Search

High-redshift protoclusters consisting of dusty starbursts are thought to play an important role in galaxy evolution. Their dusty nature makes them bright in the far-infrared (FIR)/submm but difficult to find in optical/near-infrared (NIR) surveys. Radio observations are an excellent way to study these dusty starbursts, as dust is transparent in the radio and there is a tight correlation between the FIR and radio emission of a galaxy. Here, we present MeerKAT 1.28 GHz radio imaging of three Herschel candidate protoclusters, with a synthesized beam size of |$\sim 7.5\, \mathrm{ arcsec}\times 6.6$|  arcsec and a central thermal noise down to |$4.35~\mu$| Jy beam−1. Our source counts are consistent with other radio counts with no evidence of overdensities. Around 95 per cent of the Herschel sources have 1.28 GHz IDs. Using the Herschel |$250~\mu$| m primary beam size as the searching radius, we find 54.2 per cent Herschel sources have multiple 1.28 GHz IDs. Our average FIR-radio correlation coefficient |$q_{250\mu \text{m}}$| is |$2.33\pm 0.26$|⁠. Adding |$q_{250\mu \text{m}}$| as a new constraint, the probability of finding chance-aligned sources is reduced by a factor of |$\sim 6$|⁠ , but with the risk of discarding true identifications of radio-loud/quiet sources. With accurate MeerKAT positions, we cross-match our Herschel sources to optical/NIR data followed by photometric redshift estimations. By removing |$z< 1$| sources, the density contrasts of two of the candidate protoclusters increase, suggestive of them being real protoclusters at |$z> 1$|⁠. There is also potentially a |$0.9< z< 1.2$| overdensity associated with one candidate protocluster. In summary, photometric redshifts from radio-optical cross-identifications have provided some tentative evidence of overdensities aligning with two of the candidate protoclusters. [ABSTRACT FROM AUTHOR]

Herschel surveys have found large numbers of sources with red far-IR colours, and spectral energy distributions (SEDs) rising from 250 to 500 µm: 500 risers. The nature and role of these sources is not fully understood. We here present Submillimeter Array (SMA) interferometric imaging at 200 GHz of a complete sample of five 500 risers with F500 >44 mJy selected within a 4.5 deg2 region of the XMMLSS field. These observations can resolve the separate components of multiple sources and allow cross identification at other wavelengths using the extensive optical-to-IR data in this field. Of our five targets, we find that two are likely gravitationally lensed, two are multiple sources, and one an isolated single source. Photometric redshifts, using optical-to-IR data and far-IR/submm data, suggest they lie at redshifts |$z \sim 2.5\!-\!3.5$|⁠. Star formation rates and stellar masses estimated from the SEDs show that the majority of our sources lie on the star-formation rate-stellar mass 'main sequence', though with outliers both above and below this relation. Of particular interest is our most multiple source, which consists of three submm emitters and one submm-undetected optical companion within a 7 arcsec region, all with photometric redshifts ∼3. One of the submm emitters in this group lies above the 'main sequence', while the optical companion lies well below the relation, and has an estimated stellar mass of |$3.3 \pm 1.3 \times 10^{11}$|  M |$_{\odot }$|⁠. We suggest this object is a forming brightest cluster galaxy (BCG) in the process of accreting actively star forming companions. [ABSTRACT FROM AUTHOR]

We have carried out Hubble Space Telescope (HST) snapshot observations at 1.1 μm of 281 candidate strongly lensed galaxies identified in the wide-area extragalactic surveys conducted with the Herschel Space Observatory. Our candidates comprise systems with flux densities at |$500\, \mu$| m, S 500 ≥ 80 mJy. We model and subtract the surface brightness distribution for 130 systems, where we identify a candidate for the foreground lens candidate. After combining visual inspection, archival high-resolution observations, and lens subtraction, we divide the systems into different classes according to their lensing likelihood. We confirm 65 systems to be lensed. Of these, 30 are new discoveries. We successfully perform lens modelling and source reconstruction on 23 systems, where the foreground lenses are isolated galaxies and the background sources are detected in the HST images. All the systems are successfully modelled as a singular isothermal ellipsoid. The Einstein radii of the lenses and the magnifications of the background sources are consistent with previous studies. However, the background source circularized radii (between 0.34 and 1.30 kpc) are ∼3 times smaller than the ones measured in the sub-millimetre/millimetre for a similarly selected and partially overlapping sample. We compare our lenses with those in the Sloan Lens Advanced Camera for Surveys (ACS) Survey confirming that our lens-independent selection is more effective at picking up fainter and diffuse galaxies and group lenses. This sample represents the first step towards characterizing the near-infrared properties and stellar masses of the gravitationally lensed dusty star-forming galaxies. [ABSTRACT FROM AUTHOR]

Objective: The purpose of this study was to evaluate a sit to stand test with the walk test for the identification of unilateral cranial cruciate ligament rupture in dogs. Materials and Methods: Peak vertical force and vertical impulse were measured on a pressure‐sensitive walkway, during a sit to stand test and walk test, and in 10 dogs with unilateral cranial cruciate ligament rupture and 18 non‐lame dogs. Data collected were used to calculate symmetry indices (SI) of ipsilateral and contralateral hindlimbs (HL), diagonal limb pairs (DLP) and ipsilateral limb pairs (ILP). Results: The symmetry indices of peak vertical force of HL during the walk test and sit to stand test were 100% and 90% sensitive for discriminating lame and non‐lame dogs respectively. The symmetry indices of vertical impulse of HLs during the walk test and sit to stand test were 100% and 50% sensitive for discriminating lame and non‐lame dogs respectively. Analysis of ipsilateral and diagonal limb pairs did not improve the discrimination in either test. The time taken to collect data from the sit to stand test data was shorter than for the walk test. Clinical Significance: Whilst the sit to stand test required a shorter time for collection of data than the walk test, it did not accurately identify all dogs with lameness associated with CCLR, and thus has relatively limited clinical utility in its tested form. [ABSTRACT FROM AUTHOR]

We present |$850\, \mu {\rm m}$| imaging of the XMM -LSS field observed for 170 h as part of the James Clerk Maxwell Telescope SCUBA-2 Large eXtragalactic Survey (S2LXS). S2LXS XMM -LSS maps an area of |$9\, {\rm deg}^2$|⁠ , reaching a moderate depth of |$1\sigma \simeq 4\, {\rm mJy\, beam^{-1}}$|⁠. This is the largest contiguous area of extragalactic sky mapped by James Clerk Maxwell Telescope (JCMT) at |$850\, \mu {\rm m}$| to date. The wide area of the S2LXS XMM -LSS survey allows us to probe the ultra-bright (⁠|$S_{\rm 850\mu m}\gtrsim 15\, {\rm mJy}$|⁠), yet rare submillimetre population. We present the S2LXS XMM -LSS catalogue, which comprises 40 sources detected at >5σ significance, with deboosted flux densities in the range of |$7$| – |$48\, {\rm mJy}$|⁠. We robustly measure the bright-end of the |$850\, \mu {\rm m}$| number counts at flux densities |${\gt }7\, {\rm mJy}$|⁠ , reducing the Poisson errors compared to existing measurements. The S2LXS XMM -LSS observed number counts show the characteristic upturn at bright fluxes, expected to be motivated by local sources of submillimetre emission and high-redshift strongly lensed galaxies. We find that the observed |$850\, \mu {\rm m}$| number counts are best reproduced by model predictions that include either strong lensing or source blending from a 15-arcsec beam, indicating that both may make an important contribution to the observed overabundance of bright single dish |$850\, \mu {\rm m}$| selected sources. We make the S2LXS XMM -LSS |$850\, \mu {\rm m}$| map and >5σ catalogue presented here publicly available. [ABSTRACT FROM AUTHOR]

