Light bending models in AGNs     

G. Miniutti 《Astronomische Nachrichten》2006,327(10):969-976

We review the MCG–6‐30‐15 observations and results that provided the motivation for the light bending model. We present a summary of the main properties of the model and discuss its application to MCG–6‐30‐15 briefly mentioning other X‐ray sources showing the same qualitative behaviour. Finally, we report on one of the most spectacular cases so far of short‐timescale variability of a redshifted Fe K line in the Seyfert galaxy NGC 3516, most likely due to an orbiting spot or flare in the relativistic region of the accretion disc. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

The highly spotted photosphere of the young rapid rotator Speedy Mic     

J. R. Barnes 《Monthly notices of the Royal Astronomical Society》2005,364(1):137-145

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Modelling the H Lyman lines in evolved late-type stars     

S.A. Sim 《Monthly notices of the Royal Astronomical Society》2001,326(2):821-832

The importance of partial redistribution (PRD) in the modelling of the Lyman α and Lyman β emission lines of hydrogen in stellar atmospheres is examined using simple atmospheric models of a range of late-type stars. These models represent the subgiant Procyon (F5 IV–V), and the two giants β Gem (K0 III) and α Tau (K5 III). These stars are selected to span a wide range of surface gravities: 1.25< log  g <4.00 . The calculations are performed using the computer code multi with the modifications made by Hubeny & Lites. It is found that PRD effects are highly significant, both in the direct prediction of the Lyman line profiles and in the application of hydrostatic equilibrium to calculate the atmospheric electron density in static atmospheric models.  相似文献   

Deep crustal features of the Celtic Sea from complementary processing on the SWAT data     

Jérôme Dyment  Maksim Bano 《Geophysical Journal International》1991,105(1):71-83

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Statistical assessment of geochemical pattern in overbank sediments of the river Sava,Croatia     

Gordana?PavlovicEmail author  Esad?Prohic  Darko?Tibljas 《Environmental Geology》2004,46(1):132-143

Four overbank profiles from the three terraces of different age were sampled in 10 to 20 cm intervals for the bulk content of major and minor (Ca, Mg, Fe, Ti, Al, Na, K and P) and trace (Mo, Cu, Pb, Zn, Ni, Co, Mn, As, U, Th, Sr, Cd, Sb, V, La, Cr, Ba, W, Zr, Ce, Sn, Y, Nb, Ta, Sc, Li, Rb and Hf) elements in the minus 0.125 mm fraction. Univariate statistics together with analysis of variance discriminated between the lower-lying carbonate (CA) population dominantly composed of carbonates and the overlying silicate (SI) population being dominantly of silicate mineralogy. This stratified pattern resulted from the intensive erosive action of melting glaciers exerted on limestones and dolomites in the alpine region, followed by local inputs mainly of silicate composition. Elements exhibiting the greatest between-population variability are Ca and Mg being enriched in the CA population and Fe, Mn, P, Sr, Al, Na, K, Li, Rb, Y, Zr, Ni, Cr and Ti being enriched in the SI population. Anomalously high Hg, Pb and Ba concentrations (maximum values: 6,500±2,860 ppb, 225±13 ppm and 1,519±91 ppm, respectively) in the lowermost part of the profile S7, which is nearest to the Croatian-Slovenian border, derive from the mineralized Slovenian catchment area. This profile also contains trimodal frequency distributions of Fe, Mn and P whose highest concentrations coincide with increased values of Zn and Cu which are bimodally distributed. Geochemical patterns of majority of elements in all four profiles consistently reflect the average compositions of the upstream drainage basins.  相似文献   

