[en] The studies are concerned with the fracture-mechanical evaluation of the material behaviour in the case of three or four point load. The measurements were carried out on steels as well as on electron beam welded joints. An optical testing method was enhanced for the experimental registration of the time-dependent specimen bending in the area of the notch. This permits e.g. a classification of the failure mechanisms, elastic and plastic deformations as well as of the crack propagation mechanisms. Furthermore, it is possible to determine dynamic COD values from the signals. By an analysis of the time signals (FFT, correlation function), it is possible to obtain further statements on the material behaviour and thus on the failure mechanisms. Thus, a further aid for the automation of the test set-up is available. (orig./MM) With 91 figs., 13 tabs

[en] We present the first BeppoSAX observation (0.1 to 220 keV) of the quasar Mrk 205. We have searched for the unusual Fe line profile claimed in the XMM-Newton spectrum which has been widely discussed in recent literature. We find no evidence for a broad, ionized Fe line component in our data. We find that if the continuum is modeled with a Compton reflection from cold material component, the line strength diminishes, in agreement with a recent re-analysis of the XMM-Newton data, but with better constraints on the reflection component thanks to the PDS instrument (15-220 keV). We interpret this fact as another indication for illumination of a distant and cold material rather than reprocessing in the highly ionized inner parts of an accretion disk. We detect for the first time a Compton hump in this object. However we cannot constrain the presence of a high energy cutoff. We confirm the existence of a variable soft excess

[en] The Gamma-ray instruments on-board INTEGRAL offer a unique opportunity to perform time resolved analysis on GRBs. The imager IBIS allows accurate positioning of GRBs and broad band spectral analysis, while SPI provides high resolution spectroscopy. GRB 030501 was discovered by the INTEGRAL Burst Alert System in the ISGRI field of view. Although the burst was fairly weak (fluence F_20-200keV≅3.5x10^-6 erg cm^-2) it was possible to perform time resolved spectroscopy with a resolution of a few seconds. The GRB shows a spectrum in the 20 - 400 keV range which is consistent with a spectral photon index Γ=-1.8. No emission line or spectral break was detectable in the spectrum. Although the flux seems to be correlated with the hardness of the GRB spectrum, there is no clear soft to hard evolution seen over the duration of the burst

[en] Context. A new hard X-ray transient has been discovered by INTEGRAL on 2006 Sep. 17 at 1 degree from the Galactic Centre. Aims. INTEGRAL, Swift/XRT and optical photometric observations are used to characterize IGR J17497-2821 and to unveil its nature. Methods. The X-ray position has been refined to arcsec level through a study of the optical variability of the possible counterparts. Hard X-ray variability and spectroscopy are used to determine the nature of the source outburst. Results. IGR J17497-2821 is a new X-ray Nova in low-hard state, probably a new Black-Hole Candidate. (authors)

[en] We report on the results of International Gamma-Ray Astrophysics Laboratory (INTEGRAL) observations of the neutron star low-mass X-ray binary SAX J1810.8-2609 during its latest active phase in 2007 August. The current outburst is the first one since 1998 and the derived luminosity is 1.1-2.6 x10³⁶ erg s^-1 in the 20-100 keV energy range. This low outburst luminosity and the long-term time-average accretion rate of ∼5 x 10^-12 M _sun yr^-1 suggest that SAX J1810.8-2609 is a faint soft X-ray transient. During the flux increase, spectra are consistent with a thermal Comptonization model with a temperature plasma of kT _e∼ 23-30 keV and an optical depth of τ∼ 1.2-1.5, independent of the luminosity of the system. This is a typical low hard spectral state for which the X-ray emission is attributed to the upscattering of soft seed photons by a hot, optically thin electron plasma. During the decay, spectra have a different shape, the high energy tail being compatible with a single power law. This confirm similar behavior observed by BeppoSAX during the previous outburst, with the absence of visible cutoff in the hard X-ray spectrum. INTEGRAL/JEM-X instrument observed four X-ray bursts in Fall 2007. The first one has the highest peak flux (∼3.5 crab in 3-25 keV) giving an upper limit to the distance of the source of about 5.7 kpc, for a L _Edd ∼ 3.8 x 10³⁸ erg s^-1. The observed recurrence time of ∼ 1.2 days and the ratio of the total energy emitted in the persistent flux to that emitted in the bursts (α∼ 73) allow us to conclude that the burst fuel was composed by mixed hydrogen and helium with X ≥ 0.4.

