Search

The unique characteristics of the brightest group galaxies (BGGs) serve as a link in the evolutionary continuum between galaxies such as the Milky Way and the more massive brightest cluster galaxies found in dense clusters. This research investigates the evolution of the stellar properties of BGGs over cosmic time (z = 0.08 − 1.30), extending the work from our prior studies. We analyzed the data of 246 BGGs selected from our X-ray galaxy group catalog within the COSMOS field, examining stellar age, mass, star-formation rate (SFR), specific SFR, and halo mass. We compared observations with the Millennium and Magneticum simulations. Additionally, we investigated whether stellar properties vary with the projected offset from the X-ray peak or the hosting halo center. We evaluated the accuracy of SED-derived stellar ages using a mock galaxy catalog, finding a mean absolute error of around 1 Gyr. Interestingly, the observed BGG age distributions exhibit a bias toward younger intermediate ages compared to both semi-analytical models and the Magneticum simulation. Our analysis of stellar age versus mass unveils intriguing trends with a positive slope, hinting at complex evolutionary pathways across redshifts. We observed a negative correlation between stellar age and SFR across all redshift ranges. We employed a cosmic time dependent main sequence framework to identify star forming BGGs and find that approximately 20% of BGGs in the local universe continue to exhibit characteristics typical of star forming galaxies, with this proportion increasing to 50% at z = 1.0. Our findings support an inside-out formation scenario for BGGs, where older stellar populations reside near the X-ray peak and younger populations at larger offsets indicate ongoing star-formation. The observed distribution of stellar ages, particularly for lower-mass BGGs in the range of 1010−11 M⊙, deviates from the constant ages predicted by the models across all stellar mass ranges and redshifts. This discrepancy aligns with the current models' known limitations in accurately capturing galaxies' complex star-formation histories. [ABSTRACT FROM AUTHOR]

Our current understanding of the cosmic star formation history at z > 3 is primarily based on UV-selected galaxies (Lyman-break galaxies, i.e., LBGs). Recent studies of H-dropouts (HST-dark galaxies) have revealed that we may be missing a large proportion of star formation that is taking place in massive galaxies at z > 3. In this work, we extend the H-dropout criterion to lower masses to select optically dark or faint galaxies (OFGs) at high redshifts in order to complete the census between LBGs and H-dropouts. Our criterion (H > 26:5 mag & [4.5] < 25 mag) combined with a de-blending technique is designed to select not only extremely dust-obscured massive galaxies but also normal star-forming galaxies (typically E(B V) > 0:4) with lower stellar masses at high redshifts. In addition, with this criterion, our sample is not contaminated by massive passive or old galaxies. In total, we identified 27 OFGs at zphot > 3 (with a median of zmed = 4:1) in the GOODS-ALMA field, covering a wide distribution of stellar masses with log(MM) = 9:411:1 (with a median of log(Med/M) = 10.3). We find that up to 75% of the OFGs with log(M/M) = 9:510:5 were neglected by previous LBGs and H-dropout selection techniques. After performing an optical-to-millimeter stacking analysis of the OFGs, we find that rather than being limited to a rare population of extreme starbursts, these OFGs represent a normal population of dusty star-forming galaxies at z > 3. The OFGs exhibit shorter gas depletion timescales, slightly lower gas fractions, and lower dust temperatures than the scaling relation of typical star-forming galaxies. Additionally, the total star formation rate (SFRtot = SFRIR + SFRUV) of the stacked OFGs is much higher than the SFRcorr UV (SFRUV corrected for dust extinction), with an average SFRtot/SFRcorr UV = 8 ± 1, which lies above (~0.3 dex) the 16-84th percentile range of typical star-forming galaxies at 3 z 6. All of the above suggests the presence of hidden dust regions in the OFGs that absorb all UV photons, which cannot be reproduced with dust extinction corrections. The effective radius of the average dust size measured by a circular Gaussian model fit in the uv plane is Re(1:13 mm) = 1:01 ± 0:05 kpc. After excluding the five LBGs in the OFG sample, we investigated their contributions to the cosmic star formation rate density (SFRD). We found that the SFRD at z > 3 contributed by massive OFGs (log(MM) > 10:3) is at least two orders of magnitude higher than the one contributed by equivalently massive LBGs. Finally, we calculated the combined contribution of OFGs and LBGs to the cosmic SFRD at z = 45 to be 4 102 M yr1 Mpc3, which is about 0.15 dex (43%) higher than the SFRD derived from UV-selected samples alone at the same redshift. This value could be even larger, as our calculations were performed in a very conservative way. [ABSTRACT FROM AUTHOR]

Investigating the thermal and non-thermal processes in galaxies is vital to understand their evolution over cosmic time. This can best be studied by combining the radio and optical/near-infrared observations of galaxies. The JWST can resolve the evolution of the thermal processes by mapping ionized gas and dust in distant galaxies. This information combined with the upcoming surveys with the Square Kilometer Array (SKA) will make a major breakthrough in mapping the non-thermal processes and understanding their role in the evolution of galaxies. Our simulations show that SKA surveys will be able to trace the evolution history of spiral galaxies such as M 51 and NGC 6946 back to a redshift of 3 already in its first phase of construction. This study indicates the important role of the non-thermal pressure inserted by cosmic rays and magnetic fields in deriving winds and outflows at cosmic noon as deduced by a flat synchrotron spectrum in star forming galaxies. [ABSTRACT FROM AUTHOR]

The evolution of the dust grain size distribution has been studied in recent years with great detail in cosmological hydrodynamical simulations taking into account all the channels under which dust evolves in the interstellar medium. We present a systematic analysis of the observed spectral energy distribution of a large sample of galaxies in the local Universe in order to derive not only the total dust masses but also the relative mass fraction between small and large dust grains (DS / DL). Simulations reproduce fairly well the observations except for the high-stellar mass regime where dust masses tend to be overestimated. We find that ∼45 per cent of galaxies exhibit DS / DL consistent with the expectations of simulations, while there is a subsample of massive galaxies presenting high DS / DL (log (DS / DL) ∼ −0.5), and deviating from the prediction in simulations. For these galaxies which also have high-molecular gas mass fractions and metallicities, coagulation is not an important mechanism affecting the dust evolution. Including diffusion, transporting large grains from dense regions to a more diffuse medium where they can be easily shattered, would explain the observed high DS / DL values in these galaxies. With this study, we reinforce the use of the small-to-large grain mass ratio to study the relative importance of the different mechanisms in the dust life cycle. Multiphase hydrodynamical simulations with detailed feedback prescriptions and more realistic subgrid models for the dense phase could help to reproduce the evolution of the dust grain size distribution traced by observations. [ABSTRACT FROM AUTHOR]

Compact star formation appears to be generally common in dusty star-forming galaxies (SFGs). However, its role in the framework set by the scaling relations in galaxy evolution remains to be understood. In this work we follow up on the galaxy sample from the GOODS-ALMA 2.0 survey, an ALMA blind survey at 1.1 mm covering a continuous area of 72.42 arcmin2 using two array configurations. We derived physical properties, such as star formation rates, gas fractions, depletion timescales, and dust temperatures for the galaxy sample built from the survey. There exists a subset of galaxies that exhibit starburst-like short depletion timescales, but they are located within the scatter of the so-called main sequence of SFGs. These are dubbed starbursts in the main sequence and display the most compact star formation and they are characterized by the shortest depletion timescales, lowest gas fractions, and highest dust temperatures of the galaxy sample, compared to typical SFGs at the same stellar mass and redshift. They are also very massive, accounting for ∼60% of the most massive galaxies in the sample (log(M*/M⊙) > 11.0). We find trends between the areas of the ongoing star formation regions and the derived physical properties for the sample, unveiling the role of compact star formation as a physical driver of these properties. Starbursts in the main sequence appear to be the extreme cases of these trends. We discuss possible scenarios of galaxy evolution to explain the results drawn from our galaxy sample. Our findings suggest that the star formation rate is sustained in SFGs by gas and star formation compression, keeping them within the main sequence even when their gas fractions are low and they are presumably on the way to quiescence. [ABSTRACT FROM AUTHOR]

