Search

While observations of molecular gas at cosmic noon and beyond have focused on the gas within galaxies (i.e. the interstellar medium, ISM), it is also crucial to study the molecular gas reservoirs surrounding each galaxy (i.e. in the circumgalactic medium, CGM). Recent observations of galaxies and quasars hosts at high redshift (z > 2) have revealed evidence for cold gaseous haloes of scale r CGM ∼ 10 kpc, with one discovery of a molecular halo with r CGM ∼ 200 kpc, and a molecular gas mass one order of magnitude larger than the ISM of the central galaxy. As a follow up, we present deep ACA and ALMA observations of CO(3–2) from this source and two other quasar host galaxies at z ∼ 2.2. While we find evidence for CO emission on scales of r ∼ 10 kpc, we do not find evidence for molecular gas on scales larger than r > 20 kpc. Therefore, our deep data do not confirm the existence of massive molecular haloes on scales of ∼100 kpc for these X-ray selected quasars. As an interesting byproduct of our deep observations, we obtain the tentative detection of a negative continuum signal on scales larger than r > 200 kpc, which might be tracing the Sunyaev–Zeldovich effect associated with the halo heated by the active galactic nucleus (AGN). If confirmed with deeper data, this could be direct evidence of the preventive AGN feedback process expected by cosmological simulations. [ABSTRACT FROM AUTHOR]

Large-scale outflows are believed to be an important mechanism in the evolution of galaxies. We can determine the impact of these outflows by studying either current galaxy outflows and their effect in the galaxy or by studying the effect of past outflows on the gas surrounding the galaxy. In this work, we examine the CO(7−6), [C  i ] (⁠|$^{3} \rm P_{1} \rightarrow {\rm ^3 P}_{0}$|⁠), H2O 211–202, and dust continuum emission of 15 extremely red quasars at z ∼ 2.3 using ALMA. By investigating the radial surface brightness profiles of both the individual sources and the stacked emission, we detect extended cold gas and dust emission on scales of ∼14 kpc in CO(7−6), [C  i ](2−1), and dust continuum. This is the first time that the presence of a large amount of molecular gas was detected on large, circumgalactic medium scales around quasar host galaxies using [C  i ] extended emission. We estimate the dust and molecular gas mass of these haloes to be 107.6 and 1010.6 M⊙, indicating significant dust and molecular gas reservoirs around these extreme quasars. By estimating the time-scale at which this gas can reach these distances by molecular gas outflows (7–32 Myr), we conclude that these haloes are a relic of past AGN or starburst activity, rather than an effect of the current episode of extreme quasar activity. [ABSTRACT FROM AUTHOR]

Gaseous outflows are key phenomena in the evolution of galaxies, as they affect star formation (either positively or negatively), eject gas from the core or disc, and directly cause mixing of pristine and processed material. Active outflows may be detected through searches for broad spectral line emission or high-velocity gas, but it is also possible to determine the presence of past outflows by searching for extended reservoirs of chemically enriched molecular gas in the circumgalactic medium (CGM) around galaxies. In this work, we examine the CO(3−2) emission of a set of seven z ∼ 2.0–2.5 active galactic nuclei (AGN) host galaxies, as observed with ALMA. Through a 3D stacking analysis, we find evidence for extended CO emission of radius r ∼ 13 kpc. We extend this analysis to the HST /ACS i -band images of the sample galaxies, finding a complex small-scale (r < 10 kpc) morphology but no robust evidence for extended emission. In addition, the dust emission (traced by rest-frame FIR emission) shows no evidence for significant spatial extension. This indicates that the diffuse CO emission revealed by ALMA is morphologically distinct from the stellar component, and thus traces an extended reservoir of enriched gas. The presence of a diffuse, enriched molecular reservoir around this sample of AGN host galaxies at cosmic noon hints at a history of AGN-driven outflows that likely had strong effects on the star formation history of these objects. [ABSTRACT FROM AUTHOR]

Forthcoming observational facilities will make the exploration of the early universe routine, likely probing large populations of galaxies at very low metallicities. It will therefore be important to have diagnostics that can solidly identify and distinguish different classes of objects in such low metallicity regimes. We use new photoionization models to develop diagnostic diagrams involving various nebular lines. We show that combinations of these diagrams allow the identification and discrimination of the following classes of objects in the early universe: PopIII and direct collapse black holes (DCBH) in pristine environments, PopIII and DCBH embedded in slightly enriched interstellar medium (ISM; |$\rm Z\sim 10^{-5}-10^{-4}$|⁠), and (metal poor) PopII and active galactic nucleus in enriched ISM. Diagnostics involving rest-frame optical lines (that will be accessible by James Webb Space Telescope) have a better discriminatory power but also rest-frame ultraviolet diagnostics can provide very useful information. Interestingly, we find that metal lines such as [O  iii ]λ5007 and C  iv λ1549 can remain relatively strong (about a factor of 0.1–1 relative H β and He  ii λ1640, respectively), even in extremely metal poor environments (⁠|$\rm Z\sim 10^{-5}-10^{-4}$|⁠), which could be embedding PopIII galaxies and DCBH. [ABSTRACT FROM AUTHOR]

Galactic outflows are known to consist of several gas phases; however, the connection between these phases has been investigated little and only in a few objects. In this paper, we analyse Multi Unit Spectroscopic Explorer (MUSE)/Very Large Telescope (VLT) data of 26 local (U)LIRGs and study their ionized and neutral atomic phases. We also include objects from the literature to obtain a sample of 31 galaxies with spatially resolved multiphase outflow information. We find that the ionized phase of the outflows has on average an electron density three times higher than the disc (n e,disc ∼ 145 cm−3 versus n e,outflow ∼ 500 cm−3), suggesting that cloud compression in the outflow is more important than cloud dissipation. We find that the difference in extinction between outflow and disc correlates with the outflow gas mass. Together with the analysis of the outflow velocities, this suggests that at least some of the outflows are associated with the ejection of dusty clouds from the disc. This may support models where radiation pressure on dust contributes to driving galactic outflows. The presence of dust in outflows is relevant for potential formation of molecules inside them. We combine our data with millimetre data to investigate the molecular phase. We find that the molecular phase accounts for more than 60  |${{\ \rm per\ cent}}$| of the total mass outflow rate in most objects and this fraction is higher in active galactic nuclei (AGN)-dominated systems. The neutral atomic phase contributes of the order of 10  |${{\ \rm per\ cent}}$|⁠ , while the ionized phase is negligible. The ionized-to-molecular mass outflow rate declines slightly with AGN luminosity, although with a large scatter. [ABSTRACT FROM AUTHOR]

