Hipparcos, VLA, and CCD Observations of Cygnus OB2 No. 5: Solving the Mysteryof the Radio “Companion”

Contreras, M. E.; Rodrı́guez, Luis F.; Tapia, M.; Cardini, D.; Emanuele, A.; Badiali, M.; Persi, P.

doi:10.1086/310928

Cited by 59 publications

(63 citation statements)

References 17 publications

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“…-High angular resolution imaging. In a few cases, very long baseline radio interferometer arrays are allowed to resolve individual stellar winds (producing the thermal radiation) and the non-thermal emission region: HD 93129A (Benaglia et al 2010a), Cyg OB2 #5 (Contreras et al 1997;Ortiz-León et al 2011), Cyg OB2 #9 ), WR 146 (O'Connor et al 2005, WR 147 (Williams et al 1997) and WR 140 . These results provide significant evidence that the synchrotron emission region is spatially coincident with the wind-wind interaction region, lending further support to the standard scenario for PACWBs.…”

Section: Radio Investigationsmentioning

confidence: 99%

Catalogue of particle-accelerating colliding-wind binaries

Becker

Raucq

2013

A&A

118

138

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Massive systems made of two or more stars are known to be the site for interesting physical processes -including at least in some cases -particle acceleration. Over the past decade, this topic motivated a particular effort to unveil the properties of these systems and characterize the circumstances responsible for the acceleration of particles and the potential role of pre-supernova massive stars in the production of high energy particles in our Galaxy. Although previous studies on this topic were mostly devoted to processes in general, or to a few individual objects in particular, a unified target-oriented census of particle-accelerating colliding-wind binaries (hereafter PACWBs) does not exist yet. This paper aims at making a general and unified census of these systems, emphasizing their main properties. A general discussion includes energetic considerations along with wind properties in relation with non-thermal emission processes that are likely at work in colliding-wind binaries. Finally, some guidelines for future observational and theoretical studies are drawn.

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Section: Radio Investigationsmentioning

confidence: 99%

Catalogue of particle-accelerating colliding-wind binaries

Becker

Raucq

2013

A&A

118

138

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“…Leitherer et al 1982;Persi et al 1990). Contreras et al (1997) propose an extremeṀ = 5.5 10 −5 M yr −1 that should be considered rather as an upper limit. In our present work we adopt an average value of 2.5 10 −5 M yr −1 .…”

Section: The Stellar System Cyg Ob2 Nomentioning

confidence: 97%

“…Recently, Contreras et al (1997) have obtained accurate optical (HIPPARCOS and Roque de los Muchachos) and radio (VLA) measurements that clearly show that the weak radio source is nonthermal and does not coincide with the optical position of the star detected by Herbig (1967). This star, which seems to be a B0 V star, is a third component of the system, with a long period.…”

Section: The Stellar System Cyg Ob2 Nomentioning

confidence: 99%

“…This star, which seems to be a B0 V star, is a third component of the system, with a long period. The fact that the weak radio source is located between the contact binary and the B0 V star, closer to the latter, was interpreted by Contreras et al (1997) as the effect of the particle acceleration in the region of colliding winds.…”

Section: The Stellar System Cyg Ob2 Nomentioning

confidence: 99%

“…Eichler & Usov (1993) have shown that particles locally accelerated at the strong shock front formed in the wind collision can generate observable synchrotron radio emission. Contreras et al (1997) have identified the weak non-thermal radio source in Cyg OB2 No. 5 with this emission.…”

Section: Region Of Colliding Windsmentioning

confidence: 99%

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Can the gamma-ray source 3EG J2033+4118 be produced by the stellar system Cygnus OB2 No. 5?

Benaglia

Romero

Stevens

et al. 2001

A&A

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Abstract. We discuss the possibility that the stellar system Cyg OB2 No. 5 can be a gamma-ray source in the light of recent EGRET and radio data. This system is formed by an O7 Ia + Ofpe/WN9 contact binary. A third star, probably a B0 V star also associated with the system, is located at ∼1700 AU from the primary. We estimate the expected gamma-ray luminosity from the colliding winds region, the terminal shock of the wind, and the unstable zone at the base of the wind, and conclude that, under very reasonable assumptions, Cyg OB2 No. 5 can generate about a half of the gamma-ray flux detected from the positionally coincident source 3EG J2033+4118. We suggest, then, that other O stars belonging to the association, also placed within the 95% probability EGRET location contour, could contribute to the observed gamma-ray flux.

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Non-Thermal Emission from Early-Type Binaries

Rauw

2004

Cosmic Gamma-Ray Sources

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In this chapter, I review the properties of high-energy particles in the stellar winds of hot early-type stars. Relativistic electrons are responsible for the synchrotron radio emission observed from a subsample of these stars. Most of the objects in the latter category are found to be binaries and the collision between the stellar winds of the binary components is thought to play a crucial role in the acceleration of the relativistic electrons. The interplay between these high-energy electrons and the intense stellar radiation field could produce a substantial nonthermal emission at X-ray and γ-ray energies through inverse Compton scattering. Other mechanisms, such as π 0 decay might also contribute to the production of non-thermal emission from hot stars. These various effects could possibly account for some of the yet unidentified EGRET sources found to be correlated with OB associations in our Galaxy. Finally, I review recent results from XMM-Newton observations and discuss the prospects of forthcoming γ-ray observations with INTEGRAL and GLAST.

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Hipparcos, VLA, and CCD Observations of Cygnus OB2 No. 5: Solving the Mysteryof the Radio “Companion”

Cited by 59 publications

References 17 publications

Catalogue of particle-accelerating colliding-wind binaries

Catalogue of particle-accelerating colliding-wind binaries

Can the gamma-ray source 3EG J2033+4118 be produced by the stellar system Cygnus OB2 No. 5?

Non-Thermal Emission from Early-Type Binaries

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