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We investigate the evolution of dust content in galaxies from redshifts z = 0 to z = 9.5. Using empirically motivated prescriptions, we model galactic-scale properties-including halo mass, stellar mass, star formation rate, gas mass, and metallicity-to make predictions for the galactic evolution of dust mass and dust temperature in main-sequence galaxies. Our simple analytic model, which predicts that galaxies in the early universe had greater quantities of dust than their low-redshift counterparts, does a good job of reproducing observed trends between galaxy dust and stellar mass out to z approximate to 6. We find that for fixed galaxy stellar mass, the dust temperature increases from z = 0 to z = 6. Our model forecasts a population of low-mass, high-redshift galaxies with interstellar dust as hot as, or hotter than, their more massive counterparts; but this prediction needs to be constrained by observations. Finally, we make predictions for observing 1.1 mm flux density arising from interstellar dust emission with the Atacama Large Millimeter Array.

We present an extremely deep CO(1-0) observation of a confirmed z = 1.62 galaxy cluster. We detect two spectroscopically confirmed cluster members in CO(1-0) with signal-to-noise ratio >5. Both galaxies have log (M-star/M-circle dot) > 11 and are gas rich, with M-mol/(M-star + M-mol) similar to 0.17-0.45. One of these galaxies lies on the star formation rate (SFR)-M-star sequence, while the other lies an order of magnitude below. We compare the cluster galaxies to other SFR-selected galaxies with CO measurements and find that they have CO luminosities consistent with expectations given their infrared luminosities. We also find that they have gas fractions and star formation efficiencies (SFE) comparable to what is expected from published field galaxy scaling relations. The galaxies are compact in their stellar light distribution, at the extreme end for all high-redshift star-forming galaxies. However, their SFE is consistent with other field galaxies at comparable compactness. This is similar to two other sources selected in a blind CO survey of the HDF-N. Despite living in a highly quenched protocluster core, the molecular gas properties of these two galaxies, one of which may be in the process of quenching, appear entirely consistent with field scaling relations between the molecular gas content, stellar mass, star formation rate, and redshift. We speculate that these cluster galaxies cannot have any further substantive gas accretion if they are to become members of the dominant passive population in z < 1 clusters.

We investigate the star formation history (SFH) and chemical evolution of isolated analogs of Local Group (LG) ultrafaint dwarf galaxies (UFDs; stellar mass range of 10(2)M(circle dot) < M-*< 10(5) M-circle dot) and gas-rich, low-mass dwarfs (Leo P analogs; stellar mass range of 10(5)M(circle dot) < M-*< 10(6) M-circle dot). We perform a suite of cosmological hydrodynamic zoom-in simulations to follow their evolution from the era of the first generation of stars down to z=0. We confirm that reionization, combined with supernova (SN) feedback, is primarily responsible for the truncated star formation in UFDs. Specifically, halos with a virial mass of M-vir less than or similar to 2 x 10(9) M-circle dot form greater than or similar to 90% of stars prior to reionization. Our work further demonstrates the importance of Population. III stars, with their intrinsically high [C/Fe] yields and the associated external metal enrichment, in producing low-metallicity stars ([Fe/H] less than or similar to -4) and carbon-enhanced metal-poor (CEMP) stars. We find that UFDs are composite systems, assembled from multiple progenitor halos, some of which hosted only Population. II stars formed in environments externally enriched by SNe in neighboring halos, naturally producing extremely low metallicity Population II stars. We illustrate how the simulated chemical enrichment may be used to constrain the SFHs of true observed UFDs. We find that Leo P analogs can form in halos with M-vir similar to 4 x 10(9) M-circle dot 9 (z = 0). Such systems are less affected byreionization and continue to form stars until z = 0, causing higher-metallicity tails. Finally, we predict the existence of extremely low metallicity stars in LG UFD galaxies that preserve the pure chemical signatures of Population III nucleosynthesis.

