universe

Galaxies do not form in isolation, but rather as part of a wider interconnected web mediated at their interface by an extended gaseous atmosphere - the Circum-Galactic Medium (CGM). This dynamic and multiphase region is fed and shaped by gas inflows and mergers from the intergalactic medium and by feedback-driven outflows and radiation from the central galaxy. The CGM is imprinted by the past, present and future evolution of its central galaxy and environment. The cool atomic and molecular phases are of particular interest as they dominate the mass budget of outflows and provide a reservoir of direct star forming fuel for the galaxy to accrete. In the early universe where accretion rates, mergers, and feedback processes peak, the cycle of gas through the CGM is most vigorous. Sub-mm observations have detected cold gas in extended halos and gas flows around high redshift galaxies but are thus far limited to the most massive, extreme or gravitationally lensed sources, using just a handful of the strongest emission and absorption lines. A significant increase ($5-10\times$) in spectral line sensitivity compared with the current ALMA is needed to push physical scales, densities and properties to a new regime. We present three key scientific cases for an ALMA2040 telescope: (i) direct imaging of extended [CII]-traced CGM halos around Milky-Way-progenitor galaxies at $z=4$-8; (ii) resolved detection of cold, clumpy outflows on $\sim$100 pc scales tied to individual star-forming clumps; and (iii) multi-species/-transition emission and absorption diagnostics that jointly constrain the density, chemistry, and radiation fields permeating the cool CGM and its multiphase gas flows.

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arXiv2026

From Scaling Relations to Physical Laws: Constraining the Physics of Star Formation Across Local Galaxies

The conversion of cold dense gas, traced by molecular line emission, into stars remains one of the fundamental unsolved problems in galaxy evolution. Observations over the past decades have established empirical relations between gas and star formation, yet their physical origin remains uncertain. Gravity, turbulence, and stellar feedback as main drivers provide fundamentally different pictures of how star formation is regulated, while reproducing remarkably similar galaxy-scale scaling relations. To disentangle the individual importance of each process, not only its mass and distribution, but also its temperature, density, excitation, and chemistry must be probed. However, current or planned (sub)millimetre facilities cannot combine statistical breadth, cloud-scale resolution, and multi-line diagnostics across large galaxy samples. A new, flagship interferometer with increased line sensitivity and bandwidth enables obtaining multi-transition, multi-isotopologue observations of molecular gas at GMC-resolved scales across nearby galaxies, enabling millions of independent measurements of its physical state across a wide range of extragalactic environments. This will transform molecular gas from an empirical tracer into a quantitative probe of the physical processes governing the relation between the dense gas and star formation. With the 2040s landscape of optical and radio facilities, ALMA2040 will facilitate a predictive theory of the conversion of gas into stars.

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arXiv2026

Resolving the AGN Feeding and Feedback Cycle with ALMA2040

Understanding how supermassive black holes (SMBHs) grow and regulate the growth of their host galaxies requires tracing the cold molecular interstellar medium (ISM) throughout the full AGN feeding-feedback cycle. Molecular gas constitutes both the primary fuel for star formation and black-hole accretion and one of the ISM phases most directly affected by AGN-driven radiation, winds, and radio jets. Over the past decade, ALMA has resolved circumnuclear molecular discs, rings, spirals, tori, and jet-driven outflows on scales of tens of parsecs in nearby AGN. These studies have demonstrated that combining spatially resolved gas kinematics with multi-line diagnostics is essential for disentangling the physical processes underlying the observed gas conditions. However, our current picture remains largely based on a limited number of exceptionally nearby systems. Most local AGN have instead been observed with ALMA in a single transition at moderate or low angular resolution, preventing a systematic characterisation of both the dynamics and physical state of the gas. Moreover, existing studies have largely overlooked kinetic-mode AGN hosted by massive early-type galaxies, despite their central importance for understanding maintenance-mode feedback. In this White Paper, we argue that ALMA2040 should transform these detailed case studies into a statistical framework. A $\sim10\times$ improvement in line sensitivity relative to the current ALMA, together with fast mosaicking, ultra-wide instantaneous bandwidth, and longer baselines (resolving up to $\sim9$ mas at 230 GHz), will enable homogeneous, multi-line mapping of the molecular ISM on giant molecular clouds scales across statistically significant samples of both radiative- and kinetic-mode AGN out to $z\lesssim0.1$.

