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We study the properties of the Sydney University Molonglo Sky Survey (SUMSS) 843~MHz radio AGN population in galaxy clusters from two large catalogs created using the Dark Energy Survey (DES): $\sim$11,800 optically selected RM-Y3 and $\sim$1,000 X-ray selected MARD-Y3 clusters. We show that cluster radio loud AGN are highly concentrated around cluster centers to $z\sim1$. We measure the halo occupation number for cluster radio AGN above a threshold luminosity, finding that the number of radio AGN per cluster increases with cluster halo mass as $N\propto M^{1.2\pm0.1}$ ($N\propto M^{0.68\pm0.34}$) for the RM-Y3 (MARD-Y3) sample. Together, these results indicate that radio mode feedback is favoured in more massive galaxy clusters. Using optical counterparts for these sources, we demonstrate weak redshift evolution in the host broad band colors and the radio luminosity at fixed host galaxy stellar mass. We use the redshift evolution in radio luminosity to break the degeneracy between density and luminosity evolution scenarios in the redshift trend of the radio AGN luminosity function (LF). The LF exhibits a redshift trend of the form $(1+z)^\gamma$ in density and luminosity, respectively, of $\gamma_{\rm D}=3.0\pm0.4$ and $\gamma_{\rm P}=0.21\pm0.15$ in the RM-Y3 sample, and $\gamma_{\rm D}=2.6\pm0.7$ and $\gamma_{\rm P}=0.31\pm0.15$ in MARD-Y3. We discuss the physical drivers of radio mode feedback in cluster AGN, and we use the cluster radio galaxy LF to estimate the average radio-mode feedback energy as a function of cluster mass and redshift and compare it to the core ($, Comment: 20 pages, 15 figures Replaced with published version

Our current knowledge of cosmic star-formation history during the first two billion years (corresponding to redshift z >3) is mainly based on galaxies identified in rest-frame ultraviolet light. However, this population of galaxies is known to under-represent the most massive galaxies, which have rich dust content and/or old stellar populations. This raises the questions of the true abundance of massive galaxies and the star-formation-rate density in the early universe. Although several massive galaxies that are invisible in the ultraviolet have recently been confirmed at early epochs, most of them are extreme starbursts with star-formation rates exceeding 1000 solar masses per year, suggesting that they are unlikely to represent the bulk population of massive galaxies. Here we report submillimeter (wavelength 870um) detections of 39 massive star-forming galaxies at z > 3, which are unseen in the spectral region from the deepest ultraviolet to the near-infrared. With a space density of about $2 \times 10^{-5}$ per cubic megaparsec (two orders of magnitudes higher than extreme starbursts) and star-formation rates of 200 solar masses per year, these galaxies represent the bulk population of massive galaxies that have been missed from previous surveys. They contribute a total star-formation-rate density ten times larger than that of equivalently massive ultraviolet-bright galaxies at z >3. Residing in the most massive dark matter halos at their redshifts, they are probably the progenitors of the largest present-day galaxies in massive groups and clusters. Such a high abundance of massive and dusty galaxies in the early universe challenges our understanding of massive-galaxy formation., 17 pages, 12 figures, 2 tables. Authors' version. Published online by Nature on 07 Aug 2019

VANDELS is an ESO Public Spectroscopic Survey designed to build a sample of high signal to noise, medium resolution spectra of galaxies at redshift between 1 and 6.5. Here we present the final Public Data Release of the VANDELS Survey, comprising 2087 redshift measurements. We give a detailed description of sample selection, observations and data reduction procedures. The final catalogue reaches a target selection completeness of 40% at iAB = 25. The high Signal to Noise ratio of the spectra (above 7 in 80% of the spectra) and the dispersion of 2.5�� allowed us to measure redshifts with high precision, the redshift measurement success rate reaching almost 100%. Together with the redshift catalogue and the reduced spectra, we also provide optical mid-IR photometry and physical parameters derived through SED fitting. The observed galaxy sample comprises both passive and star forming galaxies covering a stellar mass range 8.3< Log(M*/Msolar), 16 pages, 13 figures, accepted for publication in Astronomy & Astrophysics

Understanding the process of quenching is one of the major open questions in galaxy evolution and crucial insights may be obtained by studying quenched galaxies at high redshifts at epochs when the Universe and the galaxies were younger and simpler to model. However, establishing the degree of quiescence in high-redshift galaxies is a challenging task. One notable example is Hyde, a recently discovered galaxy at zspec = 3.709. Equally as compact (r1/2 ∼ 0.5 kpc) and massive (M* ∼ 1011 M⊙) as its quenched neighbor Jekyll, it is also extremely obscured yet only moderately luminous in the sub-millimeter. Panchromatic modeling has suggested it could be the first galaxy found in transition to quenching at z > 3, however, the data are also consistent with a broad range of star-formation activity, from fully quenched to moderate star-formation rates (SFR) in the lower scatter of the galaxy main-sequence. Here, we describe Atacama Large Millimeter Array observations of the [C II] 157 μm and [N II] 205 μm far-infrared emission lines. The [C II] emission within the half-light radius is dominated by ionized gas, while the outskirts are dominated by photo-dissociation regions or neutral gas. This suggests that the ionization in the center is not primarily powered by ongoing star formation, and is instead coming from remnant stellar populations formed in an older burst or from a moderate active galactic nucleus . Accounting for this information in the multi-wavelength modeling provides a tighter constraint on the star formation rate of SFR = 50−18+24 M⊙ yr−1 yr−1. This rules out fully quenched solutions and favors SFRs more than factor of two lower than expected for a main-sequence galaxy, confirming the nature of Hyde as a transition galaxy. These results suggest that quenching happens from inside-out and starts before the galaxy expels or consumes all its gas reservoirs. Similar observations of a sample of massive and obscured galaxies would determine whether this is an isolated case or the norm for quenching at high redshift.

In this paper, we extend the source detection in the GOODS-ALMA field (69 arcmin$^2$, rms sensitivity $\sigma$ $\simeq$ 0.18 mJy.beam$^{-1}$), to deeper levels than presented in Franco et al. (2018). Using positional information at 3.6 and 4.5 $\mu$m (from Spitzer-IRAC), we explore the presence of galaxies detected at 1.1 mm with ALMA below our original blind detection limit of 4.8-$\sigma$ at which the number of spurious sources starts to dominate over that of real sources. In this Supplementary Catalog, we find a total of 16 galaxies, including 2 galaxies with no counterpart in HST images (also known as optically-dark galaxies) down to a 5$\sigma$ limiting depth of H = 28.2 AB (HST/WFC3 F160W). This brings the total sample of GOODS-ALMA 1.1 mm sources to 35 galaxies. Galaxies in the new sample cover a wider dynamic range in redshift ($z$ = 0.65 - 4.73), are on average twice as large (1.3 vs 0.65 kpc) and and have lower stellar mass (M$_{\star}^{\rm SC}$ = 7.6$\times$10$^{10}$M$_\odot$ vs M$_{\star}^{\rm MC}$ = 1.2$\times$10$^{11}$M$_\odot$). Although exhibiting larger physical sizes, these galaxies have still far-infrared sizes significantly more compact than inferred from their optical emission. We show that the astrometry of the HST image does not only suffer from a global astrometric shift, as already discussed in previous papers, but also from local shifts. These distortions were artificially introduced in the process of building the mosaic of the GOODS-South HST image. By comparing the positions of almost 400 galaxies detected by HST, Pan-STARRS and ALMA, we create a distortion map which can be used to correct for these astrometric issues., Comment: 18 pages, 13 figures. Accepted for publication in A&A

