Related papers: Scattering and Iron Fluorescence Revealed During A…
We present observations of a transient He-like Fe K alpha absorption line in Suzaku observations of the black hole binary Cygnus X-1 on 2011 October 5 near superior conjunction during the high/soft state, which enable us to map the full…
We report on a 300 ks BeppoSAX (0.12-200 keV) observation of Circinus X-1 (Cir X-1) at phases between 0.62 and 0.84 and on a 90 ks BeppoSAX observation of Cir X--1 at phases 0.11-0.16. Using the canonical model adopted until now to fit the…
We report the results of a spectral analysis over the range 0.1-200 keV performed on the dipping source X 1822-371 observed by BeppoSAX. We find the best fit to the continuum using a partially covered Comptonization model, due to scattering…
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 report the first detection of highly ionized Fe species in the X-ray spectrum of the eclipsing and dipping Low Mass X-ray Binary XTE J1710-281. Using archival Chandra and Suzaku observations, we have carried out a spectro-timing analysis…
We present optical spectra and images of the X-ray binary Circinus X-1. The optical light curve of Cir X-1 is strongly variable, changing in brightness by 1.2 magnitudes in the space of four days. The shape of the light curve is consistent…
Aims. We present a 0.2--200 keV broad-band study of absorbed AGN observed with INTEGRAL, XMM-Newton, Chandra and ASCA to investigate the continuum shape and the absorbing/reflecting medium properties. Methods. The sources are selected in…
We have observed variations in the optical emission lines from the X-ray binary Circinus X-1. These variations may be attributed both to orbital variations and to long term secular changes in line strength. We have detected double-peaked…
We have monitored the Seyfert galaxy NGC 3227 with the Rossi X-ray Timing Explorer (RXTE) since January 1999. During late 2000 and early 2001 we observed an unusual hardening of the 2-10 keV X-ray spectrum which lasted several months. The…
(abridged) We analyzed the archived XMM-Newton observation of the poorly studied low-mass X-ray binary XTE J1710-281 performed in 2004 that covered one orbital period of the system (3.8 hr). The source shows dips as well as eclipses, hence…
We report on the deepest X-ray observation of the narrow-line Seyfert 1 galaxy Mrk 335 in the low-flux state obtained with Suzaku. The data are compared to a 2006 high-flux Suzaku observation when the source was ~10-times brighter.…
We have analyzed a Chandra HETGS spectrum of the Galactic black hole Cygnus X-1, obtained at a source flux which is approximately twice that commonly observed in its persistent low-intensity, spectrally-hard state. We find a myriad of…
We present results from the first radio observations of a complete orbit (~ 17 days) of the neutron star X-ray binary Circinus X-1 using the Australia Telescope Compact Array Broadband Backend, taken while the system was in an historically…
New radio observations of the radio-jet X-ray binary Circinus X-1 over nearly an entire 16.6-day orbit are presented. The source continues to undergo radio flaring in the phase interval 0.0 - 0.2 and appears to be brightening since…
High-resolution X-ray spectroscopy is a key to understanding the mass inflow and outflow of compact objects. Spectral lines carry information about the ionization, density, and velocity structures through their intensity ratios and…
The eclipsing low-mass X-ray binary AX J1745.6-2901 was observed with Suzaku in its outburst phase. Combining the Chandra observation made 1.5 month earlier than Suzaku, we determined the orbital period to be 30063.76+/-0.14 s. We found…
We present results of an observation with Suzaku of the dipping, periodic bursting low mass X-ray binary XB 1323-619. Using the energy band 0.8 - 70 keV, we show that the source spectrum is well-described as the emission of an extended…
A new Chandra observation and archival observations by ASCA are used to investigate spectral variations in the Sy1 galaxy NGC 3516 over a period of 7 years. A large change in flux (factor ~50 at 1keV) is observed between an ASCA observation…
We report the detection of narrow Fe XXV and Fe XXVI X-ray absorption lines at 6.68 +/- 0.04 keV and 6.97 +/- 0.05 keV in the persistent emission of the dipping low-mass X-ray binary 4U 1323-62 during a 2003 January XMM-Newton observation.…
We present Rossi X-ray Timing Explorer (RXTE) All-Sky Monitor observations of the X-ray binary Circinus X-1 which illustrate the variety of intensity profiles associated with the 16.55 d flaring cycle of the source. We also present eight…