Related papers: The Photoionized Accretion Disk in Her X-1
We present the analysis of several observations of the black hole binary GX 339--4 during its bright intermediate states from two different outbursts (2002 and 2004), as observed by RXTE/PCA. We perform a consistent study of its reflection…
We present the first optical circular and linear polarization measurements of two polar candidates from ROSAT: 1RXS J161008.0+035222 and 1RXS J231603.9-052713. We also present H band near-infrared photometry of the last object. The presence…
The geometry of the accretion flow around stellar mass and supermassive black holes depends on the accretion rate. Broad iron emission lines originating from the irradiation of cool matter can indicate that there is an inner disk below a…
We present the results of a long-term observation campaign of the extragalactic wind-accreting black-hole X-ray binary LMC X-1, using the Proportional Counter Array on the Rossi X-Ray Timing Explorer (RXTE). The observations show that LMC…
The X-ray spectra of the narrow line Seyfert 1 galaxy, 1H 0707-495, obtained with XMM-Newton, from time periods of varying X-ray luminosity are analysed in the context of understanding the changes to the X-ray emitting corona that lead to…
We observed at very high spectral resolution the prototype Z-source Cyg x-2 twice along its entire X-ray spectral variation pattern. In this preliminary analysis we find an extended accretion disk corona exhibiting Lyman alpha emissions…
From hot, tenuous gas dominated by Compton processes, to warm, photoionized emission-line regions, to cold, optically thick fluorescing matter, accreting gas flows in X-ray binaries span a huge portion of the parameter space accessible to…
Her X-1 is an accreting neutron star in an intermediate-mass X-ray binary. Like low-mass X-ray binaries (LMXBs), it accretes via Roche-lobe overflow, but similar to many high-mass X-ray binaries containing a neutron star, Her X-1 has a…
We investigate accretion disk winds commonly observed in galactic black hole (BH) X-ray binaries (XRB), which manifest as blueshifted absorption features in X-ray spectra. We model these winds as ideal magnetohydrodynamic outflows of hot…
We perform X-ray/ultraviolet (UV) spectral and X-ray variability studies of the radio-loud narrow-line Seyfert 1 (NLS1) galaxy RX J1633.3+4719 using XMM-Newton and Suzaku observations from 2011 and 2012. The 0.3-10 keV spectra consist of an…
We present detailed broadband X-ray spectral variability of a Seyfert 1 galaxy 1H~0419--577 based on an archival \suzaku{} observation in July 2007, a new \suzaku{} observation performed in January 2010 and the two latest \xmm{}…
X-ray observations can be used to effectively probe the galactic ecosystem, particularly its hot and energetic components. However, existing X-ray studies of nearby star-forming galaxies are limited by insufficient data statistics and a…
Recent observations reveal that a cool disk may survive in the innermost stable circular orbit (ISCO) for some black hole X-ray binaries in the canonical low/hard state. The spectrum is characterized by a power law with a photon index…
We observed the Ultraluminous X-ray Source IC 342 X-1 simultaneously in X-ray and radio with Chandra and the JVLA to investigate previously reported unresolved radio emission coincident with the ULX. The Chandra data reveal a spectrum that…
Context. High resolution X-ray observations of classical T Tauri stars (CTTSs) show a soft X-ray excess due to high density plasma (n_e=10^11-10^13 cm^-3). This emission has been attributed to shock-heated accreting material impacting onto…
Her X-1, one of the brightest and best studied X-ray binaries, shows a cyclotron resonant scattering feature (CRSF) near 37 keV. This makes it an ideal target for detailed study with the Nuclear Spectroscopic Telescope Array (NuSTAR),…
We analyze the high-resolution X-ray spectrum of Hercules X-1, an intermediate-mass X-ray binary, which was observed with the XMM-Newton Reflection Grating Spectrometer. We measure the elemental abundance ratios by use of spectral models,…
We present analyses of an Intermediate Polar, IGR J15094-6649, based on the archival optical data obtained from the Transiting Exoplanet Survey Satellite (TESS) and X-ray data obtained from the Suzaku, NuSTAR, and Neil Gehrels Swift…
The chemical properties of protoplanetary disks are especially sensitive to their ionization environment. Sources of molecular gas ionization include cosmic rays, stellar X-rays and short-lived radionuclides, each of which varies with…
Thanks to recurrent observations of the black hole binary Cyg X-1 carried out over 15 years the INTEGRAL satellite has collected the largest data set in the hard X-ray band for this source. We have analyzed these data, complemented by data…