arXiv subjects

S. Cantalupo

Publications and source records attributed to S. Cantalupo.

At least 19 recordsLinked to original sources

arXiv2026

The Multiphase CGM in the Epoch of Reionization: CII and CIV absorbers around [OIII] Emitters

We investigate the multiphase circumgalactic medium (CGM) during the Epoch of Reionization (EoR, $z>6$) by cross-correlating cool- CII and warm-ionized CIV absorption systems with star-forming [OIII] emitters. JWST/NIRCam wide-field slitless spectroscopy from the EIGER survey is combined with medium- and high-resolution optical/NIR spectra of six background quasars, including new VLT/X-Shooter observations of PSO J159-02. We analyze the relation between 16 CII and 14 CIV absorbers ($\log(N) > 13.0$) and 136 galaxies, within an impact parameter of R$_{\perp} \leq$ 1000 pkpc and a line-of-sight separation of $Δv \leq 500$ km/s. We detect a statistically significant excess of both ions around galaxies compared to a randomized background. We observe that the CIV covering fraction remains enhanced up to $\sim 1$ pMpc, whereas CII drops to the background level beyond $\sim 0.5$ pMpc, demonstrating that the warm-ionized phase is more spatially extended than cooler gas. Jointly, the 3D galaxy-absorber spatial clustering is significantly weaker than the galaxy-galaxy auto-correlation. This provides direct physical evidence that early carbon enrichment is not confined to the virial radius of massive star-forming systems; rather, a substantial fraction of these metals permeates the diffuse intergalactic medium (IGM) or is injected by a widespread population of faint, undetected dwarf galaxies. Finally, we note a rapid radial decline of the CIV covering fraction compared with lower redshift samples at $z<2$ and $z\sim3-4$ pointing out an evolving CGM ionization structure where early metals reside predominantly in lower ionization states. In conclusion, we determine a conservative lower limit for the observed carbon mass of $\rm M_{CII + CIV} \geq 2.8 \times 10^6 \, M_{\odot}$ within 300 pkpc.

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arXiv2026

The galaxy-halo connection and the dynamical evolution of a giant disc in a massive node of the Cosmic Web at z~3

Recent JWST observations revealed the surprising presence of a giant and massive disc galaxy in a Cosmic Web node at z$\sim3$. This galaxy, named the Big Wheel, has a size almost three times larger than expected for typical disc galaxies at the same redshift and similar stellar masses. Constraining the origin and formation history of the Big Wheel requires knowledge of its dark matter halo properties, which are difficult to derive from JWST observations alone. Here, we investigate the dark matter halo of the Big Wheel and provide further constraints on the galaxy baryonic content, combining a physically motivated dynamical model with deep ALMA kinematical data. By using priors based on JWST photometric data and CO kinematics, we infer a dark matter halo mass of $\log (M_{h}/M_{\odot})= 12.11^{+0.29}_{-0.17}$ and a stellar mass of $\log(M_{\star}/M_{\odot})=11.00^{+0.11}_{-0.12}$, leading to a stellar-to-halo mass (SHM) ratio of $M_\star/M_h=0.06^{+0.04}_{-0.03}$. This value is significantly higher than expected from state-of-the-art empirical SHM relations. This implies that the Big Wheel may have assembled its stellar content in a much more efficient way with respect to the general galaxy population at z$\sim3$. Combined with its morphological properties, our results suggest that the Big Wheel had a tranquil recent formation history, with probably no major mergers, violent disc instabilities, or strong ejective feedback. We perform a numerical simulation of an idealised galaxy and let it evolve adiabatically for $2.5$ Gyr to demonstrate that it does not develop gravitational instabilities during its evolution that could alter its resemblance to the observed one. Although systems alike the Big Wheel are arguably rare, our results offer new constraints on the contribution of accretion and feedback to the formation history of the most massive discs within high-redshift Cosmic Web nodes.

