Search

We present a dynamical analysis of a quasar-host galaxy at z ≃ 6 (SDSS J2310+1855) using a high-resolution ALMA observation of the [CII] emission line. The observed rotation curve was fitted with mass models that considered the gravitational contribution of a thick gas disc, a thick star-forming stellar disc, and a central mass concentration, which is likely due to a combination of a spheroidal component (i.e. a stellar bulge) and a supermassive black hole (SMBH). The SMBH mass of 5 × 109 M⊙, previously measured using the CIV and MgII emission lines, is not sufficient to explain the high velocities in the central regions. Our dynamical model suggests the presence of a stellar bulge with a mass of Mbulge ∼ 1010 M⊙ in this object, when the Universe was younger than 1 Gyr. To finally be located on the local MSMBH − Mbulge relation, the bulge mass should increase by a factor of ∼40 from z = 6 to 0, while the SMBH mass should grow by a factor of 4 at most. This points towards asynchronous galaxy-BH co-evolution. Imaging with the JWST will allow us to validate this scenario.

One of the key open questions in Cosmology is the nature of the sources that completed the cosmological hydrogen Reionization at z~5.2. High-z primeval galaxies have been long considered the main drivers for Reionization, with a minor role played by high-z AGN. However, in order to confirm this scenario, it is fundamental to measure the photo-ionization rate produced by active SMBHs close to the epoch of Reionization. Given the pivotal role played by spectroscopically complete observations of high-z QSOs, in this paper we present the first results of the RUBICON (Reionizing the Universe with BrIght COsmological Nuclei) survey. It consists of a color selected sample of bona-fide z~5 QSO candidates from the Hyper Suprime-Cam Subaru Strategic Survey. Our QSO candidates have been validated both by photometric redshifts based on SED fitting and by spectroscopic redshifts, confirming that they lie at 4.5, Comment: Accepted for publication in ApJ

We present ALMA deep observations of the [CII] 158 $\mu$m emission line and the continuum at 253 GHz and 99 GHz towards SDSS J0100+2802 at $z\simeq 6.3$, the most luminous QSO at z$>$6. It belongs to the HYPERION sample of luminous QSOs at $z\sim 6-7.5$. The observations (at 2.2$''$ resolution in band 3 and 0.9$''$ resolution in band 6) are optimized to detect extended emission around the QSO. We detect a merging, tidally disrupted companion both in [CII] and in continuum, stretching on scales up to 20 kpc from the quasar, with a knotty morphology. For the newly-detected companion we estimate a dust mass of $M_{\rm dust}=(0.6-4.3)\times 10^7\ \rm M_\odot$, an SFR in the range $[43-402]\ \rm M_\odot$, that is remarkably similar to the SFR of the QSO, and a neutral gas mass of $M_{\rm HI}=3.3\times 10^9\ \rm M_{\odot}$, suggesting that both the QSO and its companion are gas rich and that the major merging may be at the origin of the boosted star formation. This close merging companion is undetected by deep JWST imaging observations, supporting the effectiveness of ALMA in detecting dust obscured sources especially in the vicinity of optically bright quasars. We also detect a broad blueshifted component in the [CII] spectrum aligned with the radio jet of the QSO, suggesting that this may be the first detection of a radio jet - driven outflow at such high redshift. We estimate a mass outflow rate in the range $\dot{M}_{\rm out}=(115-269)\ \rm M_\odot\ yr^{-1}$. The outflow energetics is similar to that of ionized outflows found in other QSOs host at lower redshift, and the low momentum loading factor suggests that this outflow would not be very effective in removing the gas from the entire galaxy. These results highlight the importance of deep medium-resolution ALMA observations for the study of QSOs and their environment at the Epoch of Reionization., Comment: 10 pages, 7 figures, 3 Tables. Submitted to A&A

Bright quasars, powered by accretion onto billion-solar-mass black holes, already existed at the epoch of reionization, when the Universe was 0.5-1 billion years old(1). How these black holes formed in such a short time isthe subject of debate, particularly asthey lie above the correlation between black-hole mass and galaxy dynamical mass(2,3) in the local Universe. What slowed down black-hole growth, leading towards the symbioticgrowth observed in the local Universe, and when this process started, has hitherto not been known, although black-hole feedback is a likely driver(4). Here we report optical and near-infrared observations of a sample of quasars at redshifts 5.8 less than or similar to z less than or similar to 6.6. About half ofthe quasar spectra reveal broad, blueshifted absorption line troughs, tracing black-hole-driven winds with extreme outflowvelocities, up to 17% of the speed of light. The fraction of quasars with such outflow winds at z greater than or similar to 5.8 approximate to 2.4 is times higher than at z approximate to 2-4. We infer that outflows at z greater than or similar to 5.8 inject large amounts of energy into the interstellar medium and suppress nuclear gas accretion, slowing down black-hole growth. The outflow phase may then mark the beginning of substantial black-hole feedback. The red optical colours of outflow quasars at z greater than or similar to 5.8 indeed suggest that these systems are dusty and may be caught during an initial quenching phase of obscured accretion(5).

The existence of luminous quasars (QSO) at the Epoch of Reionization (EoR; i.e. z>6) powered by supermassive black holes (SMBH) with masses $\gtrsim10^9~M_\odot$ challenges models of early SMBH formation. To shed light on the nature of these sources we started a multiwavelength programme based on a sample of 18 HYPerluminous quasars at the Epoch of ReionizatION (HYPERION). These are the luminous QSOs whose SMBH must have had the fastest mass growth during the Universe first Gyr. In this paper we present the HYPERION sample and report on the first of the 3 years planned observations of the 2.4 Ms XMM-Newton Multi-Year Heritage program on which HYPERION is based. The goal of this program is to accurately characterize the X-ray nuclear properties of QSOs at the EoR. Through a joint X-ray spectral analysis of 10 sources, in the rest-frame $\sim2-50$ keV range, we report a steep average photon index ($\Gamma\sim2.4\pm0.1$). Absorption is not required. The average $\Gamma$ is inconsistent at $\geq4\sigma$ level with the canonical 1.8-2 value measured in QSO at z, Comment: 21 pages (including appendix), 12 figures, 4 tables. Accepted for pubblication in A&A

We present ALMA deep observations of the [CII] 158 $μ$m emission line and the continuum at 253 GHz and 99 GHz towards SDSS J0100+2802 at $z\simeq 6.3$, the most luminous QSO at z$>$6. It belongs to the HYPERION sample of luminous QSOs at $z\sim 6-7.5$. The observations (at 2.2$''$ resolution in band 3 and 0.9$''$ resolution in band 6) are optimized to detect extended emission around the QSO. We detect a merging, tidally disrupted companion both in [CII] and in continuum, stretching on scales up to 20 kpc from the quasar, with a knotty morphology. For the newly-detected companion we estimate a dust mass of $M_{\rm dust}=(0.6-4.3)\times 10^7\ \rm M_\odot$, an SFR in the range $[43-402]\ \rm M_\odot$, that is remarkably similar to the SFR of the QSO, and a neutral gas mass of $M_{\rm HI}=3.3\times 10^9\ \rm M_{\odot}$, suggesting that both the QSO and its companion are gas rich and that the major merging may be at the origin of the boosted star formation. This close merging companion is undetected by deep JWST imaging observations, supporting the effectiveness of ALMA in detecting dust obscured sources especially in the vicinity of optically bright quasars. We also detect a broad blueshifted component in the [CII] spectrum aligned with the radio jet of the QSO, suggesting that this may be the first detection of a radio jet - driven outflow at such high redshift. We estimate a mass outflow rate in the range $\dot{M}_{\rm out}=(115-269)\ \rm M_\odot\ yr^{-1}$. The outflow energetics is similar to that of ionized outflows found in other QSOs host at lower redshift, and the low momentum loading factor suggests that this outflow would not be very effective in removing the gas from the entire galaxy. These results highlight the importance of deep medium-resolution ALMA observations for the study of QSOs and their environment at the Epoch of Reionization., 10 pages, 7 figures, 3 Tables. Submitted to A&A

We present bolometric luminosities, black hole masses and Eddington ratios for 42 luminous quasars at z>6 using high signal-to-noise ratio VLT/X-Shooter spectra, acquired in the enlarged ESO Large Programme XQR-30. In particular, we derive bolometric luminosities from the rest-frame 3000 A, luminosities using a bolometric correction from the literature, and the black hole masses by modelling the spectral regions around the CIV 1549A and the MgII 2798A emission lines, with scaling relations calibrated in the local universe. We find that the black hole masses derived from both emission lines are in the same range, and the scatter of the measurements agrees with expectations from the scaling relations. The MgII-derived masses are between ~(0.8-12) x 10^9 Msun, and the derived Eddington ratios are within ~0.13-1.73, with a mean (median) of 0.84 (0.72). By comparing the total sample of quasars at z>5.8, from this work and from the literature, to a bolometric luminosity distribution-matched sample at z~1.5, we find that quasars at high redshift host slightly less massive black holes which accrete slightly more rapidly than at lower-z, with a difference in the mean Eddington ratios of the two samples of ~0.27, in agreement with recent literature work., 9 pages; 5 figures; accepted for publication in A&A

