The shift in marine resource management from a compartmentalized approach of dealing with resources on a species basis to an approach based on management of spatially defined ecosystems requires an ...accurate accounting of energy flow. The flow of energy from primary production through the food web will ultimately limit upper trophic-level fishery yields. In this work, we examine the relationship between yield and several metrics including net primary production, chlorophyll concentration, particle-export ratio, and the ratio of secondary to primary production. We also evaluate the relationship between yield and two additional rate measures that describe the export of energy from the pelagic food web, particle export flux and mesozooplankton productivity. We found primary production is a poor predictor of global fishery yields for a sample of 52 large marine ecosystems. However, chlorophyll concentration, particle-export ratio, and the ratio of secondary to primary production were positively associated with yields. The latter two measures provide greater mechanistic insight into factors controlling fishery production than chlorophyll concentration alone. Particle export flux and mesozooplankton productivity were also significantly related to yield on a global basis. Collectively, our analyses suggest that factors related to the export of energy from pelagic food webs are critical to defining patterns of fishery yields. Such trophic patterns are associated with temperature and latitude and hence greater yields are associated with colder, high latitude ecosystems.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
We present precise measurements of the growth rate of cosmic structure for the redshift range 0.1 < z < 0.9, using redshift-space distortions in the galaxy power spectrum of the WiggleZ Dark Energy ...Survey. Our results, which have a precision of around 10 per cent in four independent redshift bins, are well fitted by a flat Λ cold dark matter (ΛCDM) cosmological model with matter density parameter Ωm= 0.27. Our analysis hence indicates that this model provides a self-consistent description of the growth of cosmic structure through large-scale perturbations and the homogeneous cosmic expansion mapped by supernovae and baryon acoustic oscillations. We achieve robust results by systematically comparing our data with several different models of the quasi-linear growth of structure including empirical models, fitting formulae calibrated to N-body simulations, and perturbation theory techniques. We extract the first measurements of the power spectrum of the velocity divergence field, P
θθ(k), as a function of redshift (under the assumption that
, where g is the galaxy overdensity field), and demonstrate that the WiggleZ galaxy-mass cross-correlation is consistent with a deterministic (rather than stochastic) scale-independent bias model for WiggleZ galaxies for scales k < 0.3 h Mpc−1. Measurements of the cosmic growth rate from the WiggleZ Survey and other current and future observations offer a powerful test of the physical nature of dark energy that is complementary to distance-redshift measures such as supernovae and baryon acoustic oscillations.
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BFBNIB, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
ABSTRACT
We use the hydrodynamic EAGLE simulation to predict the numbers and masses of supermassive black holes in remnant nuclei of disrupted galaxies (stripped nuclei) and compare these to ...confirmed measurements of black holes in observed ultra-compact dwarf galaxies (UCDs). We find that black holes in stripped nuclei are consistent with the numbers and masses of those in observed UCDs. Approximately 50 per cent of stripped nuclei with M > 2 × 106 M⊙ should contain supermassive black holes. We further calculate how the presence of a black hole increases the dynamical mass of a stripped nucleus via the mass elevation ratio, Ψ defined as the ratio of the kinematically derived mass to the expected mass from stellar population synthesis. We find Ψsim$= 1.51^{+0.06}_{-0.04}$ for M > 107 M⊙ stripped nuclei, consistent with that of observed UCDs, which have Ψobs = 1.7 ± 0.2 above M > 107 M⊙. We also find that the mass elevation ratios of stripped nuclei with supermassive black holes can explain the observed number of UCDs with elevated mass-to-light ratios. Finally, we predict the relative number of massive black holes in stripped nuclei and galaxy nuclei and find that stripped nuclei should increase the number of black holes in galaxy clusters by 30 − 100 per cent, depending on the black hole occupation fraction of low-mass galaxies. We conclude that the population of supermassive black holes in UCDs represents a large and unaccounted-for portion of supermassive black holes in galaxy clusters.
