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Pulsar systems accelerate particles to immense energies. The detailed functioning of these engines is still poorly understood, but polarization measurements of high-energy radiation may allow us to locate where the particles are accelerated. We have detected polarized gamma rays from the vicinity of the Crab pulsar using data from the spectrometer on the(More)
Received ; accepted – 2 – ABSTRACT We present and discuss a " 3-dimensional " diagnostic diagram for Seyfert2 galaxies obtained by means of X-ray and [OIII] data on a large sample of objects (reported in the Appendix). The diagram shows the Kα iron line equivalent width as a function of both the column density derived from the photoelectric cutoff and the(More)
We investigate the relation between X-ray nuclear emission, optical emission line luminosities and black hole masses for a sample of 47 Seyfert galaxies. The sample, which has been selected from the Palomar optical spectroscopic survey of nearby galaxies (Ho, Filippenko & Sargent 1997), covers a wide range of nuclear powers, from L 2−10keV ∼ 10 43 erg/s(More)
The first IBIS galactic plane survey has provided a list of high energy emitting objects above 20 keV; these sources have been detected mostly in the crowded region of the Galactic Centre and partly along the Galactic Plane. In order to validate the detection procedure, to help in the identification process and to study the nature of these IBIS sources,(More)
An XMM–Newton study of ultraluminous X–ray sources (ULX) has been performed in a sample of 10 nearby Seyfert galaxies. Eighteen ULX have been found with positional uncertainty of about 4 ′′. The large collecting area of XMM–Newton makes the statistics sufficient to perform spectral fitting with simple models in 8 cases. The main results of the present(More)
In the present work we report the BeppoSAX observation of the Seyfert 1.9 galaxy NGC 526A in the band 0.1–150 keV. The high energy instrument onboard, PDS, has succeeded in measuring for the first time the spectrum of this source in the 13–150 keV range. The combined analysis of all Narrow Field Instruments provides a power law spectral index of ≃ 1.6 and(More)
OBJECT The authors undertook this study to analyze the efficacy of vagus nerve stimulation (VNS) in a large consecutive series of children 18 years of age and younger with treatment-resistant epilepsy and compare the safety and efficacy in children under 12 years of age with the outcomes in older children. METHODS The authors retrospectively reviewed 141(More)
We report on the first detection above ∼10 keV of the archetypal Compton–thick Seyfert 2 galaxy NGC 1068. This detection , obtained with the PDS instrument onboard BeppoSAX in the 20–100 keV range, confirms the hardness of the X–ray spectrum above a few keV (as indicated by ASCA observations) and supports models envisaging a mixture of both neutral and(More)
We present results on approximately one year of INTEGRAL observations of six AGN detected during the regular scans of the Galactic Plane. The sample is composed by five Seyfert 2 objects (MCG –05–23–16, NGC 4945, the Circinus galaxy, NGC 6300, ESO 103–G35) and the radio galaxy Centaurus A. The continuum emission of each of these sources is well represented(More)