We report on the galaxy MACSJ0032-arc at z(CO) = 3.6314 discovered during the Herschel Lensing snapshot Survey of massive galaxy clusters, and strongly lensed by the cluster MACSJ0032.1+1808. The successful detections of its rest-frame ultraviolet (UV), optical, far-infrared (FIR), millimeter, and radio continua, and of its CO emission enable us to characterize, for the first time at such a high redshift, the stellar, dust, and molecular gas properties of a compact star-forming galaxy with a size smaller than 2.5 kpc, a fairly low stellar mass of 4.8(-1.0)(+0.5) x 10(9) M circle dot, and a moderate IR luminosity of 4.8(-0.6)(+1.2) x 10(11) L circle dot. By combining the stretching effect of the lens with the high angular resolution imaging of the CO(10) line emission and the radio continuum at 5 GHz, we find that the bulk of the molecular gas mass and star formation seems to be spatially decoupled from the rest-frame UV emission. About 90% of the total star formation rate is undetected at rest-frame UV wavelengths because of severe obscuration by dust, but is seen through the thermal FIR dust emission and the radio synchrotron radiation. The observed CO(43) and CO(65) lines demonstrate that high-J transitions, at least up to J = 6, remain excited in this galaxy, whose CO spectral line energy distribution resembles that of high-redshift submm galaxies, even though the IR luminosity of MACSJ0032-arc is ten times lower. This high CO excitation is possibly due to the compactness of the galaxy. We find evidence that this high CO excitation has to be considered in the balance when estimating the CO-to-H-2 conversion factor. Indeed, the respective CO-to-H-2 conversion factors as derived from the correlation with metallicity and the FIR dust continuum can only be reconciled if excitation is accounted for. The inferred depletion time of the molecular gas in MACSJ0032-arc supports the decrease in the gas depletion timescale of galaxies with redshift, although to a lesser degree than predicted by galaxy evolution models. Instead, the measured molecular gas fraction as high as 6079% in MACSJ0032-arc favors the continued increase in the gas fraction of galaxies with redshift as expected, despite the plateau observed between z similar to 1.5 and z similar to 2.5.

We present an analysis of high-resolution ALMA interferometry of CO(4-3) line emission and dust continuum in the "Ruby" (PLCK_G244.8+54.9), a bright, gravitationally lensed galaxy at z = 3.0 discovered with the Planck all-sky survey. The Ruby is the brightest of Planck's dusty GEMS, a sample of 11 of the brightest gravitationally lensed high-redshift galaxies on the extragalactic sub-mm sky. We resolve the high-surface-brightness continuum and CO line emission of the Ruby in several extended clumps along a partial, nearly circular Einstein ring with 1.4 '' diameter around a massive galaxy at z = 1.5. Local star-formation intensities are up to 2000 M-circle dot yr(-1) kpc(-2), amongst the highest observed at high redshift, and clearly in the range of maximal starbursts. Gas-mass surface densities are a few x10(4) M-circle dot pc(-2). The Ruby lies at, and in part even above, the starburst sequence in the Schmidt-Kennicutt diagram, and at the limit expected for star formation that is self-regulated through the kinetic energy injection from radiation pressure, stellar winds, and supernovae. We show that these processes can also inject sufficient kinetic energy and momentum into the gas to explain the turbulent line widths, which are consistent with marginally gravitationally bound molecular clouds embedded in a critically Toomre-stable disk. The star-formation efficiency is in the range 1-10% per free-fall time, consistent with the notion that the pressure balance that sets the local star-formation law in the Milky Way may well be universal out to the highest star-formation intensities. AGN feedback is not necessary to regulate the star formation in the Ruby, in agreement with the absence of a bright AGN component in the infrared and radio regimes.