Aims: We present the X-ray imaging and spectral analysis of the diffuse emission around the radio galaxy J1140-2629 (the Spiderweb galaxy) at z = 2.16 and of its nuclear emission, based on a deep (700 ks) Chandra observation. Methods: We obtained a robust characterization of the unresolved nuclear emission, and carefully computed the contamination in the surrounding regions due to the wings of the instrument point spread function. Then, we quantified the extended emission within a radius of 12 arcsec. We used the Jansky Very Large Array radio image to identify the regions overlapping the jets, and performed X-ray spectral analysis separately in the jet regions and in the complementary area. Results: We find that the Spiderweb galaxy hosts a mildly absorbed quasar, showing a modest yet significant spectral and flux variability on a timescale of ∼1 year (observed frame). We find that the emission in the jet regions is well described by a power law with a spectral index of Γ ∼ 2 − 2.5, and it is consistent with inverse-Compton upscattering of the cosmic microwave background photons by the relativistic electrons. We also find a roughly symmetric, diffuse emission within a radius of ∼100 kpc centered on the Spiderweb galaxy. This emission, which is not associated with the jets, is significantly softer and consistent with thermal bremsstrahlung from a hot intracluster medium (ICM) with a temperature of kT = 2.0−0.4+0.7 keV, and a metallicity of Z < 1.6 Z⊙ at 1σ c.l. The average electron density within 100 kpc is ne = (1.51 ± 0.24 ± 0.14) × 10−2 cm−3, corresponding to an upper limit for the total ICM mass of ≤(1.76 ± 0.30 ± 0.17) × 1012 M⊙ (where error bars are 1σ statistical and systematic, respectively). The rest-frame luminosity L0.5 − 10 keV = (2.0 ± 0.5) × 1044 erg s−1 is about a factor of 2 higher than the extrapolated L − T relation for massive clusters, but still consistent within the scatter. If we apply hydrostatic equilibrium to the ICM, we measure a total gravitational mass M(

Aims. We present an analysis of the 700 ks Chandra ACIS-S observation of the field around the radio galaxy J1140-2629 (the Spiderweb Galaxy) at z = 2.156, focusing on the nuclear activity in the associated large-scale environment.Methods. We identified unresolved X-ray sources in the field down to flux limits of 1.3 x 10(-16) and 3.9 x 10(-16) erg s(-1) cm(-2) in the soft (0.5-2.0 keV) and hard (2-10 keV) band, respectively. We searched for counterparts in the optical, near-infrared, and submillimeter catalogs available in the literature to identify X-ray sources belonging to the protocluster and derived their X-ray properties.Results. We detect 107 X-ray unresolved sources within 5 arcmin (corresponding to 2.5 Mpc) of J1140-2629, among which 13 have optical counterparts with spectroscopic redshift 2.11 < z < 2.20, and 1 source has a photometric redshift consistent with this range. The X-ray-emitting protocluster members are distributed approximately over a similar to 3.2 x 1.3 Mpc(2) rectangular region. An X-ray spectral analysis for all the sources within the protocluster shows that their intrinsic spectral slope is consistent with an average similar to 1.84 +/- 0.04. Excluding the Spiderweb Galaxy, the best-fit intrinsic absorption for five protocluster X-ray members is N-H > 10(23) cm(-2), while another six have upper limits of the order of a few times 10(22) cm(-2). Two sources can only be fitted with very flat Gamma 10.5. This value corresponds to an enhancement factor of 6.0(-3.0)(+9.0) for the nuclear activity with L0.5-10 keV > 4 x 10(43 )erg s(-1 )with respect to the COSMOS field at comparable redshifts and stellar mass range.Conclusions. We conclude that the galaxy population in the Spiderweb protocluster is characterized by enhanced X-ray nuclear activity triggered by environmental effects on megaparsec scales.

The outstanding mass growth of supermassive black holes (SMBHs) at the Reionisation Epoch and how it is related to the concurrent growth of their host galaxies, poses challenges to theoretical models aimed at explaining how these systems formed in short timescales (\dot M_{\rm BH}/M_{\rm BH}$, suggesting that AGN feedback might be efficiently acting to slow down the SMBH accretion, while the stellar mass assembly is still vigorously taking place in the host galaxy. In addition, we were also able to detect high-velocity emission on the red and blue sides of the [CII] emission line, that traces a gaseous outflow, and for the first time, we mapped a spatially-resolved water vapour disk through the H$_2$O v=0 $3_{(2,2)}-3_{(1,3)}$ emission line detected at $ν_{\rm obs} = 274.074$ GHz, whose kinematic properties and size are broadly consistent with those of the [CII] disk., 15 pages, 10 figures, 4 tables. Accepted in A&A

(Abridged) We present an analysis of the 700 ks Chandra ACIS-S observation of the field around the Spiderweb Galaxy at z=2.156, focusing on the nuclear activity in the associated large-scale environment. We identify unresolved X-ray sources down to flux limits of 1.3X10^{-16} and 3.9X10^{-16} erg/s/cm^2 in the soft and hard band, respectively. We search for counterparts in the optical, NIR and submm bands to identify X-ray sources belonging to the protocluster. We detect 107 X-ray unresolved sources within 5 arcmin (corresponding to 2.5 Mpc) of J1140-2629, among which 13 have optical counterparts with spectroscopic redshift 2.11~1.84+-0.04. The best-fit intrinsic absorption for 5 protocluster X-ray members is N_H>10^{23} cm^{-2}, while other 6 have upper limits of the order of fewX10^{22} cm^{-2}. Two sources can only be fitted with very flat \Gamma10.5, corresponding to an enhancement of 6.0^{+9.0}_{-3.0} with respect to the COSMOS field at comparable redshifts and stellar mass range. We conclude that the galaxy population in the Spiderweb Protocluster is characterized by enhanced X-ray nuclear activity triggered by environmental effects on Mpc scales., Comment: Astronomy & Astrophysics. Minor changes in this version. Version accepted in A&A

Ground-based and airborne instrumentation for astronomy IX (2022), Montreal, JUL 17-22, 2022.--Proceedings of SPIE - The International Society for Optical Engineering vol. 12184 Article number 1218424.-- Complete list of authors: Marconi, A.; Abreu, M.; Adibekyan, V.; Alberti, V.; Albrecht, S.; Alcaniz, J.; Aliverti, M.; Allende Prieto, C.; Gomez, J. D. Alvarado; Amado, P. J.; Amate, M.; Andersen, M. I.; Artigau, E.; Baker, C.; Baldini, V.; Balestra, A.; Barnes, S. A.; Baron, F.; Barros, S. C. C.; Bauer, S. M.; Beaulieu, M.; Bellido-Tirado, O.; Benneke, B.; Bensby, T.; Bergin, E. A.; Biazzo, K.; Bik, A.; Birkby, J. L.; Blind, N.; Boisse, I.; Bolmont, E.; Bonaglia, M.; Bonfils, X.; Borsa, F.; Brandeker, A.; Brandner, W.; Broeg, C. H.; Brogi, M.; Brousseau, D.; Brucalassi, A.; Brynnel, J.; Buchhave, L. A.; Buscher, D. F.; Cabral, A.; Calderone, G.; Calvo-Ortega, R.; Cantalloube, F.; Canto Martins, B. L.; Carbonaro, L.; Chauvin, G.; Chazelas, B.; Cheffot, A. -L.; Cheng, Y. S.; Chiavassa, A.; Christensen, L.; Cirami, R.; Cook, N. J.; Cooke, R. J.; Coretti, I.; Covino, S.; Cowan, N.; Cresci, G.; Cristiani, S.; Cunha Parro, V.; Cupani, G.; D'Odorico, V.; de Castro Leao, I.; De Cia, A.; De Medeiros, J. R.; Debras, F.; Debus, M.; Demangeon, O.; Dessauges-Zavadsky, M.; Di Marcantonio, P.; Dionies, F.; Doyon, R.; Dunn, J.; Ehrenreich, D.; Faria, J. P.; Feruglio, C.; Fisher, M.; Fontana, A.; Fumagalli, M.; Fusco, T.; Fynbo, J.; Gabella, O.; Gaessler, W.; Gallo, E.; Gao, X.; Genolet, L.; Genoni, M.; Giacobbe, P.; Giro, E.; Goncalves, R. S.; Gonzalez, O. A.; Gonzalez Hernandez, J. I.; Gracia Temich, F.; Haehnelt, M. G.; Haniff, C.; Hatzes, A.; Helled, R.; Hoeijmakers, H. J.; Huke, P.; Jaervinen, A. S.; Jaervinen, S. P.; Kaminski, A.; Korn, A. J.; Kouach, D.; Kowzan, G.; Kreidberg, L.; Landoni, M.; Lanotte, A.; Lavail, A.; Li, J.; Liske, J.; Lovis, C.; Lucatello, S.; Lunney, D.; MacIntosh, M. J.; Madhusudhan, N.; Magrini, L.; Maiolino, R.; Malo, L.; Man, A. W. S.; Marquart, T.; Marques, E. L.; Martins, C. J. A. P.; Martins, A. M.; Maslowski, P.; Mason, E.; Mason, C. A.; McCracken, R. A.; Mergo, P.; Micela, G.; Mitchell, T.; Molliere, P.; Monteiro, M. A.; Montgomery, D.; Mordasini, C.; Morin, J.; Mucciarelli, A.; Murphy, M. T.; N'Diaye, M.; Neichel, B.; Niedzielski, A. T.; Niemczura, E.; Nortmann, L.; Noterdaeme, P.; Nunes, N. J.; Oggioni, L.; Oliva, E.; Onel, H.; Origlia, L.; Ostlin, G.; Palle, E.; Papaderos, P.; Pariani, G.; Penate Castro, J.; Pepe, F.; Levasseur, L. Perreault; Petit, P.; Pino, L.; Piqueras, J.; Pollo, A.; Poppenhaeger, K.; Quirrenbach, A.; Rauscher, E.; Rebolo, R.; Redaelli, E. M. A.; Reffert, S.; Reid, D. T.; Reiners, A.; Richter, P.; Riva, M.; Rivoire, S.; Rodriguez-Lopez, C.; Roederer, I. U.; Romano, D.; Rousseau, S.; Rowe, J.; Salvadori, S.; Sanna, N.; Santos, N. C.; Diaz, P. Santos; Sanz-Forcada, J.; Sarajlic, M.; Sauvage, J. -F.; Schaefer, S.; Schiavon, R. P.; Schmidt, T. M.; Selmi, C.; Sivanandam, S.; Sordet, M.; Sordo, R.; Sortino, F.; Sosnowska, D.; Sousa, S. G.; Stempels, E.; Strassmeier, K. G.; Suarez Mascareno, A.; Sulich, A.; Sun, X.; Tanvir, N. R.; Tenegi-Sangines, F.; Thibault, S.; Thompson, S. J.; Tozzi, A.; Turbet, M.; Vallee, P.; Varas, R.; Venn, K. A.; Veran, J. -P.; Verma, A.; Viel, M.; Wade, G.; Waring, C.; Weber, M.; Weder, J.; Wehbe, B.; Weingrill, J.; Woche, M.; Xompero, M.; Zackrisson, E.; Zanutta, A.; Zapatero Osorio, M. R.; Zechmeister, M.; Zimara, J., The first generation of ELT instruments includes an optical-infrared high resolution spectrograph, indicated as ELT-HIRES and recently christened ANDES (ArmazoNes high Dispersion Echelle Spectrograph). ANDES consists of three fibre-fed spectrographs (UBV, RIZ, YJH) providing a spectral resolution of similar to 100,000 with a minimum simultaneous wavelength coverage of 0.4-1.8 mu m with the goal of extending it to 0.35-2.4 mu m with the addition of a K band spectrograph. It operates both in seeing- and diffraction-limited conditions and the fibre-feeding allows several, interchangeable observing modes including a single conjugated adaptive optics module and a small diffraction-limited integral field unit in the NIR. Its modularity will ensure that ANDES can be placed entirely on the ELT Nasmyth platform, if enough mass and volume is available, or partly in the Coude room. ANDES has a wide range of groundbreaking science cases spanning nearly all areas of research in astrophysics and even fundamental physics. Among the top science cases there are the detection of biosignatures from exoplanet atmospheres, finding the fingerprints of the first generation of stars, tests on the stability of Nature's fundamental couplings, and the direct detection of the cosmic acceleration. The ANDES project is carried forward by a large international consortium, composed of 35 Institutes from 13 countries, forming a team of more than 200 scientists and engineers which represent the majority of the scientific and technical expertise in the field among ESO member states., The Italian effort for ANDES is supported by the Italian National Institute for Astrophysics (INAF). The Portuguese participation is supported by FCT -Fundacao para a Ciencia e a Tecnologia through national funds and by FEDER through COMPETE2020 -Programa Operacional Competitividade e Internacionalizacao by these grants: UID/FIS/04434/2019, UIDB/04434/2020 & UIDP/04434/2020; POCI-01-0145-FEDER-032113 & PTDC/FIS-AST/32113/2017. Swedish participation in the ANDES project is made possible through the national Swedish ELT Instrumentation Consortium (SELTIC), suppored by the Swedish Research Council (VR). CJM acknowledges FCT and POCH/FSE (EC) support through Investigador FCT Contract 2021.01214.CEECIND/CP1658/CT0001. JLB acknowledges funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program under grant agreement No 805445. MTM acknowledges the support of the Australian Research Council through Future Fellowship grant FT180100194 SS acknowledges funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program under grant agreement No 804240. TMS acknowledgment the support from the SNF synergia grant CRSII5-193689 (BLUVES), With funding from the Spanish government through the Severo Ochoa Centre of Excellence accreditation SEV-2017-0709