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arXiv2026

A New Hope for AGN SED Fitting: X-Ray Spectral Analysis of 12MGS AGN with the C2PO-Torus Model

In this paper, we present the results of comprehensive, broadband X-ray spectral analysis of a subsample of 43 mid-Infrared (IR) selected star-forming active galactic nuclei (AGN). We analysed archival NuSTAR, Chandra, and XMM-Newton data, and present the first pointed X-ray observation of IRASF03450+0055. We introduce a new physically-based X-ray spectral model, C2PO-Torus, based on a two-phase clumpy torus geometry. It is designed to provide constraints on physical parameters of the torus that can be directly linked to the parameters of the AGN model SKIRTOR. This model will allow us to exploit the synergies between the X-ray and IR regimes, place stronger constraints on the torus properties, and improve spectral energy distribution (SED) fitting by providing priors for the SKIRTOR parameters. We compare the results from the C2PO-Torus fitting to those obtained from traditional models, finding that it is an extremely effective tool for fitting a wide variety of X-ray spectra. We observe that our sample closely follows the established L_[OIII] - L_X AGN relation, while presenting an IR and Radio excess with respect to the L_X - L_12micron and L_X - L_1.4GHz AGN relations at low luminosities. We believe that this excess is due to contamination from star formation related emission. We anticipate that the C2PO-Torus model will aid substantially in completing full-spectrum SED fitting of this sample, allowing us to properly disentangle the different emission components of these objects, which are local analogues of AGN at Cosmic Noon.

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arXiv2026

The Drivers of Cosmic Dust Temperature Evolution

Observations of the rest-frame far-infrared (far-IR) emission of galaxies suggest a mild increase of dust temperature $T_{\rm dust}$ with redshift, although constraining $T_{\rm dust}$ in high-redshift systems remains challenging due to limited sampling of the far-IR spectral energy distribution (SED). We present and discuss the redshift evolution of $T_{\rm dust}$ predicted by a cosmological galaxy evolution simulation with dust treatment, and interpret its dependence on other galaxy physical properties. We use a semi-analytic model of galaxy formation that includes an explicit treatment of dust, post-processed with radiative transfer. Dust temperatures are derived by applying modified blackbody SED fitting to the simulated galaxies, mirroring the methodology adopted in most observational studies. The dust temperature of simulated galaxies increases with redshift, in broad agreement with observational results. A feature-importance analysis reveals that the star formation rate surface density $Σ_{\rm SFR}$ and the dust-to-gas ratio (DTG) are the main drivers of dust temperature, tracing the intensity of the interstellar radiation field and the optical depth of warm molecular clouds, respectively. Galaxies with higher star formation rate surface density and lower DTGs -- common conditions at high$-z$ -- are associated with warmer dust. We provide a simple relation to estimate DTG from $Σ_{\rm SFR}$, $T_{\rm dust}$, and redshift. Variations in dust grain size and chemical composition have a negligible impact on $T_{\rm dust}$. Our results are particularly relevant to the study of dust properties with observations of high-z galaxies, where far-IR dust emission is not fully sampled.

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arXiv2026

HYPERION. The cold ISM of rapidly growing $z>6$ quasars: diverse gas reservoirs, dust enrichment, and feedback signatures