Export of sinking particles from the surface ocean is critical for carbon sequestration and to provide energy to the deep biosphere. The magnitude and spatial patterns of this export have been estimated in the past by in situ particle flux observations, satellite‐based algorithms, and ocean biogeochemical models; however, these estimates remain uncertain. Here, we use a recent machine learning reconstruction of global ocean particle size distributions (PSDs) from Underwater Vision Profiler 5 measurements to estimate carbon fluxes by sinking particles (35 μm–5 mm equivalent spherical diameter) from the surface ocean. We combine global maps of PSD properties with empirical relationships constrained against in situ flux observations to calculate particulate carbon export from the euphotic zone (5.8 ± 0.1 Pg C y−1) and annual maximum mixed layer depths (6.1 ± 0.1 Pg C y−1). The new flux reconstructions suggest a less variable seasonal cycle in the tropical ocean and a more persistent export in the Southern Ocean than previously recognized. Smaller particles (less than 418 μm) contribute most of the flux globally, while larger particles become more important at high latitudes and in tropical upwelling regions. Export from the annual maximum mixed layer exceeds that from the euphotic zone over most of the low‐latitude ocean, suggesting shallow particle recycling and net heterotrophy in the deep euphotic zone. These estimates open the way to fully three‐dimensional global reconstructions of particle fluxes in the ocean, supported by the growing database of in situ optical observations. Key Points: A new estimate of sinking particulate carbon fluxes from the surface ocean is developed from reconstructions of particle size distributionSmaller particles contribute more to the total sinking carbon flux than large particlesCarbon flux estimates from two depth horizons suggest net heterotrophy in the deeper euphotic zone, rather than autotrophy [ABSTRACT FROM AUTHOR]

We present Submillimeter Common User Bolometer Array 2 (SCUBA-2) and Submillimeter Array (SMA) follow-up observations of four candidate high-redshift dusty star-forming galaxies, selected as sources with rising spectral energy distributions in the 250, 350, and 500  μ m Herschel SPIRE bands. Previous SMA observations showed no counterparts to these sources, but in our deeper sub-mm observations we detect counterparts to all four 500  μ m risers, with three resolving into multiple systems. For these three multiple systems, the SMA 345 GHz (≈870  μ m) observations recover |$123 \pm 73{{\ \rm per\ cent}}$|⁠ , |$60 \pm 15{{\ \rm per\ cent}}$|⁠ , and |$19 \pm 4{{\ \rm per\ cent}}$| of the integrated 850  μ m flux density from SCUBA-2, indicating that there may be additional sources below our SMA detection limit making up a dense, protocluster core. The fourth 500  μ m riser was observed at a lower frequency and so we cannot make a similar comparison. We estimate photometric redshifts based on FIR/sub-mm colours, finding that three fourths likely lie at z ≥ 2. This fits with the interpretation that the 500  μ m riser selection criterion selects both intrinsically red, individual galaxies at z > 4, and multiple systems at more moderate redshifts, artificially reddened by the effects of blending. We use the SCUBA-2 850  μ m maps to investigate the environments of these 500  μ m risers. By constructing cumulative number counts and estimating photometric redshifts for surrounding SCUBA-2 detections, we find that one of our 500  μ m risers could plausibly reside in a z ≥ 2 protocluster. We infer that bright 500  μ m risers with faint 850  μ m flux densities are typically multiple systems at z ≥ 2 that may reside in overdensities of bright sub-mm galaxies. [ABSTRACT FROM AUTHOR]

We examine the far-infrared (FIR) properties of a sample of 5391 optically selected QSOs in the 0.5 < z < 2.65 redshift range down to log [ν L ν, 2500(erg s−1)] > 44.7, using SPIRE data from Herschel -ATLAS. We split the sample in a grid of 74 luminosity–redshift bins and compute the average optical–IR spectral energy distribution (SED) in each bin. By normalizing an intrinsic active galactic nucleus (AGN) template to the AGN optical power (at 5100 Å), we decompose the total IR emission (L IR; 8–1000 µm) into an AGN (L IR, AGN) and star-forming component (L IR, SF). We find that the AGN contribution to L IR increases as a function of AGN power, manifesting as a reduction of the 'FIR bump' in the average QSO SEDs. We note that L IR, SF does not correlate with AGN power; the mean star formation rates (SFRs) of AGN host galaxies are a function of redshift only and they range from ∼6 M⊙ yr−1 at z ∼ 0 to a plateau of ≲ 200 M⊙ yr−1 at z ∼ 2.6. Our results indicate that the accuracy of FIR emission as a proxy for SFR decreases with increasing AGN luminosity. We show that, at any given redshift, observed trends between IR luminosity (whether monochromatic or total) and AGN power (in the optical or X-rays) can be explained by a simple model which is the sum of two components: (i) the IR emission from star formation, uncorrelated with AGN power and (ii) the IR emission from AGN, directly proportional to AGN power in the optical or X-rays. [ABSTRACT FROM AUTHOR]

We present the ultraviolet to submillimetre spectral energy distributions (SEDs) of the HERschel Ultra Luminous Infrared Galaxy Survey (HERUS) sample of 42 local ultraluminous infrared galaxies (ULIRGs) and fit them with a Markov chain Monte Carlo code using the CYprus models for Galaxies and their NUclear Spectra (CYGNUS) radiative transfer models for starbursts, active galactic nucleus (AGN) tori, and host galaxy. The Spitzer IRS spectroscopy data are included in the fitting. Our Bayesian SED fitting method takes comparable time to popular energy balance methods but it is more physically motivated and versatile. All HERUS galaxies harbour high rates of star formation but we also find bolometrically significant AGN in all of the galaxies of the sample. We estimate the correction of the luminosities of the AGN in the ULIRGs due to the anisotropic emission of the torus and find that it could be up to a factor of ∼10 for nearly edge-on tori. We present a comparison of our results with the smooth torus model of Fritz et al. and the two-phase models of Siebenmorgen et al. and SKIRTOR. We find that the CYGNUS AGN torus models fit significantly better the SEDs of our sample compared to all other models. We find no evidence that strong AGN appear either at the beginning or end of a starburst episode or that starbursts and AGN affect each other. IRAS 01003−2238 and Mrk 1014 show evidence of dual AGNs in their SED fits, suggesting a minimum dual AGN fraction in the sample of 5 per cent. [ABSTRACT FROM AUTHOR]

