Marion Cadolle Bel

SPECTRAL STATE DEPENDENCE OF THE 0.4–2 MEV POLARIZED EMISSION IN CYGNUS X-1 SEEN WITH INTEGRAL/IBIS, AND LINKS WITH THE AMI RADIO DATA

Polarization of the keV hard tail of the microquasar Cygnus X-1 has been independently reported by INTEGRAL/Imager on Board the INTEGRAL Satellite (IBIS), and INTEGRAL/SPectrometer on INTEGRAL and interpreted as emission from a compact jet. These conclusions were, however, based on the accumulation of all INTEGRAL data regardless of the spectral state. We utilize additional INTEGRAL exposure accumulated until 2012 December, and include the AMI/Ryle (15 GHz) radio data in our study. We separate the observations into hard, soft, and intermediate/transitional states and detect radio emission from a compact jet in hard and intermediate states (IS), but not in the soft. The 10–400 keV INTEGRAL (JEM-X and IBIS) state resolved spectra are well modeled with thermal Comptonization and reflection components. We detect a hard tail in the 0.4–2 MeV range for the hard state only. We extract the state dependent polarigrams of Cyg X-1, which are all compatible with no or an undetectable level of polarization except in the 400–2000 keV range in the hard state where the polarization fraction is 75% ± 32% and the polarization angle 40.°0 ± 14.°3. An upper limit on the 0.4–2 MeV soft state polarization fraction is 70%. Due to the short exposure, we obtain no meaningful constraint for the IS. The likely detection of a keV polarized tail in the hard state, together with the simultaneous presence of a radio jet, reinforce the notion of a compact jet origin of the keV emission.

Chandra X-ray spectroscopy of focused wind in the Cygnus X-1 system - II. The non-dip spectrum in the low/hard state – modulations with orbital phase

The accretion onto the black hole in the system HDE 226868/Cygnus X-1 is powered by the strong line driven stellar wind of the O-type donor star. We study the X-ray properties of the stellar wind in the hard state of Cyg X-1 as determined with data from the Chandra High Energy Transmission Gratings. Large density and temperature inhomogeneities are present in the wind, with a fraction of the wind consisting of clumps of matter with higher density and lower temperature embedded in a photoionized gas. Absorption dips observed in the light curve are believed to be caused by these clumps. This work concentrates on the non-dip spectra as a function of orbital phase. The spectra show lines of H-like and He-like ions of S, Si, Na, Mg, Al and highly ionized Fe (Fe xvii-Fe xxiv). We measure velocity shifts, column densities, and thermal broadening of the line series. The excellent quality of these five observations allows us to investigate the orbital phase dependence of these parameters. We show that the absorber is located close to the black hole. Doppler shifted lines point at a complex wind structure in this region, while emission lines seen in some observations are from a denser medium than the absorber. The observed line profiles are phase dependent. Their shapes vary from pure, symmetric absorption at the superior conjunction to P Cygni profiles at the inferior conjunction of the black hole.

THE 5 hr PULSE PERIOD AND BROADBAND SPECTRUM OF THE SYMBIOTIC X-RAY BINARY 3A 1954+319

We present an analysis of the highly variable accreting X-ray pulsar 3A 1954+319 using 2005-2009 monitoring data obtained with INTEGRAL and Swift. This considerably extends the pulse period history and covers flaring episodes in 2005 and 2008. In 2006 the source was identified as one of only a few known symbiotic X-ray binaries (SyXBs), i.e., systems composed of a neutron star accreting from the inhomogeneous medium around an M-giant star. The extremely long pulse period of {approx}5.3 hr is directly visible in the 2008 INTEGRAL-ISGRI outburst light curve. The pulse profile is double peaked and generally not significantly energy dependent although there is an indication of possible softening during the main pulse. During the outburst a strong spin-up of -1.8 Multiplication-Sign 10{sup -4} hr hr{sup -1} occurred. Between 2005 and 2008 a long-term spin-down trend of 2.1 Multiplication-Sign 10{sup -5} hr hr{sup -1} was observed for the first time for this source. The 3-80 keV pulse peak spectrum of 3A 1954+319 during the 2008 flare could be well described by a thermal Comptonization model. We interpret the results within the framework of a recently developed quasi-spherical accretion model for SyXBs.We present an analysis of the highly variable accreting X-ra y pulsar 3A 1954+319 using 2005–2009 monitoring data obtained with INTEGRAL andSwift. This considerably extends the pulse period history and cov ers flaring episodes in 2005 and 2008. In 2006 the source was ident ified as one of only a few known symbiotic X-ray binaries (SyXBs), i.e., systems composed of a neutron star accreting from the inhomogeneous medium around an M-giant star. The extremely long pulse period of ∼5.3 hr is directly visible in the 2008 INTEGRALISGRI outburst light curve. The pulse profile is double peake d and generally not significantly energy dependent although there is an indication of possible softening durin g the main pulse. During the outburst a strong spinup of−1.8× 10−4 hr hr−1 occurred. Between 2005 and 2008 a long-term spin-down trend of 2.1× 10−5 hr hr−1 was observed for the first time for this source. The 3–80 keV pu lse peak spectrum of 3A 1954 +319 during the 2008 flare could be well described by a thermal Comptonizatio n m del. We interpret the results within the framework of a recently developed quasi-spherical accreti on model for SyXBs. Subject headings: binaries: symbiotic — stars: individual (3A 1954 +319) — stars: neutron — X-rays: binaries