Luminous quasars powered by accretion onto billion solar mass black holes already exist at the epoch of Reionisation, when the Universe was 0.5-1 Gyr old. These objects likely reside in over-dense regions of the Universe, and will grow to form today's giant galaxies. How their huge black holes formed in such short times is debated, particularly as they lie above the local black hole mass-galaxy dynamical mass correlation, thus following the black hole-dominance growth path. It is unknown what slowed down the black hole growth, leading towards the symbiotic growth observed in the local Universe, and when this process started, although black hole feedback is a likely driver. This deadlock is due to the lack of large, homogeneous samples of high-redshift quasars with high-quality, broad-band spectroscopic information. Here we report results from a VLT/X-shooter survey of 30 quasars at redshift 5.8$\le$z$\le$6.6 (XQR-30). About 50% of their spectra reveal broad blue-shifted absorption line (BAL) throughs, tracing powerful ionised winds. The BAL fraction in z$\gtrsim$6 quasars is 2-3 times higher than in quasars at z~2-4.5. XQR-30 BAL quasars exhibit extreme outflow velocities, up to 17% of the light speed, rarely observed at lower redshift. These outflows inject large amounts of energy into the galaxy interstellar medium, which can contrast nuclear gas accretion, slowing down the black-hole growth. The star-formation rate in high-z quasar hosts is generally $>$100 M$_\odot$/yr, so these galaxies are growing at a fast rate. The BAL phase may then mark the beginning of significant feedback, acting first on black hole growth and possibly later on galaxy growth. The red optical colors of BAL quasars at z$\gtrsim$6 indeed suggest that these systems are dusty and may be caught during an initial quenching phase of obscured accretion., This preprint has not undergone peer review or any post-submission improvements or corrections. The Version of Record of this article is published in Nature, and is available online at https://doi.org/10.1038/s41586-022-04608-1

Context. Sources at the brightest end of the quasi-stellar object (QSO) luminosity function, during the peak epoch in the history of star formation and black hole accretion (z ∼ 2-4, often referred to as "Cosmic noon") are privileged sites to study the cycle of feeding & feedback processes in massive galaxies. Aims: We aim to perform the first systematic study of cold gas properties in the most luminous QSOs, by characterising their host-galaxies and environment. These targets exhibit indeed widespread evidence of outflows at nuclear and galactic scales. Methods: We analyse ALMA, NOEMA and JVLA observations of the far-infrared continuum, CO and [CII] emission lines in eight QSOs (bolometric luminosity LBol ≳ 3 × 1047 erg s-1) from the WISE-SDSS selected hyper-luminous (WISSH) QSOs sample at z ∼ 2.4-4.7. Results: We report a 100% emission line detection rate and a 80% detection rate in continuum emission, and we find CO emission to be consistent with the steepest CO ladders observed so far. Sub-millimetre data reveal presence of (one or more) bright companion galaxies around ∼80% of WISSH QSOs, at projected distances of ∼6-130 kpc. We observe a variety of sizes for the molecular gas reservoirs (∼1.7-10 kpc), mostly associated with rotating disks with disturbed kinematics. WISSH QSOs typically show lower CO luminosity and higher star formation efficiency than infrared matched, z ∼ 0-3 main-sequence galaxies, implying that, given the observed SFR ∼170-1100 M⊙ yr-1, molecular gas is converted into stars in ≲50 Myr. Most targets show extreme dynamical to black-hole mass ratios Mdyn/MBH ∼ 3-10, two orders of magnitude smaller than local relations. The molecular gas fraction in the host-galaxies of WISSH is lower by a factor of ∼10-100 than in star forming galaxies with similar M*. Conclusions: Our analysis reveals that hyper-luminous QSOs at Cosmic noon undergo an intense growth phase of both the central super-massive black hole and of the host-galaxy. These systems pinpoint the high-density sites where giant galaxies assemble, where we show that mergers play a major role in the build-up of the final host-galaxy mass. We suggest that the observed low molecular gas fraction and short depletion timescale are due to AGN feedback, whose presence is indicated by fast AGN-driven ionised outflows in all our targets.

Starburst galaxies and star-forming active galactic nuclei (AGN) are among the candidate sources thought to contribute appreciably to the extragalactic gamma-ray and neutrino backgrounds. NGC 1068 is the brightest of the star-forming galaxies found to emit gamma rays from 0.1 to 50 GeV. Precise measurements of the high-energy spectrum are crucial to study the particle accelerators and probe the dominant emission mechanisms. We have carried out 125 hours of observations of NGC 1068 with the MAGIC telescopes in order to search for gamma-ray emission in the very high energy band. We did not detect significant gamma-ray emission, and set upper limits at 95\% confidence level to the gamma-ray flux above 200 GeV f, 11 pages, 4 figures, accepted for publication in The Astrophysical Journal