Environmentally overburdened communities need information and resources to cope with hazards. We describe, and use a case study to depict, a participatory process of engaging Detroit stakeholders with academic researchers in the co-production of environmental health communication tools to enhance their capacity to address the unjust conditions. Over five years, we disseminated tools to 763 individuals who connected us to their network members so that we reached three times as many (n = 2,273) through snowball methods. On-going demand and evaluation findings indicated that our model was responsive to local circumstances, which may inform and encourage others to engage in such collaborations. [ABSTRACT FROM AUTHOR]

Background: Previous studies have reported disparities in orthopaedic care resulting from demographic factors, including insurance status. However, the effect of insurance on pediatric tibial spine fractures (TSFs), an uncommon but significant injury, is unknown. Purpose: To assess the effect of insurance status on the evaluation and treatment of TSFs in children and adolescents. Study Design: Cross-sectional study; Level of evidence, 3. Methods: We performed a retrospective cohort study of TSFs treated at 10 institutions between 2000 and 2019. Demographic data were collected, as was information regarding pre-, intra-, and postoperative treatment, with attention to delays in management and differences in care. Surgical and nonsurgical fractures were included, but a separate analysis of surgical patients was performed. Univariate analysis was followed by purposeful entry multivariate regression to adjust for confounding factors. Results: Data were collected on 434 patients (mean ± SD age, 11.7 ± 3.0 years) of which 61.1% had private (commercial) insurance. Magnetic resonance imaging (MRI) was obtained at similar rates for children with public and private insurance (41.4% vs 41.9%, respectively; P ≥.999). However, multivariate analysis revealed that those with MRI performed ≥21 days after injury were 5.3 times more likely to have public insurance (95% CI, 1.3-21.7; P =.02). Of the 434 patients included, 365 required surgery. Similar to the overall cohort, those in the surgical subgroup with MRI ≥21 days from injury were 4.8 times more likely to have public insurance (95% CI, 1.2-19.6; P =.03). Children who underwent surgery ≥21 days after injury were 2.5 times more likely to have public insurance (95% CI, 1.1-6.1; P =.04). However, there were no differences in the nature of the surgery or findings at surgery. Those who were publicly insured were 4.1 times more likely to be immobilized in a cast rather than a brace postoperatively (95% CI, 2.3-7.4; P <.001). Conclusion: Children with public insurance and a TSF were more likely to experience delays with MRI and surgical treatment than those with private insurance. However, there were no differences in the nature of the surgery or findings at surgery. Additionally, patients with public insurance were more likely to undergo postoperative casting rather than bracing. [ABSTRACT FROM AUTHOR]

The high-frequency radio sky has historically remained largely unexplored due to the typical faintness of sources in this regime, and the modest survey speed compared to observations at lower frequencies. However, high-frequency radio surveys offer an invaluable tracer of high-redshift star formation, as they directly target the faint radio free–free emission. We present deep continuum observations at 34 GHz in the COSMOS and GOODS-North fields from the Karl G. Jansky Very Large Array (VLA), as part of the COLDz survey. The deep COSMOS mosaic spans down to σ = 1.3 μJy beam−1, while the wider GOODS-N observations cover to σ = 5.3 μJy beam−1. We detect a total of 18 galaxies at 34 GHz, of which nine show radio emission consistent with being powered by star formation; although for two sources, this is likely due to thermal emission from dust. Utilizing deep ancillary radio data at 1.4, 3, 5, and 10 GHz, we decompose the spectra of the remaining seven star-forming galaxies into their synchrotron and thermal free–free components, and find typical thermal fractions and synchrotron spectral indices comparable to those observed in local star-forming galaxies. We further determine free–free star formation rates (SFRs), and show that these are in agreement with SFRs from spectral energy distribution-fitting and the far-infrared/radio correlation. Our observations place strong constraints on the high-frequency radio emission in typical galaxies at high redshift, and provide some of the first insights into what is set to become a key area of study with future radio facilities, such as the Square Kilometer Array Phase 1 and next-generation VLA. [ABSTRACT FROM AUTHOR]

We present Herschel –PACS spectroscopy of four main-sequence star-forming galaxies at z ∼ 1.5. We detect [OI]63  μ m line emission in BzK-21000 at z  = 1.5213, and measure a line luminosity, |$L_{\rm [O\, {\small I}]63\, \mu m} = (3.9\pm 0.7)\times 10^9$|  L⊙. Our PDR modelling of the interstellar medium in BzK-21000 suggests a UV radiation field strength, G ∼ 320 G 0, and gas density, n ∼ 1800 cm−3, consistent with previous LVG modelling of the molecular CO line excitation. The other three targets in our sample are individually undetected in these data, and we perform a spectral stacking analysis which yields a detection of their average emission and an [O  i ]63  μ m line luminosity, |$L_{\rm [O\, {\small I}]63\, \mu m} = (1.1\pm 0.2)\times 10^9$|  L⊙. We find that the implied luminosity ratio, |$L_{\rm [O\, {\small I}]63\, \mu m}/L_{\rm IR}$|⁠ , of the undetected BzK-selected star-forming galaxies broadly agrees with that of low-redshift star-forming galaxies, while BzK-21000 has a similar ratio to that of a dusty star-forming galaxy at z ∼ 6. The high [O  i ]63  μ m line luminosities observed in BzK-21000 and the z ∼ 1−3 dusty and sub-mm luminous star-forming galaxies may be associated with extended reservoirs of low density, cool neutral gas. [ABSTRACT FROM AUTHOR]

We investigate the properties of a sample of 35 galaxies, detected with the Atacama Large Millimeter/Submillimeter Array (ALMA) at 1.1 mm in the GOODS-ALMA field (area of 69 arcmin2, resolution = 0.60″, rms ≃ 0.18 mJy beam−1). Using the ultraviolet-to-radio deep multiwavelength coverage of the GOODS–South field, we fit the spectral energy distributions of these galaxies to derive their key physical properties. The galaxies detected by ALMA are among the most massive at z = 2−4 (M⋆, med = 8.5 × 1010M⊙) and they are either starburst or located in the upper part of the galaxy star-forming main sequence. A significant portion of our galaxy population (∼40%), located at z ∼ 2.5 − 3, exhibits abnormally low gas fractions. The sizes of these galaxies, measured with ALMA, are compatible with the trend between the rest-frame 5000 Å size and stellar mass observed for z ∼ 2 elliptical galaxies, suggesting that they are building compact bulges. We show that there is a strong link between star formation surface density (at 1.1 mm) and gas depletion time: The more compact a galaxy's star-forming region is, the shorter its lifetime will be (without gas replenishment). The identified compact sources associated with relatively short depletion timescales (∼100 Myr) are the ideal candidates to be the progenitors of compact elliptical galaxies at z ∼ 2. [ABSTRACT FROM AUTHOR]