The molecular gas content of high-redshift galaxies is a highly sought-after property. However, H2 is not directly observable in most environments, so its mass is probed through other emission lines (e.g. CO, [C  i ], [C  ii ]), or through a gas-to-dust ratio. Each of these methods depends on several assumptions, and are best used in parallel. In this work, we extend an additional molecular gas tracer to high-redshift studies by observing hydrogen deuteride (HD) emission in the strongly lensed z  = 5.656 galaxy SPT0346−52 with ALMA. While no HD(1–0) emission is detected, we are able to place an upper limit on the gas mass of |$\rm M_{H_2}\lt 6.4\times 10^{11}\, M_{\odot }$|⁠. This is used to find a limit on the |$L^{\prime }_{\mathrm{ CO}}$| conversion factor of      |$\rm \alpha _{CO}\lt 5.8\,M_{\odot}(K\,km\,s^{-1}\,pc^2)^{-1}$|⁠. In addition, we construct the most complete spectral energy distribution of this source to date, and fit it with a single-temperature modified blackbody using the nested sampling code multinest , yielding a best-fitting dust mass Mdust = 108.92 ± 0.02 M⊙, dust temperature 78.6 ± 0.5 K, dust emissivity spectral index β = 1.81 ± 0.03, and star formation rate SFR = 3800 ± 100 M⊙ yr−1. Using the continuum flux densities to estimate the total gas mass of the source, we find   |$\rm M_{H_2}\lt 2.4\times 10^{11}\, M_{\odot }$|  , assuming subsolar metallicity. This implies a CO conversion factor of αCO < 2.2, which is between the standard values for MW-like galaxies and starbursts. These properties confirm that SPT0346−52 is a heavily starbursting, gas-rich galaxy. [ABSTRACT FROM AUTHOR]

We investigate the discrepancy between oxygen abundance estimations for narrow-line regions of active galactic nuclei (AGNs) type Seyfert 2 derived using direct estimations of the electron temperature (T e-method) and those derived using photoionization models. In view of this, observational emission-line ratios in the optical range (⁠|$3000 \: \lt \: \lambda (\mathring{\rm A}) \: \lt 7000$|⁠) of Seyfert 2 nuclei compiled from the literature were reproduced by detailed photoionization models built with the cloudy code. We find that the derived discrepancies are mainly due to the inappropriate use of the relations between temperatures of the low (t 2) and high (t 3) ionization gas zones derived for H  ii regions in AGN chemical abundance studies. Using a photoionization model grid, we derived a new expression for t 2 as a function of t 3 valid for Seyfert 2 nuclei. The use of this new expression in the AGN estimation of the O/H abundances based on T e-method produces O/H abundances slightly lower (about 0.2 dex) than those derived from detailed photoionization models. We also find that the new formalism for the T e-method reduces by about 0.4 dex the O/H discrepancies between the abundances obtained from strong emission-line calibrations and those derived from direct estimations. [ABSTRACT FROM AUTHOR]

The Sunyaev–Zel'dovich (SZ) effect can potentially be used to investigate the heating of the circumgalactic medium and subsequent suppression of cold gas accretion on to the host galaxy caused by quasar feedback. We use a deep ALMA observation of HE0515-4414 in band 4, the most luminous quasar known at the peak of cosmic star formation (z  = 1.7), to search for the SZ signal tracing the heating of the galaxy's halo. ALMA's sensitivity to a broad range of spatial scales enables us to disentangle emitting compact sources from the negative, extended SZ signal. We obtain a marginal SZ detection (∼3.3σ) on scales of about 300 kpc (30–40 arcsec), at the 0.2 mJy level, 0.5 mJy after applying a correction factor for primary beam attenuation and flux that is resolved out by the array. We show that our result is consistent with a simulated ALMA observation of a similar quasar in the fable cosmological simulations. We emphasize that detecting an SZ signal is more easily achieved in the visibility plane than in the (inferred) images. We also confirm a marginal detection (3.2σ) of a potential SZ dip on smaller scales (<100 kpc) already claimed by other authors, possibly highlighting the complex structure of the halo heating. Finally, we use SZ maps from the fable cosmological simulations, convolved with ALMA simulations, to illustrate that band 3 observations are much more effective in detecting the SZ signal with higher significance, and discuss the optimal observing strategy. [ABSTRACT FROM AUTHOR]

We present ALMA deep observations of the [CII] 158 μm emission line and the continuum at 253 GHz and 99 GHz towards SDSS J0100+2802 at z ≃ 6.3, the most luminous quasi-stellar object (QSO) at z > 6. J0100+2802 belongs to the HYPERION sample of luminous QSOs at z ∼ 6 − 7.5. The observations have a 2.2 arcsec resolution in band 3 and a 0.9 arcsec resolution in band 6, and are optimized to detect extended emission around the QSO. We detect an interacting, tidally disrupted companion both in [CII], peaking at z ∼ 6.332, and in continuum, stretching on scales up to 20 kpc from the quasar, with a knotty morphology. The higher velocity dispersion in the direction of the companion emission and the complex morphology of the tidally stretched galaxy suggest a possible ongoing or future merger. For the newly detected companion, we derive the range of the dust mass, Mdust = (0.3 − 2.6)×107 M⊙, and of the star formation rate, SFR  =  [35 − 344] M⊙, obtained from the modelling of its cold dust spectral energy distribution. This shows that both the QSO and its companion are gas-rich and that a major merger may be at the origin of the boosted star formation. This close interacting companion is undetected by deep JWST imaging observations, showing 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, which we interpret as a gaseous outflow for which we estimate a mass outflow rate in the range Ṁout = (118 − 269) M⊙ yr−1. J0100+2802 was recently found to reside in a strong overdensity, however this close companion remained undetected by both previous higher resolution ALMA observations and by JWST-NIRCAM imaging. Our results highlight the importance of deep medium-resolution ALMA observations for the study of QSOs and their environment in the Epoch of Reionisation. [ABSTRACT FROM AUTHOR]

Several models have predicted that stars could form inside galactic outflows and that this would be a new major mode of galaxy evolution. Observations of galactic outflows have revealed that they host large amounts of dense and clumpy molecular gas, which provide conditions suitable for star formation. We have investigated the properties of the outflows in a large sample of galaxies by exploiting the integral field spectroscopic data of the large MaNGA-SDSS4 galaxy survey. We find evidence for prominent star formation occurring inside at least 30 per cent of the galactic outflows in our sample, whilst signs of star formation are seen in up to half of the outflows. We also show that even if star formation is prominent inside many other galactic outflows, this may have not been revealed as the diagnostics are easily dominated by the presence of even faint active galactic nucleus and shocks. If very massive outflows typical of distant galaxies and quasars follow the same scaling relations observed locally, then the star formation inside high-z outflows can be up to several 100 |$\rm M_{\odot }~yr^{-1}$| and could contribute substantially to the early formation of the spheroidal component of galaxies. Star formation in outflows can also potentially contribute to establishing the scaling relations between black holes and their host spheroids. Moreover, supernovae exploding on large orbits can chemically enrich in situ and heat the circumgalactic and intergalactic medium. Finally, young stars ejected on large orbits may also contribute to the reionization of the Universe. [ABSTRACT FROM AUTHOR]