Unusually Broadened Spectral Profiles Observed in Solar Prominences     

Eijiro Hiei 《中国天文和天体物理学报》2004,4(4):377-389

After surveying the spectra of 39 prominences observed by the Multichannel Infrared Solar Spectrograph at Purple Mountain Observatory and the 25 cm coronagraph at the Norikura Solar Observatory, we found that about 28% of them show small spatial scale (6"- 8") and short time scale (tens of seconds to a few minutes), unusual large broadening and large shift velocities in spectral lines including Hα, Hβ, Hε, Ca Ⅱ H, Ca Ⅱ K, Ca2Ⅱ 8542 A, He Ⅰ D3 and HeⅠ 10830 A. We present in detail two typical events observed respectively on 2002 May 27 and 1981 August 2. The full-width at half maximum of the widest profile of the 2001 prominence is 1.8 A for Ha and 2.9 A for He I 10830 A, while that of the 1981 prominence is 5.3 A for Hβ, 3.6 A for Ca Ⅱ K, 4.0 A for Ca Ⅱ H and 2.8 A for He Ⅰ D3. Such broadenings generally occur at a level of several-thousand kilometres above the chromosphere. Further, most of these prominences manifest a rotation of (0.4-1.35) ×10-2 rad s-1 pointing to the Sun and large line  相似文献   

Estimation of vertical water and heat fluxes in the semi-confined aquifers in tokyo metropolitan area,japan     

S. Dapaah-Siakwan  Isamu Kayane 《水文研究》1995,9(2):143-160

Groundwater circulation is known to be one of the agents responsible for the redistribution of geothermal energy by acting as a source or sink in the course of its movement through porous media. Heat transport in groundwater systems is considered to be a coupled process and the theory based on this was used to analyse temperature profiles of 30 thermally stable observation wells in a deep, semi-confined aquifer system in the Tokyo Metropolitan area. Vertical water fluxes in the semi-confined aquifers and the associated upward heat fluxes were estimated from a heat flux equation that describes convection and conduction processes of heat transport in one dimension. The vertical downward water fluxes in Shitamachi lowland, Musashino and Tachikawa terraces were 0.69.26.91 × 10^?9, 1.46-70.92 × 10^?9 and 2.61.2204 × 10^?9 m/s, respectively. A vertical upward water flux of 1.80-33.60 × 10^?9 m/s was estimated in Shitamachi lowland. The water flux generally decreased with increasing depth for observation wells which intercepted more than one semi-confining layer. The estimated upward heat fluxes for Shitamachi lowland, Musashino and Tachikawa terraces were 0.32-1.12, 0.49-1.21 and 1.00-11.62 W/m², respectively. The heat flux was highest in Tachikawa terrace where a major fault, the Tachikawa fault, is located. Generally, the estimated heat flux was higher in the semi-confining layers than in the aquifers. Areas with heat sources and sinks as well as groundwater flow patterns in the semi-confined aquifers were revealed by heat flux and temperature distributions in the study area.  相似文献   

High-Resolution Spectroscopy for Pulsation-Mode Identification     

John Telting 《Astrophysics and Space Science》2003,284(1):85-96

Asteroseismology relies on accurate mode identification.High-resolution spectroscopy allows to detect such crucial informationas the pulsational degree , the azimuthal number m, andpulsation amplitudes, directly from time series of observations. Theadvantage of high-resolution spectroscopy over standard photometrictechniques is that not only pulsational temperature variations can bedetected, but also the pulsational velocity field, yielding valuableextra information.In this paper I review the mode-identification methods that havebeen developed over the last decades, with emphasis on theapplication to hot main-sequence stars.  相似文献   

Experimental verification of sea-bed shear modulus profile inversions using surface gravity (water) wave-induced sea-bed motion     

Mark Trevorrow  Tokuo Yamamoto  Mohsen Badiey  Altan Turgut  Craig Conner 《Geophysical Journal International》1988,93(3):419-436

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Pulsar observations at decametric wavelengths using a swept-frequency dedisperser     

A. A. Deshpande  V. Radhakrishnan 《Journal of Astrophysics and Astronomy》1994,15(3):329-341

In this paper, we describe pulsar observations at decametric wavelengths using the Gauribidanur Radio Telescope made subsequent to our earlier measurements (Deshpande & Radhakrishnan 1992). To improve the time-resolution in our measurements of pulse profiles, we have used the ‘swept-frequency dedispersion’ method with some modifications to suit its application at such low radio frequencies. We also present a new scheme that simplifies the calibration of the receiver gain characteristics. We present average profiles on four pulsars from these improved measurements at 34.5 MHz.  相似文献