Superhumps in black hole X-ray transients     

C.A. Haswell  D.J. Rolfe  A.R. King  J.R. Murray  P.A. Charles 《Astrophysics and Space Science》2001,276(1):41-42

The superhumps in black hole X-ray transientsresult from a modulation in the area of the accretion disc. We discussimplications of this for parameter determinations in LMXBs.  相似文献   

Reply: Formation and reorientation of structure in the surge‐type glacier Kongsvegen,Svalbard     

J. Woodward  T. Murray  A. McCAIG 《第四纪科学杂志》2003,18(1):99-100

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Calibration of the Debris Project ISOPHOT Data     

Murray Silverstone  E. E. Becklin  Celeste Spangler 《Astrophysics and Space Science》1997,255(1-2):119-120

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The solar flares of February 1986 and the ensuing intense geomagnetic storm     

Howard A. Garcia  Murray Dryer 《Solar physics》1987,109(1):119-137

A very intense geomagnetic storm, the largest observed in 26 years, was observed in early February 1986 having just been preceded by a series of six solar flares during the period 3–7 February. The storm and its antecedent flares are currently a subject of great interest because of the unusually large magnitude of the various geomagnetic effects that obtained. The fact that the flares were moderate to large in soft X-ray intensity, but much smaller than the largest that the Sun is capable of producing, coupled with the fact that these events occurred near the minimum of the current solar activity cycle, adds to the uniqueness of the overall episode. This paper describes the special circumstances surrounding these events and offers an interpretation of the cause and effect relationships through a numerical simulation of the dynamical evolutionary processes that may have occurred in interplanetary space.  相似文献   

A three-invariant smooth cap model with mixed hardening     

Leonard E. Schwer  Yvonne D. Murray 《国际地质力学数值与分析法杂志》1994,18(10):657-688

A cap model is presented that uses a multiplicative formulation to define a smooth (continuous derivative) failure surface that includes the third stress invariant. This formulation offers several advantages over previous cap model formulations: elimination of ‘corner’ coding, resulting in a numerical algorithm suitable for vectorization; a three stress invariant implementation that is easily specialized to classical failure surfaces or generalized to represent observed material response; and a framework for easily implementing additional model features such as kinematic hardening as demonstrated.  相似文献   

Chandra HRC and HST observations of NGC 6240: resolving the active galactic nucleus and starburst     

P. Lira  M. J. Ward  A. Zezas  S. S. Murray 《Monthly notices of the Royal Astronomical Society》2002,333(3):709-714

We present high spatial resolution X-ray Chandra HRC and HST WFPC2 H α observations of the prototypical infrared-luminous galaxy NGC 6240. The central region of this system shows a remarkably complex morphology, with filaments and loops observed in the optical and X-rays. The total X-ray luminosity is dominated by the extended emission. Both nuclei are clearly detected in the HRC image and both appear to be extended. The energetics of the nuclei imply that the southern nucleus is the more plausible counterpart to the obscured active galactic nucleus. The overall spectral energy distribution of the galaxy is in good agreement with a blend of starburst and AGN components that have similar bolometric luminosities,   L _bol∼5×10⁴⁵ erg s^-1  , with the starburst dominating the observed continuum in the near-infrared ( K band), optical and soft X-ray bands.  相似文献   

Three-dimensional smoothed particle hydrodynamics simulations of radiation-driven warped accretion discs     

Stephen B. Foulkes  Carole A. Haswell  James R. Murray 《Monthly notices of the Royal Astronomical Society》2006,366(4):1399-1409