Aims. The SINFONI survey for Unveiling the Physics and Effect of Radiative feedback (SUPER) was designed to conduct a blind search for AGN-driven outflows on X-ray-selected AGNs at redshift z ∼ 2 with high (∼2 kpc) spatial resolution, and to correlate them with the properties of their host galaxy and central black hole. The main aims of this paper are: (a) to derive reliable estimates for the masses of the black holes and accretion rates for the Type-1 AGNs in this survey; and (b) to characterise the properties of the AGN-driven winds in the broad line region (BLR). Methods. We analysed rest-frame optical and UV spectra of 21 Type-1 AGNs. We used Hα, Hβ, and MgII line profiles to estimate the masses of the black holes. We used the blueshift of the CIV line profile to trace the presence of winds in the BLR. Results. We find that the Hα and Hβ line widths are strongly correlated, as is the line continuum luminosity at 5100 Å with Hα line luminosity, resulting in a well-defined correlation between black hole masses estimated from Hα and Hβ. Using these lines, we estimate that the black hole masses for our objects are in the range Log (MBH/M⊙) = 8.4–10.8 and are accreting at λEdd = 0.04–1.3. Furthermore, we confirm the well-known finding that the CIV line width does not correlate with the Balmer lines and the peak of the line profile is blueshifted with respect to the [OIII]-based systemic redshift. These findings support the idea that the CIV line is tracing outflowing gas in the BLR for which we estimated velocities up to ∼4700 km s−1. We confirm the strong dependence of the BLR wind velocity on the UV-to-X-ray continuum slope, the bolometric luminosity, and Eddington ratio. We infer BLR mass outflow rates in the range 0.005–3 M⊙ yr−1, revealing a correlation with the bolometric luminosity consistent with that observed for ionised winds in the narrow line region (NLR), and X-ray winds detected in local AGNs, and kinetic power ∼10−7 − 10−4 × LBol. The coupling efficiencies predicted by AGN-feedback models are much higher than the values reported for the BLR winds in the SUPER sample; although it should be noted that only a fraction of the energy injected by the AGN into the surrounding medium is expected to become kinetic power in the outflow. Finally, we find an anti-correlation between the equivalent width of the [OIII] line and the CIV velocity shift, and a positive correlation between this latter parameter and [OIII] outflow velocity. These findings, for the first time in an unbiased sample of AGNs at z ∼ 2, support a scenario where BLR winds are connected to galaxy-scale detected outflows, and are therefore capable of affecting the gas in the NLR located at kiloparsec scale distances. We thank the anonymous referee for the useful comments that improved the paper. The scientific results reported in this article are based on observations collected at the European organisation for Astronomical Research in the Southern Hemisphere under ESO programs 196.A-0377 (SINFONI data) and LP175.A-0839 (zCOSMOS data), and SDSS. Funding for SDSS-III has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation, and the US Department of Energy Office of Science. The SDSS-III web site is http://www.sdss3.org/. SDSS-III is managed by the Astrophysical Research Consortium for the Participating Institutions of the SDSS-III Collaboration including the University of Arizona, the Brazilian Participation Group, Brookhaven National Laboratory, Carnegie Mellon University, University of Florida, the French Participation Group, the German Participation Group, Harvard University, the Instituto de Astrofisica de Canarias, the Michigan State/Notre Dame/JINA Participation Group, Johns Hopkins University, Lawrence Berkeley National Laboratory, Max Planck Institute for Astrophysics, Max Planck Institute for Extraterrestrial Physics, New Mexico State University, New York University, Ohio State University, Pennsylvania State University, University of Portsmouth, Princeton University, the Spanish Participation Group, University of Tokyo, University of Utah, Vanderbilt University, University of Virginia, University of Washington, and Yale University. This research project was supported by the DFG Cluster of Excellence “Origin and Structure of the Universe” (universe-cluster.de). G. V. acknowledges financial support from Premiale 2015 MITic (PI B. Garilli). G. C., M. Bi, C. F. and F. F. acknowledge support from PRIN MIUR project “Black Hole winds and the Baryon Life Cycle of Galaxies: the stone-guest at the galaxy evolution supper”, contract #2017PH3WAT. M. P. is supported by the Programa Atracción de Talento de la Comunidad de Madrid via grant 2018-T2/TIC-11715.. With funding from the Spanish government through the "María de Maeztu Unit of Excellence" accreditation (MDM-2017-0737) Peer review

The SINFONI survey for Unveiling the Physics and Effect of Radiative feedback (SUPER) was designed to conduct a blind search for AGN-driven outflows on X-ray selected AGN at redshift z$\sim$2 with high ($\sim$2 kpc) spatial resolution, and correlate them to the properties of the host galaxy and central black hole. The main aims of this paper are: a) to derive reliable estimates for the BH mass and accretion rates for the Type-1 AGN in this survey; b) to characterize the properties of the AGN driven winds in the BLR. We analyzed rest-frame optical and UV spectra of 21 Type-1 AGN. We found that the BH masses estimated from H$\alpha$ and H$\beta$ lines are in agreement. We estimate BH masses in the range Log(M$\rm_{BH}/M_{\odot}$)=8.4-10.8 and Eddington ratios $\rm\lambda_{Edd}$ =0.04-1.3. We confirm that the CIV line width does not correlate with the Balmer lines and the peak of the line profile is blue-shifted with respect to the [OIII]-based systemic redshift. These findings support the idea that the CIV line is tracing outflowing gas in the BLR, with velocities up to $\sim$4700 km/s. We confirm the strong dependence of the BLR wind velocity with the UV-to-Xray continuum slope, L$\rm_{Bol}$ and $\rm\lambda_{Edd}$. We inferred BLR mass outflow rates in the range 0.005-3 M$_{\odot}$/yr, showing a correlation with the bolometric luminosity consistent with that observed for ionized winds in the NLR and X-ray winds detected in local AGN, and kinetic power $\sim$10$^{[-7:-4]}\times$ L$\rm_{Bol}$. Finally, we found an anti-correlation between the equivalent width of the [OIII] line with respect to the CIV shift, and a positive correlation with [OIII] outflow velocity. These findings, for the first time in an unbiased sample of AGN at z$\sim$2, support a scenario where BLR winds are connected to galaxy scale detected outflows, and are capable of affecting the gas in the NLR located at kpc scale., Comment: Accepted for publication in A&A

Recent advances in observations have provided a wealth of measurements of the expansions of outflows in galactic discs out to large radii in a variety of galactic hosts. To provide an updated baseline for the interpretation of such data, and to assess to what extent the present status of the modeling is consistent with the existing observations, we provide a compact two-dimensional description for the expansion of AGN-driven shocks in realistic galactic discs with exponential gas density profiles in a disc geometry. We derive solutions for the outflow expansion and the mass outflow rates in different directions with respect to the plane of the disc. These are expressed in terms of the global properties of the host galaxy and of the central AGN to allow for an easy and direct comparison with existing observations in a variety of galactic hosts with measured properties, and out to distances $\sim 10$ kpc from the centre. The results are compared with a state-of-the-art compilation of observed outflows in 19 galaxies with different measured gas and dynamical mass, allowing for a detailed, one-by-one comparison with the model predictions. The agreement we obtain for a wide range of host galaxy gas mass and AGN bolometric luminosity provides a quantitative systematic test for the modeling of AGN-driven outflows in galactic discs. We also consider a larger sample of galaxies with no reliable measurements of the gas and dynamical mass. In this case we perform a comparison of the model predictions for different bins of AGN luminosities assuming values for the gas mass and dynamical mass derived from scaling relations. The encouraging, quantitative agreement of the model predictions with a wide set of existing observations constitutes a baseline for the interpretation of forthcoming data, and for a more detailed treatment of AGN feedback in galaxy formation models., 34 pages, accepted for publication in The Astrophysical Journal

International audience; Following the success of the Plateau de Bure high-z Blue Sequence Survey (PHIBSS), we present the PHIBSS2 legacy program, a survey of the molecular gas properties of star-forming galaxies on and around the star-formation main sequence (MS) at different redshifts using IRAM's NOrthern Extended Millimeter Array (NOEMA). This survey significantly extends the existing sample of star-forming galaxies with CO molecular gas measurements, probing the peak epoch of star formation (z = 1 − 1.6) as well as its building-up (z = 2 − 3) and winding-down (z = 0.5 − 0.8) phases. The targets are drawn from the well-studied GOODS, COSMOS, and AEGIS cosmological deep fields and uniformly sample the MS in the stellar mass (M)-star formation rate (SFR) plane with log(M /M) = 10 − 11.8 and SFR = 3.5 − 500 M yr −1 without morphological selection, thus providing a statistically meaningful census of star-forming galaxies at different epochs. We describe the survey strategy and sample selection before focusing on the results obtained at redshift z = 0.5 − 0.8, where we report 60 CO(2-1) detections out of 61 targets. We determine molecular gas masses between 2 × 10 9 and 5 × 10 10 M and separately obtain disc sizes and bulge-to-total (B/T) luminosity ratios from HST I-band images. The median molecular gas-to-stellar mass ratio µ gas = 0.28 ± 0.04, gas fraction f gas = 0.22 ± 0.02, and depletion time t depl = 0.84 ± 0.07 Gyr as well as their dependence with stellar mass and offset from the MS follow published scaling relations for a much larger sample of galaxies spanning a significantly wider range of redshifts, the cosmic evolution of the SFR being mainly driven by that of the molecular gas fraction. The galaxy-averaged molecular Kennicutt-Schmidt (KS) relation between molecular gas and SFR surface densities is strikingly linear, pointing towards similar star formation timescales within galaxies at any given epoch. In terms of morphology, the molecular gas content, the SFR, the disc stellar mass, and the disc molecular gas fraction do not seem to correlate with B/T and the stellar surface density, which suggests an ongoing supply of fresh molecular gas to compensate for the build-up of the bulge. Our measurements do not yield any significant variation of the depletion time with B/T and hence no strong evidence for morphological quenching within the scatter of the MS.

