Galaxy clustering and feedback

I cross-correlate the WMAP third year data with the АСО, АРМ and 2MASS galaxy and cluster catalogues, confirming the presence of the SZ effect in the WMAP 3rd year data around АСО, АРМ and 2MASS clusters, showing an increase in detection significance compared to previous analyses of the 1-year WMAP data release. I compare the cross-correlation results for a number of clusters to their SZ β-model profiles estimated from ROSAT and Chandra X-ray data. I conclude that the SZ profiles estimated from the β -model over-predict the observed SZ effect in the cluster samples. Additionally, I develop colour cuts using the SDSS optical bands to photometrically select emission line galaxies at redshifts of z 0.55. The selections have been calibrated using a combination of photometric redshifts from the COMBO-17 survey and spectroscopic observations. I estimate correlation lengths of rо = 2.64 (^+2.64_-0.08) h (^-1) Mpc, ro = 3.62 > ± 0.06h (^-1) and rо = 5.88 ± 0.12h (^-1)Mpc for the low, mid and high redshift samples respectively. Using these photometric samples I search for the Integrated Sachs- Wolfe signal in the WMAP 5yr data, but find no significant detection. I also present a survey of star-forming galaxies at z ≈ 3. Using Lyman Break and U-dropout photometric elections, we identify a total of ≈ 21,000 candidate z > 2 galaxies and perform spectroscopic observations of a selection of these candidates with integration times of 10,000s with the VLT VIMOS. In total this survey has so far produced a total of 1149 LBGs at redshifts of 2 2 galaxy sample using the angular correlation function, measuring a clustering amplitude of rо = 4.32(^+0.13_-0.12)h (^-1) Mpc with a slope of ϒ2 = 1.90 (^+0.09_-0.14) at separations of r > 0.4h(+-1) Mpc. We then measure the redshift space clustering based on the spectroscopically observed sample and estimate the infall parameter, β, of the sample by fitting a redshift space distortion model to the ع (σ, π). To conclude this work, I analyze the correlation of LBGs with the Lya forest transmissivity of a number of z ~ 3 QSOs, with the aim of looking for the imprint of high velocity winds on the IGM. The data show a fall in the transmissivity in the Lya forest at scales of 5h(^-1)Mpc < r < 10h(^-1)Mpc away from LBGs, indicating an increase in gas densities at these scales. However we find no significant change from the mean transmissivity at scales of <3h(^-1)Mpc, potentially signifying the presence of low density ionised regions close to LBGs

Into the Lyα jungle: exploring the circumgalactic medium of galaxies at z ∼ 4 − 5 with MUSE

We present a study of the galaxy environment of 9 strong H I+C IV absorption line systems (16.2 < log(N(HI)) < 21.2) spanning a wide range in metallicity at z ∼ 4 − 5, using MUSE integral field and X-Shooter spectroscopic data collected in a z ≈ 5.26 quasar field. We identify galaxies within a 250 kpc and ±1000 km s−1 window for 6 out of the 9 absorption systems, with 2 of the absorption line systems showing multiple associated galaxies within the MUSE field of view. The space density of Lyα emitting galaxies (LAEs) around the H I and C IV systems is ≈10 − 20 times the average sky density of LAEs given the flux limit of our survey, showing a clear correlation between the absorption and galaxy populations. Further, we find that the strongest C IV systems in our sample are those that are most closely aligned with galaxies in velocity space, i.e. within velocities of ±500 km s−1. The two most metal poor systems lie in the most dense galaxy environments, implying we are potentially tracing gas that is infalling for the first time into star-forming groups at high redshift. Finally, we detect an extended Lyα nebula around the z ≈ 5.26 quasar, which extends up to ≈50 kpc at the surface brightness limit of 3.8 × 10−18 erg s−1 cm−2 arcsec−2. After scaling for surface brightness dimming, we find that this nebula is centrally brighter, having a steeper radial profile than the average for nebulae studied at z ∼ 3 and is consistent with the mild redshift evolution seen from z ≈ 2

An exponential decline at the bright end of the z=6 galaxy luminosity function

We present the results of a search for the most luminous star-forming galaxies at redshifts z~6 based on CFHT Legacy Survey data. We identify a sample of 40 Lyman break galaxies brighter than magnitude z'=25.3 across an area of almost 4 square degrees. Sensitive spectroscopic observations of seven galaxies provide redshifts for four, of which only two have moderate to strong Lyman alpha emission lines. All four have clear continuum breaks in their spectra. Approximately half of the Lyman break galaxies are spatially resolved in 0.7 arcsec seeing images, indicating larger sizes than lower luminosity galaxies discovered with the Hubble Space Telescope, possibly due to on-going mergers. The stacked optical and infrared photometry is consistent with a galaxy model with stellar mass ~ 10^{10} solar masses. There is strong evidence for substantial dust reddening with a best-fit A_V=0.7 and A_V>0.48 at 2 sigma confidence, in contrast to the typical dust-free galaxies of lower luminosity at this epoch. The spatial extent and spectral energy distribution suggest that the most luminous z~6 galaxies are undergoing merger-induced starbursts. The luminosity function of z=5.9 star-forming galaxies is derived. This agrees well with previous work and shows strong evidence for an exponential decline at the bright end, indicating that the feedback processes which govern the shape of the bright end are occurring effectively at this epoch.Comment: 14 pages, 11 figures, AJ in press, revised to address referee comment

