Astroinformation resource of the Ukrainian virtual observatory: Joint observational data archive, scientific tasks, and software

This paper reviews the most important components of the national project of the Ukrainian Virtual Observatory (UkrVO). Among them, there is the establishment of a Joint Digital Archive (JDA) of observational data, which has been obtained at Ukrainian observatories since the 1890s, including an astronegative JDA (more than 200 thousand plates). Since this task requires VO-oriented software, such issues as content verification software, integrity and administration of the JDA, compliance of image formats with the IVOA standards, and photometric and astrometric calibration of images are considered as the most important directions of software development, which carried out by members of the UkrVO. The scientific projects using local data archives of the UkrVO are discussed, namely: an analysis of a long observational series of active galactic nuclei, the study of solar flares and solar active regions based on spectral observational archives, research and discovery of variable stars, and the study of stellar fields in the vicinity of gamma-ray bursts. Particular attention is devoted to the CoLiTec Program that permits us to increase a number of observed solar system bodies and allows us to discover new bodies; for example, the C/2010 (Elenin) and P/2011 N01 comets were discovered using this program at the ISON-NM Observatory. The paper notes the creation of the UkrVO JDA prototype that provides access to the databases of the Main Astronomical Observatory, National Academy of Sciences of Ukraine (MAO NAS of Ukraine); Nikolaev Astronomical Observatory (NAO); and Lvov Astronomical Observatory.     

Optical and X-ray variability of Seyfert galaxies NGC 5548, NGC 7469, NGC 3227, NGC 4051, NGC 4151, Mrk 509, Mrk 79, and Akn 564 and quasar 1E 0754

The results of a cross-correlation analysis of the optical and X-ray light curves for eight Seyfert galaxies, NGC 5548, NGC 7469, NGC 3227, NGC 4051, NGC 4151, Mrk 509, Mrk 79, and Akn 564 and for the optical spectra of the quasar 1E 0754 are presented. In the case of the galaxies NGC 5548 and NGC 7469, the maximum values of cross-correlation coefficients for optical and X-ray variations proved to be high (0.73 and 0.79, respectively). The lag time, determined from the maximum of cross-correlation function, is 2.800 _?1.58 ^+3.12 days for NGC 5548 and 0.6 _?4.3 ^+0.9 days for NGC 7469. This result favors downscattering of the X-ray emission into the optical range (direct Compton effect) for NGC 5548 and NGC 7469. In addition to the main maximum, which corresponds to the lag of the optical flux variations behind the X-ray flux, six objects (excluding Akn 564 and NGC 4151) show the wings in the intervals of cross-correlation functions that correspond to the time lags of X-ray emission behind the optical emission of approximately 10 days. A method of determining the masses of central black holes in AGNs through spectral line widths is presented; with this method the mass of the central black hole in the quasar 1E 0754 was found (M _BH = 1.01 × 10⁸ M _sun). The position of the quasar 1E 0754 in the mass-luminosity diagram meets the position of other NLS 1 galaxies.     

Lodgement till and flow till: a discussion

A comment by J. Kriiger on I. Marcussen's paper 'Distinguishing between lodgement till and flow till in Weichselian deposits' (Boreas 4 , pp. 113–123) is followed by a reply from I. Marcussen.