We study molecular outflows in a sample of 45 local galaxies, both star forming and active galactic nucleus (AGN), primarily by using CO data from the Atacama Large Millimeter/submillimeter Array (ALMA) archive and from the literature. For a subsample, we also compare the molecular outflow with the ionized and neutral atomic phases. We infer an empirical analytical function relating the outflow rate simultaneously to the star formation rate (SFR), L AGN, and galaxy stellar mass; this relation is much tighter than the relations with the individual quantities. The outflow kinetic power shows a larger scatter than in previous, more biased studies, spanning from 0.1 to 5 per cent of L AGN, while the momentum rate ranges from 1 to 30 times L AGN/ c, indicating that these outflows can be both energy driven, but with a broad range of coupling efficiencies with the interstellar medium (ISM), and radiation pressure driven. For about 10 per cent of the objects, the outflow energetics significantly exceed the maximum theoretical values; we interpret these as 'fossil outflows' resulting from activity of a past strong AGN, which has now faded. We estimate that, in the stellar mass range probed here (⁠|$\gt 10^{10}\, {\rm M}_{\odot }$|⁠), less than 5 per cent of the outflowing gas escapes the galaxy. The molecular gas depletion time associated with the outflow can be as short as a few million years in powerful AGN; however, the total gas (H2 + H  i) depletion times are much longer. Altogether, our findings suggest that even AGN-driven outflows might be relatively ineffective in clearing galaxies of their entire gas content, although they are likely capable of clearing and quenching the central region. [ABSTRACT FROM AUTHOR]

In this work we report deep MUSE observations of a broad absorption line (BAL) quasar at z ~ 5, revealing a Ly α nebula with a maximum projected linear size of ~60 kpc around the quasar (down to our 2σ SB limit per layer of ~ 9 x 10-19 erg s-1 cm-2 arcsec-2 for a 1 arcsec² aperture). After correcting for the cosmological surface brightness dimming, we find that our nebula, at z~5, has an intrinsically less extended Ly α emission than nebulae at lower redshift. However, such a discrepancy is greatly reduced when referring to comoving distances, which take into account the cosmological growth of dark matter (DM) haloes, suggesting a positive correlation between the size of Ly α nebulae and the sizes of DM haloes/structures around quasars. Differently from the typical nebulae around radio-quiet non-BAL quasars, in the inner regions (~10 kpc) of the circumgalactic medium of our source, the velocity dispersion of the Ly α emission is very high (FWHM > 1000 km s-1), suggesting that in our case we may be probing outflowing material associated with the quasar. [ABSTRACT FROM AUTHOR]

We present new ALMA observations of the [O III]88 μm line and high angular resolution observations of the [C II]158 μm line in a normal star forming galaxy at z = 7.1. Previous [C II] observations of this galaxy had detected [C II] emission consistent with the Lyα redshift but spatially slightly offset relative to the optical (UV-rest frame) emission. The new [C II] observations reveal that the [C II] emission is partly clumpy and partly diffuse on scales larger than about 1 kpc. [O III] emission is also detected at high significance, offset relative to the optical counterpart in the same direction as the [C II] clumps, but mostly not overlapping with the bulk of the [C II] emission. The offset between different emission components (optical/UV and different far-IR tracers) is similar to that which is observed in much more powerful starbursts at high redshift. We show that the [O III] emitting clump cannot be explained in terms of diffuse gas excited by the UV radiation emitted by the optical galaxy, but it requires excitation by in-situ (slightly dust obscured) star formation, at a rate of about 7 M☉yr-1. Within 20 kpc from the optical galaxy the ALMA data reveal two additional [O III] emitting systems, which must be star forming companions. We discuss that the complex properties revealed by ALMA in the z ~ 7.1 galaxy are consistent with expectations by recent models and cosmological simulations, in which differential dust extinction, differential excitation and different metal enrichment levels, associated with different subsystems assembling a galaxy, are responsible for the various appearance of the system when observed with distinct tracers. [ABSTRACT FROM AUTHOR]

We report the ALMA observations of the most massive (star-forming) galaxy in the redshift range 3 < z < 4 within the whole Great Observatories Origins Deep Survey South field (GOODS-S) field. We detect a large elongated structure of molecular gas around the massive primeval galaxy, traced by the CO(4–3) emission, and extended over 40 kpc. We infer a mass of the large gaseous structure of Mgas ~ 2-6 × 1011 M⊙. About 60 per cent of this mass is not directly associated with either the central galaxy or its two lower mass satellites. The CO extended structure is also detected in continuum thermal emission. The kinematics of the molecular gas shows the presence of different components, which cannot be ascribed to simple rotation. Furthermore, on even larger scales, we detect nine additional CO systems within a radius of 250 kpc from the massive galaxy and mostly distributed in the same direction as the CO elongated structure found in the central 40 kpc. The stacked images of these CO systems show detections in the thermal continuum and in the X-rays, suggesting that these systems are forming stars at a rate of 30-120 M⊙ yr-1. We suggest that the extended gas structure, combined with its kinematic properties, and the gas-rich star-forming systems detected on larger scales, are tracing the inner and densest regions of large-scale accreting streams, feeding the central massive galaxy. These results corroborate models of galaxy formation, in which accreting streams are clumpy and undergo some star formation (hence enriching the streams with metals) even before accreting onto the central galaxy. [ABSTRACT FROM AUTHOR]

We present adaptive optics assisted near-IR integral field spectroscopic observations of a luminous quasar at z = 2.4, previously observed as the first known example at high redshift of large-scale quasar-driven outflow quenching star formation in its host galaxy. The nuclear spectrum shows broad and blueshifted Hβ in absorption, which is tracing outflowing gas with high densities (>108-109 cm-3) and velocities in excess of 10 000 km s-1. The properties of the outflowing clouds (covering factor, density, column density and inferred location) indicate that they likely originate from the broad line region. The energetics of such nuclear regions is consistent with that observed in the large-scale outflow, supporting models in which quasar-driven outflows originate from the nuclear region and are energy conserving. We note that the asymmetric profile of both the Hβ and Hα emission lines is likely due to absorption by the dense outflowing gas along the line of sight. This outflow-induced asymmetry has implications on the estimation of the black hole mass using virial estimators, and warns about such effects for several other quasars characterized by similar line asymmetries. More generally, our findings may suggest a broader revision of the decomposition and interpretation of quasar spectral features, in order to take into account the presence of potential broad blueshifted Balmer absorption lines. Our high spatial resolution data also reveal redshifted nebular emission lines, which could be potentially tracing an inflowing stream. [ABSTRACT FROM AUTHOR]

We use the most extensive integral field spectroscopic map of a local galaxy, NGC 628, combined with gas and stellar mass surface density maps, to study the distribution of metals in this galaxy out to three effective radii (Re). At each galactocentric distance, we compute the metal budget and thus constrain the mass of metals lost. We find that in the disc about 50 per cent of the metals have been lost throughout the lifetime of the galaxy. The fraction of metals lost is higher in the bulge (~70 per cent) and decreases towards the outer disc (~3 Re). In contrast to studies based on the gas kinematics, which are only sensitive to ongoing outflow events, our metal budget analysis enables us to infer the average outflow rate during the galaxy lifetime. By using simple physically motivated models of chemical evolution, we can fit the observed metal budget at most radii with an average outflow loading factor of order unity, thus clearly demonstrating the importance of outflows in the evolution of disc galaxies of this mass range (log (M*/M⊙) ~ 10). The observed gas phase metallicity is higher than expected from the metal budget and suggests late-time accretion of enriched gas, likely raining on to the disc from the metal-enriched halo. [ABSTRACT FROM AUTHOR]

There has been much recent work dedicated to exploring secondary correlations in the mass- metallicity relation, with significant dependence on both the SFR (SFR) and H I content being demonstrated. Previously, a paucity of molecular gas data (combined with sample selection bias) hampered the investigation of any such relation with molecular gas content. In this work, we assemble a sample of 221 galaxies from a variety of surveys in the redshift range 0