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arXiv2026

Resolving circumgalactic gas flows around a z$\approx$3.6 quasar using MUSE and ALMA

The formation and evolution of galaxies is regulated by the exchange of gas with the surrounding large-scale structures on circum- and intergalactic scales. Yet, little is known about the complex processes shaping the cycle of baryons in and out of galaxies. In this work, we present a multiline study of the gas surrounding a $z\approx3.66$ quasar known to host one of the brightest Ly$α$ nebulae at high redshift, MUSE Quasar Nebula 04 (MQN04). By combining a high-resolution MUSE detection of non-resonant HeII emission with a precise measurement of the redshift of the quasar host via the ALMA CO(4-3) line, we study the kinematics of the cool ionized gas down to $\approx1\rm\,kpc$ from the quasar. The MUSE observations reveal complex clumpy structures as well as diffuse emission extended over $\approx100\,{\rm kpc}$ and blueshifted by $\approx 0-800\,{\rm km\,s^{-1}}$ relative to the quasar systemic redshift, suggesting that the circumgalactic medium is highly asymmetric. The analysis of the HeII/Ly$α$ line ratio, and the presence of a low-column density ($\approx10^{14.6}~\rm cm^{-2}$) HI absorber along the quasar sightline suggests that MQN04 resides in a highly ionized medium. This is also supported by the gas kinematics, which, except in the most central region, shows consistent velocity shifts across the different tracers, indicative of relatively weak radiative transfer effects. Based on its morphology and kinematics, we conclude that the extended HeII emission may arise from merger-driven tidal stripping or inflows of gas illuminated by the quasar radiation. On comoving megaparsec scales, we discover a large concentration ($δ\approx41$) of star-forming galaxies lying within $|Δv_{\rm QSO}| \leq1000\rm\,km\,s^{-1}$ from the quasar. MQN04 is therefore one of the most overdense environments discovered at this epoch.

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arXiv2025

Metal enrichment of galaxies in a massive node of the Cosmic Web at $z \sim 3$

We present the mass-metallicity relation for star-forming galaxies in the MUSE Quasar Nebula 01 (MQN01) field, a massive cosmic web node at $z \sim 3.245$, hosting one of the largest overdensities of galaxies and AGNs found so far at $z > 3$. Through James Webb Space Telescope (JWST) Near Infrared Spectrograph (NIRSpec) spectra and images from JWST and Hubble Space Telescope (HST), we identify a sample of 9 star-forming galaxies in the MQN01 field with detection of nebular emission lines ($\rm Hβ$, [OIII], $\rm Hα$, [NII]), covering the mass range of $\rm 10^{7.5}M_\odot - 10^{10.5}M_\odot$. We present the relations of the emission-line flux ratios versus stellar mass for the sample and derive the gas-phase metallicity based on the strong line diagnostics of [OIII]$\lambda5008$/$\rm Hβ$ and [NII]$\lambda6585$/$\rm Hα$. Compared to the typical, field galaxies at similar redshifts, MQN01 galaxies show relatively higher [NII]$\lambda6585$/$\rm Hα$ and lower [OIII]$\lambda5008$/$\rm Hβ$ at the same stellar mass, which implies a higher metallicity by about $0.25\pm 0.07$ dex with respect to the field mass-metallicity relation. These differences are decreased considering the ``Fundamental Metallicity Relation'', i.e. if the galaxies' Star Formation Rates (SFR) are also taken into account. We argue that these results are consistent with a scenario in which galaxies in overdense regions assemble their stellar mass more efficiently (or, equivalently, start forming at earlier epochs) compared to field galaxies at similar redshifts.