In this paper we study the properties of the six optically dark galaxies detected in the 69 arcmin^2 GOODS-ALMA 1.1mm continuum survey. While none of them are listed in the deepest H-band based CANDELS catalog in the GOODS-South field down to H=28.16AB, we were able to de-blend two of them from their bright neighbor and measure an $H$-band flux for them. We note that AGS4 and AGS15 have H=25.23, 27.11AB respectively. Their extreme proximity (0.50", 0.27") to a bright optical source and their extreme faintness prevented them from being included in the H-band catalog. We present the spectroscopic scan follow-up of five of the six sources with ALMA band 4. All are detected in the 2mm continuum with signal-to-noise ratios higher than eight. One emission line is detected in AGS4 (��_{obs} =151.44GHz with a S/N=8.58) and AGS17 (��_{obs} =154.78GHz with a S/N=10.23), which we interpret in both cases as being due to the CO(6-5) line at z^{AGS4}_{spec}=3.556 and z^{AGS4}_{spec}=3.467, respectively. These redshifts match both the probability distribution of the photometric redshifts derived from the UV to near-infrared spectral energy distributions (SEDs) and the far-infrared SEDs for typical dust temperatures of galaxies at these redshifts. We present evidence that nearly 70% (4/6 of galaxies) of the optically dark galaxies belong to the same overdensity of galaxies at z~3.5. overdensity The most massive one, AGS24 (M_{\star} = 10^{11.32^{+0.02}_{-0.19}} M_{\odot}), is the most massive galaxy without an active galactic nucleus (AGN) at $z$\,>\,3 in the GOODS-ALMA field. It falls in the very center of the peak of the galaxy surface density, which suggests that the surrounding overdensity is a proto-cluster in the process of virialization and that AGS24 is the candidate progenitor of the future brightest cluster galaxy (BCG)., 17 pages, 13 figures, 3 tables, accepted by A&A

We investigate the fraction of close pairs and morphologically identified mergers on and above the star-forming main sequence (MS) at 0.2$\leq z\leq$2.0. The novelty of our work lies in the use of a non-parametric morphological classification performed on resolved stellar mass maps, reducing the contamination by non-interacting, high-redshift clumpy galaxies. We find that the merger fraction rapidly rises to $\geq$70% above the MS, implying that -- already at $z{\gtrsim}1$ -- starburst (SB) events ($\Delta_{\rm MS}\geq$0.6) are almost always associated with a major merger (1:1 to 1:6 mass ratio). The majority of interacting galaxies in the SB region are morphologically disturbed, late-stage mergers. Pair fractions show little dependence on MS-offset and pairs are more prevalent than late-stage mergers only in the lower half of the MS. In our sample, major mergers on the MS occur with a roughly equal frequency of $\sim$5-10% at all masses ${\gtrsim} 10^{10}M_{\odot}$. The MS major merger fraction roughly doubles between $z=0.2$ and $z=2$, with morphological mergers driving the overall increase at $z{\gtrsim}1$. The differential redshift evolution of interacting pairs and morphologically classified mergers on the MS can be reconciled by evolving observability timescales for both pairs and morphological disturbances. The observed variation of the late-stage merger fraction with $\Delta_{\rm MS}$ follows the perturbative 2-Star Formation Mode model, where any MS galaxy can experience a continuum of different SFR enhancements. This points to a starburst-merger connection not only for extreme events, but also more moderate bursts which merely scatter galaxies upward within the MS, rather than fully elevating them above it., Comment: Published version

We investigate the nature of star-forming galaxies with reduced specific star formation rate (sSFR) and high stellar masses, those `green valley' objects that seemingly cause a reported bending, or flattening, of the star-forming main sequence. The fact that such objects host large bulges recently led some to suggest that the internal formation of bulges was a late event that induced the sSFRs of massive galaxies to drop in a slow downfall, and thus the main sequence to bend. We have studied in detail a sample of 10 galaxies at $0.45, Comment: 26 pages, 19 figures, accepted by MNRAS

We present the first results from a galaxy population study in the highest redshift galaxy clusters identified in the 2500 deg2 South Pole Telescope Sunyaev Zel’dovich effect (SPT-SZ) survey, which is sensitive to M500 ≳ 3 × 1014 M⊙ clusters from z ∼ 0.2 out to the highest redshifts where such massive structures exist. The cluster selection is to first order independent of galaxy properties, making the SPT-SZ sample particularly well suited for cluster galaxy population studies. We carried out a four-band imaging campaign with the Hubble and Spitzer Space Telescopes of the five z ≳ 1.4, S/NSZE > 5 clusters, that are among the rarest most massive clusters known at this redshift. All five clusters show clear overdensities of red galaxies whose colors agree with the initial cluster redshift estimates, although one (SPT-CLJ0607–4448) shows a galaxy concentration much less prominent than the others. The highest redshift cluster in this sample, SPT-CLJ0459–4947 at z ∼ 1.72, is the most distant M500 > 1014 M⊙ cluster discovered thus far through its intracluster medium, and is one of only three known clusters in this mass range at z ≳ 1.7, regardless of selection. Based on UVJ-like photometric classification of quiescent and star-forming galaxies, we find that the quiescent fraction in the cluster central regions (r/r500 < 0.7) is higher than in the field at the same redshift, with corresponding environmental quenching efficiencies typically in the range ∼0.5 − 0.8 for stellar masses log(M/M⊙) > 10.85. We have explored the impact of emission from star formation on the selection of this sample, concluding that all five clusters studied here would still have been detected with S/NSZE> 5, even if they had the same quiescent fraction as measured in the field. Our results thus point towards an efficient suppression of star formation in the central regions of the most massive clusters, occurring already earlier than z ∼ 1.5.

By using the deepest available mid and far infrared surveys in the CANDELS, GOODS and COSMOS fields we study the evolution of the Main Sequence (MS) of star forming galaxies (SFGs) from z~0 to` ~2.5 at stellar masses larger than 10^{10} M_{\odot}. The MS slope and scatter are consistent with a re-scaled version of the local relation and distribution, shifted at higher values of SFR according to ~(1+z)^{3.2}. The relation exhibits a bending at the high mass end and a slightly increasing scatter as a function of the stellar mass. We show that the previously reported evolution of the MS slope, in the considered mass and redshift range, is due to a selection effect. The distribution of galaxies in the MS region at fixed stellar mass is well represented by a single log-normal distribution at all redshifts and masses, with starburst galaxies (SBs) occupying the tail at high SFR., Comment: Accepted for publication by MNRAS

By using a set of different SFR indicators, including WISE mid-infrared and Halpha emission, we study the slope of the Main Sequence (MS) of local star forming galaxies at stellar masses larger than 10^{10} M_{\odot}. The slope of the relation strongly depends on the SFR indicator used. In all cases, the local MS shows a bending at high stellar masses with respect to the slope obtained in the low mass regime. While the distribution of galaxies in the upper envelope of the MS is consistent with a log-normal distribution, the lower envelope shows an excess of galaxies, which increases as a function of the stellar mass but varies as a function of the SFR indicator used. The scatter of the best log-normal distribution increases with stellar mass from ~0.3 dex at 10^{10} M_{\odot} to ~0.45 at 10^{11} M_{\odot}. The MS high-mass end is dominated by central galaxies of group sized halos with a red bulge and a disk redder than the lower mass counterparts. We argue that the MS bending in this region is due to two processes: i) the formation of a bulge component as a consequence of the increased merger activity in groups, and ii) the cold gas starvation induced by the hot halo environment, which cuts off the gas inflow onto the disk. Similarly, the increase of the MS scatter at high stellar masses would be explained by the larger spread of star formation histories of central group and cluster galaxies with respect to lower mass systems., 16 pages with 14 figures, accepted for publication on MNRAS

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We present a census of the molecular gas properties of galaxies in the most distant known X-ray cluster, CLJ1001, at z=2.51, using deep observations of CO(1-0) with JVLA. In total 14 cluster members with $M_{*} > 10^{10.5} M_{\odot}$ are detected, including all the massive star-forming members within the virial radius, providing the largest galaxy sample in a single cluster at $z > 2$ with CO(1-0) measurements. We find a large variety in the gas content of these cluster galaxies, which is correlated with their relative positions (or accretion states), with those closer to the cluster core being increasingly gas-poor. Moreover, despite their low gas content, the galaxies in the cluster center exhibit an elevated star formation efficiency (SFE=SFR/$M_{\rm gas}$) compared to field galaxies, suggesting that the suppression on the SFR is likely delayed compared to that on the gas content. Their gas depletion time is around $t_{\rm dep} \sim 400$ Myrs, comparable to the cluster dynamical time. This implies that they will likely consume all their gas within a single orbit around the cluster center, and form a passive cluster core by $z\sim2$. This result is one of the first direct pieces of evidence for the influence of environment on the gas reservoirs and SFE of $z > 2$ cluster galaxies, thereby providing new insights into the rapid formation and quenching of the most massive galaxies in the early universe., accepted for publication in ApJ Letters