The astrophysical journal / 1 883(2), 1 - 11 (2019). doi:10.3847/1538-4357/ab3a51, Starburst galaxies and star-forming active galactic nuclei are among the candidate sources thought to contribute appreciably to the extragalactic gamma-ray and neutrino backgrounds. NGC 1068 is the brightest of the star-forming galaxies found to emit gamma-rays from 0.1 to 50 GeV. Precise measurements of the high-energy spectrum are crucial to study the particle accelerators and probe the dominant emission mechanisms. We have carried out 125 hr of observations of NGC 1068 with the MAGIC telescopes in order to search for gamma-ray emission in the very-high-energy band. We did not detect significant gamma-ray emission, and set upper limits at the 95% confidence level to the gamma-ray flux above 200 GeV f < 5.1 × 10−13 cm−2 s−1. This limit improves previous constraints by about an order of magnitude and allows us to put tight constraints on the theoretical models for the gamma-ray emission. By combining the MAGIC observations with the Fermi-LAT spectrum we limit the parameter space (spectral slope, maximum energy) of the cosmic ray protons predicted by hadronuclear models for the gamma-ray emission, while we find that a model postulating leptonic emission from a semi-relativistic jet is fully consistent with the limits. We provide predictions for IceCube detection of the neutrino signal foreseen in the hadronic scenario. We predict a maximal IceCube neutrino event rate of 0.07 yr−1., Published by Institute of Physics Publ., London

We present ALMA rest-frame 230 GHz continuum and CO(2-1) line observations of the nearby Compton-thick Seyfert galaxy ESO428-G14, with angular resolution 0.7 arcsec (78 pc). We detect CO(2-1) emission from spiral arms and a circum-nuclear ring with 200 pc radius, and from a transverse gas lane with size of $\sim100$ pc, which crosses the nucleus and connects the two portions the circumnuclear ring. The molecular gas in the host galaxy is distributed in a rotating disk with intrinsic circular velocity $v_{rot}=135$ km/s, inclination $i=57$ deg, and dynamical mass $M_{dyn }=5\times 10^9~\rm M_{\odot}$ within a radius of $\sim 1$ kpc. In the inner 100 pc region CO is distributed in a equatorial bar, whose kinematics is highly perturbed and consistent with an inflow of gas towards the AGN. This inner CO bar overlaps with the most obscured, Compton-thick region seen in X-rays. We derive a column density of $\rm N(H_2) \approx 2\times10^{23}~ cm^{-2}$ in this region, suggesting that molecular gas may contribute significantly to the AGN obscuration. We detect a molecular outflow with a total outflow rate $\rm \dot M_{of}\approx 0.8~M_{\odot}/yr$, distributed along a bi-conical structure with size of $700$ pc on both sides of the AGN. The bi-conical outflow is also detected in the $\rm H_2$ emission line at 2.12 $\mu$m, which traces a warmer nuclear outflow located within 170 pc from the AGN. This suggests that the outflow cools with increasing distance from the AGN. We find that the hard X-ray emitting nuclear region mapped with Chandra is CO-deprived, but filled with warm molecular gas traced by $\rm H_2$ - thus confirming that the hard (3-6 keV) continuum and Fe K$\alpha$ emission are due to scattering from dense neutral clouds in the ISM., Comment: Submitted to ApJ

The origin of the tight correlations observed between the masses of supermassive black holes (SMBHs) and host galaxy properties is still debated. Negative feedback from AGN can provide a viable explanation for these correlations. According to the theoretical models, the ejective feedback resulting from radiatively-efficient episodes of gas accretion onto SMBHs may be the main responsible for the rapid shut-off of star formation and black hole growth in the early stages of the evolution of present-day massive galaxies, which must have taken place at z>2. Here we present near-IR (SINFONI) and millimetre (ALMA) observations of z~2.5 luminous (Lbol>1e47 Lsun) quasars showing fast and extended ionised outflows. These AGN-driven outflows appear to be able to expel a large fraction of molecular and ionised gas and suppress star formation in the outflow region. However, the detection of Halpha emission along the edges of the outflow cone indicates on-going star formation rates of at least 50 Msun/yr, suggesting either that AGN feedback does not affect the whole galaxy or that many feedback episodes are required before star formation is completely quenched. On the other hand, the detection also lead to a positive feedback interpretation: the AGN-driven outflow compress the surrounding gas inducing star formation. Our results highlight the possible double role of galaxy-wide outflows in host galaxy evolution. This is also supported by recent observations in the local Universe indicate that massive galactic outflows may ignite star formation within the outflow itself. We also present new ALMA observations of a sample of quasars at z∼6 optimised to investigate the extended emission associated with outflows as traced by the [CII]158μm line. Although strong and powerful AGN-driven outflows are expected at these redshifts, our analysis suggests that such outflows may not be as effective as expected in removing gas out of their host galaxies.

The standard AGN-galaxy co-evolutionary scenario predicts a phase of deeply buried supermassive black hole growth coexisting with a starburst (SB) before feedback phenomena deplete the cold molecular gas reservoir of the galaxy and an optically luminous QSO is revealed ('SB-QSO evolutionary sequence'). The aim of this work is to measure the cold gas reservoir of three highly obscured QSOs to test if their gas fraction is similar to that of sub-millimeter galaxies (SMGs), as expected by some models, and place these measurements in the context of the SB-QSO framework. We target CO(1-0) transition in BzK4892, a Compton Thick (CT) QSO at z=2.6, CO(1-0) in BzK8608 and CO(2-1) in CDF153, two highly obscured QSOs at z=2.5 and z=1.5, respectively. For all these targets, we place 3$\sigma$ upper limits on the CO, with $L'_{CO} < (1.5\div 2.8)\times 10^{10}$ K km/s pc$^2$. We also compare the molecular gas conditions of our targets with those of other systems at z>1, considering normal star forming galaxies and SMGs, unobscured and obscured AGN from the literature. For the AGN samples, we provide an updated and (almost) complete collection of targets with CO follow-up. BzK4892 displays a high star formation efficiency (SFE$=L_{IR}/L'_{CO}>410$ L$_{\odot}$/(K km s$^{-1}$ pc$^2$)) and a gas fraction $f_{gas}10$). From the comparison with literature data, we found that a) obscured AGN at z>1 are associated with higher SFE and lower $f_{gas}$ with respect to star forming galaxies; b) mildly and highly obscured active galaxies have comparable gas fractions; c) the SFE of CT and obscured AGN are similar to those of unobscured AGN. Within the SB-QSO framework, these findings could be consistent with a scenario where feedback can impact the host galaxy already from the early phases of the SB-QSO sequence., Comment: 20 pages, 7 figures, accepted for publication in A&A

I will present evidence of AGN-driven outflows in the early Universe, resulting from the stacking analysis of a sample of 48 QSOs at z~5-7 with ALMA [CII] detection. Very broad [CII] wings are on average present, and extend beyond velocities of 1000 km/s. The luminosity associated with the broad [CII] wings correlates with the AGN luminosity, while it remains unchanged in low-high SFR sources. This indicates the AGN as the main driving mechanism of the observed cold [CII] outflows in distant QSOs, with associated atomic mass outflow rates of 200-350 Msun/yr. I will discuss how these outflows relate to those observed in lower-z AGNs and give an estimate of their spatial extent. Thanks to sub-millimetre observations with ALMA and NOEMA, we are also able to have an insight onto the host galaxy properties of high-z QSOs, otherwise outshined by the AGN radiation. I will focus on the high-resolution ALMA observation of a hyper luminous QSO at z=4.4, revealing an exceptional overdensity around the QSO with multiple companions as close as 2 kpc. These crowded surroundings, and the QSO host galaxy itself, are forming stars at a very high rate (hundreds of Msun/yr). I will discuss how the BH and stellar masses are growing in this multi-source system, which likely represents the cradle of what would be a giant galaxy at z = 0. Finally, I will discuss how the huge AGN radiation may regulate the SF activityin the host galaxy and suggest that substantial SF at early epochs may have taken place in the companion galaxies.

The standard QSO-galaxy co-evolutionary scenario predicts a phase of deeply "buried" supermassive black hole growth coexisting with a starburst (SB) before feedback phenomena deplete the cold molecular gas reservoir of the galaxy and an optically luminous QSO is revealed ("SB-QSO evolutionary sequence"). We tested simple SB-QSO paradigm predictions by comparing the molecular (carbon monoxide, CO) gas properties of 56 obscured and 49 unobscured QSO host galaxies at high-redshift (z~1-6) with those of ~ 170 high-z star forming galaxies from the literature. We found that, on average, obscured AGN at z >1 are associated with higher star formation efficiencies (SFEs) and lower gas fractions with respect to normal star forming galaxies and SBs at given stellar mass and redshift. These results could suggest that their cold gas content has been already depleted by powerful AGN-driven outflows. Moreover, we did not find any clear separation between the properties of unobscured and obscured QSOs (e.g. they have similar SFEs), suggesting a scenario where feedback can rapidly impact the host galaxy evolution.

The standard QSO-galaxy co-evolutionary scenario predicts a phase of deeply "buried" supermassive black hole growth coexisting with a starburst (SB) before feedback phenomena deplete the cold molecular gas reservoir of the galaxy and an optically luminous QSO is revealed ("SB-QSO evolutionary sequence"). We tested simple SB-QSO paradigm predictions by comparing the molecular (carbon monoxide, CO) gas properties of 56 obscured and 49 unobscured QSO host galaxies at high-redshift (z~1-6) with those of ~ 170 high-z star forming galaxies from the literature. We found that, on average, obscured AGN at z >1 are associated with higher star formation efficiencies (SFEs) and lower gas fractions with respect to normal star forming galaxies and SBs at given stellar mass and redshift. These results could suggest that their cold gas content has been already depleted by powerful AGN-driven outflows. Moreover, we did not find any clear separation between the properties of unobscured and obscured QSOs (e.g. they have similar SFEs), suggesting a scenario where feedback can rapidly impact the host galaxy evolution.