The abundance and size distribution of marine particles control a range of biogeochemical and ecological processes in the ocean, including carbon sequestration. These quantities are the result of complex physical‐biological interactions that are difficult to observe, and their spatial and temporal patterns remain uncertain. Here, we present a novel analysis of particle size distributions (PSDs) from a global compilation of in situ Underwater Vision Profiler 5 (UVP5) optical measurements. Using a machine learning algorithm, we extrapolate sparse UVP5 observations to the global ocean from well‐sampled oceanographic variables. We reconstruct global maps of PSD parameters (biovolume [BV] and slope) for particles at the base of the euphotic zone. These reconstructions reveal consistent global patterns, with high chlorophyll regions generally characterized by high particle BV and flatter PSD slope, that is, a high relative abundance of large versus small particles. The resulting negative correlations between particle BV and slope further suggests synergistic effects on size‐dependent processes such as sinking particle fluxes. Our approach and estimates provide a baseline for an improved understanding of particle cycles in the ocean, and pave the way to global, three‐dimensional reconstructions of PSD and sinking particle fluxes from the growing body of UVP5 observations. Key Points: We use optical observations of marine particle size distribution to reconstruct global climatological particle biovolume (BV) and spectral slopeWe describe the importance of different biogeochemical variables on particle BV and spectral slopeSpatial and seasonal variations of BV and slope are likely to have synergistic effects on carbon export [ABSTRACT FROM AUTHOR]

Four male neutered continental giant rabbits aged between 10 and 30 months were presented with femoral condylar fractures, which developed without an observed traumatic injury. Stabilisation of the condylar fracture was achieved with screw fixation in all cases, which was supplemented with additional fixation in three cases. Complications consequent to the surgical intervention occurred in two cases: a femoral fracture and loss of fixation. Three rabbits were reported to have recovered normal limb function, and the rabbit that developed a femoral fracture as a consequence of its surgical intervention was treated with amputation. [ABSTRACT FROM AUTHOR]

The luminosity function of active galactic nuclei (AGN) probes the history of supermassive black hole assembly and growth across cosmic time. To mitigate selection biases, we present a consistent analysis of the AGN luminosity functions (LFs) derived for both X-ray and mid-infrared (MIR) selected AGN in the XMM-Large Scale Structure field. There are 4268 AGN used to construct the MIR luminosity function (IRLF) and 3427 AGN used to construct the X-ray luminosity function (XLF), providing the largest census of the AGN population out to z = 4 in both bands with significant reduction in uncertainties. We are able for the first time to see the knee of the IRLF at z > 2 and observe a flattening of the faint-end slope as redshift increases. The bolometric luminosity density, a proxy for the cosmic black hole accretion history, computed from our LFs, shows a peak at z ≈ 2.25, consistent with recent estimates of the peak in the star formation rate density (SFRD). However, at earlier epochs, the AGN luminosity density is flatter than the SFRD. If confirmed, this result suggests that the build up of black hole mass outpaces the growth of stellar mass in high-mass systems at z ≳ 2.5. This is consistent with observations of redshift z ∼ 6 quasars that lie above the local M − σ relationship. The luminosity density derived from the IRLF is higher than that from the XLF at all redshifts. This is consistent with the dominant role of obscured AGN activity in the cosmic growth of supermassive black holes. [ABSTRACT FROM AUTHOR]

The Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST) will observe several Deep Drilling Fields (DDFs) to a greater depth and with a more rapid cadence than the main survey. In this paper, we describe the 'DeepDrill' survey, which used the Spitzer Space Telescope Infrared Array Camera (IRAC) to observe three of the four currently defined DDFs in two bands, centred on 3.6 and 4.5 μ m. These observations expand the area that was covered by an earlier set of observations in these three fields by the Spitzer Extragalactic Representative Volume Survey (SERVS). The combined DeepDrill and SERVS data cover the footprints of the LSST DDFs in the Extended Chandra Deep Field–South (ECDFS) field, the ELAIS-S1 field (ES1), and the XMM -Large-Scale Structure Survey field (XMM -LSS). The observations reach an approximate 5σ point-source depth of 2  μ Jy (corresponding to an AB magnitude of 23.1; sufficient to detect a 10 |$^{11} \, \mathrm{M}_{\odot}$| galaxy out to z ≈ 5) in each of the two bands over a total area of |$\approx 29\,$| deg2. The dual-band catalogues contain a total of 2.35 million sources. In this paper, we describe the observations and data products from the survey, and an overview of the properties of galaxies in the survey. We compare the source counts to predictions from the Shark semi-analytic model of galaxy formation. We also identify a population of sources with extremely red ([3.6]−[4.5] >1.2) colours which we show mostly consists of highly obscured active galactic nuclei. [ABSTRACT FROM AUTHOR]

We analyse the physical properties of 121 SNR ≥ 5 sub-millimetre galaxies (SMGs) from the STUDIES 450  μ m survey. We model their UV-to-radio spectral energy distributions using magphys +photo- z and compare the results to similar modelling of 850  μ m-selected SMG sample from AS2UDS, to understand the fundamental physical differences between the two populations at the observed depths. The redshift distribution of the 450- μ m sample has a median of z  = 1.85 ± 0.12 and can be described by strong evolution of the far-infrared luminosity function. The fainter 450- μ m sample has ∼14 times higher space density than the brighter 850- μ m sample at z  ≲ 2, and a comparable space density at z  = 2–3, before rapidly declining, suggesting LIRGs are the main obscured population at z ∼ 1–2, while ULIRGs dominate at higher redshifts. We construct rest-frame ∼180- μ m-selected and dust-mass-matched samples at z  = 1–2 and z  = 3–4 from the 450 and 850- μ m samples, respectively, to probe the evolution of a uniform sample of galaxies spanning the cosmic noon era. Using far-infrared luminosity, dust masses, and an optically thick dust model, we suggest that higher redshift sources have higher dust densities due to inferred dust continuum sizes which are roughly half of those for the lower redshift population at a given dust mass, leading to higher dust attenuation. We track the evolution in the cosmic dust mass density and suggest that the dust content of galaxies is governed by a combination of both the variation of gas content and dust destruction time-scale. [ABSTRACT FROM AUTHOR]

