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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]

We present SCUBA-2 450  and 850  |$\mu$| m data of the mature redshift 2 cluster CLJ1449. We combine this with archival Herschel data to explore the star-forming properties of CLJ1449. Using high-resolution Atacama Large Millimetre Array and Jansky Very Large Array data we identify potentially confused galaxies, and use the Bayesian inference tool XID+ to estimate fluxes for them. Using archival optical and near-infrared data with the energy-balance code cigale we calculate star formation rates and stellar masses for all our cluster members, and find that the star formation rate varies between 20 and 1600 M⊙yr−1 over the entire 3 Mpc radial range. The central 0.5 Mpc region itself has a total star formation rate of 800  ±  200 M⊙yr−1, which corresponds to a star formation rate density of (1.2  ±  0.3) × 104 M⊙ yr−1 Mpc−3, which is approximately five orders of magnitude greater than expected field values. When comparing this cluster to those at lower redshifts we find that there is an increase in star formation rate per unit volume towards the centre of the cluster. This indicates that there is indeed a reversal in the star formation/density relation in CLJ1449. Based on the radial star formation rate density profile, we see evidence for an elevation in the star formation rate density, even out to radii of 3 Mpc. At these radii the elevation could be an order of magnitude greater than field values, but the exact number cannot be determined due to ambiguity in the redshift associations. If this is the case it would imply that this cluster is still accreting material which is possibly interacting and undergoing vigorous star formation. [ABSTRACT FROM AUTHOR]

ABSTRACT The origin of interstellar dust in galaxies is poorly understood, particularly the relative contributions from supernovae and the cool stellar winds of low-intermediate-mass stars. Recently, large masses of newly formed dust have been discovered in the ejecta of core-collapse supernovae. Here, we present Herschel Photodetector Array Camera and Spectrometer (PACS) and Spectral and Photometric Imaging Receiver (SPIRE) photometry at 70-500 m of the historical, young supernova remnants: Kepler and Tycho, both thought to be the remnants of Type Ia explosion events. We detect a warm dust component in Kepler's remnant with and mass ; this is spatially coincident with thermal X-ray emission and optical knots and filaments, consistent with the warm dust originating in the circumstellar material swept up by the primary blast wave of the remnant. Similarly for Tycho's remnant, we detect warm dust at with mass . Comparing the spatial distribution of the warm dust with X-rays from the ejecta and swept-up medium, and Hα emission arising from the post-shock edge, we show that the warm dust is swept up interstellar material. We find no evidence of a cool (25-50 K) component of dust with mass ≥0.07 M⊙ as observed in core-collapse remnants of massive stars. Neither the warm or cold dust components detected here are spatially coincident with supernova ejecta material. We compare the lack of observed supernova dust with a theoretical model of dust formation in Type Ia remnants which predicts dust masses of 88(17) × 10−3 M⊙ for ejecta expanding into ambient surrounding densities of 1(5) cm−3. The model predicts that silicon- and carbon-rich dust grains will encounter, at most, the interior edge of the observed dust emission at ∼400 years, confirming that the majority of the warm dust originates from swept-up circumstellar or interstellar grains (for Kepler and Tycho, respectively). The lack of cold dust grains in the ejecta suggests that Type Ia remnants do not produce substantial quantities of iron-rich dust grains and has important consequences for the 'missing' iron mass observed in ejecta. Finally, although, we cannot completely rule out a small mass of freshly formed supernova dust, the Herschel observations confirm that significantly less dust forms in the ejecta of Type Ia supernovae than in the remnants of core-collapse explosions. [ABSTRACT FROM AUTHOR]

We present observations that were carried out with the Two HUndred Micron PhotometER (THUMPER) mounted on the James Clerk Maxwell Telescope (JCMT) in Hawaii, at a wavelength of 200 μm (frequency 1.5 THz). The observations utilize a small atmospheric window that opens up at this wavelength under very dry conditions at high-altitude observing sites. The atmosphere was calibrated using the sky-dipping method and a relation was established between the optical depth, τ, at 1.5 THz and that at 225 GHz: . Mars and Jupiter were mapped from the ground at this wavelength for the first time, and the system characteristics measured. A noise-equivalent flux density (NEFD) of ∼ 65 ± 10 Jy (1σ 1s) was measured for the THUMPER–JCMT combination, consistent with predictions based upon our laboratory measurements. The main beam resolution of 14 arcsec was confirmed and an extended error beam detected at roughly two-thirds of the magnitude of the main beam. Measurements of the Sun allow us to estimate that the fraction of the power in the main beam is ∼15 per cent, consistent with predictions based on modelling the dish surface accuracy. It is therefore shown that the sky over Mauna Kea is suitable for astronomy at this wavelength under the best conditions. However, higher or drier sites should have a larger number of useable nights per year. [ABSTRACT FROM AUTHOR]