We report new deep observations obtained with the Atacama Large Millimetre Array (ALMA) aimed at investigating the [C II] 158 µm line and continuum emission in three spectroscopically confirmed Lyman break galaxies at 6.8 < z ≤ 7.1, i.e. well within the re-ionization epoch. With star formation rates of SFR ~ 5-15Mʘ yr-1 these systems are much more representative of the high-z galaxy population than other systems targeted in the past by millimetre observations. For the galaxy with the deepest observation we detect [CII] emission at redshift z = 7.107, fully consistent with the Ly α redshift, but spatially offset by 0.7 arcsec (4 kpc) from the optical emission. At the location of the optical emission, tracing both the Ly α line and the far-UV continuum, no [C II] emission is detected in any of the three galaxies, with 3σ upper limits significantly lower than the [C II] emission observed in lower redshift galaxies. These results suggest that molecular clouds in the central parts of primordial galaxies are rapidly disrupted by stellar feedback. As a result, [C II] emission mostly arises from more external accreting/satellite clumps of neutral gas. These findings are in agreement with recent models of galaxy formation. Thermal far-infrared continuum is not detected in any of the three galaxies. However, the upper limits on the infrared-to-UV emission ratio do not exceed those derived in metal- and dust-poor galaxies. [ABSTRACT FROM AUTHOR]

We report new deep observations obtained with the Atacama Large Millimetre Array (ALMA) aimed at investigating the [C II]158 μm line and continuum emission in three spectroscopically confirmed Lyman break galaxies at 6.8 < z ≤ 7.1, i.e. well within the re-ionization epoch. With star formation rates of SFR ∼ 5-15M⊙ yr-1 these systems are much more representative of the high-z galaxy population than other systems targeted in the past by millimetre observations. For the galaxy with the deepest observation we detect [C II] emission at redshift z = 7.107, fully consistent with the Ly α redshift, but spatially offset by 0.7 arcsec (4 kpc) from the optical emission. At the location of the optical emission, tracing both the Ly α line and the far-UV continuum, no [C II] emission is detected in any of the three galaxies, with 3σ upper limits significantly lower than the [C II] emission observed in lower redshift galaxies. These results suggest that molecular clouds in the central parts of primordial galaxies are rapidly disrupted by stellar feedback. As a result, [C II] emission mostly arises from more external accreting/satellite clumps of neutral gas. These findings are in agreement with recent models of galaxy formation. Thermal far-infrared continuum is not detected in any of the three galaxies. However, the upper limits on the infrared-to-UV emission ratio do not exceed those derived in metal- and dust-poor galaxies. [ABSTRACT FROM AUTHOR]

Local galaxies are broadly divided into two main classes, star-forming (gas-rich) and quiescent (passive and gas-poor). The primary mechanism responsible for quenching star formation in galaxies and transforming them into quiescent and passive systems is still unclear. Sudden removal of gas through outflows or stripping is one of the mechanisms often proposed. An alternative mechanism is so-called 'strangulation', in which the supply of cold gas to the galaxy is halted. Here we report an analysis of the stellar metallicity (the fraction of elements heavier than helium in stellar atmospheres) in local galaxies, from 26,000 spectra, that clearly reveals that strangulation is the primary mechanism responsible for quenching star formation, with a typical timescale of four billion years, at least for local galaxies with a stellar mass less than 1011 solar masses. This result is further supported independently by the stellar age difference between quiescent and star-forming galaxies, which indicates that quiescent galaxies of less than 1011 solar masses are on average observed four billion years after quenching due to strangulation. [ABSTRACT FROM AUTHOR]

MaNGA (Mapping Nearby Galaxies at Apache Point Observatory) is a 6-yr Sloan Digital Sky Survey (SDSS-IV) survey that will obtain spatially resolved spectroscopy from 3600 to 10 300Å for a representative sample of over 10 000 nearby galaxies. In this paper, we present the analysis of nebular emission-line properties using observations of 14 galaxies obtained with P-MaNGA, a prototype of the MaNGA instrument. By using spatially resolved diagnostic diagrams, we find extended star formation in galaxies that are centrally dominated by Seyfert/LINER-like emission, which illustrates that galaxy characterizations based on single fibre spectra are necessarily incomplete. We observe extended low ionization nuclear emission-line regions (LINER)-like emission (up to 1Re) in the central regions of three galaxies. We make use of the Hα equivalent width [EW(Hα)] to argue that the observed emission is consistent with ionization from hot evolved stars. We derive stellar population indices and demonstrate a clear correlation between Dn(4000) and EW(HδA) and the position in the ionization diagnostic diagram: resolved galactic regions which are ionized by a Seyfert/LINER-like radiation field are also devoid of recent star formation and host older and/or more metal-rich stellar populations. We also detect extraplanar LINER-like emission in two highly inclined galaxies, and identify it with diffuse ionized gas.We investigate spatially resolved metallicities and find a positive correlation between metallicity and star formation rate surface density. We further study the relation between N/O versus O/H on resolved scales. We find that, at given N/O, regions within individual galaxies are spread towards lower metallicities, deviating from the sequence defined by galactic central regions as traced by Sloan 3-arcsec fibre spectra. We suggest that the observed dispersion can be a tracer for gas flows in galaxies: infalls of pristine gas and/or the effect of a galactic fountain. [ABSTRACT FROM AUTHOR]

Past observations of quasar 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 Plateau de Bure Interferometer follow-up observations of the [C II] 158 µm emission line and far-infrared (FIR) continuum in the host galaxy of SDSS J1148+5251, a luminous quasar at redshift 6.4189. We find that a large portion of the gas traced by [C II] is at high velocities, up to ~1400 km s-1relative to the systemic velocity, confirming the presence of a major outflow as 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 the quiescent gas at systemic velocity is also extremely extended. More specifically, we find that, while 30% of the [CII] within v ∊(-200, 200) km s-1 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 full width at half maximum (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 [C II] source. Overall, our results indicate that the cold gas traced by [C II] is distributed up to r ~ 30 kpc in the host galaxy of SDSS J1148+5251. A large amount of extended [CII] is likely to be associated with star formation occurring on large scales, but the [C II] source extends well beyond the FIR continuum, and additional multi-wavelength observations are needed in order to clarify the origin of this very extended [CII] . [ABSTRACT FROM AUTHOR]

We present near-infrared integral field spectroscopy of 10 Herschel selected galaxies at z ∼ 1.5. From detailed mapping of the Hα and [N ii] emission lines, we trace the dynamics, star formation rates, metallicities and also investigate gas fractions for these galaxies. For a few galaxies, the distribution of star formation as traced by Hα only traces a small fraction of the stellar disc, which could be tracing recent minor merging events. The rest-frame ultraviolet (UV) continuum emission often has a distribution completely different from Hα, which warns about the use of UV-SED (spectral energy distribution) based star formation tracers in these systems. Our analysis of galaxy dynamics shows that minor dynamical disruptions (e.g. minor merging) are generally not enough to cause a deviation from the established ‘main-sequence’ relation. Most galaxies are found to follow the fundamental metallicity relation (FMR), although with large scatter. One galaxy (a small satellite galaxy of a massive companion) is found to deviate strongly from the FMR. This deviation is in nice agreement with the correlation recently discovered in local galaxies between gas metallicity and environment, which has been ascribed to enriched intergalactic medium (IGM) in dense environments, and therefore suggests that here the IGM was already significantly enriched by z ∼ 1.5. [ABSTRACT FROM PUBLISHER]