[en] This school, dedicated to young researchers, will clarify our present knowledge of the X-ray sky and give the opportunity to learn about the observatories and tools which are available. The contributions have been organized into 3 issues: -) fundamental physics, -) X-ray and Gamma-ray instruments and analysis techniques, and -) astrophysical objects. This document gathers only the slides of the presentations

[en] Context. In its first 4 years of observing the sky above 20 keV, INTEGRAL-ISGRI has detected 500 sources, around half of which are new or unknown at these energies. Follow-up observations at other wavelengths revealed that some of these sources feature unusually large column densities, long pulsations, and other interesting characteristics. Aims. We investigate where new and previously-known sources detected by ISGRI fit in the parameter space of high-energy objects, and we use the parameters to test correlations expected from theoretical predictions. For example, the influence of the local absorbing matter on periodic modulations is studied for Galactic High-Mass X-ray Binaries (HMXBs) with OB supergiant and Be companions. We examine the spatial distribution of different types of sources in the Milky Way using various projections of the Galactic plane, in order to highlight signatures of stellar evolution and to speculate on the origin of the group of sources whose classifications are still uncertain. Methods. Parameters that are available in the literature, such as positions, photoelectric absorption (N_H), spin and orbital periods, and distances or redshifts, were collected for all sources detected by ISGRI. These values and their references are provided online. Results. ISGRI has detected similar numbers of X-ray Binaries and Active Galactic Nuclei (AGN). The former group contains new members of the class of HMXBs with supergiant stellar companions. Usually, this type of object presents strong intrinsic absorption which leads to a peak emission in an energy range that ISGRI is ideally suited to detect. Thanks to these additional systems, we are able to show that HMXBs are generally segregated in plots of intrinsic (N_H) versus the orbital period of the system and versus the spin period of the pulsar, based on whether the companion is a Be or an OB supergiant star. We also find a tentative but expected anticorrelation between (N_H) and the orbital period, and a possible and unexpected correlation between the (N_H) and the spin period. While only a handful of new Low-Mass X-ray Binaries (LMXBs) have been discovered, there are many sources that remain unclassified and they appear to follow a spatial distribution typical of Galactic sources (especially LMXBs) rather than extragalactic sources. (authors)

[en] We present results from simultaneous observations of Cyg X-1 with INTEGRAL and RXTE in 2002 November and December, employing the new RXTE calibration from HEASOFT 5.3. The broad-band X-ray/γ-ray spectrum is well described by Comptonization spectra with an additional reflection component. The temperature of the Comptonizing plasma is kTe ∼ 60-80 keV and its optical depth is τ ∼ 0.8-1.2. The covering factor of the reflector is Ω/2π ∼ 0.1. There is a possible soft excess below 10 keV, interpreted as emission from the accretion disk. The spectral parameters are slightly different from those obtained by us earlier due to the different RXTE-PCA calibration

[en] Ground-based gamma-ray astronomy has had a major breakthrough with the impressive results obtained using systems of imaging atmospheric Cherenkov telescopes. Ground-based gamma-ray astronomy has a huge potential in astrophysics, particle physics and cosmology. CTA is an international initiative to build the next generation instrument, with a factor of 5-10 improvement in sensitivity in the 100 GeV-10 TeV range and the extension to energies well below 100 GeV and above 100 TeV. CTA will consist of two arrays (one in the north, one in the south) for full sky coverage and will be operated as open observatory. The design of CTA is based on currently available technology. This document reports on the status and presents the major design concepts of CTA. (authors)