The 6dF Galaxy Survey: final redshift release (DR3) and southern large-scale structures     

D. Heath Jones  Mike A. Read  Will Saunders  Matthew Colless  Tom Jarrett  Quentin A. Parker  Anthony P. Fairall †  Thomas Mauch  Elaine M. Sadler  Fred G. Watson  Donna Burton  Lachlan A. Campbell  Paul Cass  Scott M. Croom  John Dawe †  Kristin Fiegert  Leela Frankcombe  Malcolm Hartley  John Huchra  Dionne James  Emma Kirby  Ofer Lahav  John Lucey  Gary A. Mamon  Lesa Moore  Bruce A. Peterson  Sayuri Prior  Dominique Proust  Ken Russell  Vicky Safouris  Ken-ichi Wakamatsu  Eduard Westra  Mary Williams 《Monthly notices of the Royal Astronomical Society》2009,399(2):683-698

We report the final redshift release of the 6dF Galaxy Survey (6dFGS), a combined redshift and peculiar velocity survey over the southern sky  (| b | > 10°)  . Its 136 304 spectra have yielded 110 256 new extragalactic redshifts and a new catalogue of 125 071 galaxies making near-complete samples with  ( K , H , J , r _F, b _J) ≤ (12.65, 12.95, 13.75, 15.60, 16.75)  . The median redshift of the survey is 0.053. Survey data, including images, spectra, photometry and redshifts, are available through an online data base. We describe changes to the information in the data base since earlier interim data releases. Future releases will include velocity dispersions, distances and peculiar velocities for the brightest early-type galaxies, comprising about 10 per cent of the sample. Here we provide redshift maps of the southern local Universe with   z ≤ 0.1  , showing nearby large-scale structures in hitherto unseen detail. A number of regions known previously to have a paucity of galaxies are confirmed as significantly underdense regions. The URL of the 6dFGS data base is http://www-wfau.roe.ac.uk/6dFGS .  相似文献   

Radio sources in the 2dF Galaxy Redshift Survey – II. Local radio luminosity functions for AGN and star-forming galaxies at 1.4 GHz     

Elaine M. Sadler  Carole A. Jackson  Russell D. Cannon  Vincent J. McIntyre  Tara Murphy  Joss Bland-Hawthorn  Terry Bridges  Shaun Cole  Matthew Colless  Chris Collins  Warrick Couch  Gavin Dalton  Roberto De Propris  Simon P. Driver  George Efstathiou  Richard S. Ellis  Carlos S. Frenk  Karl Glazebrook  Ofer Lahav  Ian Lewis  Stuart Lumsden  Steve Maddox  Darren Madgwick  Peder Norberg  John A. Peacock  Bruce A. Peterson  Will Sutherland  Keith Taylor 《Monthly notices of the Royal Astronomical Society》2002,329(1):227-245

We have cross-matched the 1.4-GHz NRAO VLA Sky Survey (NVSS) with the first 210 fields observed in the 2dF Galaxy Redshift Survey (2dFGRS), covering an effective area of 325 deg² (about 20 per cent of the final 2dFGRS area). This yields a set of optical spectra of 912 candidate NVSS counterparts, of which we identify 757 as genuine radio identifications – the largest and most homogeneous set of radio source spectra ever obtained. The 2dFGRS radio sources span the redshift range     to 0.438, and are a mixture of active galaxies (60 per cent) and star-forming galaxies (40 per cent). About 25 per cent of the 2dFGRS radio sources are spatially resolved by NVSS, and the sample includes three giant radio galaxies with projected linear size greater than 1 Mpc. The high quality of the 2dF spectra means we can usually distinguish unambiguously between AGN and star-forming galaxies. We make a new determination of the local radio luminosity function at 1.4 GHz for both active and star-forming galaxies, and derive a local star formation density of         .  相似文献   

Simulation of Typhoon-Driven Waves in the Yangtze Estuary with Multiple-Nested Wave Models   总被引：4，自引：0，他引：4  

徐福敏 Will Perrie张君伦  宋志尧Bechara Toulany 《中国海洋工程》2005,19(4):613-624

Typhoon-generated waves are simulated with two numerical wave models, the SWAN model for the coastal and Yangtze Estuary domain, nested within the WAVEWATCHIII （WW3） for the basin-scale East China Sea domain. Typhoon No. 8114 is chosen because it was very strong, and generated high waves in the Estuary. WW3 was implemented for the East China Sea coarse-resolution computational domain, to simulate the waves over a large spatial scale and provide boundary conditions for SWAN model simulations, implemented on a fine-resolution nested domain for the Yangtze Estuary area. The Takahashi wind model is applied to the simulation of the East China Sea scale （3-hourly） and Yangtze Estuary scale （1-hourly） winds. Simulations of significant wave heights in the East China Sea show that the highest waves are on the right side of the storm track, and maxima tend to occur at the eastern deep-water open boundary of the Yangtze Estuary. In the Yangtze Estuary, incoming swell is dominant over locally generated waves before the typhoon approaches the Estuary. As the typhoon approaches the Estuary, wind waves and swell coexist, and the wave direction is mainly influenced by the swell direction and the complex topography.  相似文献   