Luminous QSOs at $z>6$ host some of the most rapidly assembled SMBHs in the early Universe. Characterizing their cold ISM is essential to determine their evolution. We investigate the molecular gas, cold dust, star formation, gas-to-dust ratio, and ionized ISM of ten HYPERION QSOs using new ALMA Band 3 observations targeting CO(6-5) and the underlying $\sim100$ GHz continuum, complemented by archival and literature ALMA/NOEMA data. We detect $\sim100$ GHz continuum emission in eight targets and CO(6-5) emission in four QSO hosts, J025-33, J083+11, J231-20, and J0252-0503, as well as in the companion of J231-20. The inferred molecular gas masses are of order $10^{10}~M_\odot$, while the non-detections imply upper limits of a few $10^9~M_\odot$, indicating a broad range of molecular reservoirs within the HYPERION population. For J025-33 and J083+11, the FIR SEDs are well sampled and yield low dust temperatures, $T_{\rm dust}=36^{+13}_{-7}$ K and $32^{+4}_{-3}$ K, respectively, well below the average value for $z>6$ QSOs. Combining gas and dust masses, we find a gas-to-dust ratio for J083+11, ${\rm GDR}=16^{+5}_{-4}$, among the lowest measured in a high-redshift QSO host. We also detect [NII]$λ205\,μ$m emission in J025-33 and tentatively in J083+11, suggesting dense or highly structured ionized gas. Finally, we identify a tentative connection among $T_{\rm dust}$, the X-ray photon index $Γ$, and the C IV velocity shift. These trends may indicate that more powerful winds redistribute dust away from the central AGN heating source, lowering its temperature and weakening the connection between the large-scale dust reservoir and the X-ray corona. Overall, HYPERION QSOs emerge as a heterogeneous population in which SMBH growth, star formation, gas consumption, enrichment, and feedback are not necessarily synchronized.

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arXiv2026

BlackHoleWeather -- Spin-coupled chaotic cold accretion across the meso-scale: Morphology and thermodynamics

Supermassive black hole (SMBH) spin is a key but poorly constrained ingredient of the feeding-feedback loop. Chaotic cold accretion (CCA) of cold gas clouds delivers rapidly varying three-dimensional torques that drive spin evolution and jet-axis reorientation, and in turn spin regulates jet power. We introduce a time-dependent SMBH spin model linking resolved multiphase feeding at meso scales to unresolved relativistic angular-momentum transfer at the innermost stable circular orbit (ISCO). We perform GPU-accelerated hydrodynamical simulations of a group atmosphere with jet feedback and SMBH spin evolution, resolving multiphase inflow and angular-momentum direction below parsec scales. We compare fixed-axis, direct, and hybrid prescriptions, with the latter preserving the resolved torque direction while filtering its magnitude through a Kerr ISCO closure. We then apply the hybrid model to low- and high-turbulence group setups. The cold-gas reservoir is nearly independent of whether the jet is fixed, spin-coupled, or rapidly reorienting. The spin prescription instead controls the inner feeding-feedback coupling, modulating central accretion, jet efficiency, and feedback geometry. The hybrid model is bracketed by analytic limits, whereas the direct model overestimates spin variability and jet-axis wandering, showing that an ISCO closure is required. Low-spin SMBHs are easier to reorient because a misaligned torque acts on a smaller angular-momentum reservoir. The decisive quantity is the coherence of the delivered angular momentum: the low-turbulence run preserves longer feeding bridges and faster spin evolution, whereas stronger turbulence fragments the inflow and enhances torque cancellation. In CCA, turbulence regulates whether the cold reservoir remains connected, how the angular momentum reaches the SMBH, where the next jet points, and how feedback is imprinted onto the halo.

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arXiv2026

BlackHoleWeather -- Jet-regulated chaotic cold accretion across the meso scale: Morphology and thermodynamics

How mechanical AGN feedback couples to multiphase condensation across scales remains a problem in galaxy groups and clusters. It is unclear how jets reshape the chaotic cold accretion (CCA) cycle and regulate black-hole fueling. BlackHoleWeather aims to build a unified description of the AGN baryon cycle across horizon, galactic, and group scales. Here we focus on how weather states shape the morphology and thermodynamics of jet-regulated CCA. We perform two hydrodynamical simulations of a turbulent, radiatively cooling galaxy-group atmosphere with self-regulated AGN feedback. The runs are initialized in two turbulence regimes and evolved with a kinetic mass-loaded jet. The jet prevents cooling via heating, but anisotropically reorganizes condensation through compression, entrainment, and turbulent mixing. In the stronger-turbulence case, condensation starts later but becomes extended, filamentary, and mixed, with a broader hot-warm-cold bridge, a porous cocoon, and burst-dominated fueling. This run evolves toward a cloud-dominated state with inefficient central accretion. In the weaker-turbulence case, condensation starts earlier and remains coherent and centrally confined, yielding a regular cocoon, a longer-lived inner cold reservoir with sustained fueling. In both runs, condensation is suppressed inside the jet channel and survives in the surrounding atmosphere and along the jet-ambient interface. Once condensation begins, SMBH fueling becomes super-Bondi. These results extend CCA from a pure cooling + turbulence problem to a jet-regulated weather process. Ambient turbulence acts as a control parameter, producing an extended stormy phase, a centrally retained rainy cycle, and, in the high-turbulence case, a later cloudy state with inefficient central fueling. The meso scale emerges as the layer linking halo thermodynamics to SMBH feeding within the broader BlackHoleWeather framework.