We present near-infrared (NIR) spectra, obtained with SINFONI and XShooter observations at ESO VLT, of nine dusty, red QSOs at 1.2 < z < 2.6. The sources are hard X-ray detected, characterized by cold absorption (NH > 1021–1022 cm−2) and show a broad Hα component in the NIR spectra. We complement this sample with 12 additional sources taken from the literature with similar properties resulting in a total sample of 21 X-ray-obscured, intermediate-type (1.8–1.9), dusty reddened QSOs. From the broad Hα line, we have computed the black hole (BH) masses through the virial formula and derived Eddington ratios. Moreover, from optical/IR multicomponent spectral energy distribution fitting we have derived the stellar mass of their host galaxies and their star formation rates. We find that most of the sources in our sample are hosted in starburst and main-sequence star-forming galaxies with Eddington ratios λ > 0.1. We find a strong trend with the BH mass, i.e. less massive objects are scattered below and above the local relation while the most massive ones are mainly located above it. We also studied the evolution of these sources on the MBH-M* plane compared to a sample of optically blue type-1 QSOs and we find that obscured red QSOs show a ratio of MBH to M* that increases with redshift which is consistent with or slightly lower than what has been found for blue QSOs. These sources may represent the blow-out phase at the end of the rapid BH growth and immediately preceding the classical blue QSOs typically sampled in optical surveys. They in fact show evidence of outflows in the ionized gas component, but their BH has already fully formed. [ABSTRACT FROM PUBLISHER]

We used near-infrared integral field spectroscopic observations from the AMAZE and LSD ESO programs to constrain the metallicity in a sample ost of which are at z ~ 3.4). We measured metallicities by exploiting strong emission-linf 40 star-forming galaxies at 3 < z < 5 (moe diagnostics. We found that a significant fraction of star-forming galaxies at z ~ 3.4 deviate from the fundamental metallicity relation (FMR), with a metallicity of up to a factor of ten lower than expected according to the FMR. This deviation does not correlate with the dynamical properties of the galaxy or with the presence of interactions. To investigate the origin of the metallicity deviation in more detail, we also inferred information on the gas content by inverting the Schmidt-Kennicutt relation, assuming that the latter does not evolve out to z ~ 3.4. In agreement with recent CO observational data, we found that in contrast with the steeply rising trend at 0 < z < 2, the gas fraction in massive galaxies remains constant, with an indication of a marginal decline at 2 < z < 3.5. When combined with the metallicity information, we infer that to explain the low metallicity and gas content in z ~ 3.4 galaxies, both prominent outflows and massive pristine gas inflows are needed. In ten galaxies we can also spatially resolve the metallicity distribution. We found that the metallicity generally anticorrelates with the distribution of star formation and with the gas surface density. We discuss these findings in terms of pristine gas inflows toward the center, and outflows of metal-rich gas from the center toward the external regions. [ABSTRACT FROM AUTHOR]

We use deep Herschel observations taken with both PACS and SPIRE imaging cameras to estimate the dust mass of a sample of galaxies extracted from the GOODS-S, GOODS-N and the COSMOS fields. We divide the redshift-stellar mass (Mstar)-star formation rate (SFR) parameter space into small bins and investigate average properties over this grid. In the first part of the work we investigate the scaling relations between dust mass, stellar mass and SFR out to z = 2.5. No clear evolution of the dust mass with redshift is observed at a given SFR and stellar mass. We find a tight correlation between the SFR and the dust mass, which, under reasonable assumptions, is likely a consequence of the Schmidt-Kennicutt (S-K) relation. The previously observed correlation between the stellar content and the dust content flattens or sometimes disappears when considering galaxies with the same SFR. Our finding suggests that most of the correlation between dust mass and stellar mass obtained by previous studies is likely a consequence of the correlation between the dust mass and the SFR combined with the main sequence, i.e., the tight relation observed between the stellar mass and the SFR and followed by the majority of star-forming galaxies. We then investigate the gas content as inferred from dust mass measurements. We convert the dust mass into gas mass by assuming that the dust-to-gas ratio scales linearly with the gas metallicity (as supported by many observations). For normal star-forming galaxies (on the main sequence) the inferred relation between the SFR and the gas mass (integrated S-K relation) broadly agrees with the results of previous studies based on CO measurements, despite the completely different approaches. We observe that all galaxies in the sample follow, within uncertainties, the same S-K relation. However, when investigated in redshift intervals, the S-K relation shows a moderate, but significant redshift evolution. The bulk of the galaxy population at z ∼ 2 converts gas into stars with an efficiency (star formation efficiency, SFE = SFR/Mgas, equal to the inverse of the depletion time) about 5 times higher than at z ∼ 0. However, it is not clear what fraction of such variation of the SFE is due to an intrinsic redshift evolution and what fraction is simply a consequence of high-z galaxies having, on average, higher SFR, combined with the super-linear slope of the S-K relation (while other studies find a linear slope). We confirm that the gas fraction ( fgas = Mgas/(Mgas + Mstar)) decreases with stellar mass and increases with the SFR. We observe no evolution with redshift once Mstar and SFR are fixed. We explain these trends by introducing a universal relation between gas fraction, stellar mass and SFR that does not evolve with redshift, at least out to z ∼ 2.5. Galaxies move across this relation as their gas content evolves across the cosmic epochs. We use the 3D fundamental fga-Mstar-SFR relation, along with the evolution of the main sequence with redshift, to estimate the evolution of the gas fraction in the average population of galaxies as a function of redshift and as a function of stellar mass: we find that Mstar >⩾ 1011 M☉ galaxies show the strongest evolution at z ≳ 1.3 and a flatter trend at lower redshift, while fgas decreases more regularly over the entire redshift range probed in Mstar ≲1011 M☉ galaxies, in agreement with a downsizing scenario. [ABSTRACT FROM AUTHOR]

We study the properties of massive, galactic-scale outflows of molecular gas and investigate their impact on galaxy evolution. We present new IRAMPdBI CO(1-0) observations of local ultra-luminous infrared galaxies (ULIRGs) and quasar-hosts: a clear signature of massive and energetic molecular outflows, extending on kpc scales, is found in the CO(1-0) kinematics of four out of seven sources, with measured outflow rates of several 100 M☉ yr-1. We combine these new observations with data from the literature, and explore the nature and origin of massive molecular outflows within an extended sample of 19 local galaxies. We find that starburst-dominated galaxies have an outflow rate comparable to their star formation rate (SFR), or even higher by a factor of ∼2-4, implying that starbursts can indeed be effective in removing cold gas from galaxies. Nevertheless, our results suggest that the presence of an active galactic nucleus (AGN) can boost the outflow rate by a large factor, which is found to increase with the LAGN/Lbol ratio. The gas depletion time scales due to molecular outflows are anti-correlated with the presence and luminosity of an AGN in these galaxies, and range from a few hundred million years in starburst galaxies down to just a few million years in galaxies hosting powerful AGNs. In quasar hosts, the depletion time scales due to the outflow are much shorter than the depletion time scales due to star formation. We estimate the outflow kinetic power and find that, for galaxies hosting powerful AGNs, it corresponds to about 5% of the AGN luminosity, as expected by models of AGN feedback. Moreover, we find that momentum rates of about 20 LAGN/c are common among the AGNdominated sources in our sample. For "pure" starburst galaxies, our data tentatively support models in which outflows are mostly momentum-driven by the radiation pressure from young stars onto dusty clouds. Overall, our results indicate that, although starbursts are effective in powering massive molecular outflows, the presence of an AGN may strongly enhance such outflows, and therefore have a profound feedback effect on the evolution of galaxies by efficiently removing fuel for star formation, hence quenching star formation. [ABSTRACT FROM AUTHOR]

