[en] ESAs INTEGRAL Space Observatory has spent his first decade in orbit, and its scientific outcome has completely changed our view of the hard-X/soft γ-ray sky. The scientific result comprises, among other discoveries, the production of the all-sky high energy sources catalogue, confirming the time variability over all time scales of most of the soft γ-ray sources observed, the first detailed map of the Aluminium and 511 keV annihilation line in the Galaxy and the evidence of polarized γ-ray emission from the Crab Nebula and Cyg X-1. This paper will review the latest INTEGRAL discoveries in the framework of the high energy sky panorama

[en] Balloon-borne observations of the X-ray source Her X-1 in the region 20-120 KeV during its mid-ON phase are reported. It is shown that the intensity of the source may reach a level as high as the one corresponding to the ON state. It is also shown that during the mid-ON period, the cyclotron line feature persists even in the time-averaged spectrum. The observed 35-day modulation in the intensity of Her X-1 is ascribed to increased absorption effects due either to the geometrical precession of the accretion disk around the neutron star or to increased accretion flow caused by the intrinsic stellar periodicity. 22 references

[en] A balloon borne hard X-ray experiment operating in the range 15-150 keV with a large sensitive area, high spectral resolution and fine imaging capability has been developed at IAS and AIT Institutes and successfully flown the August 5th, 1985 from the stratospheric balloon Base of Trapani-Milo (Sicily, Italy). During the flight that lasted about 18 hours at an atmospheric depth of less than 3.5 g/cm/sup 2/ pointed observations were performed on the following sources: AO535+26, Crab, MCG 8-11-11 and NGC 4151. In addition several more sources were observed in a scanning mode. In this paper we describe the instrumental configuration and present the pre-flight calibration as well as the in-flight performance

[en] We report evidence of bursting activity from XTE 1709-267, following a series of deep observations of the Galactic Centre region performed with the WFC's on board BeppoSAX. The long exposure and the imaging capability of the instruments allowed for a better position determination for this source, tentatively classified as an X-ray nova by Marshall et al. (IAUC 6543) on the basis of the data collected by RXTE-PCA

[en] We report the discovery with BeppoSAX-WFC of two new X-ray sources that were only seen during bursts: SAX J1753.5-2349 and SAX J1806.5-2215. For both sources, no steady emission was detected above an upper limit of 5 mCrab (2 to 8 keV) for 3 10⁵ s around the burst events. The single burst detected from SAX J1753.5-2349 shows spectral softening and a black body color temperature of 2.0 keV. Following the analogy with bursts in other sources the burst very likely originates in a thermonuclear flash on a neutron star. The first of two burst detected from SAX J1806.5-2215 does not show spectral softening and cannot be confirmed as a thermonuclear flash

[en] A continuous monitoring of the Galactic Centre region has been performed with the WFC's on board BeppoSAX on a time spread of about 7 months for a total of 500 ks exposure time. The long repeated observations allowed for the identification of 14 bursting sources, 2 of which uncataloged (SAXJ1750-290, SAXJ1806-221) and 3 observed bursting for the first time (GS1826-238, SLX1735-269, XTE1709-267). A summary of the monitoring of the Galactic Centre bursters is reported

[en] During 6 years of the BeppoSAX operational life, the Wide Field Camera observations covered almost the full sky providing a coverage of the Galactic Plane at different epochs. We analysed the longest Wide Field Camera pointing in the Galactic Plane in different energy bands in order to predict sources detection with INTEGRAL instruments. In fact, about 30 % of INTEGRAL Core Programme (CP) observing time is dedicated to a survey of the Galactic Plane with the aim to detect new sources, trigger TOO observations for CP and General Observer programme and to map the diffuse emission. Here we focus on producing a map containing all sources detected by BeppoSAX along the Galactic Plane for comparison with the same IBIS/INTEGRAL exposed sky region

[en] The supernova SN1987A have been observed in the range of hard X-rays (15 / 180 KeV) and high energy γ-rays (50 / 500 MeV) with a payload launched from the balloon facility of Alice Springs (Australia) during April 1987 and 1988. The low energy detector based on a MWPC had a sensitive area of 500 cm/sup 2/. In the second flight a complete plastic shield was added for the first time to the Multiwire Proportional Counter (MWPC). In this way, switching on the active shield, the background counting rate dropped from 4.2 to 2.8 x 10/sup -4/ ct/cm/sup 2/ s keV with no change in the dead time of the counter. This clearly demonstrates the advantage of the use of a multitechnique rejection system for this kind of gaseous detectors

[en] An analysis of the reported spectral features of NGC 4151 in X-rays is presented. It is shown that the origin of X-rays from the source is inconsistent with a single production mechanism. A new two-component model in which soft X-rays arise from the black-body emission of a tiny hot nuclues with T approximately 2x10⁷K and the hard X-ray photons are generated in an extended region by inverse Compton scattering of electrons with the infrared photons. (Auth.)

[en] Following the results obtained from the succesful transatlantic flight launched during the summer 1976 from the CNR Milo Base, Sicily, the Laboratorio di Astrofisica Spaziale has started a new program in the hard X-ray astronomy field. It basically consists in the development of high resolution large area Multiwire Proportional Chambers to be employed in long duration balloon flights to study and monitor galactic and extragalactic sources. This note will describe the flight configuration and performances of the HXR80M payload. The experiment is expected to fly during July 1980 from the Milo Base in the framework of the CNR experimental balloon campaign. The note will analyze the main characteristics of the detectors employed, of the data handling electronics and in particular of the hardware and the software of the on-board microprocessor controlled multichannel analyzer. In fact the limitation due to the low bit rate HF link (1.2kbit/s) and the long flight duration (about one week) make imperative the use of an on-board microprocessor system to handle and select in real time the scientific data and to control the housekeeping and the telecommand systems