Ocean zoning in the Northwest Atlantic     

Penny A. Doherty  Mark Butler 《Marine Policy》2006

A workshop held in Halifax, Nova Scotia, Canada, brought together marine policy makers, resource users and experts to discuss spatial planning in the marine environment. Participants explored concepts of ocean zoning and learned from other jurisdictions and related integrated management initiatives. An ocean user perspectives panel featured plenary addresses on the significance of ocean zoning to various sectors. Discussions at the workshop emphasized the need for involving all key players and clearly defining terms used in the spatial planning process.  相似文献   

Mantle derivation of Archean amphibole-bearing granitoid and associated mafic rocks: evidence from the southern Superior Province,Canada   总被引：5，自引：0，他引：5  

Richard H. Sutcliffe  Alan R. Smith  William Doherty  Robert L. Barnett 《Contributions to Mineralogy and Petrology》1990,105(3):255-274

Amphibole-bearing, Late Archean (2.73–2.68 Ga) granitoids of the southern Superior Province are examined to constrain processes of crustal development. The investigated plutons, which range from tonalite and diorite to monzodiorite, monzonite, and syenite, share textural, mineralogical and geochemical attributes suggesting a common origin as juvenile magmas. Despite variation in modal mineralogy, the plutons are geochemically characterized by normative quartz, high Al₂O₃ (> 15 wt%), Na-rich fractionation trends (mol Na₂O/K₂O >2), low to moderate Rb (generally<100 ppm), moderate to high Sr (200–1500 ppm), enriched light rare earth elements (LREE) (Ce_N generally 10–150), fractionated REE (Ce_N/Yb_N 8–30), Eu anomaly (Eu/Eu^*) 1, and decreasing REE with increasing SiO₂. The plutons all contain amphibole-rich, mafic-ultramafic rocks which occur as enclaves and igneous layers and as intrusive units which exhibit textures indicative of contemporaneous mafic and felsic magmatism. Mafic mineral assemblages include: hornblende + biotite in tonalites; augite + biotite ± orthopyroxene ± pargasitic hornblende or hornblende+biotite in dioritic to monzodioritic rocks; and aegirine-augite ± silicic edenite ± biotite in syenite to alkali granite. Discrete plagioclase and microcline grains are present in most of the suites, however, some of the syenitic rocks are hypersolvus granitoids and contain only perthite. Mafic-ultramafic rocks have REE and Y contents indicative of their formation as amphibole-rich cumulates from the associated granitoids. Some cumulate rocks have skeletal amphibole with X_Mg(Mg/(Mg+ Fe²⁺)) indicative of crystallization from more primitive liquids than the host granitoids. Geochemical variation in the granitoid suites is compatible with fractionation of amphibole together with subordinate plagioclase and, in some cases, mixing of fractionated and primitive magmas. Mafic to ultramafic units with magnesium-rich cumulus phases and primitive granitoids (mol MgO/ (MgO+0.9 FeO^TOTAL) from 0.60 to 0.70 and C_T >150 ppm) are comagmatic with the evolved granitoids and indicate that the suites are mantle-derived. Isotopic studies of Archean monzodioritic rocks have shown LREE enrichment and initial ¹⁴³Nd/¹⁴⁴Nd ratios indicating derivation from mantle sources enriched in large ion lithophile elements (LILE) shortly before melting. Mineral assemblages record lower P_H2O with increased alkali contents of the suites. This evidence, in conjunction with experimental studies, suggests that increased alkali contents may reflect decreased P_H2O during mantle melting. These features indicate that 2.73 Ga tonalitic rocks are derived from more hydrous mantle sources than 2.68 Ga syenitic rocks, and that the spectrum of late Archean juvenile granitoid rocks is broader than previously recognized. Comparison with Phanerozoic and recent plutonic suites suggests that these Archean suites are subduction related.  相似文献   

Determination of trace elemental signatures in placer gold by laser ablation–inductively coupled plasma–mass spectrometry as a potential aid for gold exploration     

P.M. Outridge  W. Doherty  D.C. Gregoire 《Journal of Geochemical Exploration》1998,60(3):229-240