We present ALMA and ACA [CI]$^{3}P_{1}-^{3}P_{0}$ ([CI](1-0)) observations of NGC6240, which we combine with ALMA CO(2-1) and IRAM PdBI CO(1-0) data to study the physical properties of the massive molecular (H$_2$) outflow. We discover that the receding and approaching sides of the H$_2$ outflow, aligned east-west, exceed 10 kpc in their total extent. High resolution ($0.24"$) [CI](1-0) line images surprisingly reveal that the outflow emission peaks between the two AGNs, rather than on either of the two, and that it dominates the velocity field in this nuclear region. We combine the [CI](1-0) and CO(1-0) data to constrain the CO-to-H$_2$ conversion factor ($\alpha_{\rm CO}$) in the outflow, which is on average $2.1\pm1.2~\rm M_{\odot} (K~km~s^{-1}~pc^2)^{-1}$. We estimate that $60\pm20$ % of the total H$_2$ gas reservoir of NGC6240 is entrained in the outflow, for a resulting mass-loss rate of $\dot{M}_{\rm out}=2500\pm1200~M_{\odot}~yr^{-1}$ $\equiv 50\pm30$ SFR. This energetics rules out a solely star formation-driven wind, but the puzzling morphology challenges a classic radiative-mode AGN feedback scenario. For the quiescent gas we compute $\langle\alpha_{\rm CO}\rangle = 3.2\pm1.8~\rm M_{\odot} (K~km~s^{-1}~pc^2)^{-1}$, which is at least twice the value commonly employed for (U)LIRGs. We observe a tentative trend of increasing $r_{21}\equiv L^{\prime}_{\rm CO(2-1)}/L^{\prime}_{\rm CO(1-0)}$ ratios with velocity dispersion and measure $r_{21}>1$ in the outflow, whereas $r_{21}\simeq1$ in the quiescent gas. We propose that molecular outflows are the location of the warmer, strongly unbound phase that partially reduces the opacity of the CO lines in (U)LIRGs, hence driving down their global $\alpha_{\rm CO}$ and increasing their $r_{21}$ values., ERC Advanced Grant 695671 "QUENCH" STFC ST/M001172/1

We present deep high resolution (0.03", 200pc) ALMA Band 7 observations covering the dust continuum and [CII] $\lambda157.7\mu$m emission in four $z\sim4.4-4.8$ sub-millimeter galaxies (SMGs) selected from the ALESS and AS2UDS surveys. The data show that the rest-frame 160$\mu$m (observed 345 GHz) dust emission is consistent with smooth morphologies on kpc scales for three of the sources. One source, UDS47.0, displays apparent substructure but this is also consistent with a smooth morphology, as indicated by simulations showing that smooth exponential disks can appear clumpy when observed at high angular resolution (0.03") and depth of these observations ($\sigma_{345\text{GHz}} \sim27-47\mu$Jy beam$^{-1}$). The four SMGs are bright [CII] emitters, and we extract [CII] spectra from the high resolution data, and recover $\sim20-100$% of the [CII] flux and $\sim40-80$% of the dust continuum emission, compared to the previous lower resolution observations. When tapered to 0.2" resolution our maps recover $\sim80-100$% of the continuum emission, indicating that $\sim60$% of the emission is resolved out on $\sim200$pc scales. We find that the [CII] emission in high-redshift galaxies is more spatially extended than the rest-frame 160$\mu$m dust continuum by a factor of $1.6\pm0.4$. By considering the $L_{\text{[CII]}}$/$L_{\text{FIR}}$ ratio as a function of the star-formation rate surface density ($\Sigma_{\text{SFR}}$) we revisit the [CII] deficit, and suggest that the decline in the $L_{\text{[CII]}}$/$L_{\text{FIR}}$ ratio as a function of $\Sigma_{\text{SFR}}$ is consistent with local processes. We also explore the physical drivers that may be responsible for these trends and can give rise to the properties found in the densest regions of SMGs., Comment: 15 pages, 6 figures, 4 tables, accepted for publication in ApJ

We present the first attempt to detect outflows from galaxies approaching the Epoch of Reionization (EoR) using a sample of 9 star-forming ($\rm SFR=31\pm 20~M_{\odot}~yr^{-1}$) $z\sim 5.5$ galaxies for which the [CII]158$\mu$m line has been previously obtained with ALMA. We first fit each line with a Gaussian function and compute the residuals by subtracting the best fitting model from the data. We combine the residuals of all sample galaxies and find that the total signal is characterised by a flux excess of $\sim 0.5$ mJy extended over $\sim 1000$ km~s$^{-1}$. Although we cannot exclude that part of this signal is due to emission from faint satellite galaxies, we show that the most probable explanation for the detected flux excess is the presence of broad wings in the [CII] lines, signatures of starburst-driven outflows. We infer an average outflow rate of $\rm \dot{M}=54\pm23~ M_{\odot}~yr^{-1}$, providing a loading factor $\eta=\rm \dot{M}/SFR=1.7\pm1.3$ in agreement with observed local starbursts. Our interpretation is consistent with outcomes from zoomed hydro-simulations of {\it Dahlia}, a $z\sim 6$ galaxy ($\rm SFR\sim 100~\rm M_{\odot}~yr^{-1}$) whose feedback-regulated star formation results into an outflow rate $\rm \dot{M}\sim 30~ M_{\odot}~yr^{-1}$. The quality of the ALMA data is not sufficient for a detailed analysis of the [CII] line profile in individual galaxies. Nevertheless, our results suggest that starburst-driven outflows are in place in the EoR and provide useful indications for future ALMA campaigns. Deeper observations of the [CII] line in this sample are required to better characterise feedback at high-$z$ and to understand the role of outflows in shaping early galaxy formation.

The standard AGN-galaxy co-evolutionary scenario predicts a phase of deeply buried supermassive black hole growth coexisting with a starburst (SB) before feedback phenomena deplete the cold molecular gas reservoir of the galaxy and an optically luminous QSO is revealed ('SB-QSO evolutionary sequence'). The aim of this work is to measure the cold gas reservoir of three highly obscured QSOs to test if their gas fraction is similar to that of sub-millimeter galaxies (SMGs), as expected by some models, and place these measurements in the context of the SB-QSO framework. We target CO(1-0) transition in BzK4892, a Compton Thick (CT) QSO at z=2.6, CO(1-0) in BzK8608 and CO(2-1) in CDF153, two highly obscured QSOs at z=2.5 and z=1.5, respectively. For all these targets, we place 3$��$ upper limits on the CO, with $L'_{CO} < (1.5��2.8)\times 10^{10}$ K km/s pc$^2$. We also compare the molecular gas conditions of our targets with those of other systems at z>1, considering normal star forming galaxies and SMGs, unobscured and obscured AGN from the literature. For the AGN samples, we provide an updated and (almost) complete collection of targets with CO follow-up. BzK4892 displays a high star formation efficiency (SFE$=L_{IR}/L'_{CO}>410$ L$_{\odot}$/(K km s$^{-1}$ pc$^2$)) and a gas fraction $f_{gas}10$). From the comparison with literature data, we found that a) obscured AGN at z>1 are associated with higher SFE and lower $f_{gas}$ with respect to star forming galaxies; b) mildly and highly obscured active galaxies have comparable gas fractions; c) the SFE of CT and obscured AGN are similar to those of unobscured AGN. Within the SB-QSO framework, these findings could be consistent with a scenario where feedback can impact the host galaxy already from the early phases of the SB-QSO sequence., 20 pages, 7 figures, accepted for publication in A&A

We present ALMA and ACA [CI]$^{3}P_{1}-^{3}P_{0}$ ([CI](1-0)) observations of NGC6240, which we combine with ALMA CO(2-1) and IRAM PdBI CO(1-0) data to study the physical properties of the massive molecular (H$_2$) outflow. We discover that the receding and approaching sides of the H$_2$ outflow, aligned east-west, exceed 10 kpc in their total extent. High resolution ($0.24"$) [CI](1-0) line images surprisingly reveal that the outflow emission peaks between the two AGNs, rather than on either of the two, and that it dominates the velocity field in this nuclear region. We combine the [CI](1-0) and CO(1-0) data to constrain the CO-to-H$_2$ conversion factor ($\alpha_{\rm CO}$) in the outflow, which is on average $2.1\pm1.2~\rm M_{\odot} (K~km~s^{-1}~pc^2)^{-1}$. We estimate that $60\pm20$ % of the total H$_2$ gas reservoir of NGC6240 is entrained in the outflow, for a resulting mass-loss rate of $\dot{M}_{\rm out}=2500\pm1200~M_{\odot}~yr^{-1}$ $\equiv 50\pm30$ SFR. This energetics rules out a solely star formation-driven wind, but the puzzling morphology challenges a classic radiative-mode AGN feedback scenario. For the quiescent gas we compute $\langle\alpha_{\rm CO}\rangle = 3.2\pm1.8~\rm M_{\odot} (K~km~s^{-1}~pc^2)^{-1}$, which is at least twice the value commonly employed for (U)LIRGs. We observe a tentative trend of increasing $r_{21}\equiv L^{\prime}_{\rm CO(2-1)}/L^{\prime}_{\rm CO(1-0)}$ ratios with velocity dispersion and measure $r_{21}>1$ in the outflow, whereas $r_{21}\simeq1$ in the quiescent gas. We propose that molecular outflows are the location of the warmer, strongly unbound phase that partially reduces the opacity of the CO lines in (U)LIRGs, hence driving down their global $\alpha_{\rm CO}$ and increasing their $r_{21}$ values.

