423 research outputs found
Research of high-current pulsed electron beam energy distribution in depth of sheet of water
Distribution of the absorbed doze and energy of the high-current pulsed electron beam formed by accelerator TEU-500 (350...500 kV, 60 ns, current density 0,3...0,4 kA/sm2) in water sheet depth has been measured. The high-resolution measurement technique of doze and energy distribution with application of dosimetric film based on lavsan with phenazine covering was used. Spatial resolution at registration of the absorbed doze in the range of 5...100 kGr amounts to 20...30 mkm. It was shown that at absorption of electron beam with high current density (in conditions of track overlapping on surface of the absorbing layer) distribution of the absorbed doze in thedepth within the limits of ±10 % coincides with distribution obtained for low-current bea
Chirally symmetric and confining dense matter with a diffused quark Fermi surface
It is possible that at low temperatures and large density there exists a
confining matter with restored chiral symmetry, just after the dense nuclear
matter with broken chiral symmetry. Such a phase has sofar been studied within
a confining and chirally symmetric model assuming a rigid quark Fermi surface.
In the confining quarkyonic matter, however, near the Fermi surface quarks
group into color-singlet baryons. Interaction between quarks leads to a
diffusion of the quark Fermi surface. Here we study effects of such diffusion
and verify that it does not destroy a possible existence of a confining but
chirally symmetric matter at low temperatures.Comment: 7 p
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
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
Several New Active Galactic Nuclei Among X-ray Sources Detected by INTEGRAL and SWIFT Observatories
We present the results of the optical identifications of a set of X-ray
sources from the all-sky surveys of INTEGRAL and SWIFT observatories. Optical
data were obtained with Russian-Turkish 1.5-m Telescope (RTT150). Nine X-ray
sources were identified as active galactic nuclei (AGNs). Two of them are
hosted by nearby, nearly exactly edge-on, spiral galaxies MCG -01-05-047 and
NGC 973. One source, IGR J16562-3301, is most probably BL Lac object (blazar).
Other AGNs are observed as stellar-like nuclei of spiral galaxies, with broad
emission lines in their spectra.
For the majority of our hard X-ray selected AGNs, their hard X-ray
luminosities are well-correlated with the luminosities in [OIII],5007 optical
emission line. However, the luminosities of some AGNs deviate from this
correlation. The fraction of these objects can be as high as 20%. In
particular, the flux in [OIII] line turns to be lower in two nearby edge-on
spiral galaxies, which can be explained by the extinction in their galactic
disks.Comment: 9 pages, 3 figures, accepted for publication in Astronomy Letters,
the original text in Russian can be found at
http://hea.iki.rssi.ru/~rodion/poptid.pd
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