Scaling laws of dust, H  i gas, and metal mass with stellar mass, specific star formation rate, and metallicity are crucial to our understanding of the build-up of galaxies through their enrichment with metals and dust. In this work, we analyse how the dust and metal content varies with specific gas mass (M H  i / M ⋆) across a diverse sample of 423 nearby galaxies. The observed trends are interpreted with a set of Dust and Element evolUtion modelS (DEUS) – including stellar dust production, grain growth, and dust destruction – within a Bayesian framework to enable a rigorous search of the multidimensional parameter space. We find that these scaling laws for galaxies with −1.0 ≲ log  M H  i / M ⋆ ≲ 0 can be reproduced using closed-box models with high fractions (37–89  |${{\ \rm per\ cent}}$|⁠) of supernova dust surviving a reverse shock, relatively low grain growth efficiencies (ϵ = 30–40), and long dust lifetimes (1–2 Gyr). The models have present-day dust masses with similar contributions from stellar sources (50–80  |${{\ \rm per\ cent}}$|⁠) and grain growth (20–50  |${{\ \rm per\ cent}}$|⁠). Over the entire lifetime of these galaxies, the contribution from stardust (>90  |${{\ \rm per\ cent}}$|⁠) outweighs the fraction of dust grown in the interstellar medium (<10  |${{\ \rm per\ cent}}$|⁠). Our results provide an alternative for the chemical evolution models that require extremely low supernova dust production efficiencies and short grain growth time-scales to reproduce local scaling laws, and could help solving the conundrum on whether or not grains can grow efficiently in the interstellar medium. [ABSTRACT FROM AUTHOR]

Using the Eight MIxer Receiver (EMIR) instrument on the Institut de RadioAstronomie Millimétrique (IRAM) 30-m telescope, we conducted a spectroscopic redshift search of seven z phot ∼ 4 submillimetre bright galaxies selected from the Herschel Bright Sources sample with fluxes at 500 μm greater than 80 mJy. For four sources, we obtained spectroscopic redshifts between 3.4 < z < 4.1 through the detection of multiple CO-spectral lines with J  ≥ 3. Later, we detected low- J transitions for two of these sources with the Green Bank Telescope including the CO(1–0) transition. For the remaining three sources, more data are needed to determine the spectroscopic redshift unambiguously. The measured CO luminosities and line widths suggest that all these sources are gravitationally lensed. These observations demonstrate that the 2 mm window is indispensable to confirm robust spectroscopic redshifts for z < 4 sources. Finally, we present an efficient graphical method to correctly identify spectroscopic redshifts. [ABSTRACT FROM AUTHOR]

We present SMA observations at resolutions from 0.35 to 3 arcsec of a sample of 34 candidate high redshift dusty star forming galaxies (DSFGs). These sources were selected from the HerMES Herschel survey catalogues to have SEDs rising from 250 to 350 to 500  μ m, a population termed 500-risers. We detect counterparts to 24 of these sources, with four having two counterparts. We conclude that the remaining ten sources that lack detected counterparts are likely to have three or more associated sources which blend together to produce the observed Herschel source. We examine the role of lensing, which is predicted to dominate the brightest (F500 > 60 mJy) half of our sample. We find that while lensing plays a role, at least 35 per cent of the bright sources are likely to be multiple sources rather than the result of lensing. At fainter fluxes we find a blending rate comparable to, or greater than, the predicted 40 per cent. We determine far-IR luminosities and star formation rates for the non-multiple sources in our sample and conclude that, in the absence of strong lensing, our 500-risers are very luminous systems with L FIR > 1013 L⊙ and star formation rates >1000 M⊙ yr−1. [ABSTRACT FROM AUTHOR]

Objectives: To establish whether chondrocyte viability, matrix degradation and the induction of proteolytic gene expression in canine cartilage is independent of irrigation fluid osmolality and time following exposure to the irrigation fluid. Methods: Canine cartilage explants were exposed to one of three different solution types i) Culture medium (270–280 mOsmol/kg) ii) NaCl 0.9% (302 mOsmol/kg) iii) NaCl 0.9% with sucrose (600 mOsmol/kg). Chondrocyte viability and selected proteolytic gene expression were measured at two time points; immediately following exposure and 24 h following exposure. The media samples at 24 h following exposure were assessed for sulphated glycosaminoglycan (sGAG) release. Results: In all samples, no cell death was observed across the superficial or deeper layers of the cartilage. When adjusting for time, gene expression was not shown to be dependent on solution type. However for all solution types, Matrix Metalloproteinase 13 (MMP13) and A Disintegrin and Metalloproteinase with Thrombospondin Motifs 5 (ADAMTS5) expression was significantly decreased in cartilage samples at 24 h post exposure comparatively to samples tested immediately post exposure. No significant differences were identified in the relative sGAG release between the solution types. Clinical Signifcance: Arthroscopic solution irrigation of cartilage explants had no effect on cell viability or proteinase production. At present there is no indication to optimise irrigation fluid osmolarity, as conventional arthroscopic solution was not deleterious to healthy cartilage in this model. [ABSTRACT FROM AUTHOR]

The article focuses on long-bone fractures in pet rabbits (Oryctolagus cuniculus). According to the article, 2,457 rabbits were examined over a period of 12 years at one institution in Great Britain. Records of diagnosis, treatment, complications, and prognosis of fractured bones including femoral, fibula, and ulna are analyzed.

The cosmic infrared background (CIB) provides a fundamental observational constraint on the star formation history of galaxies over cosmic history. We estimate the contribution to the CIB from catalogued galaxies in the COSMOS field by using a novel map fitting technique on the Herschel SPIRE maps. Prior galaxy positions are obtained using detections over a large range in wavelengths in the K s–3 GHz range. Our method simultaneously fits the galaxies, the system foreground, and the leakage of flux from galaxies located in masked areas and corrects for an 'overfitting' effect not previously accounted for in stacking methods. We explore the contribution to the CIB as a function of galaxy survey wavelength and depth. We find high contributions to the CIB with the deep r (m AB ≤ 26.5), K s (m AB ≤ 24.0), and 3.6  |$\mathrm{ \mu}$| m (m AB ≤ 25.5) catalogues. We combine these three deep catalogues and find a total CIB contributions of 10.5 ± 1.6, 6.7 ± 1.5, and 3.1 ± 0.7 nWm−2 sr−1 at 250, 350, and 500  |$\mathrm{ \mu}$| m, respectively. Our CIB estimates are consistent with recent phenomenological models, prior based SPIRE number counts and with (though more precise than) the diffuse total measured by FIRAS. Our results raise the interesting prospect that the CIB contribution at |$\lambda \le 500\, \mu$| m from known galaxies has converged. Future large-area surveys like those with the Large Synoptic Survey Telescope are therefore likely to resolve a substantial fraction of the population responsible for the CIB at 250  |$\mathrm{ \mu}$| m ≤ λ ≤ 500  |$\mathrm{ \mu}$| m. [ABSTRACT FROM AUTHOR]

