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In the most recent IBIS survey based on observations performed during the first 1000 orbits of INTEGRAL, are listed 363 high-energy emitters firmly associated with AGN, 107 of which are reported here for the first time. We have used X-ray data to image the IBIS 90 per cent error circle of all the AGN in the sample of 107, in order to obtain the correct X-ray counterparts, locate them with arcsec accuracy and therefore pinpoint the correct optical counterparts. This procedure has led to the optical and spectral characterization of the entire sample. This new set consists of 34 broad line or type 1 AGN, 47 narrow line or type 2 AGN, 18 blazars and 8 sources of unknown class. These eight sources have been associated with AGN from their positional coincidence with 2MASX/Radio/X-ray sources. Seven high-energy emitters have been included since they are considered to be good AGN candidates. Spectral analysis has been already performed on 55 objects and the results from the most recent and/or best statistical measurements have been collected. For the remaining 52 sources, we report the spectral analysis for the first time in this work. We have been able to obtain the full X-ray coverage of the sample making use of data from Swift/XRT, XMM-Newton and NuSTAR. In addition to the spectral characterization of the entire sample, this analysis has enabled us to identify peculiar sources and by comparing different data sets, highlight flux variability in the 2-10 keV and 20-40 keV bands. [ABSTRACT FROM AUTHOR]

We report results of an extensive analysis of the X-ray nova XTE J1859+226 observed with BeppoSAX and the Rossi X-ray Timing Explorer during the 1999 source outburst. We modelled the source spectrum with a multicolour blackbody-like feature plus the generic Comptonization model bmc which has the advantage of providing spectral description of the emitted-radiation properties without assumptions on the underlying physical process. The multicolour component is attributed to the geometrically thin accretion disc, while the Comptonization spectrum is claimed to originate in the innermost sub-Keplerian region of the system (transition layer). We find that XTE J1859+226 covers all the spectral states typical of black hole sources during its evolution across the outburst; however, during the very high state, when the disc contribution to the total luminosity is more than 70 per cent and the root mean square variability ≲ 5 per cent, the high-energy photon index is closer to a hard state value (Γ ∼ 1.8). The bmc normalization and photon index Γ well correlate with the radio emission, and we also observed a possible saturation effect of Γ at the brightest radio emission levels. A strong positive correlation was found between the fractions of Comptonized seed photons and the integrated root mean square variability, which strengthens the idea that most of the fast variability in these systems is attributable to the innermost Compton cloud, which may be also identified as a jet. [ABSTRACT FROM AUTHOR]

In this paper we discuss the broad-band X-ray characteristics of a complete sample of 36 type 1 active galactic nuclei (AGN), detected by INTEGRAL in the 20–40 keV band above the 5.5σ level. We present, for all the objects in the sample, the broad-band (1–110 keV) spectral analysis obtained by using INTEGRAL/ Swift/Burst Alert Telescope observations together with XMM–Newton, Chandra, ASCA and Swift/X-Ray Telescope data. We also present the general average properties of the sample, i.e. the distribution of photon indices, high-energy cut-offs, reflection fractions and absorption properties, together with an in-depth analysis of their parameter space. We find that the average Seyfert 1 power law has an index of 1.7 with a dispersion of 0.2. The mean cut-off energy is at around 100 keV, with most objects displaying Ec in the range 50–150 keV; the average amount of Compton reflection is 1.5 with a typical dispersion of 0.7. We do not find any convincing correlation between the various parameters, an indication that our analysis is not strongly dependent by the interplay between them. Finally, we investigate how the results presented in this work fit into current frameworks for AGN spectral modelling and cosmic diffuse X-ray background synthesis models. [ABSTRACT FROM AUTHOR]

The analysis of the third INTEGRAL/Imager on Board Integral Satellite (IBIS) survey has revealed several new cataclysmic variables, most of which turned out to be intermediate polars, thus confirming that these objects are strong emitters in hard X-rays. Here, we present high-energy spectra of all 22 cataclysmic variables detected in the third IBIS survey and provide the first average spectrum over the 20–100 keV band for this class. Our analysis indicates that the best-fitting model is a thermal bremsstrahlung with an average temperature of . Recently, 11 (10 intermediate polars and one polar) of these systems have been followed up by Swift/X-ray telescope (XRT) (operating in the 0.3–10 keV energy band), thus allowing us to investigate their spectral behaviour over the range ∼0.3–100 keV. Thanks to this wide energy coverage, it was possible for these sources to simultaneously measure the soft and hard components and estimate their temperatures. The soft emission, thought to originate in the irradiated poles of the white dwarf atmosphere, is well described by a blackbody model with temperatures in the range ∼60–120 eV. The hard emission, which is supposed to be originated from optically thin plasma in the post-shock region above the magnetic poles, is indeed well modelled with a bremsstrahlung model with temperatures in the range ∼16–35 keV, similar to the values obtained from the INTEGRAL data alone. In several cases, we also find the presence of a complex absorber: one totally [with ] and one partially [with ] covering the source. Only in four cases (V709 Cas, GK Per, IGR J06253+7334 and IGR J17303−0601), we find evidence for the presence of an iron line at 6.4 keV. We discuss our findings in the light of the systems parameters and cataclysmic variables/intermediate polars modelling scenario. [ABSTRACT FROM AUTHOR]