Probing the 2D kinematic structure of early-type galaxies out to three effective radii

We detail an innovative new technique for measuring the two-dimensional (2D) velocity moments (rotation velocity, velocity dispersion and Gauss–Hermite coefficients h ₃ and h ₄) of the stellar populations of galaxy haloes using spectra from Keck DEIMOS (Deep Imaging Multi-Object Spectrograph) multi-object spectroscopic observations. The data are used to reconstruct 2D rotation velocity maps.
Here we present data for five nearby early-type galaxies to ∼three effective radii. We provide significant insights into the global kinematic structure of these galaxies, and challenge the accepted morphological classification in several cases. We show that between one and three effective radii the velocity dispersion declines very slowly, if at all, in all five galaxies. For the two galaxies with velocity dispersion profiles available from planetary nebulae data we find very good agreement with our stellar profiles. We find a variety of rotation profiles beyond one effective radius, i.e. rotation speed remaining constant, decreasing and increasing with radius. These results are of particular importance to studies which attempt to classify galaxies by their kinematic structure within one effective radius, such as the recent definition of fast- and slow-rotator classes by the Spectrographic Areal Unit for Research on Optical Nebulae project. Our data suggest that the rotator class may change when larger galactocentric radii are probed. This has important implications for dynamical modelling of early-type galaxies. The data from this study are available on-line.     

Modelling the movement of pollutants in the UK shelf seas

The EUROSPILL oil and chemical spill model has been extended to include the transport due to residual currents in the UK shelf seas. Wind-driven circulation patterns for the winter and summer have been derived, and the annual mean (long-term) flow pattern estimated. Current speeds during the winter are typically of the order of 0.05–0.10 m s⁻¹, the summer values show a similar spatial pattern but are considerably weaker. Trajectories over a period of 100 days are presented for a selection of release points arranged on a regular latitude/longitude grid. Estimates of patch size after 300 days are given for releases from sites of heavy shipping and offshore exploration. Use of the method for accident simulation is demonstrated by considering the likely spread of Lindane spilled in the English Channel during March 1989.     

AERIAL TRIANGULATION FOR CONTROL PROVISION

The author has been involved in aerial triangulation, in various capacities, for some 27 years. This period has seen some very significant changes worthy of remark. This essay is a general review of that period; it does not go into detail and no formulae are quoted. The idea has been to look at the more notable developments, skipping the earlier and well documented period in favour of more recent times, particularly as regards the references. The objective will have been achieved if it provides a starting point, indicating further reading, for those who wish to study the subject in greater depth.     

Local and central state control of black settlement in Munsieville,Krugersdorp

Munsieville, one of the Witwatersrand's oldest locations, provides a valuable insight into the forms of control exercised over the urban black population for eight decades. Aspects of this control include restrictions on black movement, on the position and layout of black residential townships, and the taxing of the black population to finance the cost of their control. Resistance by the population to this control has included formal deputations to those in control, wilful contravention of restrictions and violence against symbols of their repression.     

Vein formation and distribution,Ohio and Mt. Baldy districts,Marysvale, Piute County,Utah, USA

The Ohio and Mt. Baldy mining districts near Marysvale, Utah, are situated within a calc-alkalic rock assemblage of the Bullion Canyon Volcanics. The assemblage is divisible into three portions: 1) a lower laharic sequence of epiclastic breccias and autobreccias, 2) a middle portion containing mostly lava flows, including a dacite flow with cupola magma characteristics, and tuff and lapilli breccias, and 3) an upper portion containing a local volcanic vent complex and the ash-flow Delano Peak Tuff Member. Fissuring and veining accompanied magmatic doming. Vein types include: 1) early-stage quartz veins, 2) preproductive main-stage quartz veins, 3) productive main-stage quartz veins, and 4) alunite veins. Each vein of the latter two types is surrounded by advanced argillic, sericitic, argillic, and propylitic alteration halos. Environmental changes during vein fluid deposition account for a district wide zonation of vein types: 1) the boiling level accounts for bonanza precious metal deposits at shallower depths than base metal deposits, and 2) a change from an alkaline or neutral state to an acidic, oxygenated environment, near the paleo-water table, accounts for the presence of alunite veins at shallower depths than ore-bearing veins. Vein mineralogy and texture, wallrock alteration, and geologic structure suggest that an unexposed, ore-generating pluton underlies the area and that the districts represent fringe area mineralization and surface expression of a postulated, ore-bearing pluton.     

Rainfall interception in three contrasting lowland rain forest types in Central Kalimantan, Indonesia

Rainfall interception was quantified and modeled for a Lowland Evergreen Rain Forest (LERF) and two Heath Forests (HF) of contrasting stature during a one-year period at a remote site in Central Kalimantan, Indonesia. Throughfall was measured using a roving gauge approach using 18–20 gauges per forest type. Throughfall was 82.8% of incident rainfall in the LERF vs. 89.1% in tall HF and 76.7% in stunted HF. Corresponding stemflow fractions were 0.8%, 1.3% and 2.0% of rainfall, respectively. Interception losses derived for the LERF (16.4%) and the tall HF (9.6%) were close to findings obtained for similar forest types elsewhere but the high interception loss for the stunted HF (21.3%) was unexpected. On the basis of canopy structural characteristics and wet canopy evaporation modeling it is concluded that throughfall in the stunted HF was underestimated and that the specific nature of the HF required a more intensive sampling arrangement. Throughfall sampling schemes in tropical forests, associated errors and hydrological implications are discussed.     

Closure tests for mean field magnetohydrodynamics using a self-consistent reduced model

The mean electromotive force and α effect are computed for a forced turbulent flow using a simple non-linear dynamical model. The results are used to check the applicability of two basic analytic ansätze of mean-field magnetohydrodynamics – the second-order correlation approximation (SOCA) and the τ approximation. In the numerical simulations the effective Reynolds number Re is 2–20, while the magnetic Prandtl number P _m varies from 0.1 to 10⁷. We present evidence that the τ approximation may be appropriate in dynamical regimes where there is a small-scale dynamo. Catastrophic quenching of the α effect is found for high P _m. Our results indicate that for high P _m SOCA gives a very large value of the α coefficient compared with the 'exact' solution. The discrepancy depends on the properties of the random force that drives the flow, with a larger difference occurring for δ-correlated force compared with that for a steady random force.     

The influence of initial conditions and open boundary conditions on shelf circulation in a 3D ocean-shelf model of the North East Atlantic

Data from climatology (World Ocean Atlas) and two large scale operational ocean models (Forecasting Ocean Assimilation Model (FOAM), UK Met. Office and the Navy Coastal Ocean Model (NCOM), US Naval Research Laboratory) are used to give initial and open boundary conditions for a northeast Atlantic implementation of the Proudman Oceanographic Laboratory Coastal Ocean Model System (POLCOMS). We study the effects of using the different datasets on the temperature fields and the circulation. On the continental shelf, comparisons of POLCOMS output with Advanced Very High Resolution Radiometer sea surface temperature data suggest that the effect of using different ocean model initial and boundary conditions is small and that, after 15 months of model time, the impact of the different initial conditions is negligible. Stronger evidence of influence is seen in the deeper oceanic regions of the domain. Volume fluxes through sections governing flow into and out of the North Sea, through the Irish Sea and along the shelf edge show that the impact of the different boundary conditions is small on the shelf but significant elsewhere. These results are contrasted with the use of climatology to assess the value of these Global Ocean Data Assimilation Experiment ocean model products.