We present the 78 ks $\textit{Chandra}$ observations of the $\textit{z}$ = 6.4 quasar SDSS J1148+5251. The source is clearly detected in the energy range 0.3–7 keV with 42 counts (with a significance ≳9σ). The X-ray spectrum is best fitted by a power law with photon index Γ = 1.9 absorbed by a gas column density of N$_{H}$=2.0$^{+2.0}_{−1.5}$ %. We measure an intrinsic luminosity at 2–10 and 10–40 keV equal to ∼ 1.5 × 10$^{45}$ erg s$^{-1}$, comparable with luminous local and intermediate-redshift quasar properties. Moreover, the X-ray to optical power-law slope value (αOX = −1.76 ± 0.14) of J1148 is consistent with the one found in quasars with similar rest-frame 2500 Å luminosity ($\textit{L}$2500 ∼ 10$^{32}$ erg s$^{-1}$ Å$^{-1}$). Then we use $\textit{Chandra}$ data to test a physically motivated model that computes the intrinsic X-ray flux emitted by a quasar starting from the properties of the powering black hole and assuming that X-ray emission is attenuated by intervening, metal-rich (Z ≥ Z⊙) molecular clouds (MC) distributed on ∼kpc scales in the host galaxy. Our analysis favours a black hole mass MBH ∼ 3 × 10$^{9}$ M⊙ and a molecular hydrogen mass M$_{H2}$∼2×10$^{10}$ M⊙, in good agreement with estimates obtained from previous studies. We finally discuss strengths and limits of our analysis., RM acknowledges support from the ERC Advanced Grant 695671 ‘QUENCH’ and the Science and Technology Facilities Council (STFC).

Outflows and SF in QSO

International audience; We present millimetre dust emission measurements of two Lyman‐break galaxies at z similar to 3 and construct for the first time fully sampled infrared spectral energy distributions (SEDs), from mid‐IR to the Rayleigh‐Jeans tail, of individually detected, unlensed, UV‐selected, main sequence (MS) galaxies at z = 3. The SED modelling of the two sources confirms previous findings, based on stacked ensembles, of an increasing mean radiation field < U > with redshift, consistent with a rapidly decreasing gas metallicity in z > 2 galaxies. Complementing our study with CO[J = 3 ‐> 2] emission line observations, we have measured the molecular gas mass reservoir (MH2) of the systems using three independent approaches: 1) CO line observations; 2) the dust to gas mass ratio vs. metallicity relation; and 3) a single band, dust emission flux on the Rayleigh‐Jeans side of the SED. All techniques return consistent MH2 estimates within a factor of two or less, yielding gas depletion time‐scales (tau(dep) approximate to 0.35 Gyr) and gas‐to‐stellar mass ratios (M‐H2/M‐* approximate to 0 .5‐1) for our z similar to 3 massive MS galaxies. The overall properties of our galaxies are consistent with trends and relations established at lower redshifts, extending the apparent uniformity of star‐forming galaxies over the last 11.5 billion years.

Even 10 billion years ago, the cores of the first galaxy clusters are often found to host a characteristic population of massive galaxies with already suppressed star formation. Here we search for distant cluster candidates at z similar to 2 using massive passive galaxies as tracers. With a sample of similar to 40 spectroscopically confirmed passive galaxies at 1.3 < z < 2.1, we tuned photometric redshifts of several thousand passive sources in the 2 sq. deg COSMOS field. This allowed us to map their density in redshift slices, probing the largescale structure in the COSMOS field as traced by passive sources. We report here on the three strongest passive galaxy overdensities that we identify in the range 1.5 < z < 2.5. While the actual nature of these concentrations still needs to be confirmed, we discuss their identification procedure and the arguments supporting them as candidate galaxy clusters (probably in the mid-10(13) M-circle dot range). Although this search approach is probably biased toward more evolved structures, it has the potential of selecting still rare, clusterlike environments close to their epoch of first appearance, enabling new investigations of the evolution of galaxies in the context of structure growth.

We present the first X-ray spectrum of a hot dust-obscured galaxy (DOG), namely W1835+4355 at z similar to 2.3. Hot DOGs represent a very rare population of hyperluminous (>= 10(47) erg s(-1)), dust-enshrouded objects at z >= 2 recently discovered in the WISE All Sky Survey. The 40 ks XMM-Newton spectrum reveals a continuum as flat (Gamma similar to 0.8) as typically seen in heavily obscured AGN. This, along with the presence of strong Fe K alpha emission, clearly suggests a reflection-dominated spectrum due to Compton-thick absorption. In this scenario, the observed luminosity of L2-10 similar to 2 x 10(44) erg s(-1) is a fraction (

Aims. Outflows driven by active galactic nuclei (AGN) are invoked by galaxy evolutionary models to quench star formation and to explain the origin of the relations observed locally between super-massive black holes and their host galaxies. We here aim to detect extended ionised outflows in luminous quasars, where we expect the highest activity both in star formation and in black-hole accretion. Currently, there are only a few studies based on spatially resolved observations of outflows at high redshift, z > 2. Methods. We analysed a sample of six luminous (L > 10(47) erg/s) quasars at z similar to 2.4, observed in H-band using the near-IR integral field spectrometer SINFONI at the VLT. We performed a kinematic analysis of the [OIII] emission line at lambda = 5007 angstrom. Results. We detect fast, spatially extended outflows in five out of six targets. [OIII]lambda 5007 has a complex gas kinematic, with blue-shifted velocities of a few hundreds of km s(-1) and line widths up to 1500 km s(-1). Using the spectroastrometric method, we infer a size of the ionised outflows of up to similar to 2 kpc. The properties of the ionised outflows, mass outflow rate, momentum rate, and kinetic power, are correlated with the AGN luminosity. The increase in outflow rate with increasing AGN luminosity is consistent with the idea that a luminous AGN pushes away the surrounding gas through fast outflows that are driven by radiation pressure, which depends on the emitted luminosity. Conclusions. We derive mass outflow rates of about 6 700 M-circle dot yr(-1) for our sample, which are lower than those observed in molecular outflows. The physical properties of ionised outflows show dependences on AGN luminosity that are similar to those of molecular outflows, but indicate that the mass of ionised gas is lower than that of molecular outflows. Alternatively, this discrepancy between ionised and molecular outflows could be explained with different acceleration mechanisms.

The systematic exploration of hyper-luminous (log LBol > 47) quasars shining at the golden epoch of AGN activity (i.e. z~2-4) offer the opportunity of overcoming the luminosity bias in the exploration of the accretion phenomenon. The WISE All-Sky Survey allowed to spot the most luminous quasars in the universe. In this talk, we will present the results of our on-going study of the XMM/Chandra/NuSTAR observations of WISE-selected hyper-luminous quasars regardless of the amount of their obscuration (i.e. both blue and heavily reddened). We report on the correlations between the X-ray and Optical, UV and MIR properties, and on the behavior of the X-ray bolometric correction at the brightest end of the luminosity function. We find that WISE-selected hyper-luminous quasars show much lower X/Opt flux and X/MIR luminosity ratios than those of AGN typically studied so far. This “X-ray weakness” can be a key ingredient for accelerating powerful ionized outflows (pervasively detected in the UV/optical band) and, furthermore, radiation-driven winds can be effective in destroying the X-ray corona and quenching the X-ray emission.

The epoch between redshift of 1-3 has become the prime focus of many galaxy evolutionary studies as the accretion rates of super massive black holes at the galactic center and the star formation rates of their hosts peaked around this period, pointing to their co-evolution throughout cosmic history. We will present two different approaches to study the impact of high redshift AGN (z~1.5) on the host galaxy: a) CO(2-1) observations from ALMA in a sample of "main sequence" AGNs to compare the star formation efficiency and gas fractions in active and inactive galaxies. b) SINFONI-IFU observations of a representative sample of high redshift quasars for which we observe intermediate to high velocity outflows using [OIII]5007 line diagnostics. These outflows are extended up-to kiloparsec scales and have an asymmetric geometry. With these approaches, one is able to test the effect of AGN feedback on the molecular as well as the ionized gas content.

International audience; We used the Plateau de Bure Interferometer (PdBI) to map a sample of 15 submillimetre galaxies (SMGs) in the COSMOS field at the wavelength of 1.3 mm. The target SMGs were originally discovered in the James Clerk Maxwell Telescope (JCMT)/AzTEC 1.1 mmcontinuum survey at S/N-1.1mm = 4-4.5. This paper presents, for the first time, interferometric millimetre-wavelength observations of these sources. The angular resolution of our observations, similar to 1 `'.8, allowed us to accurately determine the positions of the target SMGs. Using a detection threshold of S/N-1.3mm \textgreater 4.5 regardless of multiwavelength counterpart association, and 4 \textless S/N-1.3 mm \textless= 4.5 if a multiwavelength counterpart within 1 `'.5 is also present, the total number of detections in our survey is 22. The most significant PdBI detection of S/N-1.3 (mm) = 10.3 is towards AzTEC19. Three of our detected SMGs (AzTEC21, 27, and 28; which corresponds to 20%) are marginally resolved at our angular resolution, and these sources are found to have elongated or clumpy morphologies and/or multiple components. Using optical to near-infrared photometric redshifts, available spectroscopic redshifts, and redshifts estimated from the radio-to-submm spectral index we infer a median redshift of \textless(z)over tilde\textgreater = 3.20 +/- 0.25 for our sample. To study the overall multiplicity and redshift distribution of flux-limited samples of SMGs we combined these sources with the 15 brightest JCMT/AzTEC SMGs detected at 1.1 mm, AzTEC1-15, and studied previously. This constitutes a complete, flux-and S/N-limited 1.1-mm selected sample. We find that the median redshift for the 15 brightest JCMT/AzTEC SMGs ((z) over tilde = 3.05 +/- 0.44) is consistent with that for AzTEC16-30. This conforms to recent observational findings that SMGs do not exhibit any significant trend between the redshift and (sub) mm flux density. For the combined AzTEC1-30 sample we derive a median redshift of (z) over tilde = 3.17 +/- 0.27, consistent with previous results based on mm-selected samples. We further infer that within the combined AzTEC1-30 sample similar to 25 +/- 9% of sources separate into multiple components.

