ar X iv : a st ro - p h / 99 01 38 1 v 1 2 7 Ja n 19 99 Central UV Spikes in two Galactic

ar X iv : a st ro - p h / 99 01 10 8 v 1 1 0 Ja n 19 99 Accretion Disk Models

Models of black hole accretion disks are reviewed, with an emphasis on the theory of hard X-ray production. The following models are considered: i) standard, ii) super-critical, iii) two-temperature, and iv) disk+corona. New developments have recently been made in hydrodynamical models of accretion and in phenomenological radiative models fitting the observed X-ray spectra. Attempts to unify th...

ar X iv : a st ro - p h / 99 01 23 3 v 1 1 8 Ja n 19 99 Long term BeppoSAX - WFC monitoring of GRS 1758 - 258

Following a series of deep observations of the Galactic Bulge region performed with the Wide Field Cameras telescopes on board BeppoSAX, it has been possible to study throughout a long time period a number of persistent X-ray sources. We report on the behaviour of GRS 1758-258, an X-ray binary suggested as a black hole candidate on the basis of its timing and spectral characteristics. The sourc...

ar X iv : a st ro - p h / 99 01 14 4 v 1 1 2 Ja n 19 99 BeppoSAX observations of bright Seyfert 2 galaxies

We report on BeppoSAX broad band (0.1-100 keV) observations of bright Seyfert 2 galaxies and discuss the results in the framework of the unified theory of AGNs. The data are used to probe N H distribution in type 2 objects and to identify heavily absorbed (10 24 ≤ N H ≤ 10 25 cm −2) sources, which are particularly bright in hard X-rays. They also provide, for the first time, high energy spectra...

ar X iv : a st ro - p h / 99 02 23 4 v 2 1 7 Fe b 19 99 OB ASSOCIATIONS

ar X iv : a st ro - p h / 97 01 22 8 v 1 2 9 Ja n 19 97 Large - scale Structures revealed by Wavelet Decomposition 1