VANDELS is a uniquely-deep spectroscopic survey of high-redshift galaxies with the VIMOS spectrograph on ESO's Very Large Telescope (VLT). The survey has obtained ultra-deep optical (0.48 < lambda < 1.0 micron) spectroscopy of ~2100 galaxies within the redshift interval 1.0 < z < 7.0, over a total area of ~0.2 sq. degrees centred on the CANDELS UDS and CDFS fields. Based on accurate photometric redshift pre-selection, 85% of the galaxies targeted by VANDELS were selected to be at z>=3. Exploiting the red sensitivity of the refurbished VIMOS spectrograph, the fundamental aim of the survey is to provide the high signal-to-noise ratio spectra necessary to measure key physical properties such as stellar population ages, masses, metallicities and outflow velocities from detailed absorption-line studies. Using integration times calculated to produce an approximately constant signal-to-noise ratio (20 < t_int < 80 hours), the VANDELS survey targeted: a) bright star-forming galaxies at 2.4 < z < 5.5, b) massive quiescent galaxies at 1.0 < z < 2.5, c) fainter star-forming galaxies at 3.0 < z < 7.0 and d) X-ray/Spitzer-selected active galactic nuclei and Herschel-detected galaxies. By targeting two extragalactic survey fields with superb multi-wavelength imaging data, VANDELS will produce a unique legacy data set for exploring the physics underpinning high-redshift galaxy evolution. In this paper we provide an overview of the VANDELS survey designed to support the science exploitation of the first ESO public data release, focusing on the scientific motivation, survey design and target selection., 19 pages, 9 figures, accepted for publication in MNRAS

This paper describes the observations and the first data release (DR1) of the ESO public spectroscopic survey "VANDELS, a deep VIMOS survey of the CANDELS CDFS and UDS fields". VANDELS' main targets are star-forming galaxies at 2.4, Comment: Submitted to A&A

Context. Probing both star formation history and evolution of distant cluster galaxies is essential to evaluate the effect of dense environment on shaping the galaxy properties we observe today., Aims. We investigate the effect of cluster environment on the processing of the molecular gas in distant cluster galaxies. We study the molecular gas properties of two star-forming galaxies separated by 6 kpc in the projected space and belonging to a galaxy cluster selected from the frac Shallow Cluster Survey, at a redshift z = 1.2, that is,similar to 2 Gyr after the cosmic star formation density peak. This work describes the first CO detection from 1 < z < 1.4 star-forming cluster galaxies with no clear reported evidence of active galactic nuclei., Methods. We exploit observations taken with the NOEMA interferometer at similar to 3 mm to detect CO(2-1) line emission from the two selected galaxies, unresolved by our observations., Results. Based on the CO(2-1) spectrum, we estimate a total molecular gas mass M(H-2) = (2.2(-0.4)(+0.5)) x 10(10) M-circle dot, where fully excited gas is assumed, and a dust mass M-dust < 4.2 x 10(8) M(circle dot )for the two blended sources. The two galaxies have similar stellar masses and H alpha-based star formation rates (SFRs) found in previous work, as well as a large relative velocity of similar to 400 km s(-1) estimated from the CO(2-1) line width. These findings tend to privilege a scenario where both sources contribute to the observed CO(2-1). Using the archival Spitzer MIPS flux at 24 mu m we estimate an SFR (24 mu m) = (24(-8)(+12)) M-circle dot/yr for each of the two galaxies. Assuming that the two sources contribute equally to the observed CO(2-1), our analysis yields a depletion timescale of tau(dep) = (3.9(-1.8)(+1.4)) x 10(8) yr, and a molecular gas to stellar mass ratio of 0.17 +/- 0.13 for each of two sources, separately. We also provide a new, more precise measurement of an unknown weighted mean of the redshifts of the two galaxies, z = 1.163 +/- 0.001., Conclusions. Our results are in overall agreement with those of other distant cluster galaxies and with model predictions for main sequence (MS) field galaxies at similar redshifts. The two target galaxies have molecular gas mass and depletion times that are marginally compatible with, but smaller than those of MS field galaxies, suggesting that the molecular gas has not been sufficiently refueled. We speculate that the cluster environment might have played a role in preventing the refueling via environmental mechanisms such as galaxy harassment, strangulation, ram-pressure, or tidal stripping. Higher-resolution and higher-frequency observations will enable us to spatially resolve the two sources and possibly distinguish between different gas processing mechanisms.

We use ALMA and JVLA observations of the galaxy cluster Cl J1449+0856 at z=1.99, in order to study how dust-obscured star-formation, ISM content and AGN activity are linked to environment and galaxy interactions during the crucial phase of high-z cluster assembly. We present detections of multiple transitions of $^{12}$CO, as well as dust continuum emission detections from 11 galaxies in the core of Cl J1449+0856. We measure the gas excitation properties, star-formation rates, gas consumption timescales and gas-to-stellar mass ratios for the galaxies. We find evidence for a large fraction of galaxies with highly-excited molecular gas, contributing $>$50% to the total SFR in the cluster core. We compare these results with expectations for field galaxies, and conclude that environmental influences have strongly enhanced the fraction of excited galaxies in this cluster. We find a dearth of molecular gas in the galaxies' gas reservoirs, implying a high star-formation efficiency (SFE) in the cluster core, and find short gas depletion timescales $��$, 29 pages, 15 figures, 7 tables + Appendix. Accepted for publication in MNRAS

We present a new, publicly available library of dust spectral energy distributions (SEDs). These SEDs are characterized by only three parameters: the dust mass (Mdust), the dust temperature (Tdust), and the mid-to-total infrared color (IR8=LIR/L8). The latter measures the relative contribution of PAH molecules to the LIR. We used this library to model star-forming galaxies at 0.51, 3.2, 3.8, and 5.7, respectively. Starburst galaxies above the MS have LIR significantly underestimated and Mdust overestimated. These results can be used immediately to interpret more accurately the large amount of archival data from Spitzer, Herschel and ALMA. [abridged], Comment: 25 pages, 13 figures, accepted for publication in A&A

We use high-resolution continuum images obtained at 870microns with the Atacama Large Millimeter Array (ALMA) to probe the surface density of star-formation in z~2 galaxies and study the different physical properties between galaxies within and above the star-formation main sequence of galaxies. This sample of eight star-forming galaxies at z~2 selected among the most massive Herschel galaxies in the GOODS-South field is supplemented with eleven galaxies from the public data of the 1.3 mm survey of the Hubble Ultra-Deep Field. ALMA reveals systematically dense concentrations of dusty star-formation close to the center of the stellar component of the galaxies. We identify two different starburst regimes: (i) the classical population of starbursts located above the SFR-M* main sequence, with enhanced gas fractions and short depletion times and (ii) a sub-population of galaxies located within the scatter of the main sequence that experience compact star formation with depletion timescales typical of starbursts of ~150 Myr. In both starburst populations, the far infrared and UV are distributed in distinct regions and dust-corrected star formation rates estimated using UV-optical-NIR data alone underestimate the total star formation rate. Starbursts hidden in the main sequence show instead the lowest gas fractions of our sample and could represent the last stage of star-formation before they become passive. Being Herschel-selected, these main sequence galaxies are located in the high-mass end of the main sequence, hence we do not know whether these "starbursts hidden in the main sequence" also exist below 10^11 Msun. Active galactic nuclei are found to be ubiquitous in these compact starbursts, suggesting that the triggering mechanism also feeds the central black hole or that the active nucleus triggers star formation., 20 pages, 17 figures, accepted for publication in Astronomy and Astrophysics

