Related papers: Wind accretion in Cygnus X-1
Aims: We have developed a new code for the three-dimensional time-dependent raditation hydrodynamic simulation of the stellar wind in interacting binaries to improve models of accretion in high-mass X-ray binaries and to quantitatively…
Cygnus X-1, as the first discovered black hole binary, is a key source for understanding the mechanisms of state transitions, and the scenarios of accretion in extreme gravity fields. We present a spectral-timing analysis of observations…
Stellar winds of massive stars are known to be driven by line absorption of UV photons, a mechanism which is prone to instabilities, causing the wind to be clumpy. The clumpy structure hampers wind mass-loss estimates, limiting our…
Accreting black holes are thought to emit the bulk of their power in the X-ray band by releasing the gravitational potential energy of the infalling matter. At the same time, they are capable of producing highly collimated jets of energy…
We present results from simultaneous observations of the high-mass X-ray binary system Cygnus X-1 / HDE 226868 with Suzaku, Chandra-HETGS, XMM-Newton, RXTE, INTEGRAL, and Swift in 2008 April. Performed shortly after orbital phase 0, when…
Gamma-ray observations of microquasars at high and very-high energies can provide valuable information of the acceleration processes inside the jets, the jet-environment interaction and the disk-jet coupling. Two high-mass microquasars have…
The interpretation of the X-ray spectra of X-ray binaries during their hard states requires a hot, optically thin medium. There are several accretion disc models in the literature that account for this aspect. However, none is designed to…
Cygnus X-1 was the first X-ray source widely accepted to be a black hole candidate and remains among the most studied astronomical objects in its class. The detection of non-thermal radio, hard X-rays and gamma rays reveals the fact that…
Hercules X-1 is a nearly edge-on X-ray binary with a warped, precessing accretion disk, which manifests through a 35-day cycle of alternating High and Low flux states. This disk precession introduces a changing line of sight towards the…
We present the results of a 2.5-year multiwavelength monitoring programme of Cygnus X-1, making use of hard and soft X-ray data, optical spectroscopy, UBVJHK photometry and radio data. In particular we confirm that the 5.6-day orbital…
Cygnus X-3 is a unique microquasar in the Galaxy hosting a Wolf-Rayet companion orbiting a compact object that most likely is a low-mass black hole. The unique source properties are likely due to the interaction of the compact object with…
We report results from a 30 ks observation of Cygnus X-1 with the High Energy Transmission Grating Spectrometer (HETGS) on board the {\em Chandra X-ray Observatory}. Numerous absorption lines were detected in the HETGS spectrum. The lines…
We review the spectral properties of the black hole candidate Cygnus X-1. Specifically, we discuss two recent sets of multi-satellite observations. One comprises a 0.5-500 keV spectrum, obtained with every flying X-ray satellite at that…
We present the first high-resolution X-ray spectral analysis of Cygnus X-1 using XRISM. The observation was carried out from April 7 to 10, 2024, covering the orbital phase range 0.65--0.17 during its low/hard state. Taking advantage of the…
Using Suzaku and the Rossi X-ray Timing Explorer, we have conducted a series of four simultaneous observations of the galactic black hole candidate Cyg X-1 in what were historically faint and spectrally hard low states. Additionally, all of…
We present results of our detailed theoretical study of the observed orbital modulation of the radio emission in Cyg X-1. The modulation occurs due to free-free absorption in the wind from the companion star varying with the orbital phase,…
Supergiant High Mass X-ray Binary systems (sgHMXBs) consist of a massive, late type, star and a neutron star. The massive stars exhibits strong, radiatively driven, stellar winds. Wind accretion onto compact object triggers X-ray emission,…
Two component X-ray spectra (soft multicolor black body plus harder power law) are frequently observed from accreting black holes. These components are presumably associated with the different parts of the accretion flow (optically thick…
In Supergiant X-ray binaries (SgXB), a compact object captures a fraction of the wind of an O/B supergiant on a close orbit. Proxies exist to evaluate the efficiency of mass and angular momentum accretion but they depend so dramatically on…
We report on a Spitzer/IRS (mid-infrared), RXTE/PCA+HEXTE (X-ray), and Ryle (radio) simultaneous multiwavelength study of the microquasar Cygnus X-1, which aimed at an investigation of the origin of its mid-infrared emission. Compact jets…