Related papers: The time-lag -- photon-index correlation in GX 339…

Obtaining simultaneous radio and X-ray data during the outburst decay of soft X-ray transients is a potentially important tool to study the disc - jet connection. Here we report results of the analysis of (nearly) simultaneous radio (VLA or…

Black hole X-ray binaries display large outbursts, during which their properties are strongly variable. We develop a systematic spectral analysis of the 3-40 keV RXTE/PCA data in order to study the evolution of these systems and apply it to…

We have analyzed the 171 RXTE data sets of the black hole candidate GX 339-4 in the low/hard state during its 1996--2005 outburst. All the broadband spectra were successfully modeled by a simple analytic model, power-law with an exponential…

We present the analysis of the high energy emission of the Galactic black hole binary GX 339-4 in a low/hard state at the beginning of its 2004 outburst. The data from 273 ks of INTEGRAL observations, spread over 4 weeks, are analyzed,…

We investigate the X-ray time lags of a recent ~630ks XMM-Newton observation of PG 1211+143. We find well-correlated variations across the XMM-Newton EPIC bandpass, with the first detection of a hard lag in this source with a mean time…

Using the Chandra X-ray Observatory and the Rossi X-ray Timing Explorer, we have studied the black hole candidate (BHC) X-ray transient XTE J1650-500 near the end of its 2001-2002 outburst after its transition to the low-hard state at X-ray…

We describe how the coherence function, a Fourier frequency-dependent measure of the linear correlation between time series measured simultaneously in two energy channels, can be used in conjunction with energy spectra, power spectra, and…

We present the first systematic physical modelling of the time-lag spectra between the soft (0.3-1 keV) and the hard (1.5-4 keV) X-ray energy bands, as a function of Fourier frequency, in a sample of 12 active galactic nuclei which have…

We have used a stringy model of quantum space-time foam to suggest that the vacuum may exhibit a non-trivial refractive index depending linearly on gamma-ray energy: eta -1 ~ E_gamma/M_QG1, where M_QG1 is some mass scale typical of quantum…

We present the X-ray variability properties of the X-ray and TeV bright blazar Mrk 421 with a ~60 ks long XMM-Newton observation performed on November 9-10, 2005. The source experienced a pronounced flare, of which the inter-band time lags…

We investigated the time lags and the evolution of the cross spectra of Z source GX~5-1, observed by the Rossi X-ray Timing Explorer (RXTE), when it is in the horizontal branch oscillations. We showed that the time lags of 3 horizontal…

We investigate the soft X-ray transients with black hole primaries which may have been the sources of gamma-ray bursts and hypernovae earlier in their evolution. We find that the black-hole mass increases with the orbital period of the…

IRAS 13224-3809 was observed in 2011 for 500 ks with the XMM-Newton observatory. We detect highly significant X-ray lags between soft (0.3 - 1 keV) and hard (1.2 - 5 keV) energies. The hard band lags the soft at low frequencies (i.e. hard…

We investigate the nature of the inner accretion disk in the neutron star source GX 5-1 by making a detailed study of time lags between X-rays of different energies. Using the cross-correlation analysis, we found anti-correlated hard and…

We analyse five observations of the X-ray binary GX 339-4 by the soft gamma-ray OSSE detector on board CGRO simultaneous with either Ginga or RXTE observations. The source was bright during four of them, with the luminosity of L ~ 10^{37}…

Previous work by Motch et al. (1985) suggested that in the low/hard state of GX339-4, the soft X-ray power-law extrapolated backward in energy agrees with the IR flux level. Corbel and Fender (2002) later showed that the typical hard state…

Evolution of variability properties of Galactic transient sources is a diagnostic tool to understand various regimes of the accretion flow and its dynamics close to the central black hole. In this paper, we concentrate on the variability…

We present the results regarding the analysis of the fast X-ray/infrared (IR) variability of the black-hole transient MAXI J1535$-$571. The data studied in this work consist of two strictly simultaneous observations performed with…

The Galactic black hole candidate X-ray binary GX339-4 spends most of its time in the low/hard state, making it an ideal candidate for modeling the assumedly low accretion phase. The radio emission correlates very tightly with the X-rays…

The microquasar GX 339-4, known to exhibit powerful compact jets that dominate its radio to near-infrared emission, entered an outburst in 2010 for the fifth time in about fifteen years. An extensive radio to X-ray multi-wavelength campaign…