Cygnus A     

C.L. Carilli  P.D. Barthel 《Astronomy and Astrophysics Review》1996,7(1):1-54

Cygnus A was the first hyper-active galaxy discovered, and it remains by far the closest of the ultra-luminous radio galaxies. As such, Cygnus A has played a fundamental role in the study of virtually all aspects of extreme activity in galaxies. We present a review of jet theory for powering the double-lobed radio emitting structures in powerful radio galaxies, followed by a review of observations of Cygnus A in the radio, optical, and X-ray relevant to testing various aspects of jet theory. Issues addressed include: jet structure from pc- to kpc-scales, jet stability, confinement, composition, and velocity, the double shock structure for the jet terminus and the origin of multiple radio hotspots, the nature of the filamentary structure in the radio lobes, and the hydrodynamic evolution of the radio lobes within a dense cluster atmosphere, including an analysis of pressure balance between the various gaseous components. Also discussed are relativistic particle acceleration and loss mechanisms in Cygnus A, as well as magnetic field strengths and geometries both within the radio source, and in the intracluster medium. We subsequently review the classification, cluster membership, and the emission components of the Cygnus A galaxy. The origin of the activity is discussed. Concentrating on the nuclear regions of the galaxy, we review the evidence for an obscured QSO, also given the constraints on the orientation of the radio source axis with respect to the sky plane. We present an overview of models of central engines in AGN and observations of Cygnus A which may be relevant to testing such models. We conclude with a brief section concerning the question of whether Cygnus A is representative of powerful high redshift radio galaxies. Received October 10, 1995  相似文献   

A reanalysis of the light curve of RT Persei with the W-D code     

M. T. Edalati  F. Zeinali 《Astrophysics and Space Science》1996,243(2):275-283

The UBV photometric observations of RT Per, from Sanwal and Chaubey (1981), were analyzed by the Wilson and Devinney code (1971). The light curves include reflection effects that for the first time has been suggested by Dugan (1911). RT Per has a semi-detached configuration where the lower-mass component is in contact with its respective Roche surface. The higher-mass component very nearly fills its Roche lobe. It has the characteristic of an Algol type system. The absolute dimensions for the primary and secondary of this system were calculated from its spectral types and by combining the photometric solution with inferred component radial velocities (Lu, 1990).  相似文献   

Ontogeny of the lymphoid organs of Japanese flounder, Paralichthys olivaceus     

Liu Yun  Jiang Guoliang  Zhang Shicui 《中国海洋大学学报(英文版)》2004,3(2):161-165

Histological study on the ontogeny of the lymphoid organs, kidney, thymus and spleen of Japanese flounder, Paralichthys olivaceus, from hatching to 40 d was carried out. The pronephric kidney duct appeared early in hatching although the primordial haemopoietic stem cells were observed within a week after hatching. The spleen was first seen after 8d of hatching. The thymus appeared after 15d, situated near the pronephric kidney. Small lymphoid cells appeared during the later phase of the post-larval stage in the sequence of thymus, kidney and spleen. During the 40d of observations, there were no distinct inner or outer zones in thymus and no red or white pulp in spleen. These results suggest that the nonspecific defense immune system plays a very important role in the early larval stage of Japanese flounder.  相似文献   

On the equivalence of two methods for computing partial derivatives of seismic waveforms—II. Laterally homogeneous initial model     

Robert J. Geller  Tatsuhiko Hara  Seiji Tsuboi 《Geophysical Journal International》1990,102(2):499-502

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A deep geoelectric survey of the Carnmenellis granite     

D. Beamish 《Geophysical Journal International》1990,102(3):679-693

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On the orthogonality of surface wave eigenfunctions in cylindrical coordinates     

M. G. Bostock 《Geophysical Journal International》1990,103(3):763-767

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穆珠朗玛峰地区土壤中稀土元素的含量和分布     

章申  孙景信 《地理研究》1990,9(2):58-66

本文论述了珠穆朗玛峯地区土壤中稀土元素的含量,以及它们在土壤中的分布模式,并发现土壤中稀土元素的含量水平在很大程度上受土壤母质的制约。  相似文献   

Erratum     

J.P. Phillips 《Astrophysics and Space Science》2004,291(1):97-97

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Ca ii K interstellar observations towards early-type disc and halo stars – distances to intermediate- and high-velocity clouds     

J. V. Smoker  B. B. Lynn  W. R. J. Rolleston  H. R. M. Kay  E. Bajaja  W. G. L. Poppel  F. P. Keenan  P. M. W. Kalberla  C. J. Mooney  P. L. Dufton  R. S. I. Ryans 《Monthly notices of the Royal Astronomical Society》2004,352(4):1279-1290

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The search for exsolved ferromagnesian olivines: A meteoritic survey     

Michail I. PETAEV 《Meteoritics & planetary science》1996,31(6):807-815

Abstract— Olivine grains from selected meteorites (the Springwater pallasite, the Lowicz mesosiderite, the ALH 84025 brachinite, the Krymka LL3 chondrite, and the Calcalong Creek lunar meteorite) and terrestrial rocks (San Carlos forsterite and Rockport fayalite) were studied by optical microscopy and high-precision electron microprobe analysis. Detailed microprobe traverses revealed regular igneous zoning in the Krymka and Calcalong Creek olivines. Traverses across the San Carlos forsterite grain are flat and display no chemical variations larger than the 2σ range of counting error (±0.2 mol% Fa). Traverses across olivine grains in the ALH 84025, Lowicz, and Springwater meteorites show regular patterns of periodic or wavy chemical variations well exceeding the 2σ uncertainty range. However, no lamellar structure was seen in backscattered electron images. It is suggested that the periodic chemical variations may be due to spinodal decomposition of primary, more or less homogeneous grains. I conclude that the absence of earlier reports of such variations simply means that olivine grains in equilibrated meteorites have not been examined closely enough to detect them.  相似文献