ABSTRACT Most theoretical models invoke quasar-driven outflows to quench star formation in massive galaxies, and this feedback mechanism is required to account for the population of old and passive galaxies observed in the local Universe. The discovery of massive, old and passive galaxies at z∼ 2 implies that such quasar feedback on to the host galaxy must have been at work very early on, close to the reionization epoch. We have observed the [C ii] 158 m transition in SDSS J114816.64+525150.3, which, at z= 6.4189, is one of the most distant quasars known. We detect broad wings of the line tracing a quasar-driven massive outflow. This is the most distant massive outflow ever detected and is likely tracing the long-sought quasar feedback, already at work in the early Universe. The outflow is marginally resolved on scales of ∼16 kpc, implying that the outflow can really affect the whole galaxy, as required by quasar feedback models. The inferred outflow rate, , is the highest ever found. At this rate, the outflow can clean the gas in the host galaxy, and therefore quench star formation, in a few million years. [ABSTRACT FROM AUTHOR]

The chemical properties of high-z galaxies provide important information for constraining galaxy evolutionary scenarios. However, widely used metallicity diagnostics based on rest-frame optical emission lines are unusable for heavily dust-enshrouded galaxies (such as submillimeter galaxies; SMGs), especially at z > 3. Here we focus on the flux ratio of the far-infrared fine-structure emission lines [N ɪɪ] 205 μm and [C ɪɪ] 158 μm to assess the metallicity of high-z SMGs. Through ALMA cycle 0 observations, we have detected the [N ɪɪ] 205 μm emission in a strongly [C ɪɪ]-emitting SMG, LESS J033229.4-275619 at z = 4.76. The velocity-integrated [N ɪɪ]/[C ɪɪ] flux ratio is 0.043 ± 0.008. This is the first measurement of the [N ɪɪ]/[C ɪɪ] flux ratio in high-z galaxies, and the inferred flux ratio is similar to the ratio observed in the nearby universe (∼0.02-0.07). The velocity-integrated flux ratio and photoionization models suggest that the metallicity in this SMG is consistent with solar, implying that the chemical evolution has progressed very rapidly in this system at z = 4.76. We also obtain a tight upper limit on the CO(12 - 11) transition, which translates into CO(12-11)/CO(2-1) < 3.8 (3σ). This suggests that the molecular gas clouds in LESS J033229.4-275619 are not significantly affected by the radiation field emitted by the AGN in this system. [ABSTRACT FROM AUTHOR]

Most galaxy evolutionary models require quasar feedback to regulate star formation in their host galaxies. In particular, at high redshift, models expect that feedback associated with quasar-driven outflows is so efficient that the gas in the host galaxy is largely swept away or heated up, hence suppressing star formation in massive galaxies. We observationally investigate this phenomenon by using VLT-SINFONI integral field spectroscopy of the luminous quasar 2QZJ002830.4-281706 at z = 2.4. The spectra sample the optical emission lines redshifted into the near-IR. The [OIII]λ5007 emission-line kinematics map reveals a massive outflow on scales of several kpc. The detection of narrow Hβemission reveals star formation in the quasar host galaxy, with SFR ∼ 100 M☉ yr-1. However, the star formation is not distributed uniformly, but is strongly suppressed in the region with the highest outflow velocity and highest velocity dispersion. This result indicates that star formation in this region is strongly quenched by the quasar outflow, which is cleaning the galaxy disk of its molecular gas. This is one of the first direct observational proofs of quasar feedback quenching the star formation at high redshift [ABSTRACT FROM AUTHOR]

Abstract: These lecture notes provide an introduction to mm/submm extragalactic astronomy, focused on AGN studies, with the final goal of preparing students to their future exploitation of the ALMA capabilities. I first provide an overview of the current results obtained through mm/submm observations of galaxies and AGNs, both local and at high redshift. Then I summarize the main mm/submm facilities that are currently available. ALMA is then presented with a general description and by providing some details on its observing capabilities. Finally, I discuss some of the scientific goals that will be achievable with ALMA in extragalactic astronomy, and for AGN studies in particular. [Copyright &y& Elsevier]

We present the results of L-band spectroscopical observations of local bright Ultraluminous Infrared Galaxies (ULIRGs), performed with the Infrared Spectrometer And Array Camera (ISAAC) at the Very Large Telescope. The excellent sensitivity of the telescope and of the instrument provided spectra of unprecedented quality for this class of objects, which allowed a detailed study of the active galactic nucleus (AGN)/starburst contribution to the energy output, and of the composition of the circumnuclear absorber. We discuss the L-band spectral features of seven single sources, and the statistical properties of a complete sample of 15 sources obtained combining our observations with other published 3–4 μm spectra. Our main results are as follows. (i) When a spectral indicator suggesting the presence of an AGN (low equivalent width of the 3.3-μm emission line, steep spectrum, presence of an absorption feature at 3.4 μm) is found, the AGN is always confirmed by independent analysis at other wavelengths. Conversely, in all known AGNs at least one of the above indicators is present. (ii) Two new diagnostic diagrams are proposed combining the above indicators, in which starbursts and AGNs are clearly and completely separated. (iii) The above diagnostic techniques are possible with spectra of relatively low quality, which can be obtained for several tens of ULIRGs with currently available telescopes. This makes L-band spectroscopy the current best tool to disentangle AGN and starburst contributions in ULIRGs. (iv) The L-band properties of ULIRGs are heterogeneous. However, we show that all the spectral differences among ULIRGs can be reproduced starting from pure intrinsic AGN and starburst spectra and two varying parameters: the amount of dust extinction of the AGN component, and the relative AGN/starburst contribution to the bolometric luminosity. (v) Using the above decomposition model, we show that AGNs in ULIRGs have a low dust-to-gas ratio and a dust extinction curve different from Galactic. (vi) The estimate of the presence and contribution of AGNs in a complete sample shows that AGNs are hosted by approximately two-thirds of ULIRGs, but their energetic contribution is relevant (>30 per cent of the bolometric luminosity) only in ∼20 per cent of the sample. [ABSTRACT FROM AUTHOR]

We have analysed the soft X-ray emission in a wide area of the Sculptor supercluster by using overlappingROSATPosition Sensitive Proportional Counter pointings. After subtraction of the point sources, we have found evidence for extended, diffuse soft X-ray emission. We have investigated the nature of such extended emission through the cross-correlation with the density of galaxies as inferred from the Münster Redshift Survey. In particular, we have analysed the correlation as a function of the temperature of the X-ray emitting gas. We have found a significant correlation of the galaxy distribution only with the softest X-ray emission (0.1 – 0.3 keV) and only for gas temperatures. We have excluded the fact that this soft X-ray diffuse emission, and its correlation with the galaxy distribution, is significantly contributed by unresolved active galactic nuclei, groups of galaxies or individual galaxies. The most likely explanation is that the soft, diffuse X-ray emission is tracing warm–hot intergalactic medium, with temperatures below 0.5 keV, associated with the large-scale structures in the Sculptor supercluster. [ABSTRACT FROM AUTHOR]