The environmental properties of a sample of 31 hard X-ray selected active galactic nuclei (AGN) are investigated, from scales of 500 kpc down to 30 kpc, and are compared to a control sample of inactive galaxies. All the AGN lie in the redshift range . The accretion luminosity density of the Universe peaks close to this redshift range, and the AGN in the sample have X-ray luminosities close to the knee in the hard X-ray luminosity function, making them representative of the population that dominated this important phase of energy conversion. Using both the spatial clustering amplitude and near-neighbour counts, it is found that the AGN have environments that are indistinguishable from normal, inactive galaxies over the same redshift range and with similar optical properties. Typically, the environments are of subcluster richness, in contrast to similar studies of high- z quasars, which are often found in clusters with comparable richness to the Abell clusters. It is suggested that minor mergers with low-mass companions are a likely candidate for the mechanism by which these modest luminosity AGN are fuelled. [ABSTRACT FROM AUTHOR]

We present the X-ray source catalogues for the XMM surveys of the 3-h and 14-h Canada–France Redshift Survey fields (0.5–10 keV flux range ). We use a subset of the XMM sources, which have Chandra positions, to determine the best method of obtaining optical identifications of sources with only XMM positions. We find optical identifications for 79 per cent of the XMM sources for which there are deep optical images. The sources without optical identifications are likely to be optically fainter and have higher redshifts than the sources with identifications. We have estimated ‘photometric redshifts’ for the identified sources, calibrating our method using ∼200 galaxies in the fields with spectroscopic redshifts. We find that the redshift distribution has a strong peak at . The host galaxies of active galactic nuclei (AGN) identified in this work cover a wide range of optical properties, with every galaxy type being represented and no obvious preference for one type over another. Redder types tend to be more luminous than blue types, particularly at lower redshifts. The host galaxies also span a wide range of optical luminosity, in contrast to the narrow range found for the starburst galaxies detected in μJy radio surveys. We find a strong correlation between optical and X-ray luminosity similar to the Magorrian relation, although selection effects cannot be ruled out. [ABSTRACT FROM AUTHOR]

We investigate the science goals achievable with the upcoming generation of ground-based cosmic microwave background polarization experiments, focusing on one particular experiment, QUaD [QUEST ( Q and U Extragalactic Submillimetre Telescope) and DASI (Degree Angular Scale Interferometer)], a proposed bolometric polarimeter operating from the South Pole. We calculate the optimal sky coverage for this experiment, including the effects of foregrounds and gravitational lensing. We find that an E-mode measurement will be sample-limited, whereas a B-mode measurement will be detector-noise-limited. We conclude that a 300 deg2 survey is an optimal compromise for a 2-yr experiment to measure both E and B modes, and that a ground-based polarization experiment can make an important contribution to B-mode surveys. QUaD can make a high significance measurement of the acoustic peaks in the E-mode spectrum, over a multipole range of , and will be able to detect the gravitational lensing signal in the B-mode spectrum. Such an experiment could also directly detect the gravitational wave component of the B-mode spectrum if the amplitude of the signal is close to current upper limits. We also investigate how QUaD can improve constraints on the cosmological parameters. We estimate that combining two years of QUaD data with the 4-yr Wilkinson Microwave Anisotropy Probe ( WMAP) data can improve constraints on and by a factor of 2. If the foreground contamination can be reduced, the measurement of r can be improved by up to a factor of 6 over that obtainable from WMAP alone. These improved accuracies will place strong constraints on the potential of the inflaton field. [ABSTRACT FROM AUTHOR]

ABSTRACT We present the results of a multiwavelength campaign during which BL Lac was observed at 17 regular epochs from 1998.23 to 2001.28. We used the Very Long Baseline Array (VLBA) in an observing mode sensitive to linear polarization at wavelength 7 mm with a resolution of the order of 0.2 mas. For the first time such observations were complemented by near-simultaneous polarization-sensitive James Clerk Maxwell Telescope (JCMT) observations at a wavelength close to 1 mm. Optical polarimetry was also obtained for the final year of observations. The VLBA images reveal a remarkable oscillating ‘nozzle’ structure with a period of ∼2 yr. The orientation of the nozzle tracks the polarization position angle measured at the JCMT, in which we detect a very similar period. We argue that these results require the same jet direction at the small scale probed by the 1-mm emission as at the larger scale probed by the 7-mm emission; there is no evidence to suggest wiggling of the jet between these scales. The picture that emerges is of a straight but precessing jet where the components form a straight line near the core, but form an apparently curved locus at larger separations where components were ejected in different directions. Two further lines of evidence support this view. First, tracing the evolution of bright components showed straight paths and ejection angles consistent with the nozzle direction at the ejection time. Secondly, a simple model of a precessing nozzle was used to predict the inner jet structure. At most epochs the agreement between the model and data was good. On angular scales >2 mas from the core a transition occurs and most components bend to follow the usual southeasterly direction on deca-milliarcsecond scales. This precession is clearly analogous to that found in the galactic jet source SS 433 albeit with a higher jet speed and a smaller precession cone opening angle. The precession observed in SS 433 is believed to be caused by the interaction of a companion star with the accretion disc around the compact object. This suggests the possibility that the black hole from which the jet from BL Lac emerges is part of a binary system. [ABSTRACT FROM AUTHOR]