We present a new technique to measure multi-wavelength "Super-deblended" photometry from highly confused images, which we apply to Herschel and ground-based far-infrared (FIR) and (sub-)millimeter (mm) data in the northern field of the Great Observatories Origins Deep Survey (GOODS). There are two key novelties. First, starting with a large database of deep Spitzer 24{\mu}m and VLA 20cm detections that are used to define prior positions for fitting the FIR/submm data, we perform an active selection of useful priors independently at each frequency band, moving from less to more confused bands. Exploiting knowledge of redshift and all available photometry, we identify hopelessly faint priors that we remove from the fitting pool. This approach significantly reduces blending degeneracies and allows reliable photometry to be obtained for galaxies in FIR+mm bands. Second, we obtain well-behaved, nearly Gaussian flux density uncertainties, individually tailored to all fitted priors in each band. This is done by exploiting extensive simulations that allow us to calibrate the conversion of formal fitting uncertainties to realistic uncertainties depending on quantities directly measurable. We achieve deeper detection limits with high fidelity measurements and uncertainties at FIR+mm bands. As an illustration of the utility of these measurements, we identify 70 galaxies with z>3 and reliable FIR+mm detections. We present new constraints on the cosmic star formation rate density at 33 dusty galaxies that are missed by optical-to-near-infrared color selection. Photometric measurements for 3306 priors, including over 1000 FIR+mm detections are released publicly with our catalog., Comment: Published in The Astrophysical Journal, Volume 853, Number 2. The entire machine-readable catalog is available from ApJ at http://iopscience.iop.org/0004-637X/853/2/172/suppdata/apjaaa600t2_mrt.txt . We also provide the same catalog in FITS format at https://goo.gl/aiJVs9

We present ALMA observations of the 870$\mu$m continuum and CO(4-3) line emission in the core of the galaxy cluster ClJ1449+0856 at z=2, a NIR-selected, X-ray detected system in the mass range of typical progenitors of today's massive clusters. The 870$\mu$m map reveals six F$_{870\mu m}$ > 0.5 mJy sources spread over an area of 0.07 arcmin$^2$, giving an overdensity of a factor ~10 (6) with respect to blank field counts down to F$_{870\mu m}$ > 1 (0.5) mJy. On the other hand, deep CO(4-3) follow-up confirms membership of three of these sources, but suggests that the remaining three, including the brightest 870$\mu$m sources in the field (F$_{870\mu m}\gtrsim$2 mJy), are likely interlopers. The measurement of 870$\mu$m continuum and CO(4-3) line fluxes at the positions of previously-known cluster members provides a deep probe of dusty star formation occurring in the core of this high-redshift structure, adding up to a total SFR~700$\pm$100 M$_{\odot}$/yr and yielding an integrated star formation rate density of ~10$^4$ M$_{\odot}$/yr/Mpc$^3$, five orders of magnitude larger than in the field at the same epoch, due to the concentration of star-forming galaxies in the small volume of the dense cluster core. The combination of these observations with previously available HST imaging highlights the presence in this same volume of a population of galaxies with already suppressed star formation. This diverse composition of galaxy populations in ClJ1449+0856 is especially highlighted at the very cluster center, where a complex assembly of quiescent and star-forming sources is likely forming the future Brightest Cluster Galaxy., Comment: 11 pages, 6 figures, ApJ in press

We present a 69 arcmin$^2$ ALMA survey at 1.1mm, GOODS-ALMA, matching the deepest HST-WFC3 H-band part of the GOODS-South field. We taper the 0"24 original image with a homogeneous and circular synthesized beam of 0"60 to reduce the number of independent beams - thus reducing the number of purely statistical spurious detections - and optimize the sensitivity to point sources. We extract a catalogue of galaxies purely selected by ALMA and identify sources with and without HST counterparts down to a 5$\sigma$ limiting depth of H=28.2 AB (HST/WFC3 F160W). ALMA detects 20 sources brighter than 0.7 mJy in the 0"60 tapered mosaic (rms sensitivity =0.18 mJy/beam) with a purity greater than 80%. Among these detections, we identify three sources with no HST nor Spitzer-IRAC counterpart, consistent with the expected number of spurious galaxies from the analysis of the inverted image; their definitive status will require additional investigation. An additional three sources with HST counterparts are detected either at high significance in the higher resolution map, or with different detection-algorithm parameters ensuring a purity greater than 80%. Hence we identify in total 20 robust detections. Our wide contiguous survey allows us to push further in redshift the blind detection of massive galaxies with ALMA with a median redshift of $z$=2.92 and a median stellar mass of M$_{\star}$ = 1.1 $\times 10^{11}$M$_\odot$. Our sample includes 20% HST-dark galaxies (4 out of 20), all detected in the mid-infrared with IRAC. The near-infrared based photometric redshifts of two of them $z\sim$4.3 and 4.8) suggest that these sources have redshifts $z$>4. At least 40% of the ALMA sources host an X-ray AGN, compared to 14% for other galaxies of similar mass and redshift. The wide area of our ALMA survey provides lower values at the bright end of number counts than single-dish telescopes, Comment: 26 pages, 23 figures, accepted to A&A

Using deep Herschel and ALMA observations, we investigate the star formation rate (SFR) distributions of X-ray selected AGN host galaxies at 0.5, Comment: 5 pages, 3 figures, 1 table; Accepted for publication in MNRAS Letters after moderate changes

We estimate the number counts of line emitters at high redshift and their evolution with cosmic time based on a combination of photometry and spectroscopy. We predict the H α, H β, [O II], and [O III] line fluxes for more than 35 000 galaxies down to stellar masses of ∼109 M in the COSMOS and GOODS-S fields, applying standard conversions and exploit ing the spectroscopic coverage of the FMOS-COSMOS survey at z ∼ 1.55 to calibrate the predictions. We calculate the number counts of H α, [O II], and [O III] emitters down to fluxes of 1 × 10−17 erg cm−2 s−1 in the range 1.4 < z < 1.8 covered by the FMOS-COSMOS survey. We model the time evolution of the differential and cumulative H α counts, steeply declining at the brightest fluxes. We expect ∼9300–9700 and ∼2300–2900 galaxies deg−2 for fluxes ≥1 × 10−16 and ≥2 × 10−16 erg cm−2 s−1 over the range of 0.9 < z < 1.8. We show that the observed evolution of the main sequence of galaxies with redshift is enough to reproduce the observed counts variation at 0.2 < z < 2.5. We characterize the physical properties of the H α emitters with fluxes ≥2 × 10−16 erg cm−2 s−1 including their stellar masses, UV sizes, [N II]/H α ratios and H α equivalent widths. An aperture of R ∼ Re ∼ 0.5 arcsec maximizes the signal-to-noise ratio for a detection, whilst causing a factor of ∼2 × flux losses, influencing the recoverable number counts, if neglected. Our approach, based on deep and large photometric data sets, reduces the uncertainties on the number counts due to the selection and spectroscopic samplings whilst exploring low fluxes. We publicly release the line flux predictions for the explored photometric samples., Monthly Notices of the Royal Astronomical Society, 472 (4), ISSN:0035-8711, ISSN:1365-2966, ISSN:1365-8711

We present deep ALMA CO(5-4) observations of a main sequence, clumpy galaxy at z=1.5 in the HUDF. Thanks to the ~0.5" resolution of the ALMA data, we can link stellar population properties to the CO(5-4) emission on scales of a few kpc. We detect strong CO(5-4) emission from the nuclear region of the galaxy, consistent with the observed $L_{\rm IR}$-$L^{\prime}_{\rm CO(5-4)}$ correlation and indicating on-going nuclear star formation. The CO(5-4) gas component appears more concentrated than other star formation tracers or the dust distribution in this galaxy. We discuss possible implications of this difference in terms of star formation efficiency and mass build-up at the galaxy centre. Conversely, we do not detect any CO(5-4) emission from the UV-bright clumps. This might imply that clumps have a high star formation efficiency (although they do not display unusually high specific star formation rates) and are not entirely gas dominated, with gas fractions no larger than that of their host galaxy (~50%). Stellar feedback and disk instability torques funnelling gas towards the galaxy centre could contribute to the relatively low gas content. Alternatively, clumps could fall in a more standard star formation efficiency regime if their actual star-formation rates are lower than generally assumed. We find that clump star-formation rates derived with several different, plausible methods can vary by up to an order of magnitude. The lowest estimates would be compatible with a CO(5-4) non-detection even for main-sequence like values of star formation efficiency and gas content., Accepted for publication in MNRAS. Minor revisions to match published version