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arXiv2025

A deep X-ray look to the most obscured quasar at z~3.6 and its environment

The most luminous and obscured quasars (QSOs) detected in infrared all-sky surveys could represent a key co-evolutionary phase from nuclear to circum-galactic (CG) scales in the formation of massive galaxies. In this context, Hot Dust Obscured Galaxies (Hot DOGs) at z ~2-4 provide a unique opportunity to study the link between cosmic mass assembly and nuclear accretion in high-z luminous QSOs/galaxies. W0410-0913 (hereafter W0410-09) is a luminous ($\rm ~L_{\rm bol} \sim 6.4 \times10^{47} \rm erg\ s^{-1}$) obscured QSO at z = 3.631, with a 30 kpc CG Ly$α$ nebula (CGLAN), smaller than the ~ 100 kpc nebulae around unobscured Type-I QSOs, and an exceptional overdense environment of ~ 19 Ly$α$ emitters (LAEs) within 300 kpc and $\pm$ 200 $\rm km ~s^{-1}$ of the Hot DOG. We aim to detect and characterize nuclear accretion in W0410-09 and its environment. Exploiting a deep proprietary ~280 ks Chandra observation, using empirical and physically motivated models for obscured sources, we show that W0410-09 exhibits Compton-thick obscuration ($\rm~ N_H > 10^{24} \rm cm^{-2}$) and high intrinsic luminosity ($\rm ~L_{2-10} > 10^{45} \rm erg ~s^{-1}$), making it one of the most luminous obscured QSOs at z $>$ 3.5. With the exclusion of W0410-09 we do not detect X-ray emission from any of the 19 LAEs, except for a 3$σ$ signal in the 6-7 keV rest-frame band, interpreted as Fe K$α$ emission, suggesting the presence of heavily obscured yet undetected AGN emission in several LAEs. Including W0410-09, the estimated AGN fraction is $f_{\rm AGN}^{\rm LAE} = 5^{+12}_{-4}$%, potentially up to ~35% if unresolved obscured AGN are considered as suggested by the Fe K$α$ line detection. We conclude that W0410-09 is in a critical transitional blow-out phase, during which powerful QSO-driven outflows are clearing the nuclear obscuration, ultimately leading to an unobscured luminous quasar.

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arXiv2025

ALMA survey of a massive node of the Cosmic Web at $z\sim 3$. II. A dynamically cold and massive disk galaxy in the proximity of a hyperluminous quasar

Advancing our understanding of the formation and evolution of early massive galaxies and black holes requires detailed studies of dense structures in the high-redshift Universe. In this work, we present high-angular resolution ($\simeq0.3''$) ALMA observations targeting the CO(4--3) line and the underlying 3-mm dust continuum toward the Cosmic Web node MQN01, a region identified through deep multiwavelength surveys as one of the densest concentrations of galaxies and AGN at cosmic noon. At the center of this structure, we identify a massive, rotationally supported disk galaxy located approximately at $\sim10\,{\rm kpc}$ projected-distance and $\sim-300\,{\rm km\,s^{-1}}$ from a hyperluminous quasar at $z=3.2510$. By accurately modeling the cold gas kinematics, we determine a galaxy dynamical mass of $2.5\times10^{11}\,{M_{\odot}}$ within the inner $\simeq 4\,{\rm kpc}$, and a high degree of rotational support of $V_{\rm rot}/σ\approx 11$. This makes it the first quasar companion galaxy confirmed as a massive, dynamically cold rotating disk at such an early cosmic epoch. Despite the small projected separation from the quasar host, we find no clear evidence of strong tidal interactions affecting the galaxy disk. This might suggest that the quasar is a satellite galaxy in the early stages of a merger. Furthermore, our spectroscopic analysis reveals a broad, blueshifted component in the CO(4--3) line profile of the quasar host, which may trace a powerful molecular outflow or kinematic disturbances induced by its interaction with the massive companion galaxy. Our findings show that rotationally supported cold disks are able to survive even in high-density environments of the early Universe.

