Evidence for an accretion stream in 4U 1907+09

Kostka, Mathew; Leahy, D. A.

doi:10.1111/j.1365-2966.2010.16968.x

Cited by 10 publications

(12 citation statements)

References 22 publications

(50 reference statements)

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“…The column density in this system reaches ∼10 24 cm −2 and is interpreted as the signature of a high density stream (Leahy & Kostka 2008). In this context, it is also interesting to remark that some intermediately obscured sgHMXBs, such as 4U 1907 + 09, feature intermediate wind terminal velocity in the range ∼1000 km s −1 (Kostka & Leahy 2010).…”

Section: Wind Terminal Velocities In Obscured Systemsmentioning

confidence: 65%

Neutron star masses from hydrodynamical effects in obscured supergiant high mass X-ray binaries

Manousakis

Walter

Blondin

2012

A&A

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Context. A population of obscured supergiant high mass X-ray binaries has been discovered by INTEGRAL. X-ray wind tomography of IGR J17252-3616 inferred a slow wind velocity to account for the enhanced obscuration. Aims. The main goal of this study is to understand under which conditions high obscuration could occur. Methods. We have used an hydrodynamical code to simulate the flow of the stellar wind around the neutron star. A grid of simulations was used to study the dependency of the absorbing column density and of the X-ray light-curves on the model parameters. A comparison between the simulation results and the observations of IGR J17252-3616 provides an estimate on these parameters. Results. We have constrained the wind terminal velocity to 500−600 km s −1 and the neutron star mass to 1.75−2.15 M . Conclusions. We have confirmed that the initial hypothesis of a slow wind velocity with a moderate mass loss rate is valid. The mass of the neutron star can be constrained by studying its impact on the accretion flow.

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Section: Wind Terminal Velocities In Obscured Systemsmentioning

confidence: 65%

Neutron star masses from hydrodynamical effects in obscured supergiant high mass X-ray binaries

Manousakis

Walter

Blondin

2012

A&A

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“…Limited random-walk spin period variations have been observed (Şahiner et al, 2012). The X-ray absorption is modulated by the orbit (Şahiner et al, 2012, but remains < 10 23 cm −2 ) and could be modelled with an accretion stream trailing the neutron star (Kostka and Leahy, 2010). 4U 1907+097 is a runaway system accompanied by a bow shock (Gvaramadze et al, 2011).…”

Section: Discussionmentioning

confidence: 99%

“…As the neutron stars can cut-off wind acceleration via ionisation (Stevens and Kallman, 1990), the wind can be slower in binaries than in isolated stars. For instance GX 301-2, 4U 1907+09 and EXO 1722-363 feature high absorbing column densities and low wind terminal velocities of 500, 1000 and 600 km/s (Kaper et al, 2006;Kostka and Leahy, 2010;Manousakis et al, 2012b). Even the companion of Vela X-1 has a wind terminal velocity less than what would be expected from its high luminosity (Kudritzki and Puls, 2000).…”

Section: Obscured Super-giant Systemsmentioning

confidence: 99%

High-mass X-ray binaries in the Milky Way

Walter

Lutovinov

Bozzo

et al. 2015

Astron Astrophys Rev

230

234

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High-mass X-ray binaries are fundamental in the study of stellar evolution, nucleosynthesis, structure and evolution of galaxies and accretion processes. Hard X-rays observations by INTEGRAL and Swift have broadened significantly our understanding in particular for the super-giant systems in the Milky Way, which number has increased by almost a factor of three. INTEGRAL played a crucial role in the discovery, study and understanding of heavily obscured systems and of fast X-ray transients. Most super-giant systems can now be classified in three categories: classical/obscured, eccentric and fast transient.The classical systems feature low eccentricity and variability factor of ∼ 10 3 , mostly driven by hydrodynamic phenomena occurring on scales larger than the accretion radius. Among them, systems with short orbital periods and close to Roche-Lobe overflow or with slow winds, appear highly obscured. In eccentric systems, the variability amplitude can reach even higher factors, because of the contrast of the wind density along the orbit. Four super-giant systems, featuring fast outbursts, very short orbital periods and anomalously low accretion rates, are not yet understood.Simulations of the accretion processes on relatively large scales have progressed and reproduce parts of the observations. The combined effects of wind

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“…For 4U 1907+09, n H increases to its maximum value after the periastron passage, which implies that the location of the absorbing material is the dense stellar wind of the companion star (Roberts et al 2001). Leahy (2001) and Kostka & Leahy (2010) have modelled the absorption profile according to theoretical wind models. They have proposed that the most probable mechanism for 4U 1907+09 is accretion from a spherical wind with an equatorially enhanced dense spiral stream of gas around the companion star.…”

Section: Spectral Analysismentioning

confidence: 99%

A comprehensive study of RXTE and INTEGRAL observations of the X-ray pulsar 4U 1907+09

Şahiner¹,

İnam²,

Baykal³

2012

Monthly Notices of the Royal Astronomical Society

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We analyse observations of the accretion‐powered pulsar 4U 1907+09 from the International Gamma‐Ray Astrophysics Laboratory (INTEGRAL; between 2005 October and 2007 November) and from the Rossi X‐ray Timing Explorer (RXTE; between 2007 June and 2011 March). Using observations from the Imager on‐board the INTEGRAL satellite (IBIS), the INTEGRAL Soft Gamma‐Ray Imager (ISGRI) and the RXTE Proportional Counter Array (PCA), we update the pulse period history of the source. We construct power spectrum density of pulse frequencies, and we find that fluctuations in the pulse frequency derivatives are consistent with the random walk model with a noise strength of 1.27 × 10−21 Hz s−2. From the X‐ray spectral analysis of RXTE/PCA observations, we find that the hydrogen column density is variable over the binary orbit, and that it tends to increase just after the periastron passage. We also show that the X‐ray spectrum becomes hardened with decreasing X‐ray flux. We discuss the pulse‐to‐pulse variability of the source near dipping ingress and egress. We find that the source is more likely to undergo dipping states after apastron until periastron when the accretion from clumpy wind might dominate. Thus, occasional transitions to a temporary propeller state might occur.

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Evidence for an accretion stream in 4U 1907+09

Cited by 10 publications

References 22 publications

Neutron star masses from hydrodynamical effects in obscured supergiant high mass X-ray binaries

Neutron star masses from hydrodynamical effects in obscured supergiant high mass X-ray binaries

High-mass X-ray binaries in the Milky Way

A comprehensive study of RXTE and INTEGRAL observations of the X-ray pulsar 4U 1907+09

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