This paper introduces EGG, the Empirical Galaxy Generator, a tool designed within the ASTRODEEP collaboration to generate mock galaxy catalogs for deep fields with realistic fluxes and simple morphologies. The simulation procedure is based exclusively on empirical prescriptions -- rather than first principles -- to provide the most accurate match with observations at 0, Comment: 24 pages, 18 figures, accepted for publication in A&A

Aims. We aim to test the impact of using variable star-forming histories (SFHs) and the IR luminosity as a constrain on the physical parameters of high redshift dusty star-forming galaxies. We explore in particular the properties (SFHs, ages, timescales) of galaxies depending on their belonging to the "main sequence" of star-forming galaxies (MS). Methods. We performed spectral energy distribution (SED) fitting of the UV-to-NIR and FIR emissions of a moderately large sample of GOODS-Herschel galaxies, for which rich multi-wavelength, optical to IR observations are available. We tested different SFHs and the impact of imposing energy conservation in the SED fitting process, to help with issues like the age-extinction degeneracy and produce SEDs consistent with observations. Results. Our simple models produce well constrained SEDs for the broad majority of the sample (84%), with the notable exception of the very high L-IR end, for which we have indications that the energy conservation hypothesis cannot hold true for a single component population approach. We observe trends in the preferences in SFHs among our sources depending on stellar mass M and z. Trends also emerge in the characteristic timescales of the SED models depending on the location on the SFR - M diagram. We show that whilst using the same available observational data, we can produce galaxies less star-forming than classically inferred, if we allow rapidly declining SFHs, while properly reproducing their observables. These sources, representing 7% of the sample, can be post-starbursts undergoing quenching, and their SFRs are potentially overestimated if inferred from their LIR. Based on the trends observed in the rising SFH fits we explore a simple evolution model for stellar mass build-up over the considered time period. Conclusions. Our approach successfully breaks the age-extinction degeneracy, and enables to evaluate properly the SFRs of the sources in the SED fitting process. Fitting without the IR constrain leads to a strong preference for declining SFHs, while its inclusion increases the preference of rising SFHs, more so at high z, in tentative agreement with the cosmic star-formation history (CSFH), although this result suffers from poor statistics. Keeping in mind that the sample is biased toward high luminosities and intense star formation, the evolution shaped by our model appears as both bursty (in its early stages) and steady-lasting (later on). The SFH of the sample considered as a whole follows the CSFH with a surprisingly small scatter, and is compatible with other studies supporting that the more massive galaxies have built most of their mass earlier than lower mass galaxies.

We present deep $J$ and $H$-band images in the extended Great Observatories Origins Deep Survey-North (GOODS-N) field covering an area of 0.22 $\rm{deg}^{2}$. The observations were taken using WIRCam on the 3.6-m Canada France Hawaii Telescope (CFHT). Together with the reprocessed $K_{\rm s}$-band image, the $5\sigma$ limiting AB magnitudes (in 2" diameter apertures) are 24.7, 24.2, and 24.4 AB mag in the $J$, $H$, and $K_{\rm s}$ bands, respectively. We also release a multi-band photometry and photometric redshift catalog containing 93598 sources. For non-X-ray sources, we obtained a photometric redshift accuracy $\sigma_{\mathrm{NMAD}}=0.036$ with an outlier fraction $\eta = 7.3\%$. For X-ray sources, which are mainly active galactic nuclei (AGNs), we cross-matched our catalog with the updated 2M-CDFN X-ray catalog from Xue et al. (2016) and found that 658 out of 683 X-ray sources have counterparts. $GALEX$ UV data are included in the photometric redshift computation for the X-ray sources to give $\sigma_{\mathrm{NMAD}} = 0.040$ with $\eta=10.5\%$. Our approach yields more accurate photometric redshift estimates compared to previous works in this field. In particular, by adopting AGN-galaxy hybrid templates, our approach delivers photometric redshifts for the X-ray counterparts with fewer outliers compared to the 3D-HST catalog, which fit these sources with galaxy-only templates.

We measure the dust and gas content of the three sub-millimeter galaxies (SMGs) in the GN20 proto-cluster at $z=4.05$ using new IRAM Plateau de Bure interferometer (PdBI) CO(4-3) and 1.2-3.3 mm continuum observations. All these three SMGs are heavily dust obscured, with UV-based star formation rate (SFR) estimates significantly smaller than the ones derived from the bolometric infrared (IR), consistent with the spatial offsets revealed by HST and CO imaging. Based also on evaluations of the specific SFR, CO-to-H$_2$ conversion factor and gas depletion timescale, we classify all the three galaxies as starbursts (SBs), although with a lower confidence for GN20.2b that might be a later stage merging event. We place our measurements in the context of the evolutionary properties of main sequence (MS) and SB galaxies. ULIRGs have 3-5 times larger $L'_{\rm CO}/M_{\rm dust}$ and $M_{\rm dust}/M_\star$ ratios than $z=0$ MS galaxies, but by $z\sim2$ the difference appears to be blurred, probably due to differential metallicity evolution. SB galaxies appear to slowly evolve in their $L'_{\rm CO}/M_{\rm dust}$ and $M_{\rm dust}/M_\star$ ratios all the way to $z>6$ (consistent with rapid enrichment of SB events), while MS galaxies rapidly increase in $M_{\rm dust}/M_\star$ from $z=0$ to 2 (due to gas fraction increase, compensated by a decrease of metallicities). While no IR/submm continuum detection is available for indisputably normal massive galaxies at $z>2.5$, we show that if metallicity indeed decrease rapidly for these systems at $z>3$ as claimed in the literature, we should expect a strong decrease of their $M_{\rm dust}/M_\star$, consistent with recent PdBI and ALMA upper limits. We conclude that the $M_{\rm dust}/M_\star$ ratio could be a powerful tool for distinguishing starbursts from normal galaxies at $z>4$., 17 pages, 9 figures. Updated to A&A accepted version

Using extremely deep PACS 100- and 160um Herschel data from the GOODS-Herschel program, we identify 21 infrared bright galaxies previously missed in the deepest 24um surveys performed by MIPS. These MIPS dropouts are predominantly found in two redshift bins, centred at z ~0.4 and ~1.3. Their S_100/S_24 flux density ratios are similar to those of local LIRGs and ULIRGs, whose silicate absorption features at 18um (at z ~ 0.4) and 9.7um (at z ~ 1.3) are shifted into the 24um MIPS band at these redshifts. The high-z sub-sample consists of 11 infrared luminous sources, accounting for ~2% of the whole GOODS-Herschel sample and putting strong upper limits on the fraction of LIRGs/ULIRGs at 1.0 43 colour cut selects galaxies with a redshift distribution similar to that of the MIPS dropouts and when combined with a second colour cut, S_16/S_8 > 4, isolates sources at 1.0 < z < 1.7. We show that these sources have elevated specific star formation rates (sSFR) compared to main sequence galaxies at these redshifts and are likely to be compact starbursts with moderate/strong 9.7um silicate absorption features in their mid-IR spectra. Herschel data reveal that their infrared luminosities extrapolated from the 24um flux density are underestimated, on average, by a factor of ~3. These silicate break galaxies account for 16% (8%) of the ULIRG (LIRG) population in the GOODS fields, indicating a lower limit in their space density of 2.0 \times 10^(-5) Mpc^(-3). Finally, we provide estimates of the fraction of z < 2 MIPS dropout sources as a function of the 24-, 100-, 160-, 250- and 350um sensitivity limits, and conclude that previous predictions of a population of silicate break galaxies missed by the major 24um extragalactic surveys have been overestimated.

