Power density spectrum of NGC 5548 and the nature of its variability

We derive power density spectra in the optical and X-ray band in the timescale range from several years down to $\sim$ a day. We suggest that the optical power density spectrum consists of two separate components: long timescale variations and short timescale variations, with the dividing timescale around 100 days. The shape of the short timescale component is similar to X-ray power density spectrum which is consistent with the interpretation of short timescale optical variations being caused by X-ray reprocessing. We show that the observed optical long timescale variability is consistent with thermal pulsations of the accretion disc.Comment: Accepted for publication in The Monthly Notices of the Royal Astronomical Societ

Disk/corona model: The transition to ADAF

We propose a model of the accretion flow onto a black hole consisting of the accretion disk with an accreting two-temperature corona. The model is based on assumptions about the radiative and conductive energy exchange between the two phases and the pressure equilibrium. The complete model is determined by the mass, the accretion rate, and the viscosity parameter. We present the radial dependencies of parameters of such a two-phase flow, with advection in the corona and the disk/corona mass exchange due to evaporation/condensation included, and we determine the transition radius from a two-phase disk/corona accretion to a single-phase optically thin flow (ADAF) in the innermost part of the disk as a function of accretion rate. We identify the NLS1 galaxies with objects accreting at a rate close to the Eddington accretion rate. The strong variability of these objects may be related to the limit cycle behaviour expected in this luminosity range, as the disk, unstable due to the dominance by the radiation pressure, oscillates between the two stable branches: the advection-dominated optically thick branch and the evaporation branch.Comment: Contributed talk presented at the Joint MPE,AIP,ESO workshop on NLS1s, Bad Honnef, Dec. 1999, to appear in New Astronomy Reviews; also available at http://wave.xray.mpe.mpg.de/conferences/nls1-worksho

Wie können Inhalte vernetzt werden, um die Nachhaltigkeit des Lernens zu verbessern?

In den letzten Jahren scheint in der Sekundarstufe das Problem der mangelnden Nachhaltigkeit zu einem Kernproblem des Unterrichts geworden zu sein. Wir wollen zeigen, wie die Nachhaltigkeit des Lernens durch verschiedene Formen des Vernetzens gestützt werden kann

Excitation functions of proton induced nuclear reactions on natW up to 40 MeV

Excitation functions for the production of the 181,182m,182g,183,184g,186Re and 183,184Ta radionuclides from proton bombardment on natural tungsten were measured using the stacked-foil activation technique for the proton energies up to 40 MeV. A new data set has been given for the formation of the investigated radionuclides. Results are in good agreement with the earlier reported experimental data and theoretical calculations based on the ALICE-IPPE code. The thick target integral yields were also deduced from the measured excitation functions. The deduced yield values were compared with the directly measured thick target yield (TTY), and found acceptable agreement. The investigated radionuclide 186Re has remarkable applications in the field of nuclear medicine, whereas the data of 183,184gRe and 183Ta have potential applications in thin layer activation analysis and biomedical tracer studies, respectively.Comment: 21papes, 14 figure

Subaru High-Dispersion Spectroscopy of Narrow-Line Region in the Seyfert Galaxy NGC 4151

We report on a study of forbidden emission-line spectrum of nearby Seyfert 1.5 galaxy NGC 4151 based on the high-resolution (R ~ 45,000) optical spectrum obtained by using the High Dispersion Spectrograph boarded on the Subaru Telescope. The profile parameters such as the emission-line widths, the velocity shifts from the recession velocity of the host galaxy, and the asymmetry indices, for emission lines including very faint ones such as [Ar IV]4712,4740 and [Fe VI]5631,5677 are investigated. Statistically significant correlations between the measured profile parameters and the critical densities of transitions are found while there are no meaningful correlations between the profile parameters and the ionization potentials of ions. By comparing the results with photoionization model calculations, we remark that a simple power-law distribution of the gas density which is independent of the radius from the nucleus cannot explain the observed correlation between the emission-line widths and the critical densities of the transitions. Taking the additional dense gas component expected to exist at the innermost of the narrow-line region into account, the observed correlations between the emission-line width and the critical density of the transitions can be understood since high-critical-density emission lines can arise at such relatively inner regions even if their ionization potentials are low. The observed correlation between the blueshift amounts of emission lines and the critical densities of the ions is also explained if such dense gas clouds located closer to the nucleus have larger outflowing velocities.Comment: 19 pages and 1 separate jpeg figure. Accepted for publication in A

Niezwykłość kobiecej natury w opowiadaniach fantastycznych Anne Richter

The objective of this article is to examine how the classic fantastic motif of metamorphosis is used by Anne Richter, a Belgian writer and theorist of women’s fantastic, not only to arouse fear in the reader but also to raise women’s issues, particularly marriage. Using studies by fantastic literature theorists (including Labbé, Millet, Malrieu, Prince and Richter), as well as feminist critique texts (Cixous, de Beauvoir, Kristeva), the author analyses the motif of metamorphosis in two of Richter’s stories – Sul passo dell’Arno [Over the Arno Pass] and Un sommeil de plante [The Sleep of Plants] – showing the interweaving of classic elements of a fantastic work with the “extraordinary nature of women” and their womanhood.Celem niniejszego artykułu jest zbadanie, w jaki sposób klasyczny motyw fantastyczny metamorfozy jest wykorzystany przez Anne Richter, belgijską pisarkę i teoretyczkę fantastyki kobiecej, nie tylko do wzbudzenia strachu u czytelnika, ale także do poruszenia tematyki kobiecej, w szczególności małżeństwa. Korzystając z opracowań teoretyków literatury fantastycznej (m.in. Labbé, Millet, Malrieu, Prince, Richter) oraz tekstów krytyki feministycznej (Cixous, de Beauvoir, Kristeva), autorka artykułu poddaje analizie motyw metamorfozy w Sul passo dell’Arno i Un sommeil de plante – dwóch opowiadaniach Richter, wskazując przeplatanie się klasycznych elementów utworu fantastycznego z „niezwykłą naturą kobiety” i jej kobiecością

Kobayhashi Masaki and the legacy of the World War II

In the 1950s there appeared numerous films which showed the futility of war and critically evaluated the past, their weakness, however, lay in a tendency to sentimentalize history and in the use of melodrama conventions which allowed for the elevation of suffering. The few exceptions are the films by Kobayashi Masaki, who managed to avoid these temptations, thus becoming the most distinguished director of the films that analysed Japan’s responsibility for war. In my paper I focus on three works: The Thick-Walled Room (Kabe atsuki heya, 1953) - the story of prisoners accused of war crimes and imprisoned in Sugamo Prison, who cannot cope with the guilt and are persecuted by the nightmares of the past; monumental trilogy The Human Condition (Ningen no jōken, 1959-1961) based on a novel by Gomikawa Junpei, which “breaks new ground with its grim descriptions of Japanese atrocities perpetrated on Asians and on fellow Japanese” (Orr 2001: 107); and five-hour documentary Tokyo Trial (Tōkyō saiban, 1983), which provides a fascinating account of the work of the International Military Tribunal. Thanks to Kobayashi’s works, the problem of war crimes, of the responsibility for one’s own actions and inability to effectively resist the system, gained a totally new dimension