Is there a redshift cutoff for submillimetre galaxies?

We present new optical and infrared photometry for a statistically complete sample of seven 1.1 mm selected sources with accurate Submillimetre Array coordinates. We determine photometric redshifts for four of the seven sources of 4.47, 4.50, 1.49 and 0.64. Of the other three sources two are undetected at optical wavelengths down to the limits of very deep Subaru and Canada-France-Hawaii Telescope images ($\sim$27 mag AB, i band) and the photometry of the remaining source is corrupted by a bright nearby galaxy. The sources with the highest redshifts are at higher redshifts than all but one of the $\sim$200 sources taken from the largest recent 850 $\mu$m surveys, which may indicate that 1.1 mm surveys are more efficient at finding sources at very high redshifts than 850 $\mu$m surveys. We investigate the evolution of the number density with redshift of our sample using a banded $V_{e}/V_{a}$ analysis and find no evidence for a redshift cutoff, although the number of sources is very small. We also perform the same analysis on a statistically complete sample of 38 galaxies selected at 850$\mu$m from the GOODS-N field and find evidence for a drop-off in the number density beyond $z\sim1$ and 2 for hot and cold dust dominated SMGs respectively, confirming the earlier conclusion of Wall, Pope & Scott. We also find strong evidence for the existence of two differently evolving sub-populations separated in luminosity, with a higher relative density of the high luminosity galaxies at higher redshifts

A panchromatic study of BLAST counterparts: total star-formation rate, morphology, AGN fraction and stellar mass

We carry out a multi-wavelength study of individual galaxies detected by the Balloon-borne Large Aperture Submillimeter Telescope (BLAST) and identified at other wavelengths, using data spanning the radio to the ultraviolet (UV). We develop a Monte Carlo method to account for flux boosting, source blending, and correlations among bands, which we use to derive deboosted far-infrared (FIR) luminosities for our sample. We estimate total star-formation rates for BLAST counterparts with z < 0.9 by combining their FIR and UV luminosities. Star formation is heavily obscured at L_FIR > 10^11 L_sun, z > 0.5, but the contribution from unobscured starlight cannot be neglected at L_FIR < 10^11 L_sun, z < 0.25. We assess that about 20% of the galaxies in our sample show indication of a type-1 active galactic nucleus (AGN), but their submillimeter emission is mainly due to star formation in the host galaxy. We compute stellar masses for a subset of 92 BLAST counterparts; these are relatively massive objects, with a median mass of ~10^11 M_sun, which seem to link the 24um and SCUBA populations, in terms of both stellar mass and star-formation activity. The bulk of the BLAST counterparts at z<1 appear to be run-of-the-mill star-forming galaxies, typically spiral in shape, with intermediate stellar masses and practically constant specific star-formation rates. On the other hand, the high-z tail of the BLAST counterparts significantly overlaps with the SCUBA population, in terms of both star-formation rates and stellar masses, with observed trends of specific star-formation rate that support strong evolution and downsizing.Comment: Accepted for publication in the Astrophysical Journal. 44 pages, 11 figures. The SED template for the derivation of L_FIR has changed (added new figure) and the discussion on the stellar masses has been improved. The complete set of full-color postage-stamps can be found at http://blastexperiment.info/results_images/moncelsi

The collective impact of rare diseases in Western Australia: an estimate using a population-based cohort.

PURPOSE: It has been argued that rare diseases should be recognized as a public health priority. However, there is a shortage of epidemiological data describing the true burden of rare diseases. This study investigated hospital service use to provide a better understanding of the collective health and economic impacts of rare diseases. METHODS: Novel methodology was developed using a carefully constructed set of diagnostic codes, a selection of rare disease cohorts from hospital administrative data, and advanced data-linkage technologies. Outcomes included health-service use and hospital admission costs. RESULTS: In 2010, cohort members who were alive represented approximately 2.0% of the Western Australian population. The cohort accounted for 4.6% of people discharged from hospital and 9.9% of hospital discharges, and it had a greater average length of stay than the general population. The total cost of hospital discharges for the cohort represented 10.5% of 2010 state inpatient hospital costs. CONCLUSIONS: This population-based cohort study provides strong new evidence of a marked disparity between the proportion of the population with rare diseases and their combined health-system costs. The methodology will inform future rare-disease studies, and the evidence will guide government strategies for managing the service needs of people living with rare diseases.Genet Med advance online publication 22 September 2016Genetics in Medicine (2016); doi:10.1038/gim.2016.143