We present the discovery of a giant $\gtrsim$100~kpc Ly$\alpha$ nebula detected in the core of the X-ray emitting cluster CL~J1449+0856 at $z=1.99$ through Keck/LRIS narrow-band imaging. This detection extends the known relation between Ly$\alpha$ nebulae and overdense regions of the Universe to the dense core of a $5-7\times10^{13}$ M$_{\odot}$ cluster. The most plausible candidates to power the nebula are two Chandra-detected AGN host cluster members, while cooling from the X-ray phase and cosmological cold flows are disfavored primarily because of the high Ly$\alpha$ to X-ray luminosity ratio ($L_{\mathrm{Ly\alpha}}/L_{\mathrm{X}} \approx0.3$, $\gtrsim10-1000\times$ higher than in local cool-core clusters) and by current modeling. Given the physical conditions of the Ly$\alpha$-emitting gas and the possible interplay with the X-ray phase, we argue that the Ly$\alpha$ nebula would be short-lived ($\lesssim10$ Myr) if not continuously replenished with cold gas at a rate of $\gtrsim1000$ M$_{\odot}$ yr$^{-1}$. We investigate the possibility that cluster galaxies supply the required gas through outflows and we show that their total mass outflow rate matches the replenishment necessary to sustain the nebula. This scenario directly implies the extraction of energy from galaxies and its deposition in the surrounding intracluster medium, as required to explain the thermodynamic properties of local clusters. We estimate an energy injection of the order of $\thickapprox2$ keV per particle in the intracluster medium over a $2$ Gyr interval. In our baseline calculation AGN provide up to $85$% of the injected energy and 2/3 of the mass, while the rest is supplied by supernovae-driven winds., Comment: 15 pages, 11 figures, 1 appendix. Accepted for publication in ApJ

We present a new method to search for candidate z~>2 Herschel 500{\mu}m sources in the GOODS-North field, using a S500{\mu}m/S24{\mu}m "color deconfusion" technique. Potential high-z sources are selected against low-redshift ones from their large 500{\mu}m to 24{\mu}m flux density ratios. By effectively reducing the contribution from low-redshift populations to the observed 500{\mu}m emission, we are able to identify counterparts to high-z 500{\mu}m sources whose 24{\mu}m fluxes are relatively faint. The recovery of known z~4 starbursts confirms the efficiency of this approach in selecting high-z Herschel sources. The resulting sample consists of 34 dusty star-forming galaxies at z~>2. The inferred infrared luminosities are in the range 1.5x10^12-1.8x10^13 Lsun, corresponding to dust-obscured star formation rates (SFRs) of ~260-3100 Msun/yr for a Salpeter IMF. Comparison with previous SCUBA 850{\mu}m-selected galaxy samples shows that our method is more efficient at selecting high-z dusty galaxies with a median redshift of z=3.07+/-0.83 and 10 of the sources at z~>4. We find that at a fixed luminosity, the dust temperature is ~5K cooler than that expected from the Td-LIR relation at z, Comment: 33 pages in emulateapj format, 24 figures, 2 tables, accepted for publication in the ApJS

We use HST/WFC3 imaging to study the red population in the IR-selected, X-ray detected, low-mass cluster Cl J1449+0856 at z=2, one of the few bona-fide established clusters discovered at this redshift, and likely a typical progenitor of an average massive cluster today. This study explores the presence and significance of an early red sequence in the core of this structure, investigating the nature of red sequence galaxies, highlighting environmental effects on cluster galaxy populations at high redshift, and at the same time underlining similarities and differences with other distant dense environments. Our results suggest that the red population in the core of Cl J1449+0856 is made of a mixture of quiescent and dusty star-forming galaxies, with a seedling of the future red sequence already growing in the very central cluster region, and already characterising the inner cluster core with respect to lower density environments. On the other hand, the color-magnitude diagram of this cluster is definitely different from that of lower-redshift (z, 5 pages, 5 figures. ApJ Letters, in press

We introduce a new color-selection technique to identify high-redshift, massive galaxies that are systematically missed by Lyman-break selection. The new selection is based on the H_{160} and IRAC 4.5um bands, specifically H - [4.5] > 2.25 mag. These galaxies, dubbed "HIEROs", include two major populations that can be separated with an additional J - H color. The populations are massive and dusty star-forming galaxies at z > 3 (JH-blue) and extremely dusty galaxies at z < 3 (JH-red). The 350 arcmin^2 of the GOODS-N and GOODS-S fields with the deepest HST/WFC3 and IRAC data contain 285 HIEROs down to [4.5] < 24 mag. We focus here primarily on JH-blue (z > 3) HIEROs, which have a median photometric redshift z ~4.4 and stellar massM_{*}~10^{10.6} Msun, and are much fainter in the rest-frame UV than similarly massive Lyman-break galaxies (LBGs). Their star formation rates (SFRs) reaches ~240 Msun yr^{-1} leading to a specific SFR, sSFR ~4.2 Gyr^{-1}, suggesting that the sSFRs for massive galaxies continue to grow at z > 2 but at a lower growth rate than from z=0 to z=2. With a median half-light radius of 2 kpc, including ~20% as compact as quiescent galaxies at similar redshifts, JH-blue HIEROs represent perfect star-forming progenitors of the most massive (M_{*} > 10^{11.2} Msun) compact quiescent galaxies at z ~ 3 and have the right number density. HIEROs make up ~60% of all galaxies with M_{*} > 10^{10.5} Msun identified at z > 3 from their photometric redshifts. This is five times more than LBGs with nearly no overlap between the two populations. While HIEROs make up 15-25% of the total SFR density at z ~ 4-5, they completely dominate the SFR density taking place in M_{*} >10^{10.5} Msun galaxies, and are therefore crucial to understanding the very early phase of massive galaxy formation., Comment: ApJS, in press

We present $\simeq$0$.\!\!^{\prime\prime}4$-resolution extinction-independent distributions of star formation and dust in 11 star-forming galaxies (SFGs) at $z = 1.3-3.0$. These galaxies are selected from sensitive, blank-field surveys of the $2' \times 2'$ Hubble Ultra-Deep Field at $\lambda = 5$ cm and 1.3 mm using the Karl G. Jansky Very Large Array (VLA) and Atacama Large Millimeter/submillimeter Array (ALMA). They have star-formation rates (SFRs), stellar masses, and dust properties representative of massive main-sequence SFGs at $z \sim 2$. Morphological classification performed on spatially-resolved stellar mass maps indicates a mixture of disk and morphologically disturbed systems; half of the sample harbor X-ray active galactic nuclei (AGN), thereby representing a diversity of $z \sim 2$ SFGs undergoing vigorous mass assembly. We find that their intense star formation most frequently occurs at the location of stellar-mass concentration and extends over an area comparable to their stellar-mass distribution, with a median diameter of $4.2 \pm 1.8$ kpc. This provides direct evidence for galaxy-wide star formation in distant, blank-field-selected main-sequence SFGs. The typical galactic-average SFR surface density is 2.5 M$_{\odot}$yr$^{-1}$kpc$^{-2}$, sufficiently high to drive outflows. In X-ray-selected AGN where radio emission is enhanced over the level associated with star formation, the radio excess pinpoints the AGN, which are found to be co-spatial with star formation. The median extinction-independent size of main-sequence SFGs is two times larger than those of bright submillimeter galaxies whose SFRs are $3-8$ times larger, providing a constraint on the characteristic SFR ($\sim300$ M$_{\odot}$yr$^{-1}$) above which a significant population of more compact star-forming galaxies appears to emerge., Comment: 11 pages, 4 figures, accepted for publication in ApJ

We report the discovery of a remarkable concentration of massive galaxies with extended X-ray emission at $z_{spec} = 2.506$, which contains 11 massive ($M_{*} \gtrsim 10^{11} M_{\odot}$) galaxies in the central 80kpc region (11.6$\sigma$ overdensity). We have spectroscopically confirmed 17 member galaxies with 11 from CO and the remaining ones from $H\alpha$. The X-ray luminosity, stellar mass content and velocity dispersion all point to a collapsed, cluster-sized dark matter halo with mass $M_{200c} = 10^{13.9\pm0.2} M_{\odot}$, making it the most distant X-ray-detected cluster known to date. Unlike other clusters discovered so far, this structure is dominated by star-forming galaxies (SFGs) in the core with only 2 out of the 11 massive galaxies classified as quiescent. The star formation rate (SFR) in the 80kpc core reaches $\sim$3400 $M_{\odot}$ yr$^{-1}$ with a gas depletion time of $\sim 200$ Myr, suggesting that we caught this cluster in rapid build-up of a dense core. The high SFR is driven by both a high abundance of SFGs and a higher starburst fraction ($\sim25\%$, compared to 3\%-5\% in the field). The presence of both a collapsed, cluster-sized halo and a predominant population of massive SFGs suggests that this structure could represent an important transition phase between protoclusters and mature clusters. It provides evidence that the main phase of massive galaxy passivization will take place after galaxies accrete onto the cluster, providing new insights into massive cluster formation at early epochs. The large integrated stellar mass at such high redshift challenges our understanding of massive cluster formation., Comment: matched to the published version by ApJ

