Interaction of two supersonic radial gas flows

Lebedev, M. G.; Myasnikov, A. V.

doi:10.1007/bf01049874

Cited by 21 publications

(18 citation statements)

References 1 publication

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“…X-ray spectra are providing detailed information on the temperature structure in shocks that are set up by powerful WR winds and will ultimately provide reliable information on wind chemical abundances that can be used to test evolutionary models. Most studies of WR star X-ray spectra have focused on WR]O binary systems because of their intrinsic X-ray brightness, which can greatly exceed that of single WR or O stars as the result of X-ray production in colliding wind (CW) shocks (Prilutskii & Usov 1976 ;Lebedev & Myasnikov 1990 ;Luo, McCray, & MacLow 1990 ;Stevens, Blondin, & Pollock 1992 ;Usov 1992 ;Myasnikov & Zhekov 1991, 1993[hereafter MZh93], 1998Pollock 1995).…”

Section: Introductionmentioning

confidence: 99%

X‐Ray Emission from Colliding Wind Shocks in the Wolf‐Rayet Binary WR 140

Zhekov

Skinner

2000

ApJ

107

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We analyze four ASCA X-ray observations of the Wolf-Rayet binary system WR 140 obtained between 1993 and 1997 by making use of hydrodynamic colliding wind (CW) shock models. The analysis shows that the CW shock models are able to accurately reproduce the X-ray spectra at di †erent orbital phases using mass-loss and orbital parameters that are within the ranges allowed by the uncertainties. However, some adjustment in the currently accepted values of the semimajor axis and time of periastron passage may eventually be required. Models that allow for di †erent electron and ion temperatures provide better Ðts to the data. Extra absorption is inferred from CW shock models above that expected from the winds and interstellar medium, the origin of which is not yet known. We also report the serendipitous discovery of hot plasma at temperatures in excess of D2 keV and X-ray emission lines in spectra extracted from the di †use Cygnus superbubble background in the vicinity of WR 140.

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Section: Introductionmentioning

confidence: 99%

X‐Ray Emission from Colliding Wind Shocks in the Wolf‐Rayet Binary WR 140

Zhekov

Skinner

2000

ApJ

107

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“…Although all these processes can be very complicated to track analytically, based on our work we can give a qualitative description of possible scenarios that can take place for asymmetric close encounters. Stellar wind encounters are characterised by their momentum flux ratio (Lebedev & Myasnikov 1990),…”

Section: Asymmetric Mass Losing Stars Encountersmentioning

confidence: 99%

Clump formation through colliding stellar winds in the Galactic Centre

Calderón

Ballone

Cuadra

et al. 2015

Mon. Not. R. Astron. Soc.

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The gas cloud G2 is currently being tidally disrupted by the Galactic Centre super-massive black hole, Sgr A*. The region around the black hole is populated by ∼ 30 Wolf-Rayet stars, which produce strong outflows. We explore the possibility that gas clumps, such as G2, originate from the collision of stellar winds via the non-linear thin shell instability. Following an analytical approach, we study the thermal evolution of slabs formed in the symmetric collision of winds, evaluating whether instabilities occur, and estimating possible clump masses. We find that the collision of relatively slow ( < ∼ 750 km s −1 ) and strong (∼ 10 −5 M ⊙ yr −1 ) stellar winds from stars at short separations (< 10 mpc) is a process that indeed could produce clumps of G2's mass and above. Such short separation encounters of single stars along their known orbits are not common in the Galactic Centre, making this process a possible but unlikely origin for G2. We also discuss clump formation in close binaries such as IRS 16SW and in asymmetric encounters as promising alternatives that deserve further numerical study.

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“…If the winds are isotropic and have a constant velocity, the distance R s to the termination shock is set by (e.g. Lebedev & Myasnikov 1990)…”

Section: Introductionmentioning

confidence: 99%

Modelling the high-energy emission from gamma-ray binaries using numerical relativistic hydrodynamics

Dubus

Lamberts

Fromang

2015

A&A

125

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Context. Detailed modelling of the high-energy emission from gamma-ray binaries has been propounded as a path to pulsar wind physics. Aims. Fulfilling this ambition requires a coherent model of the flow and its emission in the region where the pulsar wind interacts with the stellar wind of its companion. Methods. We have developed a code that follows the evolution and emission of electrons in the shocked pulsar wind based on inputs from a relativistic hydrodynamical simulation. The code is used to model the well-documented spectral energy distribution and orbital modulations from LS 5039. Results. The pulsar wind is fully confined by a bow shock and a back shock. The particles are distributed into a narrow Maxwellian, emitting mostly GeV photons, and a power law radiating very efficiently over a broad energy range from X-rays to TeV gamma rays. Most of the emission arises from the apex of the bow shock. Doppler boosting shapes the X-ray and very high energy (VHE) lightcurves, constraining the system inclination to i ≈ 35• . There is tension between the hard VHE spectrum and the level of X-ray to MeV emission, which requires differing magnetic field intensities that are hard to achieve with constant magnetisation σ and Lorentz factor Γ p of the pulsar wind. Our best compromise implies σ ≈ 1 and Γ p ≈ 5 × 10 3 , so respectively higher and lower than the typical values in pulsar wind nebulae. Conclusions. The high value of σ derived here, where the wind is confined close to the pulsar, supports the classical picture that has pulsar winds highly magnetised at launch. However, such magnetisations will require that further investigations are based on relativistic MHD simulations.

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Interaction of two supersonic radial gas flows

Cited by 21 publications

References 1 publication

X‐Ray Emission from Colliding Wind Shocks in the Wolf‐Rayet Binary WR 140

X‐Ray Emission from Colliding Wind Shocks in the Wolf‐Rayet Binary WR 140

Clump formation through colliding stellar winds in the Galactic Centre

Modelling the high-energy emission from gamma-ray binaries using numerical relativistic hydrodynamics

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