Predicting the Impact of Climate Change on Threatened Species in UK Waters

Global climate change is affecting the distribution of marine species and is thought to represent a threat to biodiversity. Previous studies project expansion of species range for some species and local extinction elsewhere under climate change. Such range shifts raise concern for species whose long-term persistence is already threatened by other human disturbances such as fishing. However, few studies have attempted to assess the effects of future climate change on threatened vertebrate marine species using a multi-model approach. There has also been a recent surge of interest in climate change impacts on protected areas. This study applies three species distribution models and two sets of climate model projections to explore the potential impacts of climate change on marine species by 2050. A set of species in the North Sea, including seven threatened and ten major commercial species were used as a case study. Changes in habitat suitability in selected candidate protected areas around the UK under future climatic scenarios were assessed for these species. Moreover, change in the degree of overlap between commercial and threatened species ranges was calculated as a proxy of the potential threat posed by overfishing through bycatch. The ensemble projections suggest northward shifts in species at an average rate of 27 km per decade, resulting in small average changes in range overlap between threatened and commercially exploited species. Furthermore, the adverse consequences of climate change on the habitat suitability of protected areas were projected to be small. Although the models show large variation in the predicted consequences of climate change, the multi-model approach helps identify the potential risk of increased exposure to human stressors of critically endangered species such as common skate (Dipturus batis) and angelshark (Squatina squatina)

The new galaxy evolution paradigm revealed by the Herschel surveys

The Herschel Space Observatory has revealed a very different galaxyscape from that shown by optical surveys, which presents a challenge for galaxy-evolution models. The Herschel surveys reveal (1) that there was rapid galaxy evolution in the very recent past and (2) that galaxies lie on a a single Galaxy Sequence (GS) rather than a star-forming ‘main sequence’ and a separate region of ‘passive’ or ‘red-and-dead’ galaxies. The form of the GS is now clearer because far-infrared surveys such as the Herschel ATLAS pick up a population of optically-red star-forming galaxies that would have been classified as passive using most optical criteria. The space-density of this population is at least as high as the traditional star-forming population. By stacking spectra of H-ATLAS galaxies over the redshift range 0.001 < z < 0.4, we show that the galaxies responsible for the rapid low-redshift evolution have high stellar masses, high star-formation rates but, even several billion years in the past, old stellar populations— they are thus likely to be relatively recent ancestors of early-type galaxies in the Universe today. The form of the GS is inconsistent with rapid quenching models and neither the analytic bathtub model nor the hydrodynamical EAGLE simulation can reproduce the rapid cosmic evolution. We propose a new gentler model of galaxy evolution that can explain the new Herschel results and other key properties of the galaxy population

The causes of the red sequence, the blue cloud, the green valley, and the green mountain

The galaxies found in optical surveys fall in two distinct regions of a diagram of optical colour versus absolute magnitude: the red sequence and the blue cloud with the green valley in between. We show that the galaxies found in a submillimetre survey have almost the opposite distribution in this diagram, forming a `green mountain'. We show that these distinctive distributions follow naturally from a single, continuous, curved Galaxy Sequence in a diagram of specific star-formation rate versus stellar mass without there being the need for a separate star-forming galaxy Main Sequence and region of passive galaxies. The cause of the red sequence and the blue cloud is the geometric mapping between stellar mass/specific star-formation rate and absolute magnitude/colour, which distorts a continuous Galaxy Sequence in the diagram of intrinsic properties into a bimodal distribution in the diagram of observed properties. The cause of the green mountain is Malmquist bias in the submillimetre waveband, with submillimetre surveys tending to select galaxies on the curve of the Galaxy Sequence, which have the highest ratios of submillimetre-to-optical luminosity. This effect, working in reverse, causes galaxies on the curve of the Galaxy Sequence to be underrepresented in optical samples, deepening the green valley. The green valley is therefore not evidence (1) for there being two distinct populations of galaxies, (2) for galaxies in this region evolving more quickly than galaxies in the blue cloud and the red sequence, (c) for rapid quenching processes in the galaxy population

The causes of the red sequence, the blue cloud, the green valley, and the green mountain