We present a study of the infrared properties of X-ray selected, moderate-luminosity (i.e. L_X= 10^(42)–10^(44) erg s^(−1)) active galactic nuclei (AGNs) up to z ≈ 3, in order to explore the links between star formation in galaxies and accretion on to their central black holes. We use 100 and 160 μ m fluxes from GOODS-Herschel – the deepest survey yet undertaken by the Herschel telescope – and show that in the vast majority of cases (i.e. >94 per cent) these fluxes are dominated by emission from the host galaxy. As such, these far-infrared bands provide an uncontaminated view of star formation in the AGN host galaxies. We find no evidence of any correlation between the X-ray and infrared luminosities of moderate AGNs at any redshift, suggesting that global star formation is decoupled from nuclear (i.e. AGN) activity in these galaxies. On the other hand, we confirm that the star formation rates of AGN hosts increase strongly with redshift, by a factor of 43^(+27)_(−18) from z < 0.1 to z = 2–3 for AGNs with the same range of X-ray luminosities. This increase is entirely consistent with the factor of 25–50 increase in the specific star formation rates (SSFRs) of normal, star-forming (i.e. main-sequence) galaxies over the same redshift range. Indeed, the average SSFRs of AGN hosts are only marginally (i.e. ≈20 per cent) lower than those of main-sequence galaxies at all surveyed redshifts, with this small deficit being due to a fraction of AGNs residing in quiescent (i.e. low SSFR) galaxies. We estimate that 79 ± 10 per cent of moderate-luminosity AGNs are hosted in main-sequence galaxies, 15 ± 7 per cent in quiescent galaxies and

Using Herschel Photodetector Array Camera (PACS) and Spectral and Photometric Imaging Receiver (SPIRE) observations of Lockman Hole-North and Great Observatories Origins Deep Survey-North (GOODS-N) as part of the Herschel Multi-tiered Extragalactic Survey (HerMES) project, we explore the far-infrared (IR) properties of a sample of mid-IR-selected starburst-dominated ultraluminous infrared galaxies (ULIRGs) at z∼ 2. The selection of the sample is based on the detection of the stellar bump that appears in the spectral energy distribution of star-forming galaxies at 1.6 μm. We derive robust estimates of infrared luminosities (LIR) and dust temperatures (Td) of the population and find that while the luminosities in our sample span less than an order of magnitude (12.24 ≤ log(LIR/L⊙) ≤ 12.94), they cover a wide range of dust temperatures (25 ≤Td≤ 62 K). Galaxies in our sample range from those that are as cold as high-z submillimetre galaxies (SMGs) to those that are as warm as optically faint radio galaxies (OFRGs) and local ULIRGs. Nevertheless, our sample has median Td= 42.3 K, filling the gap between SMGs and OFRGs, bridging the two populations. We demonstrate that a significant fraction of our sample would be missed from ground-based (sub)mm surveys (850–1200 μm), showing that the latter introduce a bias towards the detection of colder sources. We conclude that Herschel observations confirm the existence of high-z ULIRGs warmer than SMGs, show that the mid-IR selection of high-z ULIRGs is not Td dependent, reveal a large dispersion in Td of high-z ULIRGs and provide the means to characterize the bulk of the ULIRG population, free from selection biases introduced by ground-based (sub)mm surveys.

The reliability of infrared (IR) and ultraviolet (UV) emissions to measure star formation rates in galaxies is investigated for a large sample of galaxies observed with the SPIRE and PACS instruments on Herschel as part of the HerMES project. We build flux-limited 250 micron samples of sources at redshift z 10 ^{11} L_sun and 0.5< z

We use deep panchromatic datasets in the GOODS-N field, from GALEX to the deepest Herschel far-infrared and VLA radio continuum imaging, to explore, using mass-complete samples, the evolution of the star formation activity and dust attenuation of star-forming galaxies to z~4. Our main results can be summarized as follows: i) the slope of the SFR-M correlation is consistent with being constant, and equal to ~0.8 at least up to z~1.5, while its normalization keeps increasing with redshift; ii) for the first time here we are able to explore the FIR-radio correlation for a mass-selected sample of star-forming galaxies: the correlation does not evolve up to z~4; iii) we confirm that galaxy stellar mass is a robust proxy for UV dust attenuation in star-forming galaxies, with more massive galaxies being more dust attenuated, strikingly we find that this attenuation relation evolves very weakly with redshift, the amount of dust attenuation increasing by less than 0.3 magnitudes over the redshift range [0.5-4] for a fixed stellar mass, as opposed to a tenfold increase of star formation rate; iv) the correlation between dust attenuation and the UV spectral slope evolves in redshift, with the median UV spectral slope of star-forming galaxies becoming bluer with redshift. By z~3, typical UV slopes are inconsistent, given the measured dust attenuation, with the predictions of commonly used empirical laws. Finally, building on existing results, we show that gas reddening is marginally larger (by a factor of around 1.3) than stellar reddening at all redshifts probed, and also that the amount of dust attenuation at a fixed ISM metallicity increases with redshift. We speculate that our results support evolving ISM conditions of typical star-forming galaxies such that at z~1.5 Main Sequence galaxies have ISM conditions getting closer to those of local starbursts., 19 pages, 12 figure, accepted for publication in ApJ

We present high resolution (0.3") Atacama Large Millimeter Array (ALMA) 870um imaging of five z~1.5-4.5 X-ray detected AGN with luminosities of L(2-8keV)>10^42 erg/s. These data provide a >~20x improvement in spatial resolution over single-dish rest-frame FIR measurements. The sub-millimetre emission is extended on scales of FWHM~0.2"-0.5", corresponding to physical sizes of 1-3 kpc (median value of 1.8 kpc). These sizes are comparable to the majority of z=1-5 sub-millimetre galaxies (SMGs) with equivalent ALMA measurements. In combination with spectral energy distribution analyses, we attribute this rest-frame far-infrared (FIR) emission to dust heated by star formation. The implied star-formation rate surface densities are ~20-200 Mo/yr/kpc^2, which are consistent with SMGs of comparable FIR luminosities (i.e., L(IR)~[1-5]x10^(12)Lo). Although limited by a small sample of AGN, which all have high FIR luminosities, our study suggests that the kpc-scale spatial distribution and surface density of star formation in high-redshift star-forming galaxies is the same irrespective of the presence of X-ray detected AGN., Accepted for publication in MNRAS. 5 pages, 3 figures

We present an analysis of the deepest Herschel images in four major extragalactic fields GOODS-North, GOODS-South, UDS and COSMOS obtained within the GOODS-Herschel and CANDELS-Herschel key programs. The picture provided by 10497 individual far-infrared detections is supplemented by the stacking analysis of a mass-complete sample of 62361 star-forming galaxies from the CANDELS-HST H band-selected catalogs and from two deep ground-based Ks band-selected catalogs in the GOODS-North and the COSMOS-wide fields, in order to obtain one of the most accurate and unbiased understanding to date of the stellar mass growth over the cosmic history. We show, for the first time, that stacking also provides a powerful tool to determine the dispersion of a physical correlation and describe our method called "scatter stacking" that may be easily generalized to other experiments. We demonstrate that galaxies of all masses from z=4 to 0 follow a universal scaling law, the so-called main sequence of star-forming galaxies. We find a universal close-to-linear slope of the logSFR-logM* relation with evidence for a flattening of the main sequence at high masses (log(M*/Msun) > 10.5) that becomes less prominent with increasing redshift and almost vanishes by z~2. This flattening may be due to the parallel stellar growth of quiescent bulges in star-forming galaxies. Within the main sequence, we measure a non varying SFR dispersion of 0.3 dex. The specific SFR (sSFR=SFR/M*) of star-forming galaxies is found to continuously increase from z=0 to 4. Finally we discuss the implications of our findings on the cosmic SFR history and show that more than 2/3 of present-day stars must have formed in a regime dominated by the main sequence mode. As a consequence we conclude that, although omnipresent in the distant Universe, galaxy mergers had little impact in shaping the global star formation history over the last 12.5 Gyr., 30 pages, 26 figures, accepted for publication in A&A