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arXiv2025

The properties of X-ray selected AGN in protoclusters pinpointed by Enormous Lya Nebulae

Protoclusters of galaxies are overdense regions of the Universe characterized by large gas reservoirs. Such environments make them perfect laboratories to investigate galaxy-AGN co-evolution and the growth of SMBHs. Galaxies living in such a dense regions are expected to growth efficiently their SMBH, resulting in a higher incidence of AGN than in the field. Some protoclusters exhibit extended Ly$α$ nebulae in their central region, pinpointing the presence of massive gas reservoirs, but whose main powering mechanism is still debated. We aim to investigate the AGN population, and AGN enhancement, in three protoclusters at 2.3 < z < 3.2 which host enormous Ly$α$ nebulae (ELANe). Additionally, we search for the presence of X-ray diffuse emission in the same region of the Ly$α$ nebulae to reveal multi-phase gas in these protoclusters. We use deep (190-270 ks) Chandra observations to identify AGN among the protocluster members and perform X-ray spectral analysis to derive the properties of those sources. We compare the AGN fraction and space density with those observed in other known protoclusters and from the field environment. We find 11 X-ray detected AGN in the three protoclusters. Each structure hosts a central, X-ray powerful (log$(L_{\rm X}/{\rm erg \, s^{-1}}) \sim 45-46$), QSO, while the other X-ray sources are mostly moderately luminous (log$(L_{\rm X}/{\rm erg \, s^{-1}}) \sim 44$) and obscured Compton-Thin AGN. The fraction of AGN in our targets is comparable with estimates for other protoclusters, and significantly higher than what is found for low-redshift clusters. We also find a significant enhancement (2-4 dex) of AGN density with respect to the field and to non active galaxies in the protoclusters. Finally, we find no significant soft X-ray diffuse emissions from the nebulae, thus ruling out gravitational heating as the main powering mechanism of the ELANe.

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arXiv2024

The MUSE Ultra Deep Field (MUDF) VII. Probing high-redshift gas structures in the surroundings of ALMA-identified massive dusty galaxies

We present new ALMA continuum and spectral observations of the MUSE Ultra Deep Field (MUDF), a $2\times 2$ arcmin$^2$ region with ultradeep multiwavelength imaging and spectroscopy hosting two bright $z\approx 3.22$ quasars used to study intervening gas structures in absorption. Through a blind search for dusty galaxies, we identified a total of seven high-confidence sources, six of which with secure spectroscopic redshifts. We estimate galaxy dust and stellar masses ($M_{\rm dust}\simeq 10^{7.8-8.6}\,M_{\odot}$, $M_{\star}\simeq 10^{10.2-10.7}\,M_{\odot}$), as well as star formation rates (${\rm SFR}\simeq 10^{1.2-2.0}\,M_{\odot}\,{\rm yr^{-1}} $) which show that most of these galaxies are massive and dust-obscured similar to coeval (sub-)millimeter galaxies. All six spectroscopically-confirmed galaxies are within $500~\rm km~s^{-1}$ of metal absorption lines observed in the quasar sightlines, corresponding to $100\%$ association rate. We also find that four of these galaxies belong to groups in which they are among the most massive members. Within the multiple group galaxies associated to the same absorption system, the ALMA sources are not always the closest in projection, but they are often aligned with the gaseous structures in velocity space. This suggests that these massive galaxies occupy the center of the potential well of the gas structures traced in absorption. However, albeit the low number density of sources identified with ALMA, our study may indicate that absorbers seem to infrequently originate in the inner circumgalactic medium of these galaxies. Instead, they appear to be better tracers of the gas distributed in the large-scale structure that host them.

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arXiv2024

X-ray view of a massive node of the Cosmic Web at z~3 I. An exceptional overdensity of rapidly accreting SMBHs

