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Disk Dominated States of 4U 1957+11: Chandra, XMM, and RXTE Observations of Ostensibly the Most Rapidly Spinning Galactic Black Hole
Michael A. Nowak, Adrienne Juett, Jeroen Homan +4
We present simultaneous Chandra-HETG and RXTE observations of a moderate flux `soft state' of the black hole candidate 4U1957+11. These spectra, having a minimally discernible hard…
Chandra X-ray spectroscopy of the focused wind in the Cygnus X-1 system. I. The non-dip spectrum in the low/hard state
Manfred Hanke, Joern Wilms, Michael A. Nowak +3
We present analyses of a 50 ks observation of the supergiant X-ray binary system Cygnus X-1/HDE 226868 taken with the Chandra High Energy Transmission Grating Spectrometer (HETGS).…
The pre-outburst flare of the A 0535+26 August/September 2005 outburst
I. Caballero, A. Santangelo, P. Kretschmar +11
We study the spectral and temporal behavior of the High Mass X-ray Binary A 0535+26 during a `pre-outburst flare' which took place ~5 d before the peak of a normal (type I) outburs…
A model for cyclotron resonance scattering features
G. Schönherr, J. Wilms, P. Kretschmar +5
(abbreviated version of the abstract) We study the physics of cyclotron line formation in the high-energy spectra of accreting X-ray pulsars using Monte Carlo methods, assuming tha…
An ultraluminous supersoft source with a 4 hour modulation in NGC 4631
S. Carpano, A. M. T. Pollock, A. R. King +2
Context. Supersoft X-ray sources (SSSs) are characterised by very low temperatures (< 100 eV). Classical SSSs have bolometric luminosities in the range of 10^36-10^38 erg/s and are…
An X-ray Spectral Analysis of the Central Regions of NGC 4593
L. W. Brenneman, C. S. Reynolds, J. Wilms +1
We present a detailed analysis of XMM-Newton EPIC-pn data for the Seyfert-1 galaxy NGC 4593. We discuss the X-ray spectral properties of this source as well as its variations with…
A 33 hour period for the Wolf-Rayet/black hole X-ray binary candidate NGC 300 X-1
S. Carpano, A. M. T. Pollock, A. Prestwich +4
Context. NGC 300 X-1 is the second extragalactic candidate, after IC 10 X-1, in the rare class of Wolf-Rayet/compact object X-ray binary systems exemplified in the Galaxy by Cyg X-…
Long-term developments in Her X-1: Correlation between the histories of the 35 day turn-on cycle and the 1.24 sec pulse period
R. Staubert, S. Schandl, D. Klochkov +3
We have studied the long-term (1971-2005) behaviour of the 1.24 sec pulse period and the 35 day precession period of Her X-1 and show that both periods vary in a highly correlated…
Discovery of a flux-related change of the cyclotron line energy in Her X-1
R. Staubert, N. I. Shakura, K. Postnov +5
We present the results of ten years of repeated measurements of the Cyclotron Resonance Scattering Feature (CRSF) in the spectrum of the binary X-ray pulsar Her X-1 and report the…
INTEGRAL and Swift observations of EXO 2030+375 during a giant outburst
D. Klochkov, D. Horns, A. Santangelo +11
Aims: We investigate the X-ray spectral and timing properties of the high mass X-ray binary EXO 2030+375 observed during its June-September 2006 giant (type II) outburst. Methods:…
A Wolf-Rayet/black-hole X-ray binary candidate in NGC 300
S. Carpano, A. M. T. Pollock, J. Wilms +2
Context. Wolf Rayet/black hole binaries are believed to exist as a later evolutionary product of high-mass X-ray binaries. Hundreds of such binaries may exist in galaxies, but only…
Hunting the nature of IGR J17497-2821 with X-ray and NIR observations
A. Paizis, M. A. Nowak, S. Chaty +7
We report on a Chandra grating observation of the recently discovered hard X-ray transient IGR J17497-2821. The observation took place about two weeks after the source discovery at…
A new luminous supersoft X-ray source in NGC 300
S. Carpano, J. Wilms, M. Schirmer +1
Context. We report the discovery of a new luminous supersoft source, XMMU J005455.0-374117, in the nearby spiral galaxy NGC 300, in XMM-Newton observations performed on 2005 May 22…
The XMM-Newton view of the Crab
M. G. F. Kirsch, G. Schoenherr, E. Kendziorra +7
We discuss the current X-ray view of the Crab Nebula and Pulsar, summarising our analysis of observations of the source with the EPIC-pn camera on board the XMM-Newton observatory.…
Study of the cyclotron feature in MXB 0656-072
V. A. McBride, J. Wilms, M. J. Coe +7
We have monitored a Type II outburst of the Be/X-ray binary MXB 0656-072 in a series of pointed RXTE observations during October through December 2003. The source spectrum shows a…
INTEGRAL observation of the high-mass X-ray transient V0332+53 during the 2005 outburst decline
N. Mowlavi, I. Kreykenbohm, S. E. Shaw +7
The decline of the high mass X-ray transient V0332+53 during the Dec. 2004 to Feb. 2005 outburst is analysed from the data recorded by INTEGRAL. The flux is shown to decrease expon…
3A 0535+262 in outburst
P. Kretschmar, K. Pottschmidt, C. Ferrigno +10
The Be/X-ray binary 3A 0535+262 has the highest magnetic field determined by cyclotron line studies of all accreting X-ray pulsars, despite an open debate if the fundamental line w…
Observation of V0332+53 over the 2004/2005 outburst with Integral
I. Kreykenbohm, N. Mowlavi, K. Pottschmidt +8
We present the spectral and temporal analysis of the 2004/2005 outburst of the transient X-ray pulsar V0332+53 as observed with Integral. After the discovery of the third cyclotron…
Long Term Variability of Cygnus X-1. IV. Spectral Evolution 1999-2004
J. Wilms, M. A. Nowak, K. Pottschmidt +2
(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…
Going with the flow: can the base of jets subsume the role of compact accretion disk coronae?
Sera Markoff Michael A. Nowak Joern Wilms
The hard state of X-ray binaries (XRBs) is characterized by a power law spectrum in the X-ray band, and a flat/inverted radio/IR spectrum associated with occasionally imaged compac…
Probing the outer edge of an accretion disk: A Her X-1 turn-on observed with RXTE
M. Kuster, J. Wilms, R. Staubert +4
We present the analysis of Rossi X-ray Timing Explorer (RXTE) observations of the turn-on phase of a 35 day cycle of the X-ray binary Her X-1. During the early phases of the turn-o…
INTEGRAL & RXTE Power Spectra of Cygnus X-1
K. Pottschmidt, J. Wilms, M. A. Nowak +3
We evaluate 0.03-20 Hz power spectra of the bright black hole binary Cyg X-1 obtained from non-deconvolved INTEGRAL-ISGRI event data. The ISGRI power spectra are compared to contem…
Long term variability of Cygnus X-1, III. Radio-X-ray correlations
T. Gleissner, J. Wilms, G. G. Pooley +7
Long time scale radio-X-ray correlations in black holes during the hard state have been found in many sources and there seems to emerge a universal underlying relationship which qu…
GX 301-2 as seen by Integral
I. Kreykenbohm, K. Pottschmidt, P. Kretschmar +9
We present observations of the High Mass X-ray Binary GX 301-2 taken during the Galactic Plane Scan (GPS) with Integral following our RXTE observations (Kreykenbohm et al. 2004). T…