Observations of the gamma-ray flux from the X-ray source Cyg X-3 in 1994–1995

Neshpor, Yu. I.; Kalekin, O.; Степанян, А. А.; Fomin, V. P.; Chalenko, N. N.

doi:10.1134/1.1564854

Cited by 6 publications

(5 citation statements)

References 20 publications

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“…3), and note that the directly extrapolated energy flux from the TeV source lies about two orders of magnitude below the 3EG J2033+4118 flux at overlapping energies. Finally we note that earlier claims for a TeV source (Neshpor et al 1995, at a ∼1 Crab flux level) and flaring episodes coincident with a Cyg X-3 radio flare at energies >40 TeV (Merck 1993;Krawczynski 1995) positionally consistent with our TeV COG have been reported. These results are however in conflict with our estimates of the flux level and steady nature of the TeV source assuming they all have the same origin.…”

Section: Discussionsupporting

confidence: 51%

An unidentified TeV source in the vicinity of Cygnus OB2

Aharonian

Akhperjanian

Beilicke

et al. 2002

A&A

189

134

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Abstract. Deep observation (∼113 hrs) of the Cygnus region at TeV energies using the HEGRA stereoscopic system of aiř Cerenkov telescopes has serendipitously revealed a signal positionally inside the core of the OB association Cygnus OB2, at the edge of the 95% error circle of the EGRET source 3EG J2033+4118, and ∼0.5• north of Cyg X-3. The source centre of gravity is RA α J2000 : 20 hr 32 m 07 s ± 9.2 s stat ± 2.2 s sys , Dec δ J2000 : +41• 30 30 ± 2.0 stat ± 0.4 sys . The source is steady, has a post-trial significance of +4.6σ, indication for extension with radius 5.6 at the ∼3σ level, and has a differential power-law flux with hard photon index of −1.9 ± 0.3 stat ± 0.3 sys . The integral flux above 1 TeV amounts ∼3% that of the Crab. No counterpart for the TeV source at other wavelengths is presently identified, and its extension would disfavour an exclusive pulsar or AGN origin. If associated with Cygnus OB2, this dense concentration of young, massive stars provides an environment conducive to multi-TeV particle acceleration and likely subsequent interaction with a nearby gas cloud. Alternatively, one could envisage γ-ray production via a jet-driven termination shock.

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Section: Discussionsupporting

confidence: 51%

An unidentified TeV source in the vicinity of Cygnus OB2

Aharonian

Akhperjanian

Beilicke

et al. 2002

A&A

189

134

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“…• north of Cygnus X-3 (Neshpor et al 1995), and recently, the Whipple collaboration also reported an excess at the HEGRA position (+3.3σ) in their archival data of 1989/1990(Lang et al 2004.…”

Section: Introductionmentioning

confidence: 93%

The unidentified TeV source (TeV J2032+4130) and surrounding field: Final HEGRA IACT-System results

Aharonian¹,

Akhperjanian²,

Beilicke³

et al. 2005

A&A

121

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Abstract. The unidentified TeV source in Cygnus is now confirmed by follow-up observations from 2002 with the HEGRA stereoscopic system of Cherenkov Telescopes. Using all data (1999 to 2002) we confirm this new source as steady in flux over the four years of data taking, extended with radius 6.2 (±1.2 stat ± 0.9 sys ) and exhibiting a hard spectrum with photon index −1.9. It is located in the direction of the dense OB stellar association, Cygnus OB2. Its integral flux above energies E > 1 TeV amounts to ∼5% of the Crab assuming a Gaussian profile for the intrinsic source morphology. There is no obvious counterpart at radio, optical nor X-ray energies, leaving TeV J2032+4130 presently unidentified. Observational parameters of this source are updated here and some astrophysical discussion is provided. Also included are upper limits for a number of other interesting sources in the FoV, including the famous microquasar Cygnus X-3.

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“…• from Cygnus X-3 (Neshpor et al 1995). The signal was at the 6σ level before taking trial factors into account.…”

Section: Introductionmentioning

confidence: 99%

Evidence for TeV gamma ray emission from TeV J2032+4130 in Whipple archival data

Lang

Carter‐Lewis

Fegan

et al. 2004

A&A

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Abstract.A reanalysis of data taken on the Cygnus region in 1989-90 using the Whipple Observatory atmospheric Cherenkov imaging telescope confirms the existence of the TeV J2032+4130 source reported by the Crimean Astrophysical Observatory and published by the HEGRA Collaboration. The significance at the a priori HEGRA position is 3.3σ. The peak signal was found at RA = 20h32m, Dec = +41• 33 . This is 0.6• north of Cygnus X-3 which was the original target of the observations. The flux level (12% of the level of the Crab Nebula) is intermediate between the two later observations and suggests that the TeV source is variable.

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Observations of the gamma-ray flux from the X-ray source Cyg X-3 in 1994–1995

Cited by 6 publications

References 20 publications

An unidentified TeV source in the vicinity of Cygnus OB2

An unidentified TeV source in the vicinity of Cygnus OB2

The unidentified TeV source (TeV J2032+4130) and surrounding field: Final HEGRA IACT-System results

Evidence for TeV gamma ray emission from TeV J2032+4130 in Whipple archival data

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