X-ray Selected BL Lacertae Objects: Catalogue and Statistical Properties

This talk focuses on the statistical properties of X-ray selected BL Lacertae objects (XBLs) whose catalogue has been compiled. It consists of 312 sources from different X-ray surveys, unambiguously identified to mid-2010. Results of the statistical research of different observational quantities (redshift, muliwavelength luminosities, host/nucleus absolute Magnitudes, central black hole masses, synchrotron peak frequencies, broadband spectral indices) are also provided and existence of the correlation between them is proved. Overall flux variability shows an increasing trend towards greater frequencies. XBL are found to be much less active in point of intra-night optical variability compared to radio-selected BL Lacs (RBLs). A separate list of 106 XBL candidates is also created including the same characteristics for each source as in the case of XBL catalogue.Comment: 5 pages, 2 figures, invited lecture at "Young Scientits' Conference on Astronomy and Space Physics", Kiev, Taras Shevchenko National University,2011, May 2-

Maximal L p -regularity for the Laplacian on Lipschitz domains

We consider the Laplacian with Dirichlet or Neumann boundary conditions on bounded Lipschitz domains ?, both with the following two domains of definition:D1(?) = {u ? W1,p(?) : ?u ? Lp(?), Bu = 0}, orD2(?) = {u ? W2,p(?) : Bu = 0}, where B is the boundary operator.We prove that, under certain restrictions on the range of p, these operators generate positive analytic contraction semigroups on Lp(?) which implies maximal regularity for the corresponding Cauchy problems. In particular, if ? is bounded and convex and 1 < p ? 2, the Laplacian with domain D2(?) has the maximal regularity property, as in the case of smooth domains. In the last part,we construct an example that proves that, in general, the Dirichlet–Laplacian with domain D1(?) is not even a closed operator

Multifrequency variability of the blazar AO 0235+164. The WEBT campaign in 2004-2005 and long-term SED analysis

A huge multiwavelength campaign targeting the blazar AO 0235+164 was organized by the Whole Earth Blazar Telescope (WEBT) in 2003-2005 to study the variability properties of the source. Monitoring observations were carried out at cm and mm wavelengths, and in the near-IR and optical bands, while three pointings by the XMM-Newton satellite provided information on the X-ray and UV emission. We present the data acquired during the second observing season, 2004-2005, by 27 radio-to-optical telescopes. They reveal an increased near-IR and optical activity with respect to the previous season. Increased variability is also found at the higher radio frequencies, down to 15 GHz, but not at the lower ones. The radio (and optical) outburst predicted to peak around February-March 2004 on the basis of the previously observed 5-6 yr quasi-periodicity did not occur. The analysis of the optical light curves reveals now a longer characteristic time scale of 8 yr, which is also present in the radio data. The spectral energy distributions corresponding to the XMM-Newton observations performed during the WEBT campaign are compared with those pertaining to previous pointings of X-ray satellites. Bright, soft X-ray spectra can be described in terms of an extra component, which appears also when the source is faint through a hard UV spectrum and a curvature of the X-ray spectrum. Finally, there might be a correlation between the X-ray and optical bright states with a long time delay of about 5 yr, which would require a geometrical interpretation.Comment: 14 pages, 10 figures (8 included in the text and 2 PNG files), in press for A&

Objectives of the Georgian-Turkish joint group at solar eclipse in Elazig

Georgian and Turkish colleagues have started a collaborative work for the last total solar eclipse of the millennium. In this expedition we intend to carry out six experiments associated with white light corona, coronal polarization, ionic corona, chromospheric flash spectrum, solar diameter measurements, and high resolution CCD imaging of coronal plumes. Here, we will present some general information concerning these experiments and their aims, while results of these observations will be given in a forthcoming paper