相关论文: Simultaneous ASCA And RXTE Observations of Cygnus …

We present X-ray/gamma-ray spectra of Cyg X-1 observed during the transition from the hard to the soft state and in the soft state by ASCA, RXTE and OSSE in 1996 May and June. The spectra consist of a dominant soft component below ~2 keV…

We present X-ray/gamma-ray observations of Cyg X-1 in the soft state during 1996 May-June. We analyze ASCA, RXTE and OSSE data. The spectrum consists of soft X-ray blackbody emission of an optically thick accretion disk in the vicinity of a…

We summarize recent observations of Cyg X-1 during its 1996 state transition. The results favor an emission geometry with a central optically thin corona surrounded by an optically thick, geometrically thin accretion disk. As the soft state…

We present results from a 20 ksec RXTE observation of the black hole candidate Cyg X-1. We apply self-consistent accretion disk corona models to these hard state data and show that Comptonization in a spherical corona irradiated by soft…

We analyse a large number ($> 500$) pointed RXTE observations of Cyg X-1 and model the spectrum of each one. A subset of the observations for which there is simultaneous reliable measure of the hardness ratio by the All Sky Monitor, shows…

We report on the 0.5--200 keV spectral properties of Cyg X-1 observed at different epochs with the Narrow Field Instruments of the BeppoSAX satellite. The source was in its soft state during the first observation of 1996 June. In the second…

We present four X-ray/gamma-ray spectra of Cyg X-1 observed in the hard ('low') state simultaneously by Ginga and GRO/OSSE on 1991 July 6. The 3-30 keV Ginga spectra are well represented by power laws with an energy spectral index of…

From 2005 to 2009, 25 observations of Cyg X-1 were performed with Suzaku, achieving a total exposure of 446 ks. In all observations, the source was found in the low/hard state, while the 1.5--12.0 keV count rate of the All-Sky Monitor…

In this paper, we summarize key observational constraints of the accretion flow on the black hole X-ray binary Cygnus X-1 (Cyg X-1). The discussion highlights the flows of energy close to the black hole and the importance of the distance…

We observed the black hole candidate Cyg X-1 for 15 ks with the High-Energy Transmission Grating Spectrometer aboard the CHANDRA X-ray Observatory. The source was observed during a period of intense flaring activity, so it was about a…

The black-hole binary Cygnus X-1 was observed for 17 ks with the Suzaku X-ray observatory in 2005 October, while it was in a low/hard state with a 0.7-300 keV luminosity of 4.6 x 10^37 erg/s. The XIS and HXD spectra, spanning 0.7-400 keV,…

We analyze the simultaneous ASCA/RXTE observation of Cyg X-1 in the soft state on 1996 May 30. We apply a multi-color disk model with a torque-free boundary condition in the pseudo-Newtonian potential, and point out the main discrepancies…

We present the results from the RXTE observations of Cygnus X-1 in its high state. In the energy range of 2-200 keV, the observed X-ray spectrum can be described by a model consisting of a soft blackbody component and a broken power-law…

We present the results of spectral analysis of 42 simultaneous broad-band Ginga--OSSE and RXTE--OSSE observations of Cyg X-1 carried out in 1991 and 1996--1999. The hardest spectra in our sample in the energy range from 3 to \~1000 keV can…

We review observations and theoretical models of X-ray/gamma-ray spectra of radio-quiet Seyfert galaxies and of Galactic black-hole candidates (in the hard spectral state). The observed spectra share all their basic components: an…

Several galactic black holes show transitions between spectral states. In this paper we present a unifying radiation transfer model that can fit the spectral data in both states. We fit individual broad-band (from 1 keV up to 4 MeV)…

We present the broad band X-ray spectrum of Cyg X-1 in the low/hard state as observed by the instruments on board of BeppoSAX. The spectrum spans from 0.1 to 200 keV, allowing the total accretion luminosity to be observed, rather than…

We report the results from our timing analysis of 15 RXTE observations of Cygnus X-1 throughout its 1996 spectral transitions. The entire period can be divided into 3 distinct phases: (1) transition from the hard to soft state, (2) soft…

Unified X-ray spectral and timing studies of Cygnus X-1 in the low/hard and hard intermediate state were conducted in a model-independent manner, using broadband Suzaku data acquired on 25 occasions from 2005 to 2009 with a total exposure…

Any cold, optically-thick matter in the vicinity of an accreting black hole, such as the accretion disk, can intercept and reprocess some fraction of the hard X-ray continuum emission, thereby imprinting atomic features into the observed…