Exploring SMBH population in protoclusters offers valuable insights into how environment affects SMBH growth. However, research on AGN within these areas is still limited by the small number of protoclusters known at high redshift and by the availability of associated deep X-ray observations. To understand how different environments affect AGN triggering and growth at high redshift, we investigated the X-ray AGN population in the field of the MUSE Quasar Nebula 01 (MQN01) protocluster at z ~3.25. This field is known for hosting the largest Lya nebula in the Borisova+16 sample, and one of the largest overdensities of UV-continuum selected and sub-mm galaxies found so far at this redshift. We conducted a ultra deep Chandra X-ray survey (634 ks) observation of the MQN01 field and produced a comparative analyses of the properties of the X-ray AGNs detected in MQN01 against those observed in other selected protoclusters, such as Spiderweb and SSA22. By combining the X-ray, deep MUSE and ALMA data of the same field, we identified six X-ray AGNs within a volume of 16 cMpc^2 and \pm 1000 km/s, corresponding to an X-ray AGN overdensity of ~1000. This overdensity increases at the bright end, exceeding what was observed in the Spiderweb and SSA22 within similar volumes. The AGN fraction measured in MQN01 is significantly higher (f_AGN > 20%) than in the field and increases with stellar masses, reaching a value of 100% for log(M*/Msun) > 10.5. Lastly, we observe that the average specific accretion rate (λ_sBHAR) for SMBH populations in MQN01 is higher than in the field and other protoclusters, generally increasing as one moves toward the center of the overdensity. Our results, especially the large fraction of highly accreting SMBHs in the inner regions of the MQN01 overdensity, suggest that protocluster environments offer ideal physical conditions for SMBH triggering and growth.

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arXiv2024

Connecting the growth of galaxies to the large-scale environment in a massive node of the Cosmic Web at z~3

A direct link between large-scale environment and galaxy properties is very well established in the local universe. However, very little is known about the role of the environment for galaxy growth before the peak of the cosmic star formation history at $z>3$ due to the rarity of high-redshift, overdense structures. Using a combination of deep, multiwalength observations, including MUSE, JWST, Chandra, HST and ground-based imaging, we detect and study the properties of a population of star-forming galaxies in the field of a hyperluminous quasar at $z\approx3.25$ associated with the giant Ly$α$ nebula MQN01. We find that this region hosts one of the largest overdensity of galaxies found so far at $z>3$, with $ρ/\barρ=53\pm17$ within $4\times4\rm\,cMpc^2$ and $|Δv|<1000\rm\,km\,s^{-1}$ from the quasar, providing a unique laboratory to study the link between overdense regions and galaxy properties at high redshift. Even in these rare overdense regions, galaxies are forming stars at a rate consistent with the main sequence at $z\approx3$, demonstrating that their SFR is regulated by local properties correlated with their stellar mass rather than by their environment. However, the high-mass-end of the stellar mass function is significantly elevated with respect to that of galaxies in the field at $\log(M_\star/{M_\odot})\gtrsim10.5$, suggesting that massive galaxies in overdense regions build-up their stellar mass earlier or more efficiently than in average regions of the universe. Finally, the overdensity of color-selected Lyman break galaxies observed on larger scales, across $\approx24\times24\rm\,cMpc^2$, is found to be aligned toward the structure traced by the spectroscopically-confirmed galaxies identified with MUSE in the inner $4\times4\rm\,cMpc^2$, suggesting that this highly overdense region could further extend up to a few tens of comoving Mpc.