ABSTRACT We estimate the contribution of active galactic nuclei (AGN) and of their host galaxies to the infrared background. We use the luminosity function and evolution of AGN recently determined by the hard X-ray surveys, and new spectral energy distributions connecting the X-ray and the infrared emission, divided in intervals of absorption. These two ingredients allow us to determine the contribution of AGN to the infrared background by using mostly observed quantities, with only minor assumptions. We find that AGN emission contributes little to the infrared background (<5 per cent over most of the infrared bands), implying that the latter is dominated by star formation. However, AGN host galaxies may contribute significantly to the infrared background, and more specifically 10-20 per cent in the 1-20 μm range and ∼5 per cent at λ < 60 μm. We also give the contribution of AGN and of their host galaxies to the source number counts in various infrared bands, focusing on those which will be observed with Spitzer. We also report a significant discrepancy between the expected contribution of AGN hosts to the submillimetre background and bright submillimetre number counts with the observational constraints. We discuss the causes and implications of this discrepancy and the possible effects on the Spitzer far-infrared bands. [ABSTRACT FROM AUTHOR]

An increasing number of observations and simulations suggests that low-power (< 1044 erg s−1) jets may be a significant channel of feedback produced by active galactic nuclei (AGN), but little is known about their actual effect on their host galaxies from the observational point of view. We targeted four luminous type 2 AGN hosting moderately powerful radio emission (∼1044 erg s−1), two of which and possibly a third are associated with jets, with optical integral field spectroscopy observations from the Multi Unit Spectroscopic Explorer (MUSE) at the Very Large Telescope (VLT) to analyze the properties of their ionized gas as well as the properties and effects of ionized outflows. We combined these observations with Very Large Array (VLA) and e-MERLIN data to investigate the relations and interactions between the radio jets and host galaxies. We detected ionized outflows as traced by the fast bulk motion of the gas. The outflows extended over kiloparsec scales in the direction of the jet, when present. In the two sources with resolved radio jets, we detected a strong enhancement in the emission-line velocity dispersion (up to 1000 km s−1) perpendicular to the direction of the radio jets. We also found a correlation between the mass and the energetics of this high-velocity dispersion gas and the radio power, which supports the idea that the radio emission may cause the enhanced turbulence. This phenomenon, which is now being observed in an increasing number of objects, might represent an important channel for AGN feedback on galaxies [ABSTRACT FROM AUTHOR]

State-of-the-art 19th century spectroscopy led to the discovery of quantum mechanics, and 20th century spectroscopy led to the confirmation of quantum electrodynamics. State-of-the-art 21st century astrophysical spectrographs, especially ANDES at ESO’s ELT, have another opportunity to play a key role in the search for, and characterization of, the new physics which is known to be out there, waiting to be discovered. We rely on detailed simulations and forecast techniques to discuss four important examples of this point: big bang nucleosynthesis, the evolution of the cosmic microwave background temperature, tests of the universality of physical laws, and a real-time model-independent mapping of the expansion history of the universe (also known as the redshift drift). The last two are among the flagship science drivers for the ELT. We also highlight what is required for the ESO community to be able to play a meaningful role in 2030s fundamental cosmology and show that, even if ANDES only provides null results, such ‘minimum guaranteed science’ will be in the form of constraints on key cosmological paradigms: these are independent from, and can be competitive with, those obtained from traditional cosmological probes. [ABSTRACT FROM AUTHOR]

We use deep imaging from the JWST Advanced Deep Extragalactic Survey (JADES) to study the evolution of the ionizing photon production efficiency, ξion. We estimate ξion for a sample of 677 galaxies at z ∼ 4–9 using NIRCam (Near-Infrared Camera) photometry. Specifically, combinations of the medium and wide bands F 335 M–F 356 W and F 410 M–F 444 W to constrain emission lines that trace ξion: Hα and [O  iii ]. Additionally, we use the spectral energy distribution fitting code prospector to fit all available photometry and infer galaxy properties. The flux measurements obtained via photometry are consistent with FRESCO (First Reionisation Epoch Spectroscopic Complete Survey) and NIRSpec-derived fluxes. Moreover, the emission-line-inferred measurements are consistent with the prospector estimates. We also confirm the observed ξion trend with redshift and M UV, and find: log ξion(z, M UV) = (0.05 ± 0.02) z + (0.11 ± 0.02) M UV + (27.33 ± 0.37). We use prospector to investigate correlations of ξion with other galaxy properties. We see a clear correlation between ξion and burstiness in the star formation history of galaxies, given by the ratio of recent to older star formation, where burstiness is more prevalent at lower stellar masses. We also convolve our ξion relations with luminosity functions from the literature, and constant escape fractions of 10 per cent and 20 per cent, to place constraints on the cosmic ionizing photon budget. By combining our results, we find that if our sample is representative of the faint low-mass galaxy population, galaxies with bursty star formation are efficient enough in producing ionizing photons and could be responsible for the reionization of the Universe. [ABSTRACT FROM AUTHOR]

ALMA observations have revealed that [C  ii ] 158  μ m line emission in high- z galaxies is ≈2–3 × more extended than the UV continuum emission. Here we explore whether surface brightness dimming (SBD) of the [C  ii ] line is responsible for the reported [C  ii ] deficit, and the large |$L_{\rm [O\, \small {III}]}/L_{\rm [C\, \small {II}]}$| luminosity ratio measured in early galaxies. We first analyse archival ALMA images of nine z > 6 galaxies observed in both [C  ii ] and [O  iii ]. After performing several uv -tapering experiments to optimize the identification of extended line emission, we detect [C  ii ] emission in the whole sample, with an extent systematically larger than the [O  iii ] emission. Next, we use interferometric simulations to study the effect of SBD on the line luminosity estimate. About 40 per cent of the extended [C  ii ] component might be missed at an angular resolution of 0.8 arcsec, implying that |$L_{\rm [C\, \small {II}]}$| is underestimated by a factor ≈2 in data at low (<7) signal-to-noise ratio. By combining these results, we conclude that |$L_{\rm [C\, \small {II}]}$| of z > 6 galaxies lies, on average, slightly below the local |$L_{\rm [C\, \small {II}]}-\mathrm{ SFR}$| relation (Δ z  =  6–9 = −0.07 ± 0.3), but within the intrinsic dispersion of the relation. SBD correction also yields |$L_{\rm [O\, \small {III}]}/L_{\rm [C\, \small {II}]}\lt 10$|⁠ , i.e. more in line with current hydrodynamical simulations. [ABSTRACT FROM AUTHOR]

