Search Publications
The timing properties of Sco X-1 along its Z track with EXOSAT
van der Klis, Michiel; Dieters, Stefan W.
We present a systematic, homogeneous analysis of all the EXOSAT ME, high time resolution data on Sco X-1. We investigate, for the first time, all power spectral properties of the <100Hz quasi-periodic oscillations (QPO) and noise of Sco X-1 as a function of position on the Z-shaped track traced out in the X-ray colour-colour diagram. For this p…
Temperature Profiles of Accretion Disks around Rapidly Rotating Neutron Stars in General Relativity and the Implications for Cygnus X-2
Misra, Ranjeev; Bhattacharyya, Sudip; Thampan, Arun V. +1 more
We calculate the temperature profiles of (thin) accretion disks around rapidly rotating neutron stars (with low surface magnetic fields), taking into account the full effects of general relativity. We then consider a model for the spectrum of the X-ray emission from the disk that is parameterized by the mass accretion rate, the color temperature, …
The structure of Algol's corona: a consistent scenario for the X-ray and radio emission
Schmitt, J. H. M. M.; Micela, G.; Favata, F. +2 more
We present a systematic analysis of the four known large X-ray flares detected to date on the eclipsing binary system Algol, using an approach based on hydrodynamic simulations of decaying flaring loops including sustained heating. This method yields, for the large BeppoSAX Algol flare of Aug. 1997 (where a geometrical estimate of the size of the …
X1908+075: An X-Ray Binary with a 4.4 Day Period
Remillard, Ronald A.; Wen, Linqing; Bradt, Hale V.
X1908+075 is an optically unidentified and highly absorbed X-ray source that appeared in early surveys such as Uhuru, OSO 7, Ariel 5, HEAO-1, and the EXOSAT Galactic Plane Survey. These surveys measured a source intensity in the range 2-12 mcrab at 2-10 keV, and the position was localized to ~0.5d. We use the Rossi X-Ray Timing Explorer (RXTE) All…
LMC X-2: The First Extragalactic Z Source?
Kuulkers, Erik; Smale, Alan P.
We present RXTE observations of LMC X-2 obtained during a 5 day interval in 1997 December, during which the source was radiating at a mean intensity near the Eddington limit and was strongly variable on timescales of seconds to hours. The shapes of the X-ray color-color and hardness-intensity diagrams during the observations, the presence of very …
Photometric and spectroscopic studies of cool stars discovered in EXOSAT X-ray images. IV. The northern hemisphere sample
Tagliaferri, G.; de Medeiros, J. R.; Messina, S. +4 more
We present high-precision photometry, high- and medium-resolution spectroscopy for a sample of 32 stars likely to be the optical counterparts of X-ray sources serendipitously detected by the EXOSAT satellite. Using also recent results from the Hipparcos satellite, we infer spectral types, compute X-ray luminosities and Li abundances and investigat…
X-ray analysis of the cluster 3C 129
Leahy, D. A.; Yin, D.
The cluster 3C 129 is classified as a rich cluster. An analysis of the properties of the cluster 3C 129 from ROSAT PSPC and HRI, Einstein IPC, and EXOSAT ME observations is presented. The mean temperature from a joint fit of the ROSAT PSPC and EXOSAT ME data is 5.5(+/-0.2)keV. The luminosity is 0.6x1044ergs-1 in 0.2-2.4keV an…
No QPO time lags from Sco X-1 as seen with EXOSAT: a comparison with Cyg X-2
Kuulkers, Erik; van der Klis, Michiel; Lamb, Frederick K. +2 more
We have measured the phase-delay and rms amplitude spectra of Cyg X-2 and Sco X-1. Using EXOSAT data from the normal branch of Cyg X-2 we confirm earlier (Ginga) results, showing that at an energy near 6 keV there is both a minimum in the quasi-periodic oscillations QPO rms amplitude spectrum and a 150deg phase jump in the QPO phase-del…