The galaxies found in optical surveys fall in two distinct regions of a diagram of optical colour versus absolute magnitude: the red sequence and the blue cloud, with the green valley in between. We show that the galaxies found in a submillimetre survey have almost the opposite distribution in this diagram, forming a \u27green mountain\u27. We show that these distinctive distributions follow naturally from a single, continuous, curved Galaxy Sequence in a diagram of specific star formation rate versus stellar mass, without there being the need for a separate star-forming galaxy main sequence and region of passive galaxies. The cause of the red sequence and the blue cloud is the geometric mapping between stellar mass/specific star formation rate and absolute magnitude/colour, which distorts a continuous Galaxy Sequence in the diagram of intrinsic properties into a bimodal distribution in the diagram of observed properties. The cause of the green mountain isMalmquist bias in the submillimetre waveband, with submillimetre surveys tending to select galaxies on the curve of the Galaxy Sequence, which have the highest ratios of submillimetre-to-optical luminosity. This effect, working in reverse, causes galaxies on the curve of the Galaxy Sequence to be underrepresented in optical samples, deepening the green valley. The green valley is therefore not evidence (1) for there being two distinct populations of galaxies, (2) for galaxies in this region evolving more quickly than galaxies in the blue cloud and the red sequence, and (3) for rapid-quenching processes in the galaxy population

Revealing the complex nature of the strong gravitationally lensed system H-ATLAS J090311.6+003906 using ALMA

We have modelled Atacama Large Millimetre/sub-millimetre Array (ALMA) long baseline imaging of the strong gravitational lens system H-ATLAS J090311.6+003906 (SDP.81). We have reconstructed the distribution of band 6 and 7 continuum emission in the z = 3.042 source and determined its kinematic properties by reconstructing CO(5–4) and CO(8–7) line emission in bands 4 and 6. The continuum imaging reveals a highly non-uniform distribution of dust with clumps on scales of ∼200 pc. In contrast, the CO line emission shows a relatively smooth, disc-like velocity field which is well fitted by a rotating disc model with an inclination angle of (40 ± 5)° and an asymptotic rotation velocity of 320 km s−1. The inferred dynamical mass within 1.5 kpc is (3.5 ± 0.5) × 1010 M⊙ which is comparable to the total molecular gas masses of (2.7 ± 0.5) × 1010 M⊙ and (3.5 ± 0.6) × 1010 M⊙ from the dust continuum emission and CO emission, respectively. Our new reconstruction of the lensed Hubble Space Telescope near-infrared emission shows two objects which appear to be interacting, with the rotating disc of gas and dust revealed by ALMA distinctly offset from the near-infrared emission. The clumpy nature of the dust and a low value of the Toomre parameter of Q ∼ 0.3 suggest that the disc is in a state of collapse. We estimate a star formation rate in the disc of 470 ± 80 M⊙ yr−1 with an efficiency ∼65 times greater than typical low-redshift galaxies. Our findings add to the growing body of evidence that the most infrared luminous, dust obscured galaxies in the high-redshift Universe represent a population of merger-induced starbursts

Niemann-Pick C1 Is Essential for Ebolavirus Replication and Pathogenesis In Vivo

ABSTRACT Recent work demonstrated that the Niemann-Pick C1 (NPC1) protein is an essential entry receptor for filoviruses. While previous studies focused on filovirus entry requirements of NPC1 in vitro, its roles in filovirus replication and pathogenesis in vivo remain unclear. Here, we evaluated the importance of NPC1, and its partner in cholesterol transport, NPC2, by using a mouse model of Ebolavirus (EBOV) disease. We found that, whereas wild-type mice had high viral loads and succumbed to EBOV infection, Npc1−/− mice were entirely free of viral replication and completely protected from EBOV disease. Interestingly, Npc1+/− mice transiently developed high levels of viremia, but were nevertheless substantially protected from EBOV challenge. We also found Npc2−/− mice to be fully susceptible to EBOV infection, while Npc1−/− mice treated to deplete stored lysosomal cholesterol remained completely resistant to EBOV infection. These results provide mechanistic evidence that NPC1 is directly required for EBOV infection in vivo, with little or no role for NPC1/NPC2-dependent cholesterol transport. Finally, we assessed the in vivo antiviral efficacies of three compounds known to inhibit NPC1 function or NPC1-glycoprotein binding in vitro. Two compounds reduced viral titers in vivo and provided a modest, albeit not statistically significant, degree of protection. Taken together, our results show that NPC1 is critical for replication and pathogenesis in animals and is a bona fide target for development of antifilovirus therapeutics. Additionally, our findings with Npc1+/− mice raise the possibility that individuals heterozygous for NPC1 may have a survival advantage in the face of EBOV infection