We combine molecular gas masses inferred from CO emission in 500 star-forming galaxies (SFGs) between z = 0 and 3, from the IRAM-COLDGASS, PHIBSS1/2, and other surveys, with gas masses derived from Herschel far-IR dust measurements in 512 galaxy stacks over the same stellar mass/redshift range. We constrain the scaling relations of molecular gas depletion timescale (tdepl) and gas to stellar mass ratio (Mmol gas/M∗) of SFGs near the star formation "main-sequence" with redshift, specific star-formation rate (sSFR), and stellar mass (M∗). The CO- and dust-based scaling relations agree remarkably well. This suggests that the CO → H2 mass conversion factor varies little within ±0.6 dex of the main sequence (sSFR(ms, z, M∗)), and less than 0.3 dex throughout this redshift range. This study builds on and strengthens the results of earlier work. We find that tdepl scales as (1 + z)-0.3 × (sSFR/sSFR(ms, z, M∗))-0.5, with little dependence on M∗. The resulting steep redshift dependence of Mmol gas/M∗≈ (1 + z)3 mirrors that of the sSFR and probably reflects the gas supply rate. The decreasing gas fractions at high M∗are driven by the flattening of the SFR-M∗relation. Throughout the probed redshift range a combination of an increasing gas fraction and a decreasing depletion timescale causes a larger sSFR at constant M∗. As a result, galaxy integrated samples of the Mmol gas-SFR rate relation exhibit a super-linear slope, which increases with the range of sSFR. With these new relations it is now possible to determine Mmol gas with an accuracy of ±0.1 dex in relative terms, and ±0.2 dex including systematic uncertainties.

We present a long (~76 ks) Chandra observation of IRAS 09104+4109, a hyper-luminous galaxy, optically classified as a Type 2 AGN hosted in a cD galaxy in a cluster at z=0.442. We also report on the results obtained by fitting its broad-band spectral energy distribution. The Compton-thick nature of this source (which has been often referred to as an "archetype" of Compton-thick Type 2 quasars) was formerly claimed on the basis of its marginal detection in the PDS instrument onboard BeppoSAX, being then disputed using XMM-Newton data. Both Chandra analysis and optical/mid-IR spectral fitting are consistent with the presence of heavy (~1-5 10^{23} cm^{-2}) but not extreme (Compton-thick) obscuration. However, using the mid-IR and the [OIII] emission as proxies of the nuclear hard X-ray luminosity suggests the presence of heavier obscuration. The 54-month Swift BAT map shows excess hard X-ray emission likely related to a nearby (z=0.009) Type 2 AGN, close enough to IRAS 09104+4109 to significantly enhance and contaminate its emission in the early BeppoSAX PDS data., 10 pages, 4 figures, 2 tables, MNRAS. Some references added

Constraining the NH distribution of AGNs at high column densities and high X-ray luminosites is crucial to provide a reliable MIR/X-ray luminosity ratio distribution and compare it with the expectations of dust reprocessing models. Here we present the IR to X-rays broad band SED of of the hyperluminous infrared galaxy and Type 2 quasar IRAS 09104+4109 (z=0.442), taking into account our recent result suggesting the likely Compton-thin nature of its absorber.

Understanding the relationship between the formation and evolution of galaxies and their central super massive black holes (SMBH) is one of the main topics in extragalactic astrophysics. Links and feedback may reciprocally affect both black hole and galaxy growth. Observations of the CO line at redshifts of 2-4 are crucial to investigate the gas mass, star formation activity and accretion onto SMBHs, as well as the effect of AGN feedback. Potential correlations between AGN and host galaxy properties can be highlighted by observing extreme objects. Despite their luminosity, hyper-luminous QSOs at z=2-4 are still little studied at mm wavelengths. We targeted CO(3-2) in ULAS J1539+0557, an hyper-luminos QSO (Lbol> 10^48 erg/s) at z=2.658, selected through its unusual red colors in the UKIDSS Large Area Survey (ULAS). We find a molecular gas mass of 4.1+-0.8 10^10 Msun, and a gas fraction of 0.4-0.1, depending mostly on the assumed source inclination. We also find a robust lower limit to the star-formation rate (SFR=250-1600 Msun/yr) and star-formation efficiency (SFE=25-350 Lsun/(K km s-1 pc2) by comparing the observed optical-near-infrared spectral energy distribution with AGN and galaxy templates. The black hole gas consumption timescale, M(H_2)/dM(accretion)/dt, is ~160 Myr, similar or higher than the gas consumption timescale. The gas content and the star formation efficiency are similar to those of other high-luminosity, highly obscured QSOs, and at the lower end of the star-formation efficiency of unobscured QSOs, in line with predictions from AGN-galaxy co-evolutionary scenarios. Further measurements of the (sub)-mm continuum in this and similar sources are mandatory to obtain a robust observational picture of the AGN evolutionary sequence., Submitted to A&A

Past observations of QSO host galaxies at z >6 have found cold gas and star formation on compact scales of a few kiloparsecs. We present new high sensitivity IRAM PdBI follow-up observations of the [CII] 158micron emission line and FIR continuum in the host galaxy of SDSS J1148+5152, a luminous QSO at redshift 6.4189. We find that a large fraction of the gas traced by [CII] is at high velocities, up to ~1400 km/s relative to the systemic velocity, confirming the presence of a major quasar-driven outflow indicated by previous observations. The outflow has a complex morphology and reaches a maximum projected radius of ~30 kpc. The extreme spatial extent of the outflow allows us, for the first time in an external galaxy, to estimate mass-loss rate, kinetic power and momentum rate of the outflow as a function of the projected distance from the nucleus and the dynamical time-scale. These trends reveal multiple outflow events during the past 100 Myr, although the bulk of the mass, energy and momentum appear to have been released more recently, within the past ~20 Myr. Surprisingly, we discover that also the quiescent gas at systemic velocity is extremely extended. More specifically, we find that, while 30% of the [CII] within v\in(-200, 200) km/s traces a compact component that is not resolved by our observations, 70% of the [CII] emission in this velocity range is extended, with a projected FWHM size of 17.4+-1.4 kpc. We detect FIR continuum emission associated with both the compact and the extended [CII] components, although the extended FIR emission has a FWHM of 11+-3 kpc, thus smaller than the extended [CII] source. Overall, our results indicate that the cold gas traced by [CII] is distributed up to r~30 kpc. A large fraction of extended [CII] is likely associated with star formation on large scales, but the [CII] source extends well beyond the FIR continuum., Accepted for publication in A&A, 21 pages, 18 figures, 3 tables (v2: accepted version, discussion expanded in Sect. 3, 4 and in the Appendices, minor changes elsewhere)

Simbol-X is a French-Italian mission, with a participation of German laboratories, for X-ray astronomy in the wide 0.5-80 keV band. Taking advantage of emerging technology in mirror manufacturing and spacecraft formation flying, Simbol-X will push grazing incidence imaging up to ~80 keV, providing an improvement of roughly three orders of magnitude in sensitivity and angular resolution compared to all instruments that have operated so far above 10 keV. This will open a new window in X-ray astronomy, allowing breakthrough studies on black hole physics and census and particle acceleration mechanisms. We describe briefly the main scientific goals of the Simbol-X mission, giving a few examples aimed at highlighting key issues of the Simbol-X design., Proc. of the workshop "Simbol-X: The hard X-ray universe in focus", Bologna 14-16 May, 2007

In the last couple of years a population of very massive (M(*) > 10(11) M(circle dot)), high-redshift (z >= 2) galaxies has been identified, but its role in galaxy evolution has not yet been fully understood. Aims. It is necessary to perform a systematic study of high- redshift massive galaxies, in order to determine the shape of the very massive tail of the stellar mass function and determine the epoch of their assembly. Methods. We selected high- z massive galaxies at 5.8 mu m, in the SWIRE ELAIS-S1 field (1 deg(2)). Galaxies with the 1.6 mu m stellar peak redshifted into the IRAC bands (z similar or equal to 1-3, called "IR-peakers") were identified. Stellar masses were derived by means of spectrophotometric fitting and used to compute the stellar mass function (MF) at z = 1-2 and 2-3. A parametric fit to the MF was performed, based on a Bayesian formalism, and the stellar mass density of massive galaxies above z = 2 determined. Results. We present the first systematic study of the very-massive tail of the galaxy stellar mass function at high redshift. A total of 326 sources were selected. The majority of these galaxies have stellar masses in excess of 10(11) M(circle dot) and lie at z > 1.5. The availability of mid-IR data turned out to be a valuable tool to constrain the contribution of young stars to galaxy SEDs, and thus their M(*)/L ratio. The influence of near-IR data and of the chosen stellar library on the SED fitting are also discussed. The z = 2-3 stellar mass function between 10(11) and similar to 10(12) M(circle dot) is probed with unprecedented detail. A significant evolution is found not only for galaxies with M similar to 10(11) M(circle dot), but also in the highest mass bins considered. The comoving number density of these galaxies was lower by more than a factor of 10 at z = 2-3, with respect to the local estimate. SWIRE 5.8 mu m peakers more massive than 1.6 x 10(11) M(circle dot) provide 30-50% of the total stellar mass density in galaxies at z = 2-3.