Observations of Cygnus X-3 by Uhuru

Parsignault, D. R.; Gursky, H.; Kellogg, E.; Matilsky, T.; Murray, Steven; Schreier, E.; Tananbaum, H.; Giacconi, R.; Brinkman, A. C.

doi:10.1038/physci239123a0

Cited by 106 publications

(58 citation statements)

References 8 publications

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“…It shows a strong 4.8 h modulation in the X-ray (Parsignault et al 1972) and the infra-red emission which is attributed to the binary orbital motion (Becklin et al 1973). The measurement of the radial velocity in the infra-red band and its interpretation as due to binary Doppler shift has led to the derivation of a large mass function for the source (Schmutz et al 1996), but this simplistic explanation of the He II line shift is strongly disputed by the relative phasing of the infra-red and the X-ray binary modulation (van Kerkwijk 1993).…”

Section: Introductionmentioning

confidence: 99%

Binary corrected X-ray light curve of Cygnus X-3: Implications for the timing properties of the compact binary system

Choudhury

Rao

Vadawale

et al. 2004

A&A

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Abstract. We study the binary corrected X-ray light curve of Cygnus X-3 using the RXTE-ASM (All Sky Monitor) data and RXTE-PCA data. We find that the X-ray template derived from the EXOSAT observations adequately explains the binary variations. Using the recently determined quadratic binary ephemeris we correct the RXTE-PCA lightcurve and obtain the power spectrum which shows distinct features of shifting towards the low frequency regime vis-a-vis the Galactic X-ray binaries. The power spectrum doesn't vary from the hard to the soft state. We also obtain the binary corrected RXTE-ASM monitoring lightcurve and examine the previously obtained correlation between soft X-ray (2−12 keV from RXTE ASM), hard X-ray (20−100 keV from CGRO−BATSE) and radio (2.2 GHz from GBI) after the binary correction. We find that the correlation time scale is less than a day.

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Section: Introductionmentioning

confidence: 99%

Binary corrected X-ray light curve of Cygnus X-3: Implications for the timing properties of the compact binary system

Choudhury

Rao

Vadawale

et al. 2004

A&A

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“…The distance of the object is 8-12.5 kpc with an absorption on the line of sight A V ∼ 20 mag (van Kerkwijk et al 1996). The flux modulation at a period of 4.8 hours, first discovered in X-rays (Parsignault 1972), then at near infrared wavelengths (Becklin et al 1973), and observed simultaneously at X-ray and near-IR wavelengths by Mason et al (1986), is believed to be the orbital period of the binary system. Following infrared spectroscopic measurements (van Kerkwijk et al 1992), where WR-like features have been detected in I and K band spectra, the nature of the mass-donating star is suggested to be a Wolf-Rayet-like star, but an unambiguous classification, similar to the other WR stars, is still lacking.…”

Section: Introductionmentioning

confidence: 99%

A 2.4–12 μm spectrophotometric study with ISO of Cygnus X-3 in quiescence

Koch-Miramond

Ábrahám

Fuchs

et al. 2002

A&A

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Abstract. We present mid-infrared spectrophotometric results obtained with the ISO on the peculiar X-ray binary Cygnus X-3 in quiescence, at orbital phases 0.83 to 1.04. The 2.4-12 µm continuum radiation observed with ISOPHOT-S can be explained by thermal free-free emission in an expanding wind with, above 6.5 µm, a possible additional black-body component with temperature T ∼ 250 K and radius R ∼ 5000 R at 10 kpc, likely due to thermal emission by circumstellar dust. The observed brightness and continuum spectrum closely match that of the Wolf-Rayet star WR 147, a WN8 +B0.5 binary system, when rescaled at the same 10 kpc distance as Cygnus X-3. A rough mass loss estimate assuming a WN wind gives ∼1.2 × 10 −4 M yr −1 . A line at ∼4.3 µm with a more than 4.3 σ detection level, and with a dereddened flux of 126 mJy, is interpreted as the expected He I 3p-3s line at 4.295 µm, a prominent line in the WR 147 spectrum. These results are consistent with a Wolf-Rayet-like companion to the compact object in Cyg X-3 of WN8 type, a later type than suggested by earlier works.

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“…Its X-ray lightcurve (Parsignault et al 1972) shows strong 4.8-hour orbital modulation and the infrared lightcurve (Mason et al 1986) weaker modulation, typical of low-mass XRBs. However, infrared observations suggest that its mass-donating companion is a Wolf-Rayet (WR) star (van Kerkwijk et al 1992), which would make it a high-mass XRB.…”

Section: Introductionmentioning

confidence: 99%

The disk/jet connection in the enigmatic microquasar Cygnus X-3

Koljonen

Hannikainen

McCollough³

et al. 2010

Proc. IAU

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Abstract. Simultaneous multi-wavelength observations are crucial for understanding the physics of microquasars, especially the accretion disk/jet connection. The enigmatic microquasar Cygnus X-3 exhibits strong, relativistic jet ejection events producing radio flares up to 20 Jy. These events are preceded by a very soft X-ray state with quenched emission in the radio and hard X-ray bands. Recently, GeV flux was observed by the AGILE and Fermi γ-ray observatories during the newly-identified hypersoft state. By using an extensive database of simultaneous multi-wavelength observations gathered from Cygnus X-3 we can form a more unified picture of the nature of the source and show how the recent γ-ray observations fit into it.

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Observations of Cygnus X-3 by Uhuru

Cited by 106 publications

References 8 publications

Binary corrected X-ray light curve of Cygnus X-3: Implications for the timing properties of the compact binary system

Binary corrected X-ray light curve of Cygnus X-3: Implications for the timing properties of the compact binary system

A 2.4–12 μm spectrophotometric study with ISO of Cygnus X-3 in quiescence

The disk/jet connection in the enigmatic microquasar Cygnus X-3

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