Dusty star-forming galaxies (DSFGs) detected at z > 4 provide important examples of the first generations of massive galaxies. However, few examples with spectroscopic confirmation are currently known, with Hershel struggling to detect significant numbers of z > 6 DSFGs. NGP6_D1 is a bright 850 |$\mathrm{ \mu}$| m source (12.3 ± 2.5 mJy) with no counterparts at shorter wavelengths (a SPIRE dropout). Interferometric observations confirm it is a single source, with no evidence for any optical or NIR emission, or nearby likely foreground lensing sources. No >3σ detected lines are seen in both LMT Redshift Search Receiver and IRAM 30 m EMIR spectra of NGP6_D1 across 32 GHz of bandwidth despite reaching detection limits of |$\sim 1\, \mathrm{mJy}/500 \, \mathrm{km~s}^{-1}$|⁠ , so the redshift remains unknown. Template fitting suggests that NGP6_D1 is most likely between z  = 5.8 and 8.3. SED analysis finds that NGP6_D1 is a ULIRG, with a dust mass ∼108–109 M⊙ and a star-formation rate of ∼500 M⊙ yr−1. We place upper limits on the gas mass of NGP6_D1 of M H 2 <(1.1 ± 3.5) × 1011 M⊙, consistent with a gas-to-dust ratio of ∼100–1000. We discuss the nature of NGP6_D1 in the context of the broader sub-mm population, and find that comparable SPIRE dropouts account for ∼20 per cent of all SCUBA-2 detected sources, but with a similar flux density distribution to the general population. [ABSTRACT FROM AUTHOR]

We present SCUBA-2 850  |$\mathrm{ \mu}$| m observations of 13 candidate starbursting protoclusters selected using Planck and Herschel data. The cumulative number counts of the 850  |$\mathrm{ \mu}$| m sources in 9 of 13 of these candidate protoclusters show significant overdensities compared to the field, with the probability <10−2 assuming the sources are randomly distributed in the sky. Using the 250, 350, 500, and 850  |$\mathrm{ \mu}$| m flux densities, we estimate the photometric redshifts of individual SCUBA-2 sources by fitting spectral energy distribution templates with an MCMC method. The photometric redshift distribution, peaking at 2 < z < 3, is consistent with that of known z > 2 protoclusters and the peak of the cosmic star formation rate density (SFRD). We find that the 850  |$\mathrm{ \mu}$| m sources in our candidate protoclusters have infrared luminosities of |$L_{\mathrm{IR}}\gtrsim 10^{12}\, \mathrm{L}_{\odot }$| and star formation rates of SFR  = (500–1500) M⊙ yr−1. By comparing with results in the literature considering only Herschel photometry, we conclude that our 13 candidate protoclusters can be categorized into four groups: six of them being high-redshift starbursting protoclusters, one being a lower redshift cluster or protocluster, three being protoclusters that contain lensed dusty star-forming galaxies or are rich in 850  |$\mathrm{ \mu}$| m sources, and three regions without significant Herschel or SCUBA-2 source overdensities. The total SFRs of the candidate protoclusters are found to be comparable or higher than those of known protoclusters, suggesting our sample contains some of the most extreme protocluster population. We infer that cross-matching Planck and Herschel data is a robust method for selecting candidate protoclusters with overdensities of 850  |$\mathrm{ \mu}$| m sources. [ABSTRACT FROM AUTHOR]

We present the discovery of HLock01-LAB, a luminous and large Lyα nebula at z = 3.326. Medium-band imaging and long-slit spectroscopic observations with the Gran Telescopio Canarias reveal extended emission in the Lyα 1215 Å, C IV 1550 Å, and He II 1640 Å lines over ∼100 kpc, and a total luminosity LLyα = (6.4 ± 0.1)×1044 erg s−1. HLock01-LAB presents an elongated morphology aligned with two faint radio sources contained within the central ∼8 kpc of the nebula. The radio structures are consistent with faint radio jets or lobes of a central galaxy, whose spectrum shows nebular emission characteristic of a type-II active galactic nucleus (AGN). The continuum emission of the AGN at short wavelengths is however likely dominated by stellar emission of the host galaxy, for which we derive a stellar mass M* ≃ 2.3 × 1011 M⊙. Our kinematic analysis shows that the ionized gas is perturbed almost exclusively in the inner region between the radio structures, probably as a consequence of jet–gas interactions, whereas in the outer regions the ionized gas appears more quiescent. The detection of extended emission in C IV and C III] indicates that the gas within the nebula is not primordial. Feedback may have enriched the halo at at least 50 kpc from the nuclear region. Using rest-frame UV emission-line diagnostics, we find that the gas in the nebula is likely heated by the AGN. Nevertheless, at the center of the nebula we find extreme emission line ratios of Lyα/C IV ∼60 and Lyα/He II ∼80, one of the highest values measured to date, and well above the standard values of photoionization models (Lyα/He II ∼30 for case B photoionization). Our data suggest that jet-induced shocks are likely responsible for the increase of the electron temperature and, thus, the observed Lyα enhancement in the center of the nebula. This scenario is further supported by the presence of radio structures and perturbed kinematics in this region. The large Lyα luminosity in HLock01-LAB is likely due to a combination of AGN photoionization and jet-induced shocks, highlighting the diversity of sources of energy powering Lyα nebulae. Future follow-up observations of HLock01-LAB will help to reveal the finer details of the excitation conditions of the gas induced by jets and to investigate the underlying cooling and feedback processes in this unique object. [ABSTRACT FROM AUTHOR]

Summary: Increasingly, weeds have been taking on global distributions. With the proliferation of invasive weeds has come the challenge of managing these species over broad geographical regions, with diverse habitats and political jurisdictions. Here, we review the management of Mikania micrantha Kunth (Asteraceae; mile‐a‐minute) throughout its invaded range, extending through most of the Pacific islands and southern and south‐east Asia. Context matters when determining the best course of action for managing M. micrantha, as it has invaded a large variety of agricultural and natural systems. In Queensland, Australia and Florida, USA, M. micrantha has been targeted in relatively successful eradication campaigns, highlighting the importance of early detection and rapid response methods, while elsewhere in its invaded range, populations are either still increasing or showing limited signs of decline. An inter‐regional approach to research and management should incorporate successful management strategies employed throughout the invaded range including, but not limited to, chemical and cultural control practices, manual and mechanical control, classical biological control using the rust fungus Puccinia spegazzinii, plant–plant competition and integrated approaches utilising two or more control methods concurrently. Additional knowledge of M. micrantha genetics is required to determine if management approaches could be fine‐tuned for particular populations. Countries bordering the Mekong River formed a network in 2011 to co‐ordinate the management of invasive species such as M. micrantha. Expanding such a collaborative approach to other regions could further reduce populations of M. micrantha and limit its spread. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Plant Science is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Plant Science is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