We present three-dimensional smoothed particle hydrodynamics calculations of warped accretion discs in X-ray binary systems. Geometrically thin, optically thick accretion discs are illuminated by a central radiation source. This illumination exerts a non-axisymmetric radiation pressure on the surface of the disc, resulting in a torque that acts on the disc to induce a twist or warp. Initially planar discs are unstable to warping driven by the radiation torque and, in general, the warps also precess in a retrograde direction relative to the orbital flow. We simulate a number of X-ray binary systems which have different mass ratios, using a number of different luminosities for each. Radiation-driven warping occurs for all systems simulated. For mass ratios   q ∼ 0.1  a moderate warp occurs in the inner disc while the outer disc remains in the orbital plane (cf. X 1916−053). For less extreme mass ratios, the entire disc tilts out of the orbital plane (cf. Her X–1). For discs that are tilted out of the orbital plane in which the outer edge material of the disc is precessing in a prograde direction, we obtain both positive and negative superhumps simultaneously in the dissipation light curve (cf. V603 Aql).  相似文献   

Formation and reorientation of structure in the surge‐type glacier Kongsvegen,Svalbard     

John Woodward  Tavi Murray  Andrew McCaig 《第四纪科学杂志》2002,17(3):201-209

Kongsvegen, a surge‐type glacier in Spitsbergen, Svalbard, shares a tide‐water margin with the glacier Kronebreen. The complex has been in retreat since a surge advance of Kongsvegen around 1948. The surface of Kongsvegen displays suites of deformational structures highlighted by debris‐rich folia. These structures are melting out to form a network of sediment ridges in the grounded terminal area. The structures are also visible in a marginal, 1 km long, 5–20 m high cliff‐face at the terminus. Current models for the evolution of deformational structures at Kongsvegen divide the structures into suites based on their orientation and dip, before assigning a mechanism for genesis based on structure geometry. Interpretation of aerial photographs and field mapping of surface structures suggest that many structures were reorientated or advected during the surge. We suggest that many of the deformational structures highlighted by debris‐rich folia represent reorientated, sediment‐filled crevasses. Some evidence of thrusting is apparent but the process is not as ubiquitous as previously suggested. Many deformational structures also appear to have been offset by more recent structures. Mechanisms of structural development must, therefore, be considered within the context of distinct stages of glacier flow dynamics and multiple surge episodes. Furthermore, evidence for thrusting and folding within the glacier systems of Svalbard has been used as the basis for interpreting Quaternary glacial landforms in the UK. The findings of this paper, therefore, have implications for interpretations of the Quaternary record. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   

New insights into volcanic processes from deep mining of the southern diatreme within the Argyle lamproite pipe,Western Australia     

Rayner  Murray J.  Moss  Stephen W.  Lorenz  Volker  Jaques  A. Lynton  Boxer  Grant L.  Smith  Chris B.  Webb  Kimberley 《Mineralogy and Petrology》2018,112(2):351-363

Underground mining and deep drilling of the richly diamondiferous ~1.2 Ga Argyle lamproite in Western Australia has prompted a re-evaluation of the geology of the pipe. Argyle is considered to be a composite pipe that formed by the coalescence of several diatremes and has been offset and elongated by post-emplacement faulting. Recent geological studies have recognised at least five distinct volcaniclastic lamproite lithofacies with differing diamond grades. The new data suggest that the centre of the southern (main) diatreme is occupied by well-bedded, olivine lamproite lapilli tuff with very high diamond grades (>10 ct/t). Characteristic features include a clast-supported fabric and high modal abundance of densely packed lamproite lapilli and coarse-grained, likely mantle-derived olivine now replaced by serpentine and/or talc. The persistence of small-scale graded and cross-bedding in this lithofacies to depths of ~1.5 km below the original surface prior to erosion suggests phreatomagmatic volcanism forming the diatreme was syn-eruptively accompanied by subsidence of the tephra, maintaining a steep-walled diatreme in the water-saturated country rock sediments.

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Inundation of a low-lying urban atoll island: Majuro,Marshall Islands     

Ford  Murray  Merrifield  Mark A.  Becker  Janet M. 《Natural Hazards》2018,91(3):1273-1297

Natural Hazards - Majuro is a low-lying island perched on a coral atoll in the central Pacific Ocean and is home to nearly 28,000 people. Considered highly vulnerable to the impacts of marine...  相似文献