Self-similar collapse with cooling and heating in an expanding universe     

Shuji Uchida  Tatsuo Yoshida 《Monthly notices of the Royal Astronomical Society》2004,348(1):89-99

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Are we missing baryons in galaxy clusters?     

S. Ettori 《Monthly notices of the Royal Astronomical Society》2003,344(2):L13-L16

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Statistics of high-velocity outflows in regions of massive star formation     

I. I. Zinchenko 《Astronomy Letters》2002,28(5):316-323

Based on a SO and C¹⁸O survey of dense molecular-cloud cores in regions of massive star formation (selected by the presence of H₂O maser emission), we estimate the frequency of occurrence of high-velocity outflows in these regions and their parameters. The presence of extended SO-line wings (compared to C¹⁸O) is considered to be indicative of outflows. We estimate the outflow parameters (mass, momentum, and kinetic energy) from optically thin C¹⁸O lines, which increases the reliability of these estimates. According to this approach, high-velocity outflows were detected in ～40% of the observed objects, which is a lower limit on the frequency of their occurrence. There is a clear correlation between the outflow mass, momentum, and kinetic energy, on the one hand, and the bolometric luminosity of the associated infrared sources, on the other hand. The slope of the correlations is close to unity. Their comparison with similar correlations of the mass-loss rate, force, and mechanical luminosity with the bolometric luminosity shows that the spread in outflow dynamical age is small and that this age has no systematic correlation with the infrared luminosity. The mean outflow dynamical age that can be obtained from this comparison is ～7×10¹³ yr.  相似文献   

The parkes multibeam pulsar survey and interstellar scattering     

R.N. Manchester 《Astrophysics and Space Science》2001,278(1-2):33-38

The Parkes multibeam pulsar survey is a major survey for pulsars lying within a 10^°-wide strip along the southern Galactic plane, using the multibeam receiver on the Parkes 64-m radiotelescope. It is an international collaboration between groups at Jodrell Bank Observatory, Massachusetts Institute of Technology, Bologna Astronomical Observatory and the ATNF. The survey commenced in 1997 August, and has so far succeeded in finding more than 550 previously unknown pulsars. Many of these are distant, with some beyond the centre of the Galaxy according to current models of the interstellar electron density distribution. Interstellar scattering affects the pulse profile of many of the more distant pulsars even at 1374 MHz, the centre frequency of the survey. Preliminary results from the survey are presented. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Numerical study of boundary conditions for solute transport through a porous medium     

Glen P. Peters  David W. Smith 《国际地质力学数值与分析法杂志》2001,25(7):629-650

A transition region may be defined as a region of rapid change in medium properties about the interface between two porous media or at the interface between a porous medium and a reservoir. Modelling the transition region between different porous media can assist in the selection of the most appropriate boundary conditions for the standard advection–dispersion equation (ADE). An advantage of modelling the transition region is that it removes the need for explicitly defining boundary conditions, though boundary conditions may be recovered as limiting cases. As the width of a transition region is reduced, the solution of the transition region model (TR model) becomes equivalent to the solution of the standard ADE model with correct boundary conditions. In this paper numerical simulations using the TR model are employed to select the most appropriate boundary conditions for the standard ADE under a variety of configurations and conditions. It is shown that at the inlet boundary between a reservoir and porous medium, continuity of solute mass flux should be used as the boundary condition. At the boundary interface between two porous media both continuity of solute concentration and solute mass flux should be used. Finally, in a finite porous medium where the solute is allowed to advect freely from the exit point, both continuity of solute concentration and solute mass flux should be used as the outlet boundary condition. The findings made here are discussed with reference to a detailed review of previous relevant theoretical and experimental observations. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   

Erratum: Cosmic metal production and the mean metallicity of the Universe     

F. Calura  F. Matteucci 《Monthly notices of the Royal Astronomical Society》2004,351(1):384-384

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Classical and Mg ii-selected damped Lyman α absorbers: impact on Ω_H i at z < 1.7     

Céline Péroux †  Jean-Michel Deharveng  Vincent Le Brun  Stefano Cristiani 《Monthly notices of the Royal Astronomical Society》2004,352(4):1291-1301

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Pixel correlation searches for O vi in the Lyman α forest and the volume filling factor of metals in the intergalactic medium at z∼ 2–3.5     

Matthew M. Pieri  Martin G. Haehnelt 《Monthly notices of the Royal Astronomical Society》2004,347(3):985-993

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Non-linear clustering during the cosmic Dark Ages and its effect on the 21-cm background from minihaloes     

Ilian T. Iliev  Evan Scannapieco  Hugo Martel  Paul R. Shapiro 《Monthly notices of the Royal Astronomical Society》2003,341(1):81-90

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Radio structure of the most distant radio-detected quasar at the 10-mas scale     

S. Frey  L. Mosoni  Z. Paragi  L. I. Gurvits 《Monthly notices of the Royal Astronomical Society》2003,343(1):L20-L24

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