The increasing observational evidence of galactic outflows is considered as a sign of active galactic nucleus (AGN) feedback in action. However, the physical mechanism responsible for driving the observed outflows remains unclear, and whether it is due to momentum, energy, or radiation is still a matter of debate. The observed outflow energetics, in particular the large measured values of the momentum ratio (Ṗ/(L/c) ~ 10) and energy ratio (Ėk/L ~ 0.05), seems to favour the energy-driving mechanism; and most observational works have focused their comparison with wind energy-driven models. Here, we show that AGN radiation pressure on dust can adequately reproduce the observed outflow energetics (mass outflow rate, momentum flux, and kinetic power), as well as the scalings with luminosity, provided that the effects of radiation trapping are properly taken into account. In particular, we predict a sublinear scaling for the mass outflow rate (Ṁ L1/2) and a superlinear scaling for the kinetic power (Ėk L3/2), in agreement with the observational scaling relations reported in the most recent compilation of AGN outflow data. We conclude that AGN radiative feedback can account for the global outflow energetics, at least equally well as the wind energy-driving mechanism, and therefore both physical models should be considered in the interpretation of future AGN outflow observations. [ABSTRACT FROM AUTHOR]

We present new ALMA observations aimed at mapping molecular gas reservoirs through the CO(3-2) transition in three quasars at z ≃ 2.4, LBQS 0109+0213, 2QZ J002830.4-281706, and [HB89] 0329-385. Previous [OIII]λ5007 observations of these quasars showed evidence for ionised outflows quenching star formation in their host galaxies. Systemic CO(3-2) emission has been detected only in one quasar, LBQS 0109+0213, where the CO(3-2) emission is spatially anti-correlated with the ionised outflow, suggesting that most of the molecular gas may have been dispersed or heated in the region swept by the outflow. In all three sources, including the one detected in CO, our constraints on the molecular gas mass indicate a significantly reduced reservoir compared to main-sequence galaxies at the same redshift, supporting a negative feedback scenario. In the quasar 2QZ J002830.4-281706, we tentatively detect an emission line blob blue-shifted by v ~ -2000 km s-1 with respect to the galaxy systemic velocity and spatially offset by 0.2" arcsec (1.7 kpc) with respect to the ALMA continuum peak. Interestingly, such emission feature is coincident in both velocity and space with the ionised outflow as seen in [OIII]λ5007. This tentative detection must be confirmed with deeper observations but, if real, it could represent the molecular counterpart of the ionised gas outflow driven by the AGN. Finally, in all ALMA maps we detect the presence of serendipitous line emitters within a projected distance ~160 kpc from the quasars. By identifying these features with the CO(3-2) transition, the serendipitous line emitters would be located within |Δv|<500 km s-1 from the quasars, hence suggesting an overdensity of galaxies in two out of three quasars. [ABSTRACT FROM AUTHOR]

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 ∼ 1010M⊙ 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. [ABSTRACT FROM AUTHOR]

Context. Hyperluminous quasi-stellar objects (QSOs) are ideal laboratories to investigate active galactic nucleus (AGN) feedback mechanisms. Their formidable energy release causes powerful winds at all scales, and thus the maximum feedback is expected. Aims. Our aim is to derive the mean spectral energy distribution (SED) of a sample of 85 WISE-SDSS selected hyperluminous (WISSH) quasars. Since the SED provides a direct way to investigate the AGN structure, our goal is to understand if quasars at the bright end of the luminosity function have peculiar properties compared to the bulk of the QSO population. Methods. We collected all the available photometry, from X-rays to the far-infrared (FIR); each WISSH quasar is observed in at least 12 different bands. We then built a mean intrinsic SED after correcting for the dust extinction, absorption and emission lines, and intergalactic medium absorption. We also derived bolometric, IR band, and monochromatic luminosities together with bolometric corrections at λ = 5100 Å and 3 μm. We define a new relation for the 3 μm bolometric correction. Results. We find that the mean SED of hyperluminous WISSH QSOs shows some differences compared to that of less luminous sources (i.e., a lower X-ray emission and a near- and mid-IR excess which can be explained assuming a larger dust contribution. WISSH QSOs have stronger emission from both warm (T ∼ 500 − 600 K) and very hot (T ≥ 1000 K) dust, the latter being responsible for shifting the typical dip of the AGN SED from 1.3 μm to 1.1 μm. We also derived the mean SEDs of two subsamples created based on their spectral features (presence of broad absorption lines and equivalent width of CIV line). We confirm that broad absorption lines (BALs) are X-ray weak and that they have a reddened UV-optical continuum. We also find that BALs tend to have stronger emission from the hot dust component. For sources with a weaker CIV line, our main result is the confirmation of their lower X-ray emission. By populating the LIR vs. z diagram proposed by Symeonidis & Page (MNRAS, 503, 3992), we found that ∼90% of WISSH QSOs with z ≥ 3.5 have their FIR emission dominated by star-forming activity. Conclusions. This analysis suggests that hyperluminous QSOs have a peculiar SED compared to less luminous objects. It is therefore critical to use SED templates constructed exclusively from very bright quasar samples (such as this one) when dealing with particularly luminous sources, such as high-redshift QSOs. [ABSTRACT FROM AUTHOR]

Combines Chandra observations with archival X-ray data in order to obtain a first estimate of the fraction of elusive active galactic nuclei (AGN) in local galaxies and to constrain their nature. Results suggesting that elusive AGN have a local density comparable to or even higher than optically classified Seyfert nuclei; Gas column densities of most elusive AGN that are heavily absorbed in the X-rays.

The Hubble Frontier Fields represent the opportunity to probe the high-redshift evolution of the main sequence of star-forming galaxies to lower masses than possible in blank fields thanks to foreground lensing of massive galaxy clusters. We use the beagle SED-fitting code to derive stellar masses, |$\rm{{M_{\star }}}=\log ({\it M}/{\rm{M_{\odot }}})$|⁠ , SFRs, |$\rm{{\Psi }}=\log (\rm{{\psi }}/{\rm{M_{\odot }}}\, {\rm{yr}}^{-1})$|⁠ , and redshifts from galaxies within the astrodeep catalogue. We fit a fully Bayesian hierarchical model of the main sequence over 1.25 < z < 6 of the form |$\rm{{\Psi }}= \rm{\alpha _\mathrm{9.7}}(z) + \rm{\beta }({\rm{M_{\star }}}-9.7) + \mathcal {N}(0,\rm{\sigma }^2)$| while explicitly modelling the outlier distribution. The redshift-dependent intercept at |$\rm{{M_{\star }}}=9.7$| is parametrized as |$\rm{\alpha _\mathrm{9.7}}(z) = \log [{\it N}(1+{\it z})^{\rm{\gamma }}] + 0.7$|⁠. Our results agree with an increase in normalization of the main sequence to high redshifts that follows the redshift-dependent rate of accretion of gas on to dark matter haloes with |$\rm{\gamma }=2.40^{+0.18}_{-0.18}$|⁠. We measure a slope and intrinsic scatter of |$\rm{\beta }=0.79^{+0.03}_{-0.04}$| and |$\rm{\sigma }=0.26^{+0.02}_{-0.02}$|⁠. We find that the sampling of the SED provided by the combination of filters (Hubble + ground-based K s-band +  Spitzer 3.6 and 4.5 μm) is insufficient to constrain M⋆ and Ψ over the full dynamic range of the observed main sequence, even at the lowest redshifts studied. While this filter set represents the best current sampling of high-redshift galaxy SEDs out to z > 3, measurements of the main sequence to low masses and high redshifts still strongly depend on priors employed in SED fitting (as well as other fitting assumptions). Future data sets with JWST should improve this. [ABSTRACT FROM AUTHOR]