High-redshift, luminous, dusty star-forming galaxies (DSFGs) constrain the extremity of galaxy formation theories. The most extreme are discovered through follow-up on candidates in large area surveys. Here, we present extensive 850 μm SCUBA-2 follow-up observations of 188 red DSFG candidates from the Herschel Multitiered Extragalactic Survey (HerMES) Large Mode Survey, covering 274 deg2. We detected 87 per cent with a signal-to-noise ratio >3 at 850 μm. We introduce a new method for incorporating the confusion noise in our spectral energy distribution fitting by sampling correlated flux density fluctuations from a confusion limited map. The new 850 μm data provide a better constraint on the photometric redshifts of the candidates, with photometric redshift errors decreasing from σz/(1 + z) ≈ 0.21 to 0.15. Comparison spectroscopic redshifts also found little bias (〈(z - zspec)/(1 + zspec)〉 = 0.08). The mean photometric redshift is found to be 3.6 with a dispersion of 0.4 and we identify 21 DSFGs with a high probability of lying at z > 4. After simulating our selection effects we find number counts are consistent with phenomenological galaxy evolution models. There is a statistically significant excess of WISE-1 and SDSS sources near our red galaxies, giving a strong indication that lensing may explain some of the apparently extreme objects. Nevertheless, our sample includes examples of galaxies with the highest star formation rates in the Universe (≫103 M⊙ yr-1). [ABSTRACT FROM AUTHOR]

By determining the nature of all the Planck compact sources within 808.4 deg2 of large Herschel surveys, we have identified 27 candidate protoclusters of dusty star-forming galaxies (DSFGs) that are at least 3σ overdense in either 250, 350, or 500 |$\mu$| m sources. We find roughly half of all the Planck compact sources are resolved by Herschel into multiple discrete objects, with the other half remaining unresolved by Herschel. We find a significant difference between versions of the Planck catalogues, with earlier releases hosting a larger fraction of candidate protoclusters and Galactic cirrus than later releases, which we ascribe to a difference in the filters used in the creation of the three catalogues. We find a surface density of DSFG candidate protoclusters of (3.3 ± 0.7) × 10−2 sources deg−2, in good agreement with previous similar studies. We find that a Planck colour selection of S 857/ S 545 < 2 works well to select candidate protoclusters, but can miss protoclusters at z  < 2. The Herschel colours of individual candidate protocluster members indicate our candidate protoclusters all likely all lie at z  > 1. Our candidate protoclusters are a factor of 5 times brighter at 353 GHz than expected from simulations, even in the most conservative estimates. Further observations are needed to confirm whether these candidate protoclusters are physical clusters, multiple protoclusters along the line of sight, or chance alignments of unassociated sources. [ABSTRACT FROM AUTHOR]

With the advent of wide-area submillimetre surveys, a large number of high-redshift gravitationally lensed dusty star-forming galaxies have been revealed. Because of the simplicity of the selection criteria for candidate lensed sources in such surveys, identified as those with S500 µm > 100 mJy, uncertainties associated with the modelling of the selection function are expunged. The combination of these attributes makes submillimetre surveys ideal for the study of strong lens statistics. We carried out a pilot study of the lensing statistics of submillimetreselected sources by making observations with the Atacama Large Millimeter Array (ALMA) of a sample of strongly lensed sources selected from surveys carried out with the Herschel Space Observatory. We attempted to reproduce the distribution of image separations for the lensed sources using a halo mass function taken from a numerical simulation that contains both dark matter and baryons. We used three different density distributions, one based on analytical fits to the haloes formed in the EAGLE simulation and two density distributions [Singular Isothermal Sphere (SIS) and SISSA] that have been used before in lensing studies. We found that we could reproduce the observed distribution with all three density distributions, as long as we imposed an upper mass transition of ~1013M⊙ for the SIS and SISSA models, above which we assumed that the density distribution could be represented by a Navarro-Frenk-White profile. We show that we would need a sample of ~500 lensed sources to distinguish between the density distributions, which is practical given the predicted number of lensed sources in the Herschel surveys. [ABSTRACT FROM AUTHOR]

We present the Herschel-SPIRE photometric atlas for a complete flux limited sample of 43 local ultraluminous infrared galaxies (ULIRGs), selected at 60 μm by IRAS, as part of the HERschel ULIRG Survey (HERUS). Photometry observations were obtained using the SPIRE instrument at 250, 350, and 500 μm. We describe these observations, present the results, and combine the new observations with data from IRAS to examine the far-infrared spectral energy distributions (SEDs) of these sources. We fit the observed SEDs of HERUS objects with a simple parametrized modified blackbody model, where temperature and emissivity β are free parameters. We compare the fitted values to those of non-ULIRG local galaxies, and find, in agreement with earlier results, that HERUS ULIRGs have warmer dust (median temperature T = 37.9 ± 4.7K compared to 21.3 ± 3.4K) but a similar β distribution (median β = 1.7 compared to 1.8) to the Herschel reference sample (HRS, Cortese et al. 2014) galaxies. Dust masses are found to be in the range of 107.5-109 M☉, significantly higher than that of HRS sources. We compare our results for local ULIRGs with higher redshift samples selected at 250 and 850 μm. These latter sources generally have cooler dust and/or redder 100-to-250 μm colours than our 60 μm-selected ULIRGs.We showthat this difference may in part be the result of the sources being selected at different wavelengths rather than being a simple indication of rapid evolution in the properties of the population. [ABSTRACT FROM AUTHOR]

We present 1.3- and/or 3-mm continuum images and 3-mm spectral scans, obtained using Northern Extended Millimeter Array (NOEMA) and Atacama Large Millimeter Array (ALMA), of 21 distant, dusty, star-forming galaxies. Our sample is a subset of the galaxies selected by Ivison et al. on the basis of their extremely red far-infrared (far-IR) colours and low Herschel flux densities; most are thus expected to be unlensed, extraordinarily luminous starbursts at z ≳ 4, modulo the considerable cross-section to gravitational lensing implied by their redshift. We observed 17 of these galaxies with NOEMA and four with ALMA, scanning through the 3-mm atmospheric window. We have obtained secure redshifts for seven galaxies via detection of multiple CO lines, one of them a lensed system at z = 6.027 (two others are also found to be lensed); a single emission line was detected in another four galaxies, one of which has been shown elsewhere to lie at z = 4.002. Where we find no spectroscopic redshifts, the galaxies are generally less luminous by 0.3-0.4 dex, which goes some way to explaining our failure to detect line emission. We show that this sample contains the most luminous known star-forming galaxies. Due to their extreme star-formation activity, these galaxies will consume their molecular gas in ≲ 100 Myr, despite their high molecular gas masses, and are therefore plausible progenitors of the massive, 'red-and-dead' elliptical galaxies at z ≈ 3. [ABSTRACT FROM AUTHOR]

