The optical counterpart of the ultraluminous X-ray source NGC 5204 X-1   总被引：1，自引：0，他引：1  

M. R. Goad  T. P. Roberts  C. Knigge  P. Lira 《Monthly notices of the Royal Astronomical Society》2002,335(3):L67-L70

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Response of distance measures to the equation of state     

Tarun Deep Saini  T. Padmanabhan  Sarah Bridle 《Monthly notices of the Royal Astronomical Society》2003,343(2):533-538

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Effects of the North Head deep-water sewage outfall on nearshore coastal reef macrobenthic assemblages   总被引：1，自引：0，他引：1  

D. E. Roberts 《Marine pollution bulletin》1996,33(7-12):303-308

The macrobenthos on the coastal reefs near the North Head deep-water outfall were sampled nine times over a 3 year period to determine whether patterns in diversity and abundance were affected by the outfall. The assemblages were sampled using an asymmetrical after control/impact design (ACI). Ten replicate quadrats at each of three sites nested within each of three locations were photographed using a jump camera. These photographs were sampled to provide estimates of the number and abundance of major taxa and abundances of individual species. Significant interactions between outfall vs control through time were detected for the total number of species, bryozoans, cnidarians and the abundances of a silt matrix and two species of bryozoans. Smaller scale interactions among sites through time occurred for the abundances of total fauna, sponges and an ascidian species representing some evidence for the effect of the outfall at these smaller spatial scales. This paper summarizes the correlative evidence of effects from the outfall.  相似文献   

Galaxies as fluctuations in the ionizing background radiation at low redshift     

Suzanne M. Linder  Roland Gunesch  Jonathan I. Davies  Maarten Baes  Rhodri Evans  Sarah Roberts  Sabina Sabatini  Rodney Smith 《Monthly notices of the Royal Astronomical Society》2003,342(4):1093-1101

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Chandra reveals a black hole X-ray binary within the ultraluminous supernova remnant MF 16   总被引：1，自引：0，他引：1  

T. P. Roberts  E. J. M. Colbert 《Monthly notices of the Royal Astronomical Society》2003,341(4):L49-L54

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Debris-covered piedmont glaciers along the northwest flank of the Olympus Mons scarp: Evidence for low-latitude ice accumulation during the Late Amazonian of Mars     

Sarah M. Milkovich  James W. Head 《Icarus》2006,181(2):388-407

We use Viking and new MGS and Odyssey data to characterize the lobate deposits superimposed on aureole deposits along the west and northwest flanks of Olympus Mons, Mars. These features have previously been interpreted variously as landslide, pyroclastic, lava flow or glacial features on the basis of Viking images. The advent of multiple high-resolution image and topography data sets from recent spacecraft missions allow us to revisit these features and assess their origins. On the basis of these new data, we interpret these features as glacial deposits and the remnants of cold-based debris-covered glaciers that underwent multiple episodes of advance and retreat, occasionally interacting with extrusive volcanism from higher on the slopes of Olympus Mons. We subdivide the deposits into fifteen distinctive lobes. Typical lobes begin at a theater-like alcove in the escarpment at the base of Olympus Mons, interpreted to be former ice-accumulation zones, and extend outward as a tongue-shaped or fan-shaped deposit. The surface of a typical lobe contains (moving outward from the basal escarpment): a chaotic facies of disorganized hillocks, interpreted as sublimation till in the accumulation zone; arcuate-ridged facies characterized by regular, subparallel ridges and interpreted as the ridges of surface debris formed by the flow of underlying ice; and marginal ridges interpreted as local terminal moraines. Several lobes also contain a hummocky facies toward their margins that is interpreted as a distinctive type of sublimation till shaped by structural dislocations and preferential loss of ice. Blocky units are found extending from the escarpment onto several lobes; these units are interpreted as evidence of lava-ice interaction and imply that ice was present at a time of eruptive volcanic activity higher on the slopes of Olympus Mons. Other than minor channel-like features in association with lava-ice interactions, we find no evidence for the flow of liquid water in association with these lobate features that might suggest: (1) near-surface groundwater as a source for ice in the alcoves in the lobe source region at the base of the scarp, or (2) basal melting and drainage emanating from the lobes that might indicate wet-based glacial conditions. Instead, the array of features is consistent with cold-based glacial processes. The glacial interpretations outlined here are consistent with recent geological evidence for low-latitude ice-rich features at similar positions on the Tharsis Montes as well as with orbital dynamic and climate models indicating extensive snow and ice accumulation associated with episodes of increased obliquity during the Late Amazonian period of the history of Mars.  相似文献   

The H i detection of low column density clouds and galaxies     

Suzanne M. Linder  Robert F. Minchin  Jonathan I. Davies  Maarten Baes  Rhodri Evans  Sarah Roberts  Sabina Sabatini  Rodney Smith 《Monthly notices of the Royal Astronomical Society》2004,353(1):201-210

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Origin and flatness of ponds on asteroid 433 Eros     

James H. Roberts  Eliezer G. Kahn  Olivier S. Barnouin  Carolyn M. Ernst  Louise M. Prockter  Robert W. Gaskell 《Meteoritics & planetary science》2014,49(10):1735-1748

NEAR‐Shoemaker Multi‐Spectral Imager data reveal several hundred “ponds” on 433 Eros: smooth deposits that sharply embay the bounding depressions in which they lie, and whose spectra appear blue relative to that of the surrounding terrain. We investigate the topography of these ponds on Eros using a new shape model derived from stereophotoclinometric analysis, and validated against altimetry from the NEAR Laser Rangefinder, to constrain the mode of pond formation from three existing models. We update the locations of 55 pond candidates identified in images registered to the new shape model. We classify the flatness of these features according to the behavior of the first and second derivatives of the topography. We find that less than half of pond candidates have clearly flat floors. Based on the pond topography, we favor an external origin for the ponds' deposits. We suggest that fine dust may be transported into bounding depressions by electrostatic levitation, but may adhere to slopes, and that seismic shaking may not be sufficient to bring the deposits to an equipotential surface. Disaggregation of a central boulder should result in an obvious break in slope, such a variation is only observed in roughly half the pond candidates.  相似文献   

Saari’s conjecture for the restricted three-body problem     

G. E. Roberts  L. Melanson 《Celestial Mechanics and Dynamical Astronomy》2007,97(3):211-223

Saari’s conjecture adapted to the restricted three-body problem is proven analytically using BKK theory. Specifically, we show that it is not possible for a solution of the planar, circular, restricted three-body problem to travel along a level curve of the amended potential function unless it is fixed at a critical point (one of the five libration points.) Due to the low dimension of the problem, our proof does not rely on the use of a computer.  相似文献   

Development with Identity: Community, Culture and Sustainability in the Andes – Edited by Robert Rhoades     

Sarah A. Radcliffe 《Singapore journal of tropical geography》2007,28(3):371-373

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