We present new Atacama Large Millimeter/submillimeter Array (ALMA) observations of the dust continuum and [C II] 158 mu m fine structure line emission toward a far-infrared-luminous quasar, ULAS J131911.29+095051.4 at z = 6.13, and combine the new Cycle 1 data with ALMA Cycle 0 data. The combined data have an angular resolution of similar to 0.'' 3, and resolve both the dust continuum and the [C II] line emission on a few kiloparsec scales. The [C II] line emission is more irregular than that of the dust continuum emission, which suggests different distributions between the dust and the [C II] emitting gas. The combined data confirm the [C II] velocity gradient that we had previously detected in a lower-resolution ALMA image from the Cycle 0 data alone. We apply a tilted ring model to the [C II] velocity map to obtain a rotation curve, and constrain the circular velocity to be 427 +/- 55 kms(-1) at a radius of 3.2 kpc with an inclination angle of 34 degrees. We measure the dynamical mass within the 3.2 kpc region to be 13.4(-5.3)(+7.8) x 10(10) M-circle dot. This yields a black-hole and host galaxy mass ratio of 0.020(-0.007)(+0.013), which is about 4(-2)(+3) times higher than that of the present-day M-BH/M-bulge ratio. This suggests that the supermassive black hole grows the bulk of its mass before the formation of most of the stellar mass in this quasar host galaxy in the early universe.

Bright Ly alpha blobs (LABs)-extended nebulae with sizes of similar to 100 kpc and Ly alpha luminosities of similar to 10(44) erg s(-1)-often reside in overdensities of compact Ly alpha emitters (LAEs) that may be galaxy protoclusters. The number density, variance, and internal kinematics of LABs suggest that they themselves trace group-like halos. Here, we test this hierarchical picture, presenting deep, wide-field Ly alpha narrowband imaging of a 1 degrees x. 0 degrees.5 region around a LAB pair at z = 2.3 discovered previously by a blind survey. We find 183 Lya emitters, including the original LAB pair and three new LABs with Ly alpha luminosities of (0.9-1.3) x 10(43) erg s(-1) and isophotal areas of 16-24 arcsec2. Using the LAEs as tracers and a new kernel density estimation method, we discover a large-scale overdensity (Bootes J1430+3522) with a surface density contrast of delta(Sigma) = 2.7, a volume density contrast of delta similar to 10.4, and a projected diameter of approximate to 20 comoving Mpc. Comparing with cosmological simulations, we conclude that this LAE overdensity will evolve into a present-day Coma-like cluster with log(M/M-circle dot) similar to 15.1 +/- 0.2. In this and three other wide-field LAE surveys re-analyzed here, the extents and peak amplitudes of the largest LAE overdensities are similar, not increasing with survey size, and implying that they were indeed the largest structures then and today evolve into rich clusters. Intriguingly, LABs favor the outskirts of the densest LAE concentrations, i.e., intermediate LAE overdensities of delta(Sigma) = 1-2. We speculate that these LABs mark infalling protogroups being accreted by the more massive protocluster.

We present a sample of similar to 1000 emission-line galaxies at z = 0.4-4.7 from the similar to 0.7deg(2) High-z Emission-Line Survey in the Bootes field identified with a suite of six narrow-band filters at approximate to 0.4-2.1 mu m. These galaxies have been selected on their Ly alpha (73), [O (II)] (285), H beta/[O (III)] (387) or H alpha (362) emission line, and have been classified with optical to near-infrared colours. A subsample of 98 sources have reliable redshifts from multiple narrow-band (e.g. [O (II)]-H alpha) detections and/or spectroscopy. In this survey paper, we present the observations, selection and catalogues of emitters. We measure number densities of Ly alpha, [O (II)], H beta/[O (III)] and H alpha and confirm strong luminosity evolution in star-forming galaxies from z similar to 0.4 to similar to 5, in agreement with previous results. To demonstrate the usefulness of dual-line emitters, we use the sample of dual [O (II)]-H alpha emitters to measure the observed [O (II)]/H alpha ratio at z = 1.47. The observed [O (II)]/H alpha ratio increases significantly from 0.40 +/- 0.01 at z = 0.1 to 0.52 +/- 0.05 at z = 1.47, which we attribute to either decreasing dust attenuation with redshift, or due to a bias in the (typically) fibre measurements in the local Universe that only measure the central kpc regions. At the bright end, we find that both the H alpha and Ly alpha number densities at z approximate to 2.2 deviate significantly from a Schechter form, following a power law. We show that this is driven entirely by an increasing X-ray/active galactic nucleus fraction with line luminosity, which reaches approximate to 100 per cent at line luminosities L greater than or similar to 3 x 10(44) erg s(-1).