MUSE Analysis of Gas around Galaxies (MAGG) - I: Survey design and the environment of a near pristine gas cloud at z ≈ 3.5

We present the design, methods, and first results of the MUSE Analysis of Gas around Galaxies (MAGG) survey, a large programme on the Multi Unit Spectroscopic Explorer (MUSE) instrument at the Very Large Telescope (VLT) which targets 28 z > 3.2 quasars to investigate the connection between optically-thick gas and galaxies at z ∼ 3 − 4. MAGG maps the environment of 52 strong absorption line systems at z ≳ 3, providing the first statistical sample of galaxies associated with gas-rich structures in the early Universe. In this paper, we study the galaxy population around a very metal poor gas cloud at z ≈ 3.53 towards the quasar J124957.23−015928.8. We detect three Lyα emitters within ≲200 km s−1 of the cloud redshift, at projected separations ≲185 kpc (physical). The presence of star-forming galaxies near a very metal-poor cloud indicates that metal enrichment is still spatially inhomogeneous at this redshift. Based on its very low metallicity and the presence of nearby galaxies, we propose that the most likely scenario for this LLS is that it lies within a filament which may be accreting onto a nearby galaxy. Taken together with the small number of other LLSs studied with MUSE, the observations to date show a range of different environments near strong absorption systems. The full MAGG survey will significantly expand this sample and enable a statistical analysis of the link between gas and galaxies to pin down the origin of these diverse environments at z ≈ 3 − 4

Metal-enriched halo gas across galaxy overdensities over the last 10 billion years

We present a study of metal-enriched halo gas traced by Mg II and C IV absorption at z 1. It is clear from our results that environmental processes have a significant impact on the distribution of metals around galaxies and need to be fully accounted for when analysing correlations between gaseous haloes and galaxy properties

Is the Presence of Microalbuminuria a Relevant Marker of Kidney Disease?

Levels of urinary albumin excretion that are below the usual limit of detection by qualitative testing, but are above normal levels (microalbuminuria; MA), can be readily identified by simple measures, such as the urinary albumin to creatinine ratio in untimed urine samples. Such measurements, particularly when combined with assessment of estimated glomerular filtration rate (eGFR), have utility as biomarkers for enhanced risk of all-cause mortality, cardiovascular events, progressive chronic kidney disease, and end-stage renal disease in diabetic and nondiabetic subjects. However, it is controversial whether “isolated” MA (MA in the absence of a clear reduction in eGFR, urine sediment abnormalities, or structural renal disease) should be regarded as kidney disease. Such MA could also be regarded as a manifestation of a diffuse endothelial (microvascular) injury and thereby collateral kidney damage. This article reviews the current evidence concerning MA as a marker of kidney disease or kidney damage

Demography and Life Histories of Sympatric Patas Monkeys, Erythrocebus patas, and Vervets, Cercopithecus aethiops, in Laikipia, Kenya

Mortality patterns are thought to be strong selective forces on life history traits, with high adult mortality and low immature mortality favoring early and rapid reproduction. Patas monkeys (Erythrocebus patas) have the highest potential rates of population increase for their body size of any haplorhine primate because they reproduce both earlier and more often. We report here 10 yr of comparative demographic data on a population of patas monkeys and a sympatric population of vervet monkeys (Cercopithecus aethiops), a closely related species differing in aspects of social system, ecology, and life history. The data reveal that 1) adult female patas monkeys have significantly higher mortality than adult female vervets; 2) infant mortality in patas monkeys is relatively low compared to the norm for mammals because it is not significantly different from that of adult female patas monkeys; and 3) infant mortality is significantly higher than adult female mortality in vervets. For both species, much of the mortality could be attributed to predation. An epidemic illness was also a major contributor to the mortality of adult female patas monkeys whereas chronic exposure to pathogens in a cold and damp microenvironment may have contributed to the mortality of infant vervets. Both populations experienced large fluctuations during the study period. Our results support the prediction from demographic models of life history evolution that high adult mortality relative to immature mortality selects for early maturation

The status of the world's land and marine mammals: diversity, threat, and knowledge

Knowledge of mammalian diversity is still surprisingly disparate, both regionally and taxonomically. Here, we present a comprehensive assessment of the conservation status and distribution of the world's mammals. Data, compiled by 1700+ experts, cover all 5487 species, including marine mammals. Global macroecological patterns are very different for land and marine species but suggest common mechanisms driving diversity and endemism across systems. Compared with land species, threat levels are higher among marine mammals, driven by different processes (accidental mortality and pollution, rather than habitat loss), and are spatially distinct (peaking in northern oceans, rather than in Southeast Asia). Marine mammals are also disproportionately poorly known. These data are made freely available to support further scientific developments and conservation action