We present significant improvements in cosmic distance measurements from the WiggleZ Dark Energy Survey, achieved by applying the reconstruction of the baryonic acoustic feature technique. We show ...using both data and simulations that the reconstruction technique can often be effective despite patchiness of the survey, significant edge effects and shot-noise. We investigate three redshift bins in the redshift range 0.2 < z < 1, and in all three find improvement after reconstruction in the detection of the baryonic acoustic feature and its usage as a standard ruler. We measure model-independent distance measures D
V(r
s
fid/r
s) of 1716 ± 83, 2221 ± 101, 2516 ± 86 Mpc (68 per cent CL) at effective redshifts z = 0.44, 0.6, 0.73, respectively, where D
V is the volume-averaged distance, and r
s is the sound horizon at the end of the baryon drag epoch. These significantly improved 4.8, 4.5 and 3.4 per cent accuracy measurements are equivalent to those expected from surveys with up to 2.5 times the volume of WiggleZ without reconstruction applied. These measurements are fully consistent with cosmologies allowed by the analyses of the Planck Collaboration and the Sloan Digital Sky Survey. We provide the D
V(r
s
fid/r
s) posterior probability distributions and their covariances. When combining these measurements with temperature fluctuations measurements of Planck, the polarization of Wilkinson Microwave Anisotropy Probe 9, and the 6dF Galaxy Survey baryonic acoustic feature, we do not detect deviations from a flat Λ cold dark matter (ΛCDM) model. Assuming this model, we constrain the current expansion rate to H
0 = 67.15 ± 0.98 km s−1Mpc−1. Allowing the equation of state of dark energy to vary, we obtain w
DE = −1.080 ± 0.135. When assuming a curved ΛCDM model we obtain a curvature value of ΩK = −0.0043 ± 0.0047.
The volume of literature on fitness testing in court sports such as basketball is considerably less than for field sports or individual sports such as running and cycling. Team sport performance is ...dependent upon a diverse range of qualities including size, fitness, sport-specific skills, team tactics, and psychological attributes. The game of basketball has evolved to have a high priority on body size and physical fitness by coaches and players. A player's size has a large influence on the position in the team, while the high-intensity, intermittent nature of the physical demands requires players to have a high level of fitness. Basketball coaches and sport scientists often use a battery of sport-specific physical tests to evaluate body size and composition, and aerobic fitness and power. This testing may be used to track changes within athletes over time to evaluate the effectiveness of training programmes or screen players for selection. Sports science research is establishing typical (or 'reference') values for both within-athlete changes and between-athlete differences. Newer statistical approaches such as magnitude-based inferences have emerged that are providing more meaningful interpretation of fitness testing results in the field for coaches and athletes. Careful selection and implementation of tests, and more pertinent interpretation of data, will enhance the value of fitness testing in high-level basketball programmes. This article presents reference values of fitness and body size in basketball players, and identifies practical methods of interpreting changes within players and differences between players beyond the null-hypothesis.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
6.
The two formation pathways of S0 galaxies Deeley, Simon; Drinkwater, Michael J; Sweet, Sarah M ...
Monthly notices of the Royal Astronomical Society,
11/2021, Volume:
508, Issue:
1
Journal Article
Peer reviewed
Open access
ABSTRACT
Despite their ubiquity throughout the Universe, the formation of S0 galaxies remains uncertain. Recent observations have revealed that S0 galaxies make up a diverse population that is ...difficult to explain with a single formation pathway, suggesting that the picture of how these galaxies form is more complicated than originally envisioned. Here, we take advantage of the latest hydrodynamical cosmological simulations and follow up these studies with an investigation into the formation histories of S0s in IllustrisTNG. We first classify IllustrisTNG galaxies in a way that is fully consistent with the observations, and reproduce the observed photometric and environmental distributions seen for the S0 population. We then trace the formation histories of S0 galaxies back through time, identifying two main distinct pathways: those that experienced gas stripping via group infalls (37 per cent of S0s) or significant merger events (57 per cent). We find that those forming via mergers feature a transient star-forming ring, whose present-day occurrence rate matches observations. We find that these formation pathways together can reproduce the range in rotational support in observed S0s, concluding that there are two main formation pathways for S0 galaxies.