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arXiv2024

MUSE view of PDS 456: kpc-scale wind, extended ionized gas and close environment

PDS 456 is the most luminous RQQ at z<0.3 and can be regarded as a local counterpart of the powerful QSOs shining at Cosmic Noon. It hosts a strong nuclear X-ray ultra-fast outflow, and a massive and clumpy CO(3-2) molecular outflow extending up to 5 kpc from the nucleus. We analyzed the first MUSE WFM and AO-NFM optical integral field spectroscopic observations of PDS456. The AO-NFM observations provide an unprecedented spatial resolution, reaching up to 280 pc. Our findings reveal a complex circumgalactic medium around PDS 456, extending up to a maximum projected size of ~46 kpc. This includes a reservoir of gas with a mass of ~1e7-1e8 Modot, along with eight companion galaxies, and a multi-phase outflow. WFM and NFM MUSE data reveal an outflow on a large scale (~12 kpc from the quasar) in [OIII], and on smaller scales (within 3 kpc) with higher resolution (about 280 pc) in Halpha, respectively. The [OIII] outflow mass rate is 2.3 +/- 0.2 Modot/yr which is significantly lower than those typically found in other luminous quasars. Remarkably, the Ha outflow shows a similar scale, morphology, and kinematics to the CO(3-2) molecular outflow, with the latter dominating in terms of kinetic energy and mass outflow rate by two and one orders of magnitude, respectively. Our results therefore indicate that mergers, powerful AGN activity, and feedback through AGN-driven winds will collectively contribute to shaping the host galaxy evolution of PDS 456, and likely, that of similar objects at the brightest end of the AGN luminosity function across all redshifts. Moreover, the finding that the momentum boost of the total outflow deviates from the expected energy-conserving expansion for large-scale outflows highlights the need of novel AGN-driven outflow models to comprehensively interpret these phenomena.

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arXiv2024

ALMA survey of a massive node of the Cosmic Web at z~3. I. Discovery of a large overdensity of CO emitters

Sub-mm surveys toward overdense regions in the early Universe are essential to uncover the obscured star-formation and the cold gas content of assembling galaxies within massive dark matter halos. In this work, we present deep ALMA mosaic observations covering an area of $\sim 2'\times2'$ around MQN01 (MUSE Quasar Nebula 01), one of the largest and brightest Ly-$α$ emitting nebulae discovered thus far surrounding a radio-quiet quasar at $z\simeq3.25$. Our observations target the 1.2- and the 3-mm dust continuum, as well as the carbon monoxide CO(4-3) transition in galaxies in the vicinity of the quasar. We identify a robust sample of eleven CO line-emitting galaxies (including a closely-separated quasar companion) which lie within $\pm 4000\,{\rm km\,s^{-1}}$ relatively to the quasar systemic redshift. A fraction of these objects are missed in previous deep rest-frame optical/UV surveys thus highlighting the critical role of (sub-)mm imaging. We also detect a total of eleven sources revealed in their 1.2-mm dust continuum with six of them having either high-fidelity spectroscopic redshift information from rest-frame UV metal absorptions, or CO line which place them in the same narrow redshift range. A comparison of the CO luminosity function (LF) and 1.2-mm number count density with that of the general fields points to a galaxy overdensity of $δ> 10$. We find evidence of a systematic flattening at the bright-end of the CO LF with respect to the trend measured in blank fields. Our findings reveal that galaxies in dense regions at $z\sim3$ are more massive and significantly richer in molecular gas than galaxies in fields, hence enabling a faster and accelerated assembly. This is the first of a series of studies to characterize one of the densest regions of the Universe found so far at $z > 3$.

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arXiv2023

The Ly$α$, CIV, and HeII nebulae around J1000+0234: a galaxy pair at the center of a galaxy overdensity at $z=4.5$

Ly$α$ $λ$1216 (Ly$α$) emission extending over $\gtrsim\,\rm 10\,kiloparsec\,(kpc)$ around dusty, massive starbursts at $z\gtrsim3$ might represent a short-lived phase in the evolution of present-day, massive quiescent galaxies. To obtain empirical constraints on this emerging scenario, we present Ly$α$, CIV $λ$1550 (CIV), and HeII $λ$1640 (HeII) observations taken with the Multi Unit Spectroscopic Explorer towards J1000$+$0234: a galaxy pair at $z=4.5$ composed of a low-mass starburst (J1000$+$0234$-$South) neighboring a massive Submillimeter Galaxy (SMG; J1000$+$0234$-$North) that harbors a rotationally supported gas disk. Based on the spatial distribution and relative strength of Ly$α$, CIV, and HeII, we find that star formation in J1000+0234$-$South and an active galactic nucleus in J1000+0234$-$North are dominant factors in driving the observed 40 kiloparsec-scale Ly$α$ blob (LAB). We use the non-resonant HeII line to infer kinematic information of the LAB. We find marginal evidence for two spatially and spectrally separated HeII regions, which suggests that the two-peaked Ly$α$ profile is mainly a result of two overlapping and likely interacting HI clouds. We also report the serendipitous identification of three Ly$α$ emitters spanning over a redshift bin $Δz \leq 0.007$ (i.e., $\lesssim 380\,\rm km\,s^{-1}$) located at $\lesssim 140\,\rm kpc$ from J1000+0234. A galaxy overdensity analysis confirms that J1000+0234 lies near the center of a Megaparsec-scale galaxy overdensity at $z= 4.5$ that might evolve into a galaxy cluster at $z=0$. The properties of J1000+0234 and its large-scale environment strengthen the link between SMGs within LABs, tracing overdense regions, as the progenitors of local massive ellipticals in galaxy clusters.

