Identification of 8 INTEGRAL hard X-ray sources with Chandra

We report the results of identification of 8 hard X-ray sources discovered by the INTEGRAL observatory during the ongoing all-sky survey. These sources have been observed by Chandra. In 6 cases a bright X-ray source was found within the INTEGRAL localization region, which permitted to unambigously identify 5 of the objects with nearby galaxies, implying that they have an active galactic nucleus (AGN), whereas one source is likely an X-ray binary in LMC. 4 of the 5 newly discovered AGNs have measured redshifts in the range 0.025-0.055. The X-ray spectra reveal the presence of significant amounts of absorbing gas (NH in the range 10^22-10^24 cm^-2) in all 5 AGNs, demonstrating that INTEGRAL is starting to fill in the sample of nearby obscured AGNs.Comment: 4 pages, 2 figures, corrected Fig.

A hard X-ray survey of the Crux Galactic spiral arm tangent. A catalog of sources

This work is part of a large solid angle hard X-ray survey. We analized a number of observations by the IBIS telescope aboard the INTEGRAL observatory covering the Crux Galactic spiral arm tangent. We have detected 46 hard X-ray sources, with 15 of them being new. Among the identified sources there are 12 AGNs, 11 HMXBs, 6 LMXBs and 2 active stars. 13 sources remain unidendified.Comment: Accepted for publication in Astronomy Letter

Boron-doped nanocrystalline silicon thin films for solar cells

This article reports on the structural, electronic, and optical properties of boron-doped hydrogenated nanocrystalline silicon (nc-Si: H) thin films. The films were deposited by plasma-enhanced chemical vapour deposition (PECVD) at a substrate temperature of 150 degrees C. Crystalline volume fraction and dark conductivity of the films were determined as a function of trimethylboron-to-silane flow ratio. Optical constants of doped and undoped nc-Si: H were obtained from transmission and reflection spectra. By employing p(+) nc-Si: H as a window layer combined with a p' a-SiC buffer layer, a-Si: H-based p-p'-i-n solar cells on ZnO:Al-coated glass substrates were fabricated. Device characteristics were obtained from current-voltage and spectral-response measurements. (C) 2011 Elsevier B. V. All rights reserved

Constraints on the late X-ray emission from the low-energy GRB 031203: INTEGRAL data

Comparison of the INTEGRAL upper limits on the hard X-ray flux before and after the low-energy GRB 031203 with the XMM measurements of the dust-scattered radiation at lower energies suggests that a significant fraction of the total burst energy could be released in the form of soft X-rays at an early afterglow stage with a characteristic duration of ~100-1000s. The overall time evolution of the GRB 031203 afterglow may have not differed qualitatively from the behavior of standard (i.e., more intense) bursts studied by the SWIFT observatory. The available data also admit the possibility that the dust-scattered radiation was associated with an additional soft component in the spectrum of the gamma-ray burst itself.Comment: 9 pages, 3 figure

Optical Identification of Four Hard X-ray Sources from the Swift All-Sky Survey

We present the results of our optical identifications of four hard X-ray sources from the Swift all-sky survey. We obtained optical spectra for each of the program objects with the 6-m BTA telescope (Special Astrophysical Observatory, Russian Academy of Sciences, Nizhnii Arkhyz), which allowed their nature to be established. Two sources (SWIFT J2237.2+6324} and SWIFT J2341.0+7645) are shown to belong to the class of cataclysmic variables (suspected polars or intermediate polars). The measured emission line width turns out to be fairly large (FWHM ~ 15-25 A), suggesting the presence of extended, rapidly rotating (v~400-600 km/s) accretion disks in the systems. Apart from line broadening, we have detected a change in the positions of the line centroids for SWIFT J2341.0+7645, which is most likely attributable to the orbital motion of the white dwarf in the binary system. The other two program objects (SWIFT J0003.3+2737 and SWIFT J0113.8+2515) are extragalactic in origin: the first is a Seyfert 2 galaxy and the second is a blazar at redshift z=1.594. Apart from the optical spectra, we provide the X-ray spectra for all sources in the 0.6-10 keV energy band obtained from XRT/Swift data.Comment: 9 pages, 6 figures, will be published in Astronomy Letters, 38, No.5, pp.281-289 (2012

Luminosity Function of High-Mass X-ray Binaries and Anisotropy in the Distribution of Active Galactic Nuclei toward the Large Magellanic Cloud

In 2003-2012, the INTEGRAL observatory has performed long-term observations of the Large Magellanic Cloud (LMC). At present, this is one of the deepest hard X-ray (20-60 keV) surveys of extragalactic fields in which more than 20 sources of different natures have been detected. We present the results of a statistical analysis of the population of high-mass X-ray binaries in the LMC and active galactic nuclei (AGNs) observed in its direction. The hard X-ray luminosity function of high-mass X-ray binaries is shown to be described by a power law with a slope alpha~1.8, that in agreement with the luminosity function measurements both in the LMC itself, but made in the soft X-ray energy band, and in other galaxies. At the same time, the number of detected AGNs toward the LMC turns out to be considerably smaller than the number of AGNs registered in other directions, in particular, toward the source 3C 273. The latter confirms the previously made assumption that the distribution of matter in the local Universe is nonuniform.Comment: 5 pages, 5 figures, will be published in Astronomy Letters, 2012, Vol. 38, No. 8, p. 492--49

Low temperature magnetic structure of CeRhIn5_5 by neutron diffraction on absorption-optimized samples

Two aspects of the ambient pressure magnetic structure of heavy fermion material CeRhIn$_5$ have remained under some debate since its discovery: whether the structure is indeed an incommensurate helix or a spin density wave, and what is the precise magnitude of the ordered magnetic moment. By using a single crystal sample optimized for hot neutrons to minimize neutron absorption by Rh and In, here we report an ordered moment of $m=0.54(2)~\mu_B$. In addition, by using spherical neutron polarimetry measurements on a similar single crystal sample, we have confirmed the helical nature of the magnetic structure, and identified a single chiral domain

Evaluation of the implementation of a competence module "Information technologies" in the educational process of the university

The peculiarities of the formation of competences in the field of information technology. The approach to the evaluation of the implementation of a competence module "Information technologies" in the educational process of the UniversityРассмотрены особенности формирования компетенций в области информационных технологий. Предложен подход к оцениванию реализации компетентностного модуля «Информационные технологии» в учебном процессе вуз