Observational investigations of the abundance of massive precursors of local galaxy clusters ('proto-clusters') allow us to test the growth of density perturbations, to constrain cosmological parameters that control it, to test the theory of non-linear collapse and how the galaxy formation takes place in dense environments. The Planck collaboration has recently published a catalogue of ≳2000 cold extragalactic sub-millimeter sources, i.e. with colours indicative of z ≲ 2, almost all of which appear to be overdensities of star-forming galaxies. They are thus considered as proto-cluster candidates. Their number densities (or their flux densities) are far in excess of expectations from the standard scenario for the evolution of large-scale structure. Simulations based on a physically motivated galaxy evolution model show that essentially all cold peaks brighter than S545GHz = 500 mJy found in Planck maps after having removed the Galactic dust emission can be interpreted as positive Poisson fluctuations of the number of high-z dusty proto-clusters within the same Planck beam, rather then being individual clumps of physically bound galaxies. This conclusion does not change if an empirical fit to the luminosity function of dusty galaxies is used instead of the physical model. The simulations accurately reproduce the statistic of the Planck detections and yield distributions of sizes and ellipticities in qualitative agreement with observations. The redshift distribution of the brightest proto-clusters contributing to the cold peaks has a broad maximum at 1.5 ≤ z ≤ 3. Therefore follow-up of Planck proto-cluster candidates will provide key information on the high-z evolution of large scale structure. [ABSTRACT FROM AUTHOR]

Alternanthera philoxeroides is a problematic invasive plant in many regions of the world that is difficult to control once naturalised. It poses a threat to agricultural productivity, biodiversity and social amenity values of aquatic environments. Significant research has been conducted internationally, regarding the efficacy of different herbicides for control of A. philoxeroides. However, no studies have looked at key aspects of control for effective management in an early stage of invasion of aquatic environments, hindering eradication and control programmes. This study evaluates the efficacy of herbicides and surfactants on key A. philoxeroides response metrics, including control of above-ground biomass, below-ground biomass and production of viable stem fragments. This study concluded that glyphosate (isopropylamine salt) minimises viable stem fragment production post-herbicide application, compared with imazapyr and metsulfuron, thus reducing the potential for dispersal throughout catchments and waterways. In contrast, imazapyr and metsulfuron provided more effective control than glyphosate for A. philoxeroides growing on exposed embankments. We propose that an effective management strategy for early invasion of aquatic A. philoxeroides, using herbicides, would be to conduct initial applications of glyphosate to control overwater biomass and limit dispersal of viable stem fragments. Once infestations have been forced back to the embankment, imazapyr or metsulfuron treatments will provide longer term control. [ABSTRACT FROM AUTHOR]

Selecting sources with rising flux densities towards longerwavelengths from Herschel/Spectral and Photometric Imaging Receiver (SPIRE) maps is an efficient way to produce a catalogue rich in high-redshift (z>4) dusty star-forming galaxies. The effectiveness of this approach has already been confirmed by spectroscopic follow-up observations, but the previously available catalogues made this way are limited by small survey areas. Here we apply a map-based search method to 274 deg² of the Herschel Multi-tiered Extragalactic Survey (HerMES) Large Mode Survey and create a catalogue of 477 objects with SPIRE flux densities S500 > S350 > S250 and a 5σ cut-off S500 > 52 mJy. From this catalogue we determine that the total number of these 'red' sources is at least an order of magnitude higher than predicted by galaxy evolution models. These results are in agreement with previous findings in smaller HerMES fields; however, due to our significantly larger sample size we are also able to investigate the shape of the red source counts for the first time. We have obtained spectroscopic redshift measurements for two of our sources using the Atacama Large Millimeter/submillimeter Array. The redshifts z = 5.1 and 3.8 confirm that with our selection method we can indeed find high-redshift dusty star-forming galaxies. [ABSTRACT FROM AUTHOR]

We investigate the region around the Planck-detected z = 3.26 gravitationally lensed galaxy HATLAS J114637.9-001132 (hereinafter HATLAS12-00) using both archival Herschel data from the H-ATLAS survey and using submm data obtained with both LABOCA and SCUBA2. The lensed source is found to be surrounded by a strong overdensity of both Herschel-SPIRE sources and submm sources. We detect 17 bright (S870 > ~7 mJy) sources at >4σ closer than 5 arcmin to the lensed object at 850/870 μm. 10 of these sources have good cross-identifications with objects detected by Herschel-SPIRE which have redder colours than other sources in the field, with 350 μm flux >250 μm flux, suggesting that they lie at high redshift. Submillimeter Array (SMA) observations localise one of these companions to ~1 arcsec, allowing unambiguous cross identification with a 3.6 and 4.5 μm Spitzer source. The optical/near-IR spectral energy distribution of this source is measured by further observations and found to be consistent with z > 2, but incompatible with lower redshifts. We conclude that this system may be a galaxy cluster/protocluster or larger scale structure that contains a number of galaxies undergoing starbursts at the same time. [ABSTRACT FROM AUTHOR]

We combine Herschel/SPIRE submillimetre (submm) observations with existing multiwavelength data to investigate the characteristics of low-redshift, optically red galaxies detected in submm bands. We select a sample of galaxies in the redshift range 0.01 ≤ z ≤ 0.2, having >5σ detections in the SPIRE 250 µm submm waveband. Sources are then divided into two sub-samples of red and blue galaxies, based on their UV-optical colours. Galaxies in the red sample account for ≈4.2 per cent of the total number of sources with stellar masses M∗ ≳ 1010 M⊙. Following visual classification of the red galaxies, we find that ≳30 per cent of them are early-type galaxies and ≳40 per cent are spirals. The colour of the red-spiral galaxies could be the result of their highly inclined orientation and/or a strong contribution of the old stellar population. It is found that irrespective of their morphological types, red and blue sources occupy environments with more or less similar densities (i.e. the Σ5 parameter). From the analysis of the spectral energy distributions of galaxies in our samples based on MAGPHYS, we find that galaxies in the red sample (of any morphological type) have dust masses similar to those in the blue sample (i.e. normal spiral/star-forming systems). However, in comparison to the red-spirals and in particular blue systems, red-ellipticals have lower mean dust-to-stellar mass ratios. Besides galaxies in the red-elliptical sample have much lower mean star formation/specific star formation rates in contrast to their counterparts in the blue sample. Our results support a scenario where dust in early-type systems is likely to be of an external origin. [ABSTRACT FROM AUTHOR]

