897 research outputs found

    Digital Preservation and Web Access to the Konkoly Observatory Schmidt Telescope Plate Archive

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    ACM Computing Classification System (1998): J.2.The digital preservation of the Konkoly Observatory Schmidt telescope plates, as well as the web access to the plate previews, aim for the preservation of this scientific heritage and the re-use of the astronomical photographic plates in time domain astronomy. The photographic plates used as detectors and information storage at astronomical observations with the Konkoly Schmidt telescope had been obtained in the period 1962–1996. The work on the digital plate preservation and web access started in 2001 with creation of an electronic plate catalogue and the digitization of selected representative plates as well as with interlinking of the publishing in Konkoly Observatory Information Bulletin on Variable Stars (IBVS) with the Wide-Field Plate Database (WFPDB) developing in Sofia. We describe the process of the digitization of the Konkoly Schmidt telescope plates.This work is supported by the bilateral project between the Bulgarian Academy of Sciences and the Hungarian Academy of Sciences and partially by the grants BG NSF DO-02-273 and BG NSF DO-02-275

    Coherent amplitudon generation in K_0.3MoO_3 through ultrafast inter-band quasi particle decay

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    The charge density wave system K_0.3MoO_3 has been studied using variable energy pump-probe spectroscopy, ellipsometry, and inelastic light scattering. The observed transient reflectivity response exhibits quite a complex behavior, containing contributions due to quasi particle excitations, coherent amplitudons and phonons, and heating effects. The generation of coherent amplitudons is discussed in terms of relaxation of photo-excited quasi particles, and is found to be resonant with the interband plasmon frequency. Two additional coherent excitations observed in the transients are assigned to zone-folding modes of the charge density wave state

    A Study of Lyman-Alpha Quasar Absorbers in the Nearby Universe

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    Spectroscopy of ten quasars obtained with the Goddard High Resolution Spectrograph (GHRS) of the Hubble Space Telescope (HST) is presented. A clustering analysis reveals an excess of nearest neighbor line pairs on velocity scales of 250-750 km/s at a 95-98% confidence level. The hypothesis that the absorbers are randomly distributed in velocity space can be ruled out at the 99.8% confidence level. No two-point correlation power is detected (xi < 1 with 95% confidence). Lyman-alpha absorbers have correlation amplitudes on scales of 250-500 km/s at least 4-5 times smaller than the correlation amplitude of bright galaxies. A detailed comparison between absorbers in nearby galaxies is carried out on a limited subset of 11 Lyman- alpha absorbers where the galaxy sample in a large contiguous volume is complete to M_B = -16. Absorbers lie preferentially in regions of intermediate galaxy density but it is often not possible to uniquely assign a galaxy counterpart to an absorber. This sample provides no explicit support for the hypothesis that absorbers are preferentially associated with the halos of luminous galaxies. We have made a preliminary comparison of the absorption line properties and environments with the results of hydrodynamic simulations. The results suggest that the Lyman-alpha absorbers represent diffuse or shocked gas in the IGM that traces the cosmic web of large scale structure. (abridged)Comment: 36 pages of text, 15 figures, 4 tables, 36 file

    Genetic diversity in native Bulgarian grapevine germplasm (Vitis vinifera L.) based on nuclear and chloroplast microsatellite polymorphisms

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    Fifty one wild specimens collected in different areas in Bulgaria and nineteen native Bulgarian grapevine cultivars were genotyped with 7 nuclear and 5 chloroplast SSR markers. Based on the microsatellite allelic profile six wild samples, collected from the Danube Riverbank, were considered non vinifera genotypes. The genetic diversity for nuclear loci observed in the cultivated grapevines was comparable to that found in other cultivated collections. However, lower genetic diversity was observed in the set of wild samples. The dendrogram based on nuclear SSRs separated most of the cultivated grapevines from the wild samples. Four chlorotypes corresponding to previously determined chlorotypes A, B, C and D, were identified in the analyzed samples that occurred with different frequencies in groups of wild and cultivated plants. The most frequent chlorotype among wild samples was A, while it was C in the cultivated samples. The differentiation of Bulgarian grape chlorotypes in the context of differentiation of chlorotypes in Eurasian grape flora is discussed.
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