We present an analysis of the dust attenuation of star-forming galaxies at z  = 2.5–4.0 through the relationship between the UV spectral slope (β), stellar mass (M *), and the infrared excess (IRX = L IR/ L UV) based on far-infrared continuum observations from the Atacama Large Millimeter/sub-millimeter Array (ALMA). Our study exploits the full ALMA archive over the COSMOS field processed by the A3COSMOS team, which includes an unprecedented sample of ∼1500 galaxies at z ∼ 3 as primary or secondary targets in ALMA band 6 or 7 observations with a median continuum sensitivity of 126 |$\rm {\mu Jy\, beam}^{-1}$| (1σ). The detection rate is highly mass dependent, decreasing drastically below log (M */M⊙) = 10.5. The detected galaxies show that the IRX–β relationship of massive (log  M */M⊙ > 10) main-sequence galaxies at z  = 2.5–4.0 is consistent with that of local galaxies, while starbursts are generally offset by |$\sim 0.5\, {\rm dex}$| to larger IRX values. At the low-mass end, we derive upper limits on the infrared luminosities through stacking of the ALMA data. The combined IRX– M * relation at |$\rm {log\, ({\it M}_{\ast }/\mathrm{M}_{\odot })\gt 9}$| exhibits a significantly steeper slope than reported in previous studies at similar redshifts, implying little dust obscuration at log  M */M⊙ < 10. However, our results are consistent with earlier measurements at z ∼ 5.5, indicating a potential redshift evolution between z ∼ 2 and z ∼ 6. Deeper observations targeting low-mass galaxies will be required to confirm this finding. [ABSTRACT FROM AUTHOR]

We present Atacama Large Millimetre Array and Atacama Compact Array observations of the Sunyaev-Zel'dovich effect in the z = 2 galaxy cluster Cl J1449+0856, an X-ray-detected progenitor of typical massive clusters in the present day Universe. While in a cleaned but otherwise untouched 92 GHz map of this cluster little to no negative signal is visible, careful subtraction of known sub-millimetre emitters in the uv plane reveals a decrement at 5σ significance. The total signal is −190 ± 36 μJy, with a peak offset by 5″–9″ (∼50 kpc) from both the X-ray centroid and the still-forming brightest cluster galaxy. A comparison of the recovered uv-amplitude profile of the decrement with different pressure models allows us to derive total mass constraints consistent with the ∼6 × 1013M⊙ estimated from X-ray data. Moreover, we find no strong evidence for a deviation of the pressure profile with respect to local galaxy clusters, although a slight tension at small-to-intermediate spatial scales suggests a flattened central profile, opposite to that seen in a cool core and possibly an AGN-related effect. This analysis of the lowest mass single SZ detection so far illustrates the importance of interferometers when observing the SZ effect in high-redshift clusters, the cores of which cannot be considered quiescent, such that careful subtraction of galaxy emission is necessary. [ABSTRACT FROM AUTHOR]

Context. Given the unprecedented depth achieved in current large radio surveys, we are starting to probe populations of radio sources that have not been studied in the past. However, identifying and categorising these objects, differing in size, shape and physical properties, is becoming a more difficult task. Aims. In this data paper we present and characterise the multi-component radio sources identified in the VLA-COSMOS Large Project at 3 GHz (0.75 arcsec resolution, 2.3 μJy beam−1 rms), i.e. the radio sources which are composed of two or more radio blobs. Methods. The classification of objects into multi-components was done by visual inspection of 351 of the brightest and most extended blobs from a sample of 10,899 blobs identified by the automatic code BLOBCAT. For that purpose we used multi-wavelength information of the field, such as the 1.4 GHz VLA-COSMOS data and the Ultra Deep Survey with the VISTA telescope (UltraVISTA) stacked mosaic available for COSMOS. Results. We have identified 67 multi-component radio sources at 3 GHz: 58 sources with active galactic nucleus (AGN) powered radio emission and nine star-forming galaxies. We report eight new detections that were not observed by the VLA-COSMOS Large Project at 1.4 GHz, due to the slightly larger area coverage at 3 GHz. The increased spatial resolution of 0.75 arcsec has allowed us to resolve (and isolate) multiple emission peaks of 28 extended radio sources not identified in the 1.4 GHz VLA-COSMOS map. We report the multi-frequency flux densities (324 MHz, 325 MHz, 1.4 GHz & 3 GHz), star formation rates, and stellar masses of these objects. We find that multi-component objects at 3 GHz VLA-COSMOS inhabit mainly massive galaxies (> 1010.5 M⊙). The majority of the multi-component AGN lie below the main sequence of star-forming galaxies (SFGs), in the green valley and the quiescent region. Furthermore, we provide detailed descriptions of the objects and find that amongst the AGN there are two head-tail, ten core-lobe, nine wide-angle-tail (WAT), eight double-double or Z-/X-shaped, three bent-tail radio sources, and 26 symmetric sources, while amongst the SFGs we find the only star-forming ring seen in radio emission in COSMOS. Additionally, we report a large number (32 out of 58) of disturbed/bent multi-component AGN, 18 of which do not lie within X-ray groups in COSMOS (redshift range 0.08 ≤ z <  1.53). Conclusion. The high angular resolution and sensitivity of the 3 GHz VLA-COSMOS data set give us the opportunity to identify peculiar radio structures and sub-structures of multi-component objects, and relate them to physical phenomena such as AGN or star-forming galaxies. This study illustrates the complexity of the μJy radio-source population; at the sensitivity and resolution of 3 GHz VLA-COSMOS, the radio structures of AGN and SFG both emitting radio continuum emission, become comparable in the absence of clear, symmetrical jets. Thus, disentangling the AGN and SFG contributions using solely radio observations can be misleading in a number of cases. This has implications for future surveys, such as those done by square kilometre array (SKA) and precursors, which will identify hundreds of thousands of multi-component objects. [ABSTRACT FROM AUTHOR]

We investigate the fraction of close pairs and morphologically identified mergers on and above the star-forming main sequence (MS) at 0.2 ≤  z  ≤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 ≥70 per cent above the MS, implying that – already at z ≳ 1 – starburst (SB) events (ΔMS ≥ 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 ∼5–10 per cent at all masses ≳ 1010  M ⊙. The MS major merger fraction roughly doubles between z = 0.2 and 2, with morphological mergers driving the overall increase at z ≳ 1. The differential redshift evolution of interacting pairs and morphologically classified mergers on the MS can be reconciled by evolving observability time-scales for both pairs and morphological disturbances. The observed variation of the late-stage merger fraction with ΔMS follows the perturbative 2-Star Formation Mode model, where any MS galaxy can experience a continuum of different star formation rate enhancements. This points to an SB–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. [ABSTRACT FROM AUTHOR]

We present deep continuum observations at a wavelength of 2 mm centered on the COSMOS field using the Goddard IRAM Superconducting Millimeter Observer (GISMO) at the IRAM 30 m telescope. These data constitute the widest deep 2 mm survey to date, reaching a uniform σ ∼ 0.23 mJy beam−1 sensitivity over ∼250 arcmin2 at ∼24″ resolution. We detect four sources at high significance (S/N ≥ 4.4) with an expected number of false detections of 0.09 sources and five sources at 4.4 > S/N ≥ 3.7 with an expected number of false detections of 1.65 sources. Combined with deep GISMO observations in GOODS-N, we constrain the 2 mm number counts over one decade in flux density. These measurements agree with most galaxy evolution models tested here, except those with a large population of dusty star-forming galaxies at z > 7. Five GISMO sources have counterparts in (sub)millimeter catalogs available in COSMOS. Their redshifts suggest that all but one lie above z ∼ 3. These four high-redshift (z > 3) galaxies have = 3.9, SFRs ∼ 400–1200 M⊙ yr−1, and Mdust ∼ 109.5M⊙. They provide a relatively complete selection (∼66%) of the most luminous (LIR > 1012.6L⊙) and highest-redshift (z > 3) galaxies detected within our survey area by AzTEC at 1.1 mm. We thus conclude that 2 mm surveys favor the selection of massive, vigorously star-forming, high-redshift galaxies. This is corroborated by GISMO-C4, a source with a low false-detection probability (∼6.2%), for which the absence of a (sub)millimeter counterpart supports a high-redshift origin (z ≳ 3). [ABSTRACT FROM AUTHOR]

