Related papers: Long term variability of Cygnus X-1: VI. Energy-re…
We present the analysis of two long, quasi-uninterrupted RXTE observations of Cygnus X-1 that span several days within a 10 d interval. The spectral characteristics during this observation cover the region where previous observations have…
We present first results from the spectral and temporal analysis of an RXTE monitoring campaign of the black hole candidate Cygnus X-1 in 1999. The timing properties of this hard state black hole show considerable variability, even though…
Long-term X-ray variability of the black hole binary, Cygnus X-1, was studied with five years of MAXI data from 2009 to 2014, which include substantial periods of the high/soft state, as well as the low/hard state. In each state, Normalized…
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…
Cygnus X-1 is a persistent, high-mass black hole X-ray binary (BHXRB) which in the hard state shows many similar properties to transient BHXRBs, along with intriguing differences, such as the lack of quasi-periodic oscillations. Here, we…
We present timing analysis for a Rossi X-ray Timing Explorer observation of Cygnus X-1 in its hard/low state. This was the first RXTE observation of Cyg X-1 taken after it transited back to this state from its soft/high state. RXTE's large…
We present temporal and spectral results from monitoring Cygnus X-1 with the Rossi X-ray Timing Explorer (RXTE) in 1998 and 1999. We concentrate on the long term evolution of the hard state timing properties, comparing it to the 1996 soft…
We present the long term evolution of the timing properties of the black hole candidate Cygnus X-1 in the 0.002-128 Hz frequency range as monitored from 1998 to 2001 with the RXTE. The hard state power spectral density (PSD) is well modeled…
We present a comprehensive timing analysis of the black hole X-ray binary Cygnus X-1 using 26 NuSTAR observations spanning 2012-2024, providing the most detailed characterization to date of its accretion flow variability across spectral…
We present an analysis of all observations of Cygnus X-1 by the BATSE (20-300 keV) and by ASM (1.5-12 keV) until 2002 June, including 1200 days of simultaneous data. We find a number of correlations between fluxes and hardnesses in…
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…
We develop new techniques to deconvolve the radial structure of the X-ray emission region in the bright low/hard state of the black hole Cygnus X-1 using both spectral and timing data in the 3-35~keV range. The spectrum at these energies is…
We present simultaneous multi-band radio and X-ray observations of the black hole X-ray binary Cygnus X-1, taken with the Karl G. Jansky Very Large Array and the Nuclear Spectroscopic Telescope Array. With these data, we detect clear flux…
For the very first time, we report the high frequency analysis of Cyg X-1 up to hard X-ray using SPI on-board INTEGRAL. After analyzing the possible contribution fromthe background, and using INTEGRAL archive from March 2005 to May 2008,…
(abbreviated abstract) We present the long term spectral evolution of the Galactic black hole candidate Cygnus X-1 in the X-rays and at 15GHz using ~200 pointed observations taken between early 1999 and late 2004 with RXTE and the Ryle…
We present results of recurrence analysis of the black hole X-ray binary Cygnus X-1 using combined observations from the Rossi X-ray Timing Explorer All-sky Monitor and the Japanese Monitor of All-sky X-ray Image aboard the ISS. From the…
We study the soft X-ray variability of Cygnus X-3. By combining data from the All-Sky Monitor and Proportional Counter Array instruments on the RXTE satellite with EXOSAT Medium Energy (ME) detector observations, we are able to analyse the…
We present the long term evolution of the frequency-dependent X-ray time lags of the black hole candidate Cygnus X-1 as measured in 1996 and 1998 with the Rossi X-ray Timing Explorer (RXTE). Lag spectra measured during the 1996 June soft…
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 time variability characteristics of Cygnus X-1 in its two spectral states. The observations were carried out using the Pointed Proportional Counters (PPC) on-board the Indian X-ray Astronomy Experiment (IXAE). The details of…