It is possible that placer gold retains the trace element composition (`signature') of the parent lode. Laser ablation–inductively coupled plasma–mass spectrometry (LA–ICP–MS) offers sensitive detection limits of 59 elements with sub-millimetre sample spot sizes, ideal for signature analysis of placer. Here, the optimum laser parameters, analytical precision and reproducibility of elemental signatures are determined in placer nuggets by infrared LA–ICP–MS. The highest precision was offered by Q-switched ablation at a relatively low energy level, using Au as an internal standard; these parameters gave median precision values of 33–82% RSD for trace elements in nuggets. In addition to major constituents such as Ag, Cu and Hg, placer from several rivers world-wide commonly contained a wide range of trace elements including, in some cases, unusual REE patterns. At least two distinct signatures could be distinguished in placer from most of the rivers examined, while multiple examples of certain signatures were also seen. Tracking these signatures back to their original tributaries may offer a means of identifying the number and approximate location of deposits within a river watershed, thereby significantly aiding exploration.  相似文献   

Displacement‐based seismic analysis for out‐of‐plane bending of unreinforced masonry walls     

K. Doherty  M. C. Griffith  N. Lam  J. Wilson 《地震工程与结构动力学》2002,31(4):833-850

This paper addresses the problem of assessing the seismic resistance of brick masonry walls subject to out‐of‐plane bending. A simplified linearized displacement‐based procedure is presented along with recommendations for the selection of an appropriate substitute structure in order to provide the most representative analytical results. A trilinear relationship is used to characterize the real nonlinear force–displacement relationship for unreinforced brick masonry walls. Predictions of the magnitude of support motion required to cause flexural failure of masonry walls using the linearized displacement‐based procedure and quasi‐static analysis procedures are compared with the results of experiments and non‐linear time‐history analyses. The displacement‐based procedure is shown to give significantly better predictions than the force‐based method. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   

Electrical conductivity measurements on olivines Mg2SiO4-Fe2SiO4 under defined thermodynamic conditions     

L. Cemič  G. Will  E. Hinze 《Physics and Chemistry of Minerals》1980,6(2):95-107

The isobaric (P=10 kb) temperature dependence of the electrical conductivities of forsterite, fayalite and forsterite-fayalite mixed crystals was measured with special regard to the thermodynamics of point defects in these minerals. Measurements, taken at increasing and decreasing temperature, were performed on synthetic powders of the following compositions: Fo 100/Fa 0, Fo 90/Fa 10, Fo 80/Fa 20, Fo 60/Fa 40, and Fo 0/Fa100. Control of oxygen partial pressure was achieved with solid state buffers (Fa/Q/M, Fa/Q/I, and Fe/FeO). Activities of the binary components were controlled by equilibrating the sample with its neighbouring phases. All values for σ, obtained with controlled pO₂ and fixed activities of the binary components, agree well upon either heating or cooling. From the gradient of lg σ vs. 1/T plots, the following activation energies were estimated: 2,461 eV (970°–1075°C) and 0.984 eV (522°–970°C) for Fo 100/Fa 0 equilibrated with MgO; 0.777 eV and 0.683 eV for Fo 90/Fa 10 and Fo 80/Fa 20 equilibrated with enstatite and pO₂ controlled by Fe/FeO buffer; 0.622 eV, 0.528 eV, and 0.479 eV for Fo 90/Fa 10, Fo 80/Fa 20, and Fo 60/Fa 40 equilibrated with enstatite and pO₂ controlled by Fa/Q/M buffer; and 0.524 eV and 0.383 eV for Fo 0/Fa 100 equilibrated with Q/I and Q/M respectively.  相似文献   

Conditions during syntectonic vein formation in the footwall of the Absaroka Thrust Fault, Idaho–Wyoming–Utah fold and thrust belt     

David V. Wiltschko  George R. Lambert  Will Lamb 《Journal of Structural Geology》2009,31(9):1039

The Twin Creek Limestone in the footwall of the Absaroka thrust sheet contains three sets of bed-normal syntectonic calcite veins. Vein formation occurred during Cretaceous motion along the Absaroka thrust fault as indicated by (1) crosscutting relationships among these vein sets, (2) a previously dated solution cleavage, and (3) calcite twin analysis. Fluid inclusions in the veins and overburden estimates constrain inclusion entrapment temperatures to be between 175 °C and 328 °C. Results from stable oxygen isotopes indicate that the host and vein fluid compositions were in near isotopic equilibrium. Applying both reasonable geothermal gradients and constraints on overburden temperature yields fluid pressures during vein precipitation that are near hydrostatic. All data taken together suggest both that vein formation within the Twin Creek Formation occurred in a relatively closed system, and that the veins filled near hydrostatic fluid pressure. Because the veins fill precursory cracks, vein filling might not reflect the maximum fluid pressure that existed during the complete vein forming process.  相似文献   

The luminosity dependence of clustering and higher order correlations in the PSCz survey     

István Szapudi  †  Enzo Branchini  C. S. Frenk  Steve Maddox  Will Saunders 《Monthly notices of the Royal Astronomical Society》2000,318(4):L45-L50

  相似文献