Fabrizio Arrigoni Battaia

The impact of feedback from active supermassive black holes on their host galaxies is a key phenomenon in understanding galaxy evolution. We study ionised gas properties in a sample of 18 luminous (log L _bol ≥ 45 erg s ⁻¹ ) obscured Quasi-stellar objects (QSOs) in the nearby Universe (0.085 < z < 0.2) observed with VLT/MUSE as part of the multi-wavelength Quasar Feedback Survey (QFeedS) and with VLA at low- and high-resolution data, 1″ and 0.3″ respectively. Our main goal is to characterise the disturbed gas kinematics in this galaxy sample. We compare the outflow-related quantities with values reported in the literature and investigate possible correlations between the outflows and other properties of the ionised gas, such as the electron density. We adopt a non-parametric approach to characterise the ionised gas kinematics, traced by the [O III ] 5007 Å emission line, and use W ₈₀ measured from the unresolved nuclear spectra as a threshold to identify outflow-dominated spaxels. A qualitative comparison between the radio and the W ₈₀ maps shows that, in general, the peak of the radio coincides with the peak of the W ₈₀ . [O III ] 5007 Å is used as a proxy for the ionised gas mass, and the outflow-related properties are obtained in two different ways: the global, using flux-weighted velocities and radii and the peak, which relies on radial profiles. We correct the [O III ] 5007 Å flux for extinction using the Balmer decrement. We take advantage of the MUSE sensitivity and use the [Ar IV ] 4711,4740 doublet, only observable in the integrated r = 1.5″ spectra, to measure the electron density in each galaxy. We obtain 500 < n _e [cm ⁻³ ] < 27 700, leading to 0.03 < Ṁ _out /[M _⊙ yr ⁻¹ ] < 4.17 and 39 < log Ė _kin /[erg s ⁻¹ ] < 42. Our results emphasize the importance of accurate electron density determination, leading to a difference of 1 dex in the outflow rates and kinetic powers. We observe a positive correlation between n _e and V _out , interpreted as compression of the gas at higher velocities. This correlation should be further investigated at other luminosity and redshift ranges, but it can inform future outflow simulation studies.

We present the discovery and first characterization of Nāpōwawā‘enakaulua , the most compact known quasar pair candidate in the Epoch of Reionization, with a projected separation of only 0 . ″ 98 (≈5.56 pkpc at z ∼ 6.08) and a velocity offset of Δ v ≃ 15km s ⁻¹ . Using spectroscopy from JWST/NIRSpec integral field unit, as part of the Aether survey , Gemini/GNIRS and GMOS, we characterize the continuum and emission line properties of the two quasars, enabling constraints on their black hole masses ( M _BH ≃ 1.5 × 10 ⁹ and 4.0 × 10 ⁸ M _⊙ ), accretion states ( λ _Edd ≃ 1.23 and 1.07), and systemic redshifts ( z _sys ≃ 6.0781 and 6.0785). We place this pair in the cosmological context by comparing the chance of occurrence to extrapolations of high- z quasar clustering measurements at larger scales, resulting in a ∼2–3 order of magnitude excess with respect to expectations. This excess hints at an underlying population of merger-triggered quasar pairs at cosmic dawn or to a denser-than-average galactic environment. Nāpōwawā‘enakaulua thus represents a crucial signpost to investigate the mass assembly of the first massive galaxies and black holes.

We present a complete and homogeneous analysis of the Ly α emission properties of the cosmic web at 3 ≲ z ≲ 5 as a function of the overdensity of Ly α emitters (LAEs) in the MUSE Ultra Deep Field (MUDF) and the MUSE Extremely Deep Field (MXDF). We identified 41 overdensities, probing environments that are δ ≈ 2 − 10 times denser than the field. We searched for extended emission down to surface brightness (SB) levels of 3 − 5 × 10 ⁻²⁰ erg s ⁻¹ cm ⁻² arcsec ⁻² , revealing filamentary structures beyond the scale of the circumgalactic medium, confirming that LAEs act as signposts of the cosmic web. A trend with overdensity emerges: non-detections are mainly at δ < 2, a ≈1 dex scatter in SB appears for 2 ≲ δ ≲ 3.5, and detections reach a maximum intrinsic SB of ≈2 × 10 ⁻¹⁹ erg s ⁻¹ cm ⁻² arcsec ⁻² for δ ≳ 3.5. Emitting regions occupy a fraction of projected area f _s ≈ 0.20 − 0.25 inside filaments, yielding a cosmological incidence for Ly α emission in the cosmic web ℓ (Ly α ) of ≈1.22, which is similar to the one of partially neutral Lyman limit systems. This analysis indicates that the emitting gas is partially ionized at moderate densities ( n _H ≈ 10 ⁻³ − 10 ⁻¹ cm ⁻³ ), likely tracing the denser spines of intergalactic filaments and embedded substructures. Finally, we forecast how oriented stacking in larger samples of overdensities from shallower observations could yield an expanded view of the cosmic web before the next-generation wide-field spectroscopic instruments become operational.