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arXiv2022

Detection of companion galaxies around hot dust-obscured hyper-luminous galaxy W0410-0913

The phase transition between galaxies and quasars is often identified with the rare population of hyper-luminous, hot dust-obscured galaxies. Galaxy formation models predict these systems to grow via mergers, that can deliver large amounts of gas toward their centers, induce intense bursts of star formation and feed their supermassive black holes. Here we report the detection of 24 galaxies emitting Lyman-alpha emission on projected physical scales of about 400 kpc around the hyper-luminous hot dust-obscured galaxy W0410-0913, at redshift z = 3.631, using Very Large Telescope observations. While this indicates that W0410-0913 evolves in a very dense environment, we do not find clear signs of mergers that could sustain its growth. Data suggest that if mergers occurred, as models expect, these would involve less massive satellites, with only a moderate impact on the internal interstellar medium of W0410-0913, which is sustained by a rotationally-supported fast-rotating molecular disk, as Atacama Large Millimeter Array observations suggest.

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arXiv2022

Tomography of the environment of the COSMOS/AzTEC-3 submillimeter galaxy at z=5.3 revealed by Lyalpha and MUSE observations

We study the members of the protocluster around AzTEC3 submillimeter galaxy at z=5.3. We analyzed the data from the MUSE instrument in an area of 1.4x1.4 arcmin^2 around AzTEC3 and derived information on the Lya line in emission. We compared the Lya profile of various regions of the environment with the zELDA radiative transfer model, revealing the neutral gas distribution and kinematics. We identified 10 Lya emitting sources, including 2 regions with extended emission: one embedding AzTEC3 and LBG3, a star-forming galaxy located 12 kpc north of the SMG and another toward LBG-1, a star-forming galaxy located 90 kpc to the southeast. The sources appear distributed in an elongated configuration of about 70'' in extent. The number of sources confirms the overdensity around AzTEC3. For the AzTEC3+LBG3 system, the Lya emission appears redshifted and more spatially extended than the [CII] line emission. Similarly, the Lya line spectrum is broader in velocity than [CII] for LBG1. In the former spectrum, the Lya emission is elongated to the north of LBG3 and to the south of AzTEC3, where a faint Lya emitting galaxy is also located. The elongated structures could resemble tidal features due to the interaction of the two galaxies with AzTEC3. Also, we find a bridge of gas, revealed by the Lya emission between AzTEC3 and LBG3. The Lya emission toward LBG1 embeds its three components. The HI kinematics support the idea of a merger of the three components. Given the availability of CO and [CII] observations from previous campaigns, and our Lya information, we find evidence of starburst-driven phenomena and interactions around AzTEC-3. The stellar mass of the galaxies of the overdensity and the Lya luminosity of the HI nebula associated with AzTEC-3 imply a dark matter halo of 10^12 Msun at z=5.3 that could evolve into a cluster of 2x10^14 Msun at z=0.