Revealing the broad iron Kα line in Cygnus X-1 through simultaneous XMM-Newton, RXTE, and INTEGRAL observations

We report on the analysis of the broad Fe K α line feature of Cyg X-1 in the spectra of four simultaneous hard intermediate state observations made with the X-ray Multiple Mirror mission ( XMM-Newton ), the Rossi X-ray Timing Explorer (RXTE), and the International Gamma-Ray Astrophysics Laboratory (INTEGRAL). The high quality of the XMM-Newton data taken in the Modified Timing Mode of the EPIC-pn camera provides a great opportunity to investigate the broadened Fe K α reflection line at 6.4 keV with a very high signal to noise ratio. The 4–500 keV energy range is used to constrain the underlying continuum and the reflection at higher energies. We first investigate the data by applying a phenomenological model that consists of the sum of an exponentially cutoff power law and relativistically smeared reflection. Additionally, we apply a more physical approach and model the irradiation of the accretion disk directly from the lamp post geometry. All four observations show consistent values for the black hole parameters with a spin of a ~ 0.9, in agreement with recent measurements from reflection and disk continuum fitting. The inclination is found to be i ~ 30°, consistent with the orbital inclination and different from inclination measurements made during the soft state, which show a higher inclination. We speculate that the difference between the inclination measurements is due to changes in the inner region of the accretion disk.

Cygnus X-1: shedding light on the spectral variability of the hard state of black holes

E-mail: Victoria.Grinberg@sternwarte.uni-erlangen.de 1Remeis-Observatory/ECAP/FAU, Bamberg, Germany 2CRESST/NASA-GSFC, Greenbelt, MD, USA 3UMBC, Baltimore, MD, USA 4GMU, Fairfax, VA, USA 5ESAC, Madrid, Spain 6UMCP, College Park, MD, USA 7MIT Kavli Institute, Cambridge, MA, US 8UVA, Amsterdam, NL 9UCSD, La Jolla, CA, USA 10SSL, UC Berkeley, Berkeley, CA, USA 11DSM/DAPNIA/SAp, CEA Saclay, France 12University of Cambridge, Cambridge, UK

Broadband Comparisons between the Multiwavelength Behavior of Two Interesting X‐ray Novae, XTE J1817–330 and XTE J1818–245

The INTEGRAL satellite extensively observed XTE J1817–330 and XTE J1818–245 which underwent X‐ray outbursts from, respectively, Jan. 2006 and Feb. 2005 to Nov. 2006, during the INTEGRAL Core Program and Target of Opportunity observations, dedicated to new X‐ray novae, and during Galactic Bulge observations. We report some results of simultaneous multiwavelength observations of these black holes candidates performed with INTEGRAL, RXTE and with REM and ATCA for XTE J1817–330 and Swift, VLA, REM and EMMI for XTE J1818–245. Both sources are active up to 250 keV. Component evolutions occur in the accretion disk and in the hot medium (well fitted by Comptonization), with spectral changes in the hard and soft components correlated with puzzling changes in the radio and excess over a black body disk in the optical.

An INTEGRAL monitoring of GRS 1915+105 using simultaneous space and ground based instruments

We report the results of 3 observations of GRS 1915+105 during which the source is found to show the X-ray dips/spike sequences (cycles). These observations were performed simultaneously with \integral, RXTE, the Ryle and Nancay radio telescopes. They show the so-called

INTEGRAL Observations of GRS 1758–258

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Detection of pair plasma in recent V404 Cygni flares

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Chandra X-ray spectroscopy of focused wind in the Cygnus X-1 system

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