We used wide-area surveys over 39 deg² by the HerMES (Herschel Multi-tiered Extragalactic Survey) collaboration, performed with the Herschel Observatory SPIRE multiwavelength camera, to estimate the low-redshift, 0.02 < z < 0.5, monochromatic luminosity functions (LFs) of galaxies at 250, 350 and 500 ㎛. Within this redshift interval, we detected 7087 sources in five independent sky areas, ~40 per cent of which have spectroscopic redshifts, while for the remaining objects photometric redshifts were used. The SPIRE LFs in different fields did not show any field-to-field variations beyond the small differences to be expected from cosmic variance. SPIRE flux densities were also combined with Spitzer photometry and multiwavelength archival data to perform a complete spectral energy distribution fitting analysis of SPIRE detected sources to calculate precise k-corrections, as well as the bolometric infrared (IR; 8-1000 ㎛) LFs and their low-z evolution from a combination of statistical estimators. Integration of the latter prompted us to also compute the local luminosity density and the comoving star formation rate density (SFRD) for our sources, and to compare them with theoretical predictions of galaxy formation models. The LFs show significant and rapid luminosity evolution already at low redshifts, 0.02 < z < 0.2, with L∗ IR ∝ (1 + z)6.0±0.4 and Φ ∗ IR ∝ (1 + z)-2.1±0.4, L∗ 250 ∝ (1 + z)5.3±0.2 and Φ ∗ 250 ∝ (1 + z)-0.6±0.4 estimated using the IR bolometric and the 250 ㎛ LFs, respectively. Converting our IR LD estimate into an SFRD assuming a standard Salpeter initial mass function and including the unobscured contribution based on the UV dust-uncorrected emission from local galaxies, we estimate an SFRD scaling of SFRD0 + 0.08z, where SFRD0 ≃ (1.9 ± 0.03) × 10-2 [M⊙ Mpc-3] is our total SFRD estimate at z ~ 0.02. [ABSTRACT FROM AUTHOR]

Two cats that developed bilateral calcaneal stress fractures are reported. One cat developed lameness associated with incomplete fractures at the base of both calcanei, both of which progressed to acute, complete fractures 2 months later. The second cat presented with acute complete calcaneal fracture, with evidence of remodelling of the contralateral calcaneus, which subsequently fractured two years later. The calcaneal fractures were successfully stabilised with lateral bone plates in each case. Stress fractures were suspected because of the bilateral nature, the simple and similar configuration, the consistent location of the fractures, the absence of other signs of trauma in both cases and the suspected insidious onset of the lameness. The feline calcaneus is susceptible to stress fracture, and cats presenting with calcaneal fractures without evidence of trauma should be evaluated for concurrent skeletal pathology. [ABSTRACT FROM AUTHOR]

A systematic programme of calibration observations was carried out to monitor the performance of the Spectral and Photometric Imaging REceiver (SPIRE) Fourier Transform Spectrometer (FTS) instrument on board the Herschel Space Observatory. Observations of planets (including the prime point-source calibrator, Uranus), asteroids, line sources, dark sky and cross-calibration sources were made in order to monitor repeatability and sensitivity, and to improve FTS calibration. We present a complete analysis of the full set of calibration observations and use them to assess the performance of the FTS. Particular care is taken to understand and separate out the effect of pointing uncertainties, including the position of the internal beam steering mirror for sparse observations in the early part of the mission. The repeatability of spectral-line centre positions is <5 km s-1, for lines with signal-to-noise ratios >40, corresponding to <0.5-2.0 per cent of a resolution element. For spectral-line flux, the repeatability is better than 6 per cent, which improves to 1-2 per cent for spectra corrected for pointing offsets. The continuum repeatability is 4.4 per cent for the SPIRE Long Wavelength spectrometer (SLW) band and 13.6 per cent for the SPIRE Short Wavelength spectrometer (SSW) band, which reduces to ~1 per cent once the data have been corrected for pointing offsets. Observations of dark sky were used to assess the sensitivity and the systematic offset in the continuum, both of which were found to be consistent across the FTS-detector arrays. The average point-source calibrated sensitivity for the centre detectors is 0.20 and 0.21 Jy [1σ; 1 h], for SLW and SSW. The average continuum offset is 0.40 Jy for the SLW band and 0.28 Jy for the SSW band. [ABSTRACT FROM AUTHOR]

We combine a large, homogeneous sample of ~3000 local mergers with the Imperial IRAS Faint Source Redshift Catalogue (IIFSCz), to perform a blind far-infrared (FIR) study of the local merger population. The IRAS-detected mergers are mostly (98%) spiral-spiral systems, residing in low density environments, a median FIR luminosity of 1011 L☉ (which translates to a median star formation rate of around 15 M☉ yr-1). The FIR luminosity - and therefore the star formation rate - shows little correlation with group richness and scales with the total stellar mass of the system, with little or no dependence on the merger mass ratio. In particular, minor mergers (mass ratios <1:3) are capable of driving strong star formation (between 10 and 173 M☉ yr-1) and producing systems that are classified as luminous infrared galaxies (LIRGS; 65% of our LIRGs are minor mergers), with some minor-merging systems being close to the ultra luminous infrared galaxy (ULIRG) limit. Optical emission line ratios indicate that the AGN fraction increases with increasing FIR luminosity, with all ULIRG mergers having some form of AGN activity. Finally, we estimate that the LIRG-to-ULIRG transition along a merger sequence typically takes place over a relatively short timescale of ~160 Myr. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Plant Science is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We study the relation of AGN accretion, star formation rate (SFR) and stellar mass (M*) using a sample of ≈8600 star-forming galaxies up to z = 2.5 selected with Herschel imaging in the GOODS and COSMOS fields. For each of them we derive SFR and M*, both corrected, when necessary, for emission from an active galactic nucleus (AGN), through the decomposition of their spectral energy distributions (SEDs). About 10 per cent of the sample are detected individually in Chandra observations of the fields. For the rest of the sample, we stack the X-ray maps to get average X-ray properties. After subtracting the X-ray luminosity expected from star formation and correcting for nuclear obscuration, we derive the average AGN accretion rate for both detected sources and stacks, as a function of M*, SFR and redshift. The average accretion rate correlates with SFR and with M*. The dependence on SFR becomes progressively more significant at z > 0.8. This may suggest that SFR is the original driver of these correlations. We find that average AGN accretion and star formation increase in a similar fashion with offset from the star-forming 'main-sequence'. Our interpretation is that accretion on to the central black hole and star formation broadly trace each other, irrespective of whether the galaxy is evolving steadily on the main-sequence or bursting. [ABSTRACT FROM AUTHOR]

We present Herschel (PACS and SPIRE) far-infrared (FIR) photometry of a complete sample of z > 1 3CR sources, from the Herschel guaranteed time project The Herschel Legacy of distant radio-loud AGN. Combining these with existing Spitzer photometric data, we perform an infrared (IR) spectral energy distribution (SED) analysis of these landmark objects in extragalactic research to study the star formation in the hosts of some of the brightest active galactic nuclei (AGN) known at any epoch. Accounting for the contribution from an AGN-powered warm dust component to the IR SED, about 40% of our objects undergo episodes of prodigious, ULIRG-strength star formation, with rates of hundreds of solar masses per year, coeval with the growth of the central supermassive black hole. Median SEDs imply that the quasar and radio galaxy hosts have similar FIR properties, in agreement with the orientation-based unification for radio-loud AGN. The star-forming properties of the AGN hosts are similar to those of the general population of equally massive non-AGN galaxies at comparable redshifts, thus there is no strong evidence of universal quenching of star formation (negative feedback) within this sample. Massive galaxies at high redshift may be forming stars prodigiously, regardless of whether their supermassive black holes are accreting or not. [ABSTRACT FROM AUTHOR]