BeppoSAX observations of Seyfert 1s in the Piccinotti sample I: poorly studied sources

In this work we present the first of two papers devoted to the study of the X-ray spectral characteristics of Seyfert 1 galaxies in the Piccinotti sample. In particular we analyse here the BeppoSAX broad band (0.1-100 keV) data of 4 objects which, despite their X-ray brightness, have been historically poorly studied due to their late identification with an AGN; these are H0111-149 (MKN1152), H0235-525 (ESO198-G24), H0557-385 (IRAS F05563-3820) and H1846-786 (IRAS F18389-7834). We have assumed for all the sources a baseline model which includes a power law with an exponential cut-off plus a reflection component and an iron K_alpha line; we have also searched for the presence of intrinsic absorption and/or a soft excess component. Our analysis indicates the presence of complex absorption in two objects (H0557-385 and H0111-149) best described by a combination of two uniform absorbers, one cold and one warm. Only in one source, H0557-385, a soft excess component has been measured. The primary continuum is best described by a canonical power law (Gamma=1.7-2) with a high energy cut-off in the range 40-130 keV. A cold reflection component is likely present in all sources with values ranging from less than 0.6 to higher than 2. In 3 out of 4 objects we find a cold iron line having equivalent width typical of Seyfert 1s (100-200 eV).Comment: 6 pages, 2 figures, accepted for publication as a Research Note in Astronomy and Astrophysic

Effect of symmetry distortions on photoelectron selection rules and spectra of Bi_2Sr_2CaCu_2O_{8+ delta}

We derive photoelectron selection rules along the glide plane in orthorhombic Bi_2Sr_2CaCu_2O_{8+\delta} (Bi2212). These selection rules explain the reversed intensity behavior of the shadow and the main band of the material as a natural consequence of the variating representation of the final state as a function of k_\parallel. Our one-step simulations strongly support the structural origin of the shadow band but we also introduce a scenario for detecting antiferromagnetic signatures in low doping.Comment: AMS-LaTeX, 5 pages, 4 figure

The X-ray spectra of Compton-thick Seyfert 2 galaxies as seen by BeppoSAX

Results from BeppoSAX observations of Compton--thick Seyfert 2 galaxies are summarized and reviewed, and their general properties derived and discussed. In five out of the seven observed sources, the nucleus is directly visible at high X-ray energies, where the photons penetrate absorbers with column densities in the range 1.1-4.3x10^{24} cm-2 (in the other two sources, NGC 1068 and NGC 7674, the nucleus is instead totally obscured at all energies, implying even larger column densities). In most sources there is unambiguous evidence of a reflection component from optically thick, cold matter, while in two (or maybe four) cases there is also evidence of reflection from ionized matter. For the sources with a measured X-ray luminosity, a comparison with the infrared luminosity is made; while in two cases (the Circinus galaxy and NGC 4945) the IR emission appears to be dominated by starburst activity, in the other three sources (NGC 6240, Mrk 3 and TOL 0109-383) it is likely to be dominated by reprocessing of the UV and X-ray photons emitted by an AGN.Comment: Accepted for publication in MNRA