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arXiv2026

BlackHoleWeather -- Spin-coupled chaotic cold accretion across the meso scale: Variability and kinematics

Supermassive black hole (SMBH) spin records the vector history of accretion. In chaotic cold accretion (CCA), this history is set by clouds and filaments whose torques can add coherently, cancel, or reverse before reaching the horizon-scale closure. We test whether halo stirring regulates SMBH spin by changing the radial continuity and torque coherence of the meso-scale accretion bridge. We focus on spin evolution, jet-axis reorientation, accretion variability, and CCA kinematics. We analyse four 3D hydrodynamical simulations in a 100-kpc box, reaching sub-pc resolution, including SMBH spin-coupled jet feedback. All runs use the Hybrid SMBH spin model validated in a companion paper. Two simulations maintain continuous driven solenoidal turbulence, while two matched controls let the same initial turbulent field decay. The main effect of persistent stirring is to disrupt mass and angular-momentum continuity across the meso-scale bridge. Although all runs develop comparable macro-scale inflow, in the driven-turbulence suite, gas struggles to reach pc scales, and the radial accretion rate drops by 2-3 orders of magnitude. Torque delivery in this case is fragmented and cancellation-dominated. The interrupted-turbulence suite, on the other hand, preserves a connected gas channel to the sink, while sustaining higher torque coherence. Driven runs therefore settle to slow effective jet-axis drift, whereas interrupted runs maintain reorientation rates higher by about two orders of magnitude and can briefly reach a few degrees during coherent retrograde episodes. The same split appears in power spectra and k-plots: connected rain enhances low-frequency accretion power and produces narrower, phase-ordered kinematics, while stirring steepens high-frequency damping and broadens the gas velocity loci for all phases.

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arXiv2026

BlackHoleWeather -- Jet-regulated chaotic cold accretion across the meso scale: Variability and kinematics

Chaotic cold accretion (CCA) predicts that supermassive black holes are fed by multiphase clouds condensing from turbulent hot atmospheres. In jet-regulated systems cold gas must also remain dynamically connected to the central accretion region. We investigate how a self-regulated kinetic jet modifies the kinematics, radial transport, and variability of CCA across the meso-scale of a typical galaxy-group atmosphere. The runs differ only in turbulent driving strength. We measure accretion histories, Eddington ratios, power spectra, phase-separated mass fluxes, projected k-plots, and cooling-to-eddy-time (C-ratio) profiles. Both runs become CCA-fed once precipitation begins, with accretion rising from Bondi-like to strongly super-Bondi values while remaining mostly low-Eddington and mechanically dominated. The strongly stirred run develops an early stormy phase with extended condensation, bursty feeding, and strong inflow/outflow variability, but later enters a cloudy phase in which cold and warm gas persist at meso- and inner macro-scales while sink coupling weakens. The calmer run maintains a compact rainy state with a longer-lived central reservoir. Accretion-rate spectra show flicker-like low-frequency slopes and red-noise tails; in the cloudy phase, the normalization drops and the low-frequency slope flattens. Phase-separated fluxes show fountain-like recycling in the strongly stirred run, but inner-kpc recycling in the calmer run. The jet excavates a hot channel where sustained condensation is suppressed, while C~1 is reached mostly outside the cone and near the jet-ambient interface. Jet-regulated CCA is controlled by meso-scale transport, not only by cold-gas production. Within the BlackHoleWeather framework, combined k-plot and C-ratio diagnostics are crucial to distinguish cold gas that is merely present from cold gas dynamically linked to SMBH feeding.