We study a population of significantly sub-solar enrichment galaxies at z  = 1.99, to investigate how molecular gas, dust, and star formation relate in low-metallicity galaxies at the peak epoch of star formation. We target our sample with several deep Atacama Large Millimeter/submillimeter Array and Very Large Array datasets, and find no individual detections of CO[4–3], CO[1–0], or dust, in stark contrast to the  >60 per cent detection rate expected for solar-enrichment galaxies with these MS H α star formation rates (SFRs). We find that both low- and high-density molecular gas (traced by CO[1–0] and CO[4–3], respectively) are affected by the low enrichment, showing sample average (stacked) luminosity deficits >0.5–0.7 dex below expectations. This is particularly pertinent for the use of high-J CO emission as a proxy of instantaneous SFR. Our individual galaxy data and stacked constraints point to a strong inverse dependence ∝  Z γ of gas-to-dust ratios (G/D) and CO-to-H2 conversion factors (αCO) on metallicity at z  ∼ 2, with γG/D <−2.2 and |$\gamma _{\alpha _{\rm CO}}\lt $| −0.8, respectively. We quantify the importance of comparing G/D and αCO versus metallicity trends from the literature on a common, suitably normalized metallicity scale. When accounting for systematic offsets between different metallicity scales, our z  ∼ 2 constraints on these scaling relations are consistent with the corresponding relations for local galaxies. However, among those local relations, we favour those with a steep/double power-law dependence of G/D on metallicity. Finally, we discuss the implications of these findings for (a) gas mass measurements for sub- M * galaxies, and (b) efforts to identify the characteristic galaxy mass scale contributing most to the comoving molecular gas density at z  = 2. [ABSTRACT FROM AUTHOR]

To better constrain the physical mechanisms driving star formation, we present the first systematic study of the radio continuum size evolution of star-forming galaxies (SFGs) over the redshift range 0.35 <  z <  2.25. We use the VLA COSMOS 3 GHz map (noise rms = 2.3 μJy beam−1, θbeam = 0.75 arcsec) to construct a mass-complete sample of 3184 radio-selected SFGs that reside on and above the main sequence (MS) of SFGs. We constrain the overall extent of star formation activity in galaxies by applying a 2D Gaussian model to their radio continuum emission. Extensive Monte Carlo simulations are used to validate the robustness of our measurements and characterize the selection function. We find no clear dependence between the radio size and stellar mass, M⋆, of SFGs with 10.5 ≲ log(M⋆/M⊙) ≲ 11.5. Our analysis suggests that MS galaxies are preferentially extended, while SFGs above the MS are always compact. The median effective radius of SFGs on (above) the MS of Reff = 1.5 ± 0.2 (1.0 ± 0.2) kpc remains nearly constant with cosmic time; a parametrization of the form Reff ∝ (1 + z)α yields a shallow slope of only α = −0.26 ± 0.08 (0.12 ± 0.14) for SFGs on (above) the MS. The size of the stellar component of galaxies is larger than the extent of the radio continuum emission by a factor ∼2 (1.3) at z = 0.5 (2), indicating star formation is enhanced at small radii. The galactic-averaged star formation rate surface density (ΣSFR) scales with the distance to the MS, except for a fraction of MS galaxies (≲10%) that harbor starburst-like ΣSFR. These "hidden" starbursts might have experienced a compaction phase due to disk instability and/or a merger-driven burst of star formation, which may or may not significantly offset a galaxy from the MS. We thus propose to use ΣSFR and distance to the MS in conjunction to better identify the galaxy population undergoing a starbursting phase. [ABSTRACT FROM AUTHOR]

Exploring how radio-emitting active galactic nuclei (AGNs) behave and evolve with time is critical for understanding how AGN feedback impacts galaxy evolution. In this work, we investigate the relationship between 1.4 GHz radio continuum AGN luminosity (⁠|$L^{\rm AGN}_{\rm 1.4}$|⁠), specific black hole accretion rate (s-BHAR, defined as the accretion luminosity relative to the galaxy stellar mass), and redshift, for a luminosity-complete sample of radio-selected AGNs in the VLA COSMOS 3 GHz Large Project. The sample was originally selected from radio-continuum observations at 3 GHz, and includes about 1800 radio AGNs identified via (>2 σ) radio-excess relative to the infrared-radio correlation of star-forming galaxies. We further select a subsample of over 1200 radio AGNs that is complete in |$L^{\rm AGN}_{\rm 1.4}$| over different redshift ranges, out to |$z$| ∼ 4, and use X-ray stacking to calculate the average s-BHAR in each |$L^{\rm AGN}_{\rm 1.4}$| – |$z$| bin. We find that the average s-BHAR is independent of |$L^{\rm AGN}_{\rm 1.4}$|⁠, at all redshifts. However, we see a strong increase of s-BHAR with redshift, at fixed |$L^{\rm AGN}_{\rm 1.4}$|⁠. This trend resembles the strong increase in the fraction of star-forming host galaxies [based on the (NUV − r)/(r − J) colours] with redshift, at fixed |$L^{\rm AGN}_{\rm 1.4}$|⁠. A possible explanation for this similarity might imply a link between average AGN radiative power and availability of cold gas supply within the host galaxy. This study corroborates the idea that radio-selected AGNs become more radiatively efficient towards earlier epochs, independently of their radio power. [ABSTRACT FROM AUTHOR]

We present ALMA Band 9 observations of the [C ii ]158 |$\mu$| m emission for a sample of 10 main-sequence galaxies at redshift |$z$| ∼ 2, with typical stellar masses (log M ⋆/M⊙∼ 10.0–10.9) and star formation rates (∼35–115 M⊙yr−1). Given the strong and well-understood evolution of the interstellar medium from the present to |$z$| = 2, we investigate the behaviour of the [C ii ] emission and empirically identify its primary driver. We detect [C ii ] from six galaxies (four secure and two tentative) and estimate ensemble averages including non-detections. The [C ii ]-to-infrared luminosity ratio (⁠|${\rm [C\, {\small II}]}$| / L IR) of our sample is similar to that of local main-sequence galaxies (∼2 × 10−3), and ∼10 times higher than that of starbursts. The [C ii ] emission has an average spatial extent of 4–7 kpc, consistent with the optical size. Complementing our sample with literature data, we find that the [C ii ] luminosity correlates with galaxies' molecular gas mass, with a mean absolute deviation of 0.2 dex and without evident systematics: the [C ii ]-to-H2conversion factor (⁠|$\alpha _{\rm [C\, {\small II}]} \sim 30$| M⊙/L⊙) is largely independent of galaxies' depletion time, metallicity, and redshift. [C ii ] seems therefore a convenient tracer to estimate galaxies' molecular gas content regardless of their starburst or main-sequence nature, and extending to metal-poor galaxies at low and high redshifts. The dearth of [C ii ] emission reported for |$z$| > 6–7 galaxies might suggest either a high star formation efficiency or a small fraction of ultraviolet light from star formation reprocessed by dust. [ABSTRACT FROM AUTHOR]

