ROSAT High-Resolution Imager monitoring of extreme X-ray variability in the narrow-line quasar PHL 1092   总被引：1，自引：0，他引：1  

W. N. Brandt  Th. Boller  A. C. Fabian  M. Ruszkowski 《Monthly notices of the Royal Astronomical Society》1999,303(4):L53-L57

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ROSAT observations of Cepheus OB3: the discovery of low-mass stars     

Tim Naylor  A. C. Fabian 《Monthly notices of the Royal Astronomical Society》1999,302(4):714-722

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SN 1988Z: spectro-photometric catalogue and energy estimates^★     

Itziar Aretxaga  †  S. Benetti  R. J. Terlevich  ‡  A. C. Fabian  E. Cappellaro  M. Turatto  M. Della Valle 《Monthly notices of the Royal Astronomical Society》1999,309(2):343-354

We present a spectro-photometric catalogue of the evolution of supernova 1988Z, which combines new and published observations in the radio, optical and X-ray bands, with the aim of offering a comprehensive view of the evolution of this object and deriving the total energy radiated since its discovery. The major contribution to the total radiated energy comes at optical to X-ray frequencies, with a total emission of at least 2×10⁵¹ erg (for H₀=50 km s⁻¹ Mpc⁻¹) in 8.5 yr. A model-dependent extrapolation of this value indicates that the total radiated energy may be as high as 10⁵² erg. The high value of the radiated energy supports a scenario in which most of the kinetic energy of the ejecta is thermalized and radiated in a short interaction with a dense circumstellar medium of nearly constant density. In this sense, 1988Z is not a supernova but a young and compact supernova remnant.  相似文献   

Strong observational constraints on advection-dominated accretion in the cores of elliptical galaxies     

T. Di Matteo †  A. C. Fabian  M. J. Rees  C. L. Carilli  R. J. Ivison 《Monthly notices of the Royal Astronomical Society》1999,305(3):492-504

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Interpolation of Daily Global Solar Radiation with Thin Plate Smoothing Splines   总被引：3，自引：0，他引：3  

Y. Xia  M. Winterhalter  P. Fabian 《Theoretical and Applied Climatology》2000,66(1-2):109-115

Summary Thin plate smoothing splines incorporating topographic dependence were used to interpolate daily global solar radiation in the Bavarian forest ecosystem monitoring network, with the degree of data smoothing determined by minimizing the generalized cross validation. A simple cross validation method was used to discuss the spatial distribution of mean relative errors at 18 forest climate stations. The results show that, from this network 14%–30% mean relative errors can be expected for most of these forest climate stations in summer, and 20%–30% mean relative errors can be found at a few of forest climate stations in winter. Time-averaging can reduce these interpolation errors. In this network a mean relative error of 10% can be expected for weekly and biweekly mean solar radiation at most of forest climate stations in summer. Large errors are related to low radiation amount under heavy cloud cover. Mean relative errors increase as daily global solar radiation decreases. Received April 20, 1999 Revised January 20, 2000  相似文献   

Investigating ionized disc models of the variable narrow-line Seyfert 1 PG 1404+226     

J. Crummy  A. C. Fabian  W. N. Brandt  Th. Boller 《Monthly notices of the Royal Astronomical Society》2005,361(4):1197-1202

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High energy particles and quanta in astrophysics: Frank B. McDonald and Carl E. Fichtel (Eds.): M.I.T. Press,Cambridge, Mass. 1974. xii + 476. $18.50.     

A.C. Fabian 《Planetary and Space Science》1975,23(9):1348

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BeppoSAX observations of three distant, highly luminous clusters of galaxies: RXJ1347−1145, Zwicky 3146 and Abell 2390     

S. Ettori  S. W. Allen  A. C. Fabian 《Monthly notices of the Royal Astronomical Society》2001,322(1):187-194

We present an analysis of BeppoSAX observations of three clusters of galaxies that are amongst the most luminous in the Universe: RXJ1347−1145, Zwicky 3146 and Abell 2390. Using data from both the Low Energy (LECS) and Medium Energy (MECS) Concentrator Spectrometers, and a joint analysis with the Phoswich Detection System (PDS) data above 10 keV, we constrain, with a relative uncertainty of between 7 and 42 per cent (90 per cent confidence level), the mean gas temperature in the three clusters. These measurements are checked against any possible non-thermal contribution to the plasma emission and are shown to be robust.
We confirm that RXJ1347−1145 has a gas temperature that lies in the range between 13.2 and 22.3 keV at the 90 per cent confidence level, and is larger than 12.1 keV at 3 σ level. The existence of such a hot galaxy cluster at redshift of about 0.45 implies an upper limit on the mean mass density in the Universe, Ω_m, of 0.5.
Combining the BeppoSAX estimates for gas temperature and luminosity of the three clusters presented in this work with ASCA measurements available in the literature, we obtain a slope of 2.7 in the L – T relation once the physical properties are corrected from the contamination from the central cooling flows.  相似文献   

Meridional distribution of tropospheric ozone from ground-based registrations between Norway and South Africa     

Fabian  P.  Pruchniewicz  P. G. 《Pure and Applied Geophysics》1973,106(1):1027-1035

By means of a meridional chain of 19 stations between Tromso, Norway, and Hermanus, South Africa, a permanent registration of ozone near the ground has been obtained since 1970. From the first year of operation surprisingly systematic annual variations come out, which agree with theoretical calculations on stratospheric-tropospheric exchange.  相似文献   

Coulomb interactions in the intracluster medium     

Ettori  & Fabian 《Monthly notices of the Royal Astronomical Society》1998,293(1):L33-L36

In this paper we discuss the effect of Coulomb collisions on the temperature profiles of the intracluster medium in clusters of galaxies, motivated by recent reports of negative temperature gradients in some clusters by Markevitch et al. The time-scale for electrons and protons to reach temperature equilibrium can exceed a few × 10⁹ years beyond radii of a megaparsec, if the intracluster gas is assumed to be at the usual cluster virial temperature. If a cluster merger has occurred within that time causing the protons, but not the electrons, to be rapidly heated then a small negative temperature gradient can result. This gradient is larger in clusters with higher temperatures and steeper density profiles.   Applying these considerations to the cluster of galaxies A2163, we conclude that, more plausibly, the observed gradient is due to a lack of hydrostatic equilibrium following a merger.  相似文献