We present three outliers on the quasar main sequence at z > 6, as revealed by JWST/NIRSpec integral field unit (IFU) observations from the Aether survey, a program targeting ∼200 quasars at cosmic dawn. The quasars, J0216−5226, J0320−3521, and J1429+5447, exhibit exceptionally strong Fe ii emission and weak H β and [O iii ] lines, indicating rapid chemical enrichment within the first Gyr of cosmic history. Their Fe ii strengths ( R _{Fe II, λ 4570} ≡ EW _{Fe II} /EW _{H β} ) range between ∼2.5 and 3.6, placing them among the top ∼3% of Sloan Digital Sky Survey quasars at (0 ≲ z ≲ 1). The H α emission lines of J0216−5226 and J1429+5447 imply black hole masses of ∼1–7 × 10 ⁹ M _⊙ with λ _Edd ∼ 0.1–0.6, comparable to typical high- z quasars, although virial black hole masses may be systematically overestimated in strong Fe ii emitters. In contrast, J0320−3521 hosts a lower-mass black hole of ∼0.2–2 × 10 ⁹ M _⊙ , suggesting possible super-Eddington rate accretion with λ _Edd ∼ 0.5–6.0. The IFU data of J0320−3521 reveal a distinct emission-line region at a projected distance of ∼1.5 kpc, consistent with either an interacting companion or ionized gas associated to the quasar. We further identify a complex environment around J1429+5447, including two candidate companion galaxies or extended ionized gas structures. These quasars with bright emission-line regions, J0320−3521 and J1429+5447, are radio-loud sources, while J0216−5226 remains undetected in radio ( R _{5GHz, 3 σ} ≲ 4). Together, these results confirm previous findings that highly enriched, rapidly growing black holes were already in place at cosmic dawn. Despite the small sample size, our results further highlight the diversity in environment and radio-jet properties among quasars that otherwise share the same extreme region of the quasar fundamental plane.

Context . Extended Ly α emission is ubiquitously observed around quasars. This emission traces the cool gas within the circumgalactic medium and provides insights into the complex interplay between gas dynamics and active galactic nucleus feedback. However, its connection to the cold molecular gas of the host galaxies remains largely unexplored. Aims . We aim to characterize the molecular gas reservoirs in quasars at cosmic noon and investigate how they are linked to extended Ly α emission. Methods . We present ALMA observations of the CO(4-3) transition in 37 quasars at z ∼ 3 from the QSO MUSEUM survey, which have been previously mapped in Ly α with VLT/MUSE. We derive molecular gas masses and gas fractions, explore correlations with Ly α nebula and quasar properties, and search for CO-emitting companions in the fields. Results . Of 37 quasars, 21 are detected in CO(4-3), with gas masses of M _gas ≈ (3 − 40)×10 ⁹ M _⊙ . Quasars with the most massive molecular gas reservoirs are associated with the centrally dimmest Ly α nebulae, while those hosting the centrally brightest Ly α nebulae are generally not detected in CO. This suggests that gas and dust in the hosts regulate Ly α escape and consequently affect the emission from halo gas. We find evidence that quasars with lower Eddington ratios harbor more massive gas reservoirs, while strongly accreting quasars ( λ _Edd 0.9) likely deplete their gas; for example, through powerful quasar-driven outflows. Despite their higher molecular gas masses within the sample, the low-Eddington quasars with CO detections exhibit low gas fractions with a median of M _gas /M _∗ ∼ 0.10, below what is typically found for inactive star-forming galaxies. Six quasars are marginally resolved in CO, with effective radii up to ∼8 kpc. In addition, we detect 14 companion galaxies at high fidelity, indicating an overall overdense environment in the quasar fields with a derived quasar-galaxy cross-correlation length of 9.81 ^+2.22 _−2.05 h ⁻¹ cMpc.

