Search Publications
Blazars and INTEGRAL
Pian, E.; Hudec, R.; Kubánek, P. +1 more
We refer to analysis of the ESA INTEGRAL satellite data for specific class of active galactic nuclei - blazars. These objects represent promising sources to be observed by INTEGRAL, especially during their active states. Suitable strategy for the future analysis is proposed and discussed.
Quasi-null lens optical system for the fabrication of an oblate convex ellipsoidal mirror: application to the Wide Angle Camera of the Rosetta space mission
Naletto, Giampiero; Ragazzoni, Roberto; da Deppo, Vania +2 more
The design of a quasi-null lens system for the fabrication of an aspheric oblate convex ellipsoidal mirror is presented. The Performance and tolerance of the system have been analyzed. The system has been applied successfully for the fabrication of the primary mirror of the Wide Angle Camera (WAC), the imaging system onboard the Rosetta, the Europ…
Discovery of a double peaked Fe emission line in the Cloverleaf quasar H 1413+117
Agol, E.; Dai, X.; Chartas, G. +2 more
Our spatial and spectral analysis of a recent deep Chandra observation of H 1413+117 confirms a microlensing event in a previous Chandra observation of this object performed about 5 years earlier. We present constraints on the structure of H 1413+117 based on the time-scale of this microlensing event. The analysis of the combined spectrum of the i…
Spectral behaviour of an INTEGRAL sample of black hole candidates: Initial results
Capitanio, F.; Bazzano, A.; Cadolle Bel, M. +13 more
In this paper, we present the spectral characteristics of a sample of Black Hole Candidates observed with the IBIS, SPI and JEM-X instruments on board the INTEGRAL Gamma-ray Observatory. This work is part of the long term, systematic, spectral study programme of intermediate intensity BHC (<500 mCrab) within the INTEGRAL Core Programme observat…
Unveiling hidden AGN by IR observations
Haas, Martin
AGN can be dust-hidden by two ways and this talk considers how to unveil them in the infrared: firstly, the powerful 3CR radio galaxies, i.e., type-2 AGN which suffer from anisotropic obscuration of the nuclear region by the dust torus, and secondly, type-1 quasars, which seem to be isotropically reddened by dust, so that they escape detection via…
X-ray emission from PTT stars
Mason, H. E.; Bromage, G. E.; Landini, M. +4 more
We present preliminary results on an XMM-Newton observation dedicated to Post-T-Tauri (PTT) stars. We observed the visual binary 2RE J0241-53 of the Horologium association of nearby PTT stars. The XMM observations have been complemented with ground-based optical spectroscopy and photometry. Several flares have been observed. The X-ray spectrum of …
A highly-ionized absorber as a new explanation for the spectral changes during dips from X-ray binaries
Kaastra, J. S.; Díaz Trigo, M.; Parmar, A. N. +2 more
We report the XMM-Newton detection of narrow Fe XXV and Fe XXVI X-ray absorption lines at 7 keV in the persistent emission of the dipping low-mass X-ray binary (LMXB) 4U 1323-62. Such features have now been reported in a growing number of LMXBs seen almost edge-on, indicating that the highly-ionized plasma probably originates in an accretion disk …
Effects of the photo-ionized absorber on the continuum spectra of EXO 0748 676
Asai, Kazumi; Dotani, Tadayasu
We report on the analysis of XMM-Newton archival data of EXO 0748-676. We studied changes of the continuum spectra due to the presence of photo-ionized plasma on the line of sight. We show that the ionization degree of the plasma could change largely during the X-ray bursts and the dips. These changes can significantly modify the soft-band spectru…
Microquasars: What do radio and X-ray observations tell us?
Wu, Kinwah; Rodriguez, Jérôme; Vilhu, Osmi +4 more
Microquasars, or X-ray binaries exhibiting radio jets, have been observed extensively at all wavelengths for the past decade or so. Primarily, they have been observed in the X-ray regimes and the radio. In this paper we review the radio and the X-ray behavior of the first two superluminal microquasars, GRS 1915+105 and GRO J1655-40. We show how GR…
Pulsation Modes and Fundamental Parameters of Mira Stars
Barthes, D.
Linear pulsation models are generated using the absolute magnitudes of long period variables (LPVs) in the Large Magellanic Cloud (LMC) and in the solar neighborhood (HIPPARCOS parallaxes), as well as effective temperature estimates. The results support the hypothesis that linear modeling may be used provided that a lower mixing length (possibly e…