Can simulations reproduce the observed temperature–mass relation for clusters of galaxies?     

Peter A.Thomas  OrrarujeeMuanwong  Scott T.Kay  rew R.Liddle 《Monthly notices of the Royal Astronomical Society》2002,330(2):L48-L52

It has become increasingly apparent that traditional hydrodynamical simulations of galaxy clusters are unable to reproduce the observed properties of galaxy clusters, in particular overpredicting the mass corresponding to a given cluster temperature. Such overestimation may lead to systematic errors in results using galaxy clusters as cosmological probes, such as constraints on the density perturbation normalization σ ₈. In this paper we demonstrate that inclusion of additional gas physics, namely radiative cooling and a possible pre-heating of gas prior to cluster formation, is able to bring the temperature–mass relation in the innermost parts of clusters into good agreement with recent determinations by Allen, Schmidt & Fabian using Chandra data.  相似文献   

A comparison of three approaches to spatial generalization of rainfall–runoff models     

A. L. Kay  D. A. Jones  S. M. Crooks  A. Calver  N. S. Reynard 《水文研究》2006,20(18):3953-3973

The generalization of the parameters of rainfall–runoff models, to enable application at ungauged sites, is an important and ongoing area of research. This paper compares the performance of three alternative methods of generalization, for two parameter‐sparse conceptual models (PDM and TATE), specifically for use in flood frequency estimation using continuous simulation. Two of the methods are based on fitting regression relationships between catchment properties and calibrated parameter values, using weighted or sequential regression (with weights based on estimates of calibration uncertainty), and the third is based on the use of pooling groups, defined through measures of site‐similarity based on catchment properties. The study uses a relatively large sample of catchments in Britain. For the PDM, the site‐similarity method performs best, but not greatly better than either regression method, so there may be cases where the use of regression would be preferable. For the TATE model, weighted regression performs best (with a very similar level of performance to that of the PDM with site‐similarity), whereas site‐similarity performs worst (due to poor performance for catchments with higher baseflow), indicating that the choice of model and generalization method should not be separated. The use of sequential regression, which was developed to try to allow for parameter interdependence, shows no clear advantage for either model. Other than the poor performance of the TATE model with site‐similarity for catchments with a higher baseflow index, there are no clear relationships between performance of any model/method and catchment type. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

Simulated X-ray cluster temperature maps     

Lesley I. Onuora  Scott T. Kay  Peter A. Thomas 《Monthly notices of the Royal Astronomical Society》2003,341(4):1246-1252

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The power spectrum amplitude from clusters revisited: σ₈ using simulations with pre-heating and cooling     

Pedro T. P. Viana  Scott T. Kay  rew R. Liddle  Orrarujee Muanwong  Peter A. Thomas 《Monthly notices of the Royal Astronomical Society》2003,346(1):319-326

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The merger history of clusters and its effect on the X-ray properties of the intracluster medium     

David R. Rowley  Peter A. Thomas  Scott T. Kay 《Monthly notices of the Royal Astronomical Society》2004,352(2):508-522

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The Monitor project: data processing and light curve production     

Jonathan Irwin  Mike Irwin  Suzanne Aigrain  Simon Hodgkin  Leslie Hebb  Estelle Moraux 《Monthly notices of the Royal Astronomical Society》2007,375(4):1449-1462

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On the potential of transit surveys in star clusters: impact of correlated noise and radial velocity follow-up     

Suzanne Aigrain  Frédéric Pont 《Monthly notices of the Royal Astronomical Society》2007,378(2):741-752

We present an extension of the formalism recently proposed by Pepper and Gaudi to evaluate the yield of transit surveys in homogeneous stellar systems, incorporating the impact of correlated noise on transit time-scales on the detectability of transits, and simultaneously incorporating the magnitude limits imposed by the need for radial velocity (RV) follow-up of transit candidates. New expressions are derived for the different contributions to the noise budget on transit time-scales and the least-squares detection statistic for box-shaped transits, and their behaviour as a function of stellar mass is re-examined. Correlated noise that is constant with apparent stellar magnitude implies a steep decrease in detection probability at the high -mass end which, when considered jointly with the RV requirements, can severely limit the potential of otherwise promising surveys in star clusters. However, we find that small-aperture, wide-field surveys may detect hot Neptunes whose RV signal can be measured with present-day instrumentation in very nearby (<100 pc) clusters.  相似文献   

A search for low surface brightness dwarf galaxies in different environments     

Sarah Roberts  Jonathan Davies  Sabina Sabatini  Wim van Driel  Karen O'Neil  Maarten Baes  Suzanne Linder  Rodney Smith  Rhodri Evans 《Monthly notices of the Royal Astronomical Society》2004,352(2):478-492

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Trace-element fingerprints of chromite,magnetite and sulfides from the 3.1 Ga ultramafic–mafic rocks of the Nuggihalli greenstone belt,Western Dharwar craton (India)     

Ria Mukherjee  Sisir K. Mondal  José M. González-Jiménez  William L. Griffin  Norman J. Pearson  Suzanne Y. O’Reilly 《Contributions to Mineralogy and Petrology》2015,169(6):1-23

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Resetting of the U-Pb Zircon System in Cambro-Ordovician Intrusives of the Deep Freeze Range, Northern Victoria Land, Antarctica   总被引：5，自引：0，他引：5  

Bomparola  R. M.; Ghezzo  C.; Belousova  E.; Griffin  W. L.; O'Reilly  Suzanne Y. 《Journal of Petrology》2007,48(2):327-364

A detailed in situ isotopic (U–Pb, Lu–Hf) and geochemicalstudy of zircon populations in a composite sequence of foliatedto massive Cambro-Ordovician intrusions in the Deep Freeze Range(North Victoria Land, Antarctica), has highlighted great complexityin zircon systematics. Zircons in deformed granitoids and tonalitesdisplay complex internal textures, a wide spread of concordantU–Pb ages (between 522 and 435 Ma) and unusual trace-elementcompositions (anomalous enrichment of light rare earth elements,U, Th and Y) within single zircon grains. In contrast, zirconsfrom undeformed samples display a limited range of U–Pbages and trace-element compositions. Zircons from all age andtextural populations in most of the deformed and undeformedsamples show a relatively narrow range of _Hf values, suggestingthat the Lu–Hf system remained undisturbed. Inferred emplacementages cover a time interval of about 30 Myr: from 508 to 493Ma for the oldest strongly foliated synkinematic Howard Peaksmegacrystic monzogranites and high-K calc-alkaline mafic tointermediate rocks of the ‘Corner Tonalite’ unit;from about 489 to 481 Ma for the younger massive shoshoniticmafic dyke suite and the high-K calc-alkaline Keinath granite.The observed isotopic and chemical variations in zircon areattributed to a sub-solidus recrystallization under hydrousconditions and varying temperature, in a setting characterizedby a transpressional to extensional stress regime. KEY WORDS: Antarctica; Cambro-Ordovician intrusives; Ross Orogen; zircon U–Pb geochronology  相似文献