We report JWST/NIRSpec integral field unit (IFU) observations of the quasar J1512+4422 at z ∼ 6.2 from the Aether survey. At ∼900 Myr after the Big Bang, this object already lies on the M _BH – σ _* relation found in the local Universe, with an M _BH ≃ 8.9 × 10 ⁸ M _⊙ and a stellar velocity dispersion σ _* ≃ 288 km s ⁻¹ . We detect an outflow with a velocity of ∼478 km s ⁻¹ in the nuclear region, which likely extends to ∼3.2 kpc in projection and has a median velocity of ∼352 km s ⁻¹ . The outflow dynamical timescale (∼9 Myr) is consistent with the timescale of the current quenching process based on the star formation history as reported previously. The total mass outflow rate (92.6 − 74.1 + 92.6 M _⊙ yr ⁻¹ ) is larger than the current star formation rate (0.9 − 0.8 + 3.8 or 4.3 − 3.7 + 5.8 M _⊙ yr ⁻¹ ), and the total kinetic energy outflow rate (0.6% − 0.5 % + 0.6 % of quasar luminosity) meets the threshold for negative quasar feedback as suggested by simulations. These results suggest that the outflow is capable of suppressing or quenching the star formation activity within the host galaxy. Furthermore, J1512+4422 exhibits σ _* , stellar mass, and size similar to those of z ≳ 3 quiescent and poststarburst galaxies, implying a link between the two. Overall, for objects like J1512+4422, the evolution of their supermassive black holes and host galaxies appears to be tightly coupled within the first billion years. The quasar feedback likely plays a critical role in both placing them on the M _BH – σ _* relation and quenching.

We present James Webb Space Telescope (JWST) NIRSpec integral field unit (IFU) observations of six galaxies at z ∼ 6, obtained as part of the Aether project (General Observers program 5645). The targets were originally identified by the Subaru High- z Exploration of Low-Luminosity Quasars (SHELLQs) survey as candidate obscured quasars with luminous (≳10 ⁴³ erg s ⁻¹ ) but narrow (≲500 km s ⁻¹ ) Ly α emission. Two objects exhibit a broad component in their Balmer lines (FWHM > 3000 km s ⁻¹ ), indicating the presence of active galactic nuclei (AGNs), while the remaining four show similar profiles in permitted and forbidden lines. Combining these data with similar SHELLQs objects reported previously, we find that the presence of broad lines is strongly correlated with Ly α luminosity ( L _{Ly α} ); the inferred AGN fraction is >77% and L _{Ly α} = 10 ⁴⁴ erg s ⁻¹ , respectively. Dust-extinction corrections inferred from the Balmer decrement would imply unrealistically high Ly α luminosities, suggesting that the line-emitting gas consists of multiple zones. The IFU data reveal diverse spatial structures. The AGN hosts are compact, whereas the other galaxies show extended ionized gas on scales up to 10 kpc and star formation rates of 60–600 M _⊙ yr ⁻¹ . One of the extended objects exhibits a signature of rotation, while most of the others show little ordered kinematics, with velocity widths (FWHM) up to 200–300 km s ⁻¹ . These objects populate the intermediate luminosity regime between classical luminous quasars and the low-luminosity AGNs discovered by JWST, including little red dots, potentially linking the two populations.

Measurements of quasar lifetimes at high redshift indicate that the earliest billion-solar-mass supermassive black holes (SMBHs) have only been active as luminous quasars for less than a million years. Recently, extended Ly α nebulae around z ∼ 6 quasars have revealed that these short observed lifetimes are unlikely to be a sight-line-dependent effect. However, the interpretation of Ly α emission is not straightforward due to its resonant nature. In this work, we use rest-frame optical emission lines, which more directly trace photoionization by the quasar, to unambiguously validate the short line-of-sight quasar lifetimes observed at early cosmic epochs. We use deep James Webb Space Telescope/NIRSpec integral field unit observations of five z ∼ 6 quasars with small proximity zones to search for their extended emission line nebulae in H α and [O III ]5007, and detect extended emission in both emission lines around four quasars in our sample. We then use the light-crossing time of these nebulae to measure quasar lifetimes along transverse sight lines. Using their H α nebulae, we also confirm that recombination is likely the dominant emission mechanism behind their previously detected Ly α nebulae. Our results confirm the existence of high-redshift quasars with extremely short lifetimes, t _Q ≲ 10 ⁵ yr, hosting billion-solar-mass black holes, indicating that rapid or obscured accretion is likely responsible for the assembly of SMBHs in the early Universe.