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arXiv2020

Probing the AGN Unification Model at redshift z $\sim$ 3 with MUSE observations of giant Ly$α$ nebulae

A prediction of the classic active galactic nuclei (AGN) unification model is the presence of ionisation cones with different orientations depending on the AGN type. Confirmations of this model exist for present times, but it is less clear in the early Universe. Here, we use the morphology of giant Ly$α$ nebulae around AGNs at redshift z$\sim$3 to probe AGN emission and therefore the validity of the AGN unification model at this redshift. We compare the spatial morphology of 19 nebulae previously found around type I AGNs with a new sample of 4 Ly$α$ nebulae detected around type II AGNs. Using two independent techniques, we find that nebulae around type II AGNs are more asymmetric than around type I, at least at radial distances $r>30$~physical kpc (pkpc) from the ionizing source. We conclude that the type I and type II AGNs in our sample show evidence of different surrounding ionising geometries. This suggests that the classical AGN unification model is also valid for high-redshift sources. Finally, we discuss how the lack of asymmetry in the inner parts (r$\lesssim$30 pkpc) and the associated high values of the HeII to Ly$α$ ratios in these regions could indicate additional sources of (hard) ionizing radiation originating within or in proximity of the AGN host galaxies. This work demonstrates that the morphologies of giant Ly$α$ nebulae can be used to understand and study the geometry of high redshift AGNs on circum-nuclear scales and it lays the foundation for future studies using much larger statistical samples.

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arXiv2020

The WISSH quasars project VII. Outflows and metals in the circumgalactic medium around the hyper-luminous z~3.6 quasar J1538+08

During the last years, Ly$α$ nebulae have been routinely detected around high-z, radio-quiet quasars (RQQs) thanks to the advent of sensitive integral field spectrographs. Constraining the physical properties of the Ly$α$ nebulae is crucial for a full understanding of the circum-galactic medium (CGM), which is a venue of feeding and feedback processes. The most luminous quasars are privileged test-beds to study these processes, given their large ionizing fluxes and dense CGM environments in which they are expected to be embedded. We aim at characterizing the rest-frame UV emission lines in the CGM around a hyper-luminous, broad emission line, RQQ at z~3.6, that exhibits powerful outflows at both nuclear and host galaxy scales. We analyze VLT/MUSE observations of the quasar J1538+08 and perform a search for extended UV emission lines to characterize its morphology, emissivity, kinematics and metal content. We report the discovery of a very luminous ($\sim2 \times10^{44}~erg~s^{-1}$), giant Ly$α$ nebula and a likely associated extended CIV nebula. The Ly$α$ nebula emission exhibits moderate blueshift compared with the quasar systemic redshift and large average velocity dispersion ($σ_{v}$ ~700 $km~s^{-1}$) across the nebula, while the CIV nebula shows $σ_{v}$~$350~km~s^{-1}$. The Ly$α$ line profile exhibits a significant asymmetry towards negative velocity values at 20-30 kpc south of the quasar and is well parameterized by two Gaussian components: a narrow ($σ$~$470~km~s^{-1}$) systemic one plus a broad ($σ$~1200 $km~s^{-1}$), blueshifted (~1500 $km~s^{-1}$) one. Our analysis of the MUSE observation of J1538+08 reveals metal-enriched CGM around this hyper-luminous quasar and our detection of blueshifted emission in the line profile of the Ly$α$ nebula suggests that powerful nuclear outflows can propagate through the CGM over tens of kpc.

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arXiv2019

Gas filaments of the cosmic web located around active galaxies in a proto-cluster

Cosmological simulations predict the Universe contains a network of intergalactic gas filaments, within which galaxies form and evolve. However, the faintness of any emission from these filaments has limited tests of this prediction. We report the detection of rest-frame ultraviolet Lyman-alpha radiation from multiple filaments extending more than one megaparsec between galaxies within the SSA 22 proto-cluster at a redshift of 3.1. Intense star formation and supermassive black-hole activity is occurring within the galaxies embedded in these structures, which are the likely sources of the elevated ionizing radiation powering the observed Lyman-alpha emission. Our observations map the gas in filamentary structures of the type thought to fuel the growth of galaxies and black holes in massive proto-clusters.

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