We study the properties of satellites in the environment of massive star-forming galaxies at z~1.8 in the COSMOS field, using a sample of 215 galaxies on the main sequence of star formation with an average mass of 10^11 Msun. At z>1.5, these galaxies typically trace halos of mass >10^13 Msun. We use optical-near-infrared photometry to estimate stellar masses and star formation rates (SFR) of centrals and satellites down to ~6*10^9 Msun. We stack data around 215 central galaxies to statistically detect their satellite halos, finding an average of ~3 galaxies in excess of the background density. We fit the radial profiles of satellites with simple beta-models, and compare their integrated properties to model predictions. We find that the total stellar mass of satellites amounts to 68% of the central galaxy, while SED modeling and far-infrared photometry consistently show their total SFR to be 25-35% of the central's rate. We also see significant variation in the specific SFR of satellites within the halo with, in particular, a sharp decrease at, 12 pages, 12 figures. Accepted for publication in Astronomy & Astrophysics

We introduce the ALMA Redshift 4 Survey (AR4S), a systematic ALMA survey of all the known galaxies with stellar mass (M*) larger than 5e10 Msun at 3.5, Comment: 7 pages, 4 figures, accepted for publication in A&A

We present the most complete study to date of the X-ray emission from star-formation in high redshift (median z=0.7; z-3 in both hard and soft X-ray bands. From the sources which are star-formation dominated, only a small fraction are individually X-ray detected and for the bulk of the sample we calculate average X-ray luminosities through stacking. We find an average soft X-ray to infrared ratio of log[L_SX/L_IR]=-4.3 and an average hard X-ray to infrared ratio of log[L_HX/L_IR]=-3.8. We report that the X-ray/IR correlation is approximately linear through the entire range of L_IR and z probed and, although broadly consistent with the local (z, Comment: 16 pages, 13 figures, accepted for publication in MNRAS

Using a phenomenological approach, we self-consistently model the redshift evolution of the ultraviolet (UV) and infrared (IR) luminosity functions across cosmic time, as well as a range of observed IR properties of UV-selected galaxy population. This model is an extension of the 2SFM (2 star-formation modes) formalism, which is based on the observed "main-sequence" of star-forming galaxies, i.e. a strong correlation between their stellar mass and their star formation rate (SFR), and a secondary population of starbursts with an excess of star formation. The balance between the UV light from young, massive stars and the dust-reprocessed IR emission is modeled following the empirical relation between the attenuation (IRX for IR excess hereafter) and the stellar mass, assuming a scatter of 0.4\,dex around this relation. We obtain a good overall agreement with the measurements of the IR luminosity function up to z~3 and the UV luminosity functions up to z~6, and show that a scatter on the IRX-M relation is mandatory to reproduce these observables. We also naturally reproduce the observed, flat relation between the mean IRX and the UV luminosity at L$_{\rm UV}>$10$^{9.5}$ L$_\odot$. Finally, we perform predictions of the UV properties and detectability of IR-selected samples and the vice versa, and discuss the results in the context of the UV-rest-frame and sub-millimeter surveys of the next decade., Accepted for publication in MNRAS; 14 pages; 7 figures

Emission line diagnostic diagrams probing the ionization sources in galaxies, such as the Baldwin-Phillips-Terlevich (BPT) diagram, have been used extensively to distinguish active galactic nuclei (AGN) from purely star-forming galaxies. However, they remain poorly understood at higher redshifts. We shed light on this issue with an empirical approach based on a z ~ 0 reference sample built from ~300,000 Sloan Digital Sky Survey galaxies, from which we mimic selection effects due to typical emission line detection limits at higher redshift. We combine this low-redshift reference sample with a simple prescription for luminosity evolution of the global galaxy population to predict the loci of high-redshift galaxies on the BPT and Mass-Excitation (MEx) diagnostic diagrams. The predicted bivariate distributions agree remarkably well with direct observations of galaxies out to z ~ 1.5, including the observed stellar mass-metallicity (MZ) relation evolution. As a result, we infer that high-redshift star-forming galaxies are consistent with having normal interstellar medium (ISM) properties out to z ~ 1.5, after accounting for selection effects and line luminosity evolution. Namely, their optical line ratios and gas-phase metallicities are comparable to that of low-redshift galaxies with equivalent emission-line luminosities. In contrast, AGN narrow-line regions may show a shift toward lower metallicities at higher redshift. While a physical evolution of the ISM conditions is not ruled out for purely star-forming galaxies and may be more important starting at z 2, we find that reliably quantifying this evolution is hindered by selections effects. The recipes provided here may serve as a basis for future studies toward this goal. Code to predict the loci of galaxies on the BPT and MEx diagnostic diagrams and the MZ relation as a function of emission line luminosity limits is made publicly available.

We present deep IRAM Plateau de Bure Interferometer (PdBI) observations, searching for CO-emission toward two massive, non-lensed Lyman break galaxies (LBGs) at z=3.216 and 4.058. With one low significance CO detection (3.5 sigma) and one sensitive upper limit, we find that the CO lines are >~ 3-4 times weaker than expected based on the relation between IR and CO luminosities followed by similarly, massive galaxies at z=0-2.5. This is consistent with a scenario in which these galaxies have low metallicity, causing an increased CO-to-H_2 conversion factor, i.e., weaker CO-emission for a given molecular (H_2) mass. The required metallicities at z>3 are lower than predicted by the fundamental metallicity relation (FMR) at these redshifts, consistent with independent evidence. Unless our galaxies are atypical in this respect, detecting molecular gas in normal galaxies at z>3 may thus remain challenging even with ALMA., 9 pages, 3 figures, accepted for publication in Astrophysical Journal Letters

We present results from the deepest Herschel-PACS (Photodetector Array Camera and Spectrometer) far-infrared blank field extragalactic survey, obtained by combining observations of the GOODS (Great Observatories Origins Deep Survey) fields from the PACS Evolutionary Probe (PEP) and GOODS-Herschel key programmes. We describe data reduction and the construction of images and catalogues. In the deepest parts of the GOODS-S field, the catalogues reach 3-sigma depths of 0.9, 0.6 and 1.3 mJy at 70, 100 and 160 um, respectively, and resolve ~75% of the cosmic infrared background at 100um and 160um into individually detected sources. We use these data to estimate the PACS confusion noise, to derive the PACS number counts down to unprecedented depths and to determine the infrared luminosity function of galaxies down to LIR=10^11 Lsun at z~1 and LIR=10^12 Lsun at z~2, respectively. For the infrared luminosity function of galaxies, our deep Herschel far-infrared observations are fundamental because they provide more accurate infrared luminosity estimates than those previously obtained from mid-infrared observations. Maps and source catalogues (>3-sigma) are now publicly released. Combined with the large wealth of multi-wavelength data available for the GOODS fields, these data provide a powerful new tool for studying galaxy evolution over a broad range of redshifts., Accepted for publication in A&A; 22 pages, 13 figures; V2: updated to match accepted version

We present here a new spectral energy distribution (SED) fitting approach that we adopt to select radio-excess sources amongst distant star-forming galaxies in the GOODS-Herschel (North) field and to reveal the presence of hidden, highly obscured AGN. Through extensive SED analysis of 458 galaxies with radio 1.4 GHz and mid-IR 24 um detections using some of the deepest Chandra X-ray, Spitzer and Herschel infrared, and VLA radio data available to date, we have robustly identified a sample of 51 radio-excess AGN (~1300 deg^-2) out to redshift z~3. These radio-excess AGN have a significantly lower far-IR/radio ratio (q, 28 pages, 13 figures, (abstract abridged). Accepted for publication in A&A