Disk galaxies at intermediate redshift (z ~ 0.7) have been found in previous work to display more optically thick behaviour than their local counterparts in the rest-frame B-band surface brightness, suggesting an evolution in dust properties over the past ~6 Gyr. We compare the measured luminosities of face-on and edge-on star-forming galaxies at different wavelengths (Ultraviolet (UV), mid-infrared (MIR), far-infrared (FIR), and radio) for two well-matched samples of disk-dominated galaxies: a local Sloan Digital Sky Survey (SDSS)-selected sample at z ~ 0.07 and a sample of disks at z ~ 0.7 drawn from Cosmic Evolution Survey (COSMOS). We have derived correction factors to account for the inclination dependence of the parameters used for sample selection. We find that typical galaxies are transparent at MIR wavelengths at both redshifts, and that the FIR and radio emission is also transparent as expected. However, reduced sensitivity at these wavelengths limits our analysis; we cannot rule out opacity in the FIR or radio. Ultra-violet attenuation has increased between z ~ 0 and z ~ 0.7, with the z ~ 0.7 sample being a factor of ~3.4 more attenuated. The larger UV attenuation at z ~ 0.7 can be explained by more clumpy dust around nascent star-forming regions. There is good agreement between the fitted evolution of the normalisation of the SFRUV versus 1 − cos(i) trend (interpreted as the clumpiness fraction) and the molecular gas fraction/dust fraction evolution of galaxies found out to z < 1. [ABSTRACT FROM AUTHOR]

We studied the molecular gas properties of AzTEC/C159, a star-forming disk galaxy at z = 4.567, in order to better constrain the nature of the high-redshift end of the submillimeter-selected galaxy (SMG) population. We secured 12CO molecular line detections for the J = 2 →1 and J = 5 →4 transitions using the Karl G. Jansky Very Large Array (VLA) and the NOrthern Extended Millimeter Array (NOEMA) interferometer. The broad (FWHM ~ 750 km s−1) and tentative double-peaked profiles of the two 12CO lines are consistent with an extended molecular gas reservoir, which is distributed in a rotating disk, as previously revealed from [CII] 158 μm line observations. Based on the 12CO(2 →1) emission line, we derived L′CO=(3.4±0.6)×1010 K km s−1 pc2, which yields a molecular gas mass of MH2(αCO/4.3)=(1.5±0.3)×1011 M⊙ and unveils a gas-rich system with μgas(αCO/4.3)≡MH2/M⋆=3.3±0.7. The extreme star formation efficiency of AzTEC/C159, parametrized by the ratio LIR/L′CO=(216±80) L⊙ (K km s−1 pc2)−1, is comparable to merger-driven starbursts such as local ultra-luminous infrared galaxies and SMGs. Likewise, the 12CO(5 →4)/CO(2 →1) line brightness temperature ratio of r52 = 0.55 ± 0.15 is consistent with high-excitation conditions as observed in SMGs. Based on mass budget considerations, we constrained the value for the L′CO – H2 mass conversion factor in AzTEC/C159, that is, αCO=3.9−1.3+2.7 M⊙ K−1 km−1 s pc−2, which is consistent with a self-gravitating molecular gas distribution as observed in local star-forming disk galaxies. Cold gas streams from cosmological filaments might be fueling a gravitationally unstable gas-rich disk in AzTEC/C159, which breaks into giant clumps and forms stars as efficiently as in merger-driven systems and generates high gas excitation. These results support the evolutionary connection between AzTEC/C159-like systems and massive quiescent disk galaxies at z ~ 2. [ABSTRACT FROM AUTHOR]

We present results on the dust attenuation of galaxies at redshift ∼3-6 by studying the relationship between the UV spectral slope (βUV) and the infrared excess (IRX; LIR/LUV) using Atacama Large Millimeter/submillimeter Array (ALMA) far-infrared continuum observations. Our study is based on a sample of 67 massive, star-forming galaxies with a median mass of M∼ ∼ 1010.7 M☉ spanning a redshift range z = 2.6-3.7 (median z = 3.2) that were observed with ALMA at λrest = 300 μm. Both the individual ALMA detections (41 sources) and stacks including all galaxies show the IRX-βUV relationship at z ∼ 3 is mostly consistent with that of local starburst galaxies on average. However, we find evidence for a large dispersion around the mean relationship by up to ±0.5 dex. Nevertheless, the locally calibrated dust correction factors based on the IRX-βUV relation are on average applicable to main-sequence z ∼ 3 galaxies. This does not appear to be the case at even higher redshifts, however. Using public ALMA observations of z ∼ 4-6 galaxies we find evidence for a significant evolution in the IRX-βUV and the IRX-M* relations beyond z ∼ 3 towards lower IRX values. We discuss several caveats that could affect these results, including the assumed dust temperature. ALMA observations of larger z > 3 galaxy sample spanning a wide range of physical parameters (e.g. lower stellar mass) will be important to investigate this intriguing redshift evolution further. [ABSTRACT FROM AUTHOR]

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 kiloparsec. We detect strong CO(5-4) emission from the nuclear region of the galaxy, consistent with the observed LIR-L'CO(5-4) correlation and indicating ongoing 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 per cent). Stellar feedback and disc 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. [ABSTRACT FROM AUTHOR]

Similarly to the cosmic star formation history, the black hole accretion rate density of the Universe peaked at 1CO ∼ 6.3-25.1 × 109 L⊚, which translates to a molecular hydrogen gas mass of 2.5–10 × 1010M⊚ assuming conventional conversion factor of αCO ∼ 3.6. Our results indicate a >99 per cent probability of lower depletion time-scales and lower molecular gas fractions in AGN hosts with respect to the non-AGN comparison sample. We discuss the implications of these observations on the impact that AGN feedback may have on star formation efficiency of z >1 galaxies. [ABSTRACT FROM AUTHOR]

We make use of the deep Karl G. Jansky Very Large Array (VLA) COSMOS radio observations at 3 GHz to infer radio luminosity functions of star-forming galaxies up to redshifts of z ~ 5 based on approximately 6000 detections with reliable optical counterparts. This is currently the largest radio-selected sample available out to z ~ 5 across an area of 2 square degrees with a sensitivity of rms ≈2:3 μJy beam-1. By fixing the faint and bright end shape of the radio luminosity function to the local values, we find a strong redshift trend that can be fitted with a pure luminosity evolution L1.4 GHz ∝ (1 + z)(3:16±0:2)-(0:32±0:07)z. We estimate star formation rates (SFRs) from our radio luminosities using an infrared (IR)-radio correlation that is redshift dependent. By integrating the parametric fits of the evolved luminosity function we calculate the cosmic SFR density (SFRD) history since z ~ 5. Our data suggest that the SFRD history peaks between 2 < z < 3 and that the ultraluminous infrared galaxies (100 M⊙ yr-1 < SFR < 1000 M⊙ yr-1) contribute up to ~25% to the total SFRD in the same redshift range. Hyperluminous infrared galaxies (SFR > 1000 M⊙ yr-1) contribute an additional ≲2% in the entire observed redshift range. We find evidence of a potential underestimation of SFRD based on ultraviolet (UV) rest-frame observations of Lyman break galaxies at high redshifts (z & 4) on the order of 15-20%, owing to appreciable star formation in highly dust-obscured galaxies, which might remain undetected in such UV observations. [ABSTRACT FROM AUTHOR]