Recent surveys have shown that z ≳ 2 quasars are surrounded by hydrogen Lyman- α (Ly α ) glows with diverse emission levels and extents. These characteristics seem to depend on the activity of embedded quasars, on the number of active galactic nucleus (AGN) photons that are able to reach the halo gas or circumgalactic medium (CGM), and on the physical properties of the CGM. In this framework, we present VLT/MUSE snapshot observations (45 minutes/source) of 59 z ∼ 3 quasars extending the long-term QSO MUSEUM campaign to the fainter SDSS sources. The whole survey is homogeneously reduced and analyzed here and now targets 120 quasars with a median redshift z = 3.13 and bolometric luminosities, black hole masses, and Eddington ratios in the ranges 45.1 < log( L _bol /[erg s ⁻¹ ]) < 48.7, 7.9 < log( M _BH /[M _⊙ ]) < 10.3, and 0.01 < λ _Edd < 1.8. We detected extended Ly α emission in 110 of the 120 systems, with all the nondetections in the newly added fainter sample. The surface brightness of the CGM Ly α emission (SB _Lyα ) increases with quasar luminosity. Stacking of the nondetections unveiled emission just below our individual field detection limit. Moreover, the Ly α line width increases in the central regions (projected radius R < 40 kpc or ∼40% R _vir ) of the CGM around quasars with stronger radiation. The variation in surface brightness and the velocity dispersion as a function of quasar luminosity indicate that we witness the instantaneous AGN feedback in action on CGM scales. Assuming that all targeted quasars sit in halos of M _DM ∼ 10 ^12.5 M _⊙ independent of luminosity, as suggested by clustering studies, we explain the trend in SB _Lyα naturally by a larger fraction of cool gas mass that is illuminated, which implies that brighter quasars have larger ionization cone opening angles. Similarly, brighter AGN seem to perturb the cool ( T ∼ 10 ⁴ K) gas more strongly. We show that QSO MUSEUM starts to have enough statistics to study this instantaneous AGN feedback while controlling for black hole properties (e.g., mass), which will be key to constraining AGN models.

Some cosmological hydrodynamical simulations predict that outflows driven by active galactic nuclei (AGN) play a key role in powering the Ly α nebulae observed around high-redshift quasars. In such simulations, AGN feedback seeded as powerful outflows leads to extended and luminous nebulae whose morphology and surface-brightness profiles accurately reproduce the observations, while suppressing AGN feedback leads to compact and faint nebulae. This link might arise from outflows opening up a channel for Ly α photons to escape from the galactic nucleus to the circumgalactic medium (CGM). The main aim of this paper is to test this theoretical prediction using observations, by comparing the physical properties of outflows and Ly α nebulae. We analyze integral-field unit data obtained with VLT/ERIS and GEMINI/GNIRS to trace the ionized gas in the interstellar medium (ISM) of a sample of six quasars at z ∼ 2 − 3, using the [O III ] emission line. We detect powerful outflows in all the quasars of our sample, with velocities > 1500 km s ⁻¹ and kinetic energies ≳2 × 10 ⁴³ erg s ⁻¹ . Four of our quasars are spatially resolved and show signs of extended [O III ] emission out to distances > 2 kpc from the central supermassive black hole. When excluding one outlier, we find a positive monotonic correlation between the outflow power and the Ly α nebulae size ( ρ = 0.89, p = 0.03) and luminosity ( ρ = 0.6, p = 0.28). Additionally, we find evidence of spatial alignment between the ionization cone and the inner and brightest regions of the Ly α nebula. Our results provide tentative evidence in support of the theoretical prediction that AGN-driven outflows at ISM scales open a low-optical-depth path for central Ly α photons to reach the CGM and create extended nebulae.