We present a high-resolution millimetre interferometric image of the brightest SCUBA-selected galaxy from the Canada–UK Deep SCUBA survey (CUDSS). We make a very clear detection at 1.3 mm, but fail to resolve any structure in the source. The interferometric position is within 1.5 arcsec of the SCUBA 850-μm centroid, and also within 1.5 arcsec of a 44-μJy radio source and a very faint, extremely red galaxy which we had previously identified as the submillimetre source. We also present new optical and infrared imaging, and infrared spectroscopy of this source. We model the overall spectral energy distribution and conclude that it lies within the redshift range 2

Submillimetre mapping observations of the active edge-on spiral galaxy NGC 3079 are presented. These maps at 850 and 450 μm were made with the Submillimetre Common User Bolometer Array (SCUBA) at the James Clerk Maxwell Telescope (JCMT). The source structure at these wavelengths consists of a central unresolved source embedded in diffuse disc emission, similar to that displayed at 1.2 mm. The disc emission is fitted with two optically thin, isothermal dust models which give temperatures of 12 and 31 K, similar to those derived previously by Braine et al. The core component is well described by a single-temperature fit (∼32 K). The combined dust mass from these observations, using the same mass absorption coefficient as Devereux & Young (1990) is 3.5×10[sup 8] M[sub ⊙], of which ∼90 per cent resides in the cold component of the galactic disc. The effect of the cold dust component detected by SCUBA is thus to reduce the global gas-to-dust mass ratio from ∼1400 found in the above study to 85, very similar to the Galactic level. Calculations using the models of Draine & Lee and/or alternative molecular gas mass estimates yield gas-to-dust mass ratios in the range 60–190. The data presented here, together with previously published 1.2-mm mapping observations and IRAS data, are inconsistent with detections made with the Infrared Space Observatory (ISO). In particular, the latter give an excess of flux at 200 and 180 μm relative to that predicted by our simple model fits (approximately a factor of 2–3). [ABSTRACT FROM AUTHOR]

ABSTRACT The origin of interstellar dust in galaxies is poorly understood, particularly the relative contributions from supernovae and the cool stellar winds of low-intermediate-mass stars. Recently, large masses of newly formed dust have been discovered in the ejecta of core-collapse supernovae. Here, we present Herschel Photodetector Array Camera and Spectrometer (PACS) and Spectral and Photometric Imaging Receiver (SPIRE) photometry at 70-500 m of the historical, young supernova remnants: Kepler and Tycho, both thought to be the remnants of Type Ia explosion events. We detect a warm dust component in Kepler's remnant with and mass ; this is spatially coincident with thermal X-ray emission and optical knots and filaments, consistent with the warm dust originating in the circumstellar material swept up by the primary blast wave of the remnant. Similarly for Tycho's remnant, we detect warm dust at with mass . Comparing the spatial distribution of the warm dust with X-rays from the ejecta and swept-up medium, and Hα emission arising from the post-shock edge, we show that the warm dust is swept up interstellar material. We find no evidence of a cool (25-50 K) component of dust with mass ≥0.07 M⊙ as observed in core-collapse remnants of massive stars. Neither the warm or cold dust components detected here are spatially coincident with supernova ejecta material. We compare the lack of observed supernova dust with a theoretical model of dust formation in Type Ia remnants which predicts dust masses of 88(17) × 10−3 M⊙ for ejecta expanding into ambient surrounding densities of 1(5) cm−3. The model predicts that silicon- and carbon-rich dust grains will encounter, at most, the interior edge of the observed dust emission at ∼400 years, confirming that the majority of the warm dust originates from swept-up circumstellar or interstellar grains (for Kepler and Tycho, respectively). The lack of cold dust grains in the ejecta suggests that Type Ia remnants do not produce substantial quantities of iron-rich dust grains and has important consequences for the 'missing' iron mass observed in ejecta. Finally, although, we cannot completely rule out a small mass of freshly formed supernova dust, the Herschel observations confirm that significantly less dust forms in the ejecta of Type Ia supernovae than in the remnants of core-collapse explosions. [ABSTRACT FROM AUTHOR]