We examine the behaviour of the infrared-radio correlation (IRRC) over the range 0 < z ≲ 6 using new, highly sensitive 3 GHz observations with the Karl G. Jansky Very Large Array (VLA) and infrared data from the Herschel Space Observatory in the 2 deg2 COSMOS field. We distinguish between objects where emission is believed to arise solely from star-formation, and those where an active galactic nucleus (AGN) is thought to be present. We account for non-detections in the radio or in the infrared using a doublycensored survival analysis. We find that the IRRC of star-forming galaxies, quantified by the infrared-to-1.4 GHz radio luminosity ratio (qTIR), decreases with increasing redshift: qTIR(z) = (2:88 ± 0:03)(1 + z)-0:19±0:01. This is consistent with several previous results from the literature. Moderate-to-high radiative luminosity AGN do not follow the same qTIR(z) trend as star-forming galaxies, having a lower normalisation and steeper decrease with redshift. We cannot rule out the possibility that unidentified AGN contributions only to the radio regime may be steepening the observed qTIR(z) trend of the star-forming galaxy population. We demonstrate that the choice of the average radio spectral index directly affects the normalisation, as well as the derived trend with redshift of the IRRC. An increasing fractional contribution to the observed 3 GHz flux by free-free emission of star-forming galaxies may also affect the derived evolution. However, we find that the standard (M82-based) assumption of the typical radio spectral energy distribution (SED) for star-forming galaxies is inconsistent with our results. This suggests a more complex shape of the typical radio SED for star-forming galaxies, and that imperfect K corrections in the radio may govern the derived trend of decreasing qTIR with increasing redshift. A more detailed understanding of the radio spectrum is therefore required for robust K corrections in the radio and to fully understand the cosmic evolution of the IRRC. Lastly, we present a redshift-dependent relation between rest-frame 1.4 GHz radio luminosity and star formation rate taking the derived redshift trend into account. [ABSTRACT FROM AUTHOR]

HE0450-2958, an interacting quasar-starburst galaxy pair at z = 0.285, is one of the best- known examples of strong star formation activity in the presence of a quasar-driven jet. We present new multiband Karl G. Jansky Very Large Array-imaging covering 1-6 GHz and reaching an angular resolution of up to 0.6 arcsec (a sixfold improvement over existing radio data). We confirm the previous detection of a spatially extended radio component around the quasar, indicating that there is ongoing star formation activity in the quasar host galaxy. For the first time, we directly detect a jet-like bipolar outflow from the quasar aligned with its companion star-forming galaxy (SFG) and several blobs of ionized gas in its vicinity identified in previous studies. Within the companion SFG, we find evidence for a flattening of the synchrotron spectral index towards the point of intersection with the jet axis, further suggesting that the outflow may actually be impacting its interstellar medium. We discuss two possible mechanisms that could have triggered the starburst in the companion SFG: a wet-dry merger with the quasar and jet-induced star formation. While triggering through interaction-driven gas dynamics cannot be excluded with current data, our new observations make HE0450-2958 a strong candidate for jet-induced star formation, and one of the rare links between local systems (like Minkowski's Object or Centaurus A) and the high-z regime where radio-optical alignments suggest that this phenomenon could be more common. [ABSTRACT FROM AUTHOR]

We investigate the evolution of the galaxy star formation rate function (SFRF) and cosmic star formation rate density (CSFRD) of z ~ 1-4 galaxies, using cosmological smoothed particle hydrodynamic (SPH) simulations and a compilation of ultraviolet (UV), infrared (IR) and Ha observations. These tracers represent different populations of galaxies with the IR light being a probe of objects with high star formation rates and dust contents, while UV and Ha observations provide a census of low star formation galaxies where mild obscuration occurs. We compare the above SFRFs with the results of SPH simulations run with the code P-GADGET3(XXL). We focus on the role of feedback from active galactic nuclei (AGN) and supernovae in form of galactic winds. The AGN feedback prescription that we use decreases the simulated CSFRD at z < 3 but is not sufficient to reproduce the observed evolution at higher redshifts. We explore different wind models and find that the key factor for reproducing the evolution of the observed SFRF and CSFRD at z ~ 1-4 is the presence of a feedback prescription that is prominent at high redshifts (z = 4) and becomes less efficient with time. We show that variable galactic winds which are efficient at decreasing the SFRs of low-mass objects are quite successful in reproducing the observables. [ABSTRACT FROM AUTHOR]

This work focuses on understanding the formation of the first massive, passive galaxies in clusters, as a first step to the development of environmental trends seen at low redshift. Cl J1449 + 0856 is an excellent case to study this - a galaxy cluster at redshift z = 1.99 that already shows evidence of a virialised atmosphere. Here we highlight two recent results: the discovery of merger-driven star formation and highly-excited molecular gas in galaxies at the core of Cl J1449, along with the lowest-mass Sunyaev-Zel'dovich detection to date. [ABSTRACT FROM AUTHOR]

Background: The uncommon nature of tibial spine fractures may result in delayed presentation, diagnosis, and treatment. Elucidation of the contributing factors to such delays may provide an opportunity to improve patient care. Additionally, the outcomes of delayed surgery are unknown. Hypothesis/Purpose: The purpose of this study is to evaluate risk factors for, and consequences of, delayed surgical treatment of pediatric tibial spine fractures. Methods: We performed a retrospective cohort study of tibial spine fractures treated surgically at 10 institutions between 2000 and 2019. Demographic and pre-operative data were collected, as was intra-operative information and post-operative complications. Attention was focused on delays in evaluation and treatment, which were treated as both continuous and categorical variables. Surgery ≥21 days after injury was considered "delayed". Univariate analysis was followed by purposeful entry multivariate regression to adjust for confounding factors. Results: A total of 368 subjects (mean age 11.7±2.9 years) were included, 21.2% of which underwent surgery ≥21 days after injury. Patients who experienced delayed surgery had 3.8 times higher odds of being diagnosed with a TSF 1 or more weeks after injury [95% confidence interval (CI) 1.1-14.3, p=0.04], 2.3 times higher odds of having seen multiple clinicians prior to the treating surgeon (95% CI 1.1-4.8, p=0.02), 5.8 times higher odds of having magnetic resonance imaging 1 or more weeks after injury (MRI; 95% CI 1.6-20.8, p<0.007), and were 2.4 times more likely to have public insurance (95% CI 1.3-4.2, p=0.003). Meniscal injuries were encountered intra-operatively in 42.3% of those that had delayed surgery compared to 16.6% of patients that did not (p<0.001), resulting in 2.8 times higher odds in multivariate analysis (95% CI 1.6-5.0, p<0.001). Delayed surgery was also a risk factor for procedure duration longer than 2.5 hours (odds ratio 3.3, 95% CI 1.4-7.9; p=0.006). Patients who experienced delayed surgical management and an operation longer than 2.5 hours had 3.7 times higher odds of developing arthrofibrosis (95% CI 1.1-12.5, p=0.03). Conclusion: When surgery for a TSF was performed ≥21 days after injury, patients were at increased risk for concomitant meniscal pathology, longer case duration, and possibly post-operative arthrofibrosis. Those who experienced delays in diagnosis or MRI, saw multiple clinicians, and had public insurance were more likely to have a delay to surgery. These results provide an opportunity to optimize care for children that are at highest risk for delayed treatment. [ABSTRACT FROM AUTHOR]

We have developed a new prior-based source extraction tool, XID+, to carry out photometry in the Herschel SPIRE (Spectral and Photometric Imaging Receiver) maps at the positions of known sources. XID+ is developed using a probabilistic Bayesian framework that provides a natural framework in which to include prior information, and uses the Bayesian inference tool Stan to obtain the full posterior probability distribution on flux estimates. In this paper, we discuss the details of XID+ and demonstrate the basic capabilities and performance by running it on simulated SPIRE maps resembling the COSMOS field, and comparing to the current prior-based source extraction tool DESPHOT. Not only we show that XID+ performs better on metrics such as flux accuracy and flux uncertainty accuracy, but we also illustrate how obtaining the posterior probability distribution can help overcome some of the issues inherent with maximum-likelihood-based source extraction routines. We run XID+ on the COSMOS SPIRE maps from Herschel Multi-Tiered Extragalactic Survey using a 24-µm catalogue as a positional prior, and a uniform flux prior ranging from 0.01 to 1000 mJy. We show the marginalized SPIRE colour--colour plot and marginalized contribution to the cosmic infrared background at the SPIRE wavelengths. XID+ is a core tool arising from the Herschel Extragalactic Legacy Project (HELP) and we discuss how additional work within HELP providing prior information on fluxes can and will be utilized. The software is available at https://github.com/H-E-L-P/XID_plus.We also provide the data product for COSMOS. We believe this is the first time that the full posterior probability of galaxy photometry has been provided as a data product. [ABSTRACT FROM AUTHOR]