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arXiv2025

The evolution of obscured AGN across cosmic time -- A large quasar survey for the 2040s

We propose a large quasar demographic optical multi-object spectroscopic (MOS) survey targeting over 50 million AGN candidates up to the highest redshifts possible in the optical (z~6.5), with repeat visits, using a variety of selection criteria available by 2040. A large MOS survey combining all AGN selection methods is the only way to unify a diverse range of different obscured AGN populations within a single, variability- and spectroscopy-based framework, rather than as disjoint classes selected by different methods.

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arXiv2025

High$-z$ [OI] emission lines: ColdSIM simulations and ALMA observations

Neutral-oxygen [OI] far-infrared emission lines at $63μ$m and $145μ$m are powerful probes of the physical conditions in the interstellar medium, although they have not been fully exploited in high-redshift studies. We investigate the connection between [OI] emission lines and key galaxy properties, such as star formation rate (SFR) and H$_2$ content. Our predictions are compared with existing observations and new data analysed in this work. We post-process the outputs of the ColdSIM cosmological simulations with the DESPOTIC model, taking into account [OI]$63μ$m self-absorption by cold foreground material. A Random Forest algorithm is employed to accelerate computations and new observational ALMA data for galaxies at redshift $z\simeq 5-7$ are used to validate our model. Our predictions show significant [OI]$63μ$m luminosities ($\approx 10^8\,\rm L_\odot$) for galaxies with SFRs of $\approx 10^2\,\rm M_\odot\,{\rm yr}^{-1}$. The $145μ$m line luminosity is typically $15 \%$ the [OI]$63μ$m one and is a factor $\approx 2-20$ below high-$z$ observations. Both [OI] lines correlate with SFR and molecular mass, but exhibit flattening in scaling relations with metallicity and stellar mass. Foreground self-absorption reduces the [OI] flux by a factor of $2-4$, consistent with empirical corrections in observational studies. We find typical line ratios of [OI]$63μ$m / [CII]$158μ$m $\approx 1$ and [OI]$145μ$m / [CII]$158μ$m $ \approx 0.2 \, -$ consistent with $z\gtrsim 6$ observations, but only when [OI]$63μ$m self-absorption is included. Both [OI]$63μ$m and [OI]$145μ$m lines serve as tracers of star formation and molecular gas at high redshift. Their joint detection can provide constraints on the properties of the early interstellar medium and self-absorption of the [OI]$63μ$m line.

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arXiv2025

ALMA reveals bright circumgalactic emission and a biconical outflow in z~6.4 quasar PSOJ183+05

Understanding gas flows between galaxies and their surrounding circum-galactic medium (CGM) is crucial to unveil the mechanisms regulating galaxy evolution, especially in the early Universe. However, observations of the CGM around massive galaxies at $z>6$ remain limited, particularly in the cold gas phase. In this work, we present multi-configuration ALMA observations of [CII]$\lambda158μ$m and millimetre continuum emission in the $z\sim6.4$ quasar PSOJ183+05. We find clumpy [CII] emission, tracing gas up to a $\sim6$ kpc radius, consistent with the interface region between the interstellar medium (ISM) and CGM. The [CII] kinematics shows a rotating disk and a high-velocity, biconical outflow extending up to 5 kpc. The inferred mass outflow rate is $\dot{M}_{\rm of}\sim930$ M$_\odot$ yr$^{-1}$, among the highest at $z>6$, and comparable to the star-formation rate. These findings suggest that quasar-driven outflows can rapidly transfer energy and momentum to the CGM, without immediately quenching star formation in the host galaxy ISM. This supports a delayed feedback scenario, in which outflows reshape CGM conditions and regulate future gas accretion over longer timescales. We find that neither the high-velocity component nor the extended CGM emission in PSOJ183+05 are recovered when using the high-resolution dataset alone, which may explain the conflicting results reported regarding [CII] sizes and the detection of outflows at $z\gtrsim6$. Combining multi-configuration ALMA data with observations from JWST and MUSE will be crucial to map the CGM across its different phases and build a comprehensive picture of the baryon cycle in the first massive galaxies.

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