Abstract
We perform a joint determination of the distance-redshift relation and cosmic expansion rate at redshifts z = 0.44, 0.6 and 0.73 by combining measurements of the baryon acoustic peak and ...Alcock-Paczynski distortion from galaxy clustering in the WiggleZ Dark Energy Survey, using a large ensemble of mock catalogues to calculate the covariance between the measurements. We find that D
A(z) = (1205 ± 114, 1380 ± 95, 1534 ± 107) Mpc and H(z) = (82.6 ± 7.8, 87.9 ± 6.1, 97.3 ± 7.0) km s−1 Mpc−1 at these three redshifts. Further combining our results with other baryon acoustic oscillation and distant supernovae data sets, we use a Monte Carlo Markov Chain technique to determine the evolution of the Hubble parameter H(z) as a stepwise function in nine redshift bins of width Δz = 0.1, also marginalizing over the spatial curvature. Our measurements of H(z), which have precision better than 7 per cent in most redshift bins, are consistent with the expansion history predicted by a cosmological constant dark energy model, in which the expansion rate accelerates at redshift z < 0.7.
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BFBNIB, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
Abstract
We present hydrodynamical N-body models which demonstrate that elliptical galaxies can transform into S0s by acquiring a disc. In particular, we show that the merger with a massive gas-rich ...satellite can lead to the formation of a baryonic disc around an elliptical. We model the elliptical as a massive, compact galaxy which could be observed as a ‘red nugget’ in the high-z universe. This scenario contrasts with existing S0 formation scenarios in the literature in two important ways. First, the progenitor is an elliptical galaxy whereas scenarios in the literature typically assume a spiral progenitor. Secondly, the physical conditions underlying our proposed scenario can exist in low-density environments such as the field, in contrast to scenarios in the literature which typically address dense environments like clusters and groups. As a consequence, S0s in the field may be the most likely candidates to have evolved from elliptical progenitors. Our scenario also naturally explains recent observations which indicate that field S0s may have older bulges than discs, contrary to cluster S0s which seem to have older discs than bulges.
We present measurements of the baryon acoustic peak at redshifts z= 0.44, 0.6 and 0.73 in the galaxy correlation function of the final data set of the WiggleZ Dark Energy Survey. We combine our ...correlation function with lower redshift measurements from the 6-degree Field Galaxy Survey and Sloan Digital Sky Survey, producing a stacked survey correlation function in which the statistical significance of the detection of the baryon acoustic peak is 4.9σ relative to a zero-baryon model with no peak. We fit cosmological models to this combined baryon acoustic oscillation (BAO) data set comprising six distance-redshift data points, and compare the results with similar cosmological fits to the latest compilation of supernovae (SNe) and cosmic microwave background (CMB) data. The BAO and SNe data sets produce consistent measurements of the equation-of-state w of dark energy, when separately combined with the CMB, providing a powerful check for systematic errors in either of these distance probes. Combining all data sets we determine w=−1.03 ± 0.08 for a flat universe, consistent with a cosmological constant model. Assuming dark energy is a cosmological constant and varying the spatial curvature, we find Ωk=−0.004 ± 0.006.
ABSTRACT
Compact elliptical (cE) galaxies remain an elusively difficult galaxy class to study. Recent observations have suggested that isolated and host-associated cEs have different formation ...pathways, while simulation studies have also shown different pathways can lead to a cE galaxy. However, a solid link has not been established, and the relative contributions of each pathway in a cosmological context remains unknown. Here, we combine a spatially resolved observational sample of cEs taken from the Sydney-AAO Multi-object Integral field spectrograph Galaxy Survey with a matched sample of galaxies within the IllustrisTNG cosmological simulation to establish an overall picture of how these galaxies form. The observed cEs located near a host galaxy appear redder, smaller, and older than isolated cEs, supporting previous evidence for multiple formation pathways. Tracing the simulated cEs back through time, we find two main formation pathways; 32 ± 5 per cent formed via the stripping of a spiral galaxy by a larger host galaxy, while 68 ± 4 per cent formed through a gradual build-up of stellar mass in isolated environments. We confirm that cEs in different environments do indeed form via different pathways, with all isolated cEs in our sample having formed via in situ formation (i.e. none were ejected from a previous host), and 77 ± 6 per cent of host-associated cEs having formed via tidal stripping. Separating them by their formation pathway, we are able to reproduce the observed differences between isolated and host-associated cEs, showing that these differences can be fully explained by the different formation pathways dominating in each environment.
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