The Herschel Extragalactic Legacy Project (HELP) brings together a vast range of data from many astronomical observatories. Its main focus is on the Herschel data, which maps dustobscured star formation over 1300 deg². With this unprecedented combination of data sets, it is possible to investigate how the star formation versus stellar mass relation (main sequence) of star-forming galaxies depends on environment. In this pilot study, we explore this question within 0.1 2. We also estimate the evolution of the star formation rate density in the COSMOS field, and our results are consistent with previous measurements at z < 1.5 and z > 2 but we find a 1.4+0.3-0.2 times higher peak value of the star formation rate density at z ~ 1.9. [ABSTRACT FROM AUTHOR]

Background Proton pump inhibitor ( PPI) use is associated with an increased risk of Clostridium difficile infection ( CDI), though the mechanism is unclear. PPI induced alterations to the gut microbiome may facilitate the emergence of CDI, though the effects of PPIs on gut microbiota are not well characterised. [Correction added on 10 March 2016, after first online publication: microflora has been changed to microbiota throughout the article.] Aim To compare the faecal microbiomes of long-term PPI users to those with no history of PPI use. Methods We used a population-based database to identify individuals with ≥5 years of continuous PPI use along with non- PPI using controls. Stool samples were subjected to microbiological analysis, with hierarchical clustering at genus level, along with alpha and beta diversity measures comparing the two groups. Metadata was accounted for using quantile regression to eliminate potential confounding variables in taxonomic abundance comparisons. Results Sixty-one subjects (32 PPI, 29 controls) were analysed. While no significant differences in alpha diversity were found between the PPI users and controls, a moderate shift of the PPI users away from the non- PPI user cluster in the beta diversity was observed. After controlling for pertinent confounders, we discovered a decrease in Bacteroidetes and an increase in Firmicutes at the phylum level. We also performed species classifications and found Holdemania filiformis and Pseudoflavonifractor capillosus to be increased and decreased in the PPI cohort, respectively. Conclusions Long-term PPIs use has an effect on the gut microbiome. The alteration in the ratio of Firmicutes to Bacteroidetes may pre-dispose to the development of CDI. [ABSTRACT FROM AUTHOR]

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 ~1011 M⊙. At z > 1.5, these galaxies typically trace halos of mass ≲1013 M⊙. We use optical-near-infrared photometry to estimate stellar masses and star formation rates (SFR) of centrals and satellites down to ~6 x 109 M⊙. 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 β-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 spectral energy distribution 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 <100 kpc. After considering different potential explanations, we conclude that this is likely an environmental signature of the hot inner halo. This effect can be explained in the first order by a simple free-fall scenario, suggesting that these low-mass environments can shut down star formation in satellites on relatively short timescales of ~0.3 Gyr. [ABSTRACT FROM AUTHOR]

Aims. Gas outflows are believed to play a pivotal role in shaping galaxies, as they regulate both star formation and black hole growth. Despite their ubiquitous presence, the origin and the acceleration mechanism of these powerful and extended winds is not yet understood. Direct observations of the cold gas component in objects with detected outflows at other wavelengths are needed to assess the impact of the outflow on the host galaxy interstellar medium (ISM). Methods. We observed with the Plateau de Bure Interferometer an obscured quasar at z ~ 1:5, XID2028, for which the presence of an ionized outflow has been unambiguously signalled by NIR spectroscopy. The detection of 12CO(3-2) emission in this source allows us to infer the molecular gas content and compare it to the ISM mass derived from the dust emission. We then analyzed the results in the context of recent insights on scaling relations, which describe the gas content of the overall population of star-forming galaxies at a similar redshifts. Results. The star formation effciency (~100) and gas mass (Mgas = 2:1-9:5 × 1010 MΘ) inferred from the CO(3-2) line depend on the underlying assumptions on the excitation of the transition and the CO-to-H2 conversion factor. However, the combination of this information and the ISM mass estimated from the dust mass suggests that the ISM/gas content of XID2028 is significantly lower than expected for its observed M*, sSFR and redshift, based on the most up-to-date calibrations (with gas fraction <20% and depletion timescale <340 Myr). Conclusions. Overall, the constraints we obtain from the far infrared and millimeter data suggest that we are observing QSO feedback able to remove the gas from the host. [ABSTRACT FROM AUTHOR]

We investigate the CO excitation of normal (near-IR selected BzK) star-forming (SF) disk galaxies at z = 1.5 using IRAM Plateau de Bure observations of the CO[2-1], CO[3-2], and CO[5-4] transitions for four galaxies, including VLA observations of CO[1-0] for three of them, with the aim of constraining the average state of H2 gas. By exploiting previous knowledge of the velocity range, spatial extent, and size of the CO emission, we measure reliable line fluxes with a signal-to-noise ratio >4-7 for individual transitions. While the average CO spectral line energy distribution (SLED) has a subthermal excitation similar to the Milky Way (MW) up to CO[3-2], we show that the average CO[5-4] emission is four times stronger than assuming MW excitation. This demonstrates that there is an additional component of more excited, denser, and possibly warmer molecular gas. The ratio of CO[5-4] to lower-J CO emission is lower than in local (ultra-)luminous infrared galaxies (ULIRGs) and high-redshift starbursting submillimeter galaxies, however, and appears to be closely correlated with the average intensity of the radiation field (U) and with the star formation surface density, but not with the star formation efficiency. The luminosity of the CO[5-4] transition is found to be linearly correlated with the bolometric infrared luminosity over four orders of magnitudes. For this transition, z = 1.5 BzK galaxies follow the same linear trend as local spirals and (U)LIRGs and high-redshift star-bursting submillimeter galaxies. The CO[5-4] luminosity is thus empirically related to the dense gas and might be a more convenient way to probe it than standard high-density tracers that are much fainter than CO. We see excitation variations among our sample galaxies that can be linked to their evolutionary state and clumpiness in optical rest-frame images. In one galaxy we see spatially resolved excitation variations, where the more highly excited part of the galaxy corresponds to the location of massive SF clumps. This provides support to models that suggest that giant clumps are the main source of the high-excitation CO emission in high-redshift disk-like galaxies. [ABSTRACT FROM AUTHOR]

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 star formation picture provided by a total of 10 497 individual far-infrared detections is supplemented by the stacking analysis of a mass complete sample of 62 361 star-forming galaxies from the Hubble Space Telescope (HST) H band-selected catalogs of the CANDELS survey and from two deep ground-based Ks band-selected catalogs in the GOODS-North and the COSMOS-wide field 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", which may be easily generalized to other experiments. The combination of direct UV and far-infrared UV-reprocessed light provides a complete census on the star formation rates (SFRs), allowing us to demonstrate that galaxies at z = 4 to 0 of all stellar masses (M∗) follow a universal scaling law, the so-called main sequence of star-forming galaxies. We find a universal close-to-linear slope of the log?10(SFR)-log?10(M∗) relation, with evidence for a flattening of the main sequence at high masses (log?10(M∗/M⊙) > 10.5) that becomesless 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, which mostly happens over the same redshift range. Within the main sequence, we measure a nonvarying SFR dispersion of 0.3 dex: at a fixed redshift and stellar mass, about 68% of star-forming galaxies form stars at a universal rate within a factor 2. 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 on the origin of present-day stars: more than two-thirds 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 billion years. [ABSTRACT FROM AUTHOR]

The objectives of the study were (1) to determine the interobserver variation in interpretation of abdominal radiographs in children with clinically suspected intussusception, and (2) to determine the diagnostic value of abdominal radiographs in these patients. One hundred and eighty-two plain abdominal radiographic examinations (AXR) performed in children with clinically suspected intussusception were reviewed blind to the clinical history and findings of air enema. The presence or absence of nine AXR signs relevant to intussusception was documented. Each AXR was categorized as equivocal, positive or negative for intussusception, with the aim of achieving no false negatives. Interobserver variation in the identification of AXR signs and radiologic diagnoses was calculated using the kappa statistic for 60 cases assessed independently by three observers. Using the findings of air enema as gold standard, the prevalence of AXR signs in all patients with (60) and without (122) intussusception was determined and their diagnostic values calculated. The best observer agreement was for the presence of sparse small bowel gas (supine, k = 0.68) and the worst for the presence of cecal gas (erect, k = 0.18). All three observers agreed intussusception to be present or absent in only 7 of 60 cases and the majority agreement was equivocal in more than half. Overall agreement between observers for the diagnosis of intussusception was k = 0.30. The best positive predictors of intussusception were the soft tissue mass and sparse large bowel gas, with likelihood ratios of 3.9 and 2.5. Cecal feces predicted against intussusception, likelihood ratio 0.11. AXR was equivocal in 53%, positive in 21% and negative in 26%. Where a firm radiographic diagnosis was made, the diagnostic accuracy of AXR was 84%.(ABSTRACT TRUNCATED AT 250 WORDS) [ABSTRACT FROM AUTHOR]

The hydrostatic pressures and flow rates of barium sulphate and water soluble contrast in concentrations representative of those used for intussusception reduction were measured. The change of height with discharge of fluid from the filled kit was also assessed. A group of experienced paediatric radiologists and radiographers significantly underestimated the height to which contrast should be placed for intussusception reduction. The results indicate that baseline hydrostatic reduction pressures tend to be less and maximum pressures significantly less than those presently advocated for pneumatic reduction. This disparity may account for the apparent improvement in intussusception reduction rates reported for air enema when compared with barium enema. Intraluminal pressure monitoring during contrast enema would aid control of intussusception reduction but hydrostatic reduction would still be at a disadvantage because of lower flow rates. Where hydrostatic reduction is performed, the contrast density and height used should be set to give known pressure, according to local guidelines. [ABSTRACT FROM AUTHOR]

We measure the dust and gas content of the three submillimeter 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-H2 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' CO/Mdust and Mdust/M* ratios than z = 0 MS galaxies, but by z ∼ 2 the difference appears to be blurred, probably due to differential metallicity evolution. SB galaxies appear to slowly evolve in their L' CO/Mdust and Mdust/M* ratios all the way to z > 6 (consistent with rapid enrichment of SB events), while MS galaxies rapidly increase in Mdust/M* 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 Mdust/M*, consistent with recent PdBI and ALMA upper limits.We conclude that the Mdust/M* ratio could be a powerful tool for distinguishing starbursts from normal galaxies at z > 4. [ABSTRACT FROM AUTHOR]

The mitochondrial phosphate carrier (PiC) is critical for ATP synthesis by serving as the primary means for mitochondrial phosphate import across the inner membrane. In addition to its role in energy production, PiC is hypothesized to have a role in cell death as either a component or a regulator of the mitochondrial permeability transition pore (MPTP) complex. Here, we have generated a mouse model with inducible and cardiac-specific deletion of the Slc25a3 gene (PiC protein). Loss of PiC protein did not prevent MPTP opening, suggesting it is not a direct pore-forming component of this complex. However, Slc25a3 deletion in the heart blunted MPTP opening in response to Ca2+ challenge and led to a greater Ca2+ uptake capacity. This desensitization of MPTP opening due to loss or reduction in PiC protein attenuated cardiac ischemic-reperfusion injury, as well as partially protected cells in culture from Ca2+ overload induced death. Intriguingly, deletion of the Slc25a3 gene from the heart long-term resulted in profound hypertrophy with ventricular dilation and depressed cardiac function, all features that reflect the cardiomyopathy observed in humans with mutations in SLC25A3. Together, these results demonstrate that although the PiC is not a direct component of the MPTP, it can regulate its activity, suggesting a novel therapeutic target for reducing necrotic cell death. In addition, mice lacking Slc25a3 in the heart serve as a novel model of metabolic, mitochondrial-driven cardiomyopathy. [ABSTRACT FROM AUTHOR]

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, 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 modelled 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 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 LUV > 109.5 L⊙. 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-millimetre surveys of the next decade. [ABSTRACT FROM AUTHOR]

We present detections of the CO(J = 1–0) emission line in a sample of four massive star-forming galaxies at z ∼ 1.5–2.2 obtained with the Karl G. Jansky Very Large Array. Combining these observations with previous CO(2–1) and CO(3–2) detections of these galaxies, we study the excitation properties of the molecular gas in our sample sources. We find an average line brightness temperature ratios of R21 = 0.70 ± 0.16 and R31 = 0.50 ± 0.29, based on measurements for three and two galaxies, respectively. These results provide additional support to previous indications of sub-thermal gas excitation for the CO(3–2) line with a typically assumed line ratio R31 ∼ 0.5. For one of our targets, BzK-21000, we present spatially resolved CO line maps. At the resolution of 0.18 arcsec (1.5 kpc), most of the emission is resolved out except for some clumpy structure. From this, we attempt to identify molecular gas clumps in the data cube, finding four possible candidates. We estimate that <40 per cent of the molecular gas is confined to giant clumps (∼1.5 kpc in size), and thus most of the gas could be distributed in small fainter clouds or in fairly diffuse extended regions of lower brightness temperatures than our sensitivity limit. [ABSTRACT FROM AUTHOR]

Context. Understanding the relationship between the formation and evolution of galaxies and their central super-massive black holes (SMBH) is one of the main topics in extragalactic astrophysics. Links and feedback may reciprocally affect both black hole and galaxy growth. Aims. Observations of the CO line at the main epoch of galaxy and SMBH assembly (z = 2−4) are crucial to investigating the gas mass, star formation, and accretion onto SMBHs, and the effect of AGN feedback. Potential correlations between AGN and host galaxy properties can be highlighted by observing extreme objects. Methods. We targeted CO(3–2) in ULAS J1539+0557, a hyper-luminous quasar (Lbol > 1048 erg/s) at z = 2.658, selected through its unusual red colour in the UKIDSS Large Area Survey (ULAS). Results. We find a molecular gas mass of 4.1 ± 0.8 × 1010 M, by adopting a conversion factor α = 0.8 M K−1 km s−1 pc2, and a gas fraction of ∼0.4−0.1, depending mostly on the assumed source inclination. We also find a robust lower limit to the star-formation rate (SFR = 250−1600 M/yr) and star-formation efficiency (SFE = 25−350 L/(K kms−1 pc2) by comparing the observed opticalnear- infrared spectral energy distribution with AGN and galaxy templates. The black hole gas consumption timescale, M(H2)/ ˙Macc, is ∼160 Myr, similar to or higher than the gas consumption timescale. Conclusions. The gas content and the star formation efficiency are similar to those of other high-luminosity, highly obscured quasars, and at the lower end of the star-formation efficiency of unobscured quasars, in line with predictions from AGN-galaxy co-evolutionary scenarios. Further measurements of the (sub)mm continuum in this and similar sources are mandatory to obtain a robust observational picture of the AGN evolutionary sequence. [ABSTRACT FROM AUTHOR]