The quiescent level of Cygnus X-3 at 2.25 and 8.3 GHz: 1988-1992

Waltman, E. B.; Fiedler, Russell; Johnston, K. J.; Ghigo, F. D.

doi:10.1086/117056

Cited by 70 publications

(86 citation statements)

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“…Cyg X-3 is the brightest X-ray binary in the radio and has displayed frequent flaring activity since the discovery of a giant flare in 1972 (Gregory & Kronberg 1972;Waltman et al 1994Waltman et al , 1995Waltman et al , 1996. Waltman et al (1994) identified three types of variability in the 1988-1992 light curves at 2.25 and 8.3 GHz: frequent minor flaring activity of <1 Jy, intermediate flares (>1 Jy), and major flares (>10 Jy). In addition, there are pre-flare quenched states of tens of mJy prior to the flares, and flickering activity during quiescence.…”

Section: Introductionmentioning

confidence: 99%

Vlbi Observation of Microquasar Cyg X-3 During an X-Ray State Transition From Soft to Hard in the 2007 May-June Flare

Kim

Kurayama

et al. 2013

ApJ

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We present a radio observation of microquasar Cyg X-3 during an X-ray state transition from ultrasoft to hard state in the 2007 May-June flare using the VLBI Exploration of Radio Astrometry at 22 GHz. During the transition, a short-lived mini-flare of 3 hr was detected prior to the major flare. In such a transition, a jet ejection is believed to occur, but there have been no direct observations to support it. An analysis of Gaussian fits to the observed visibility amplitudes shows a time variation of the source axis, or a structural change, during the mini-flare. Our model fits, together with other multiwavelength observations in the radio, soft, and hard X-rays, and the shock-in-jet models for other flaring activities at GHz wavebands, suggest a high possibility of synchrotron flares during the mini-flare, indicative of a predominant contribution from jet activity. Therefore, the mini-flare with an associated structural change is indicative of a jet ejection event in the state transition from ultrasoft to hard state.

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Section: Introductionmentioning

confidence: 99%

Vlbi Observation of Microquasar Cyg X-3 During an X-Ray State Transition From Soft to Hard in the 2007 May-June Flare

Kim

Kurayama

et al. 2013

ApJ

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“…In the transition from the X-ray hard/radio quiescent state to the SS, the radio emission is strongly suppressed, and if it reaches the quenched level, the source usually produces a major radio flare (Waltman et al 1994).…”

Section: Introductionmentioning

confidence: 99%

MAGIC CONSTRAINTS ON Γ-Ray EMISSION FROM CYGNUS X-3

Aleksić

Antonelli

Antoranz

et al. 2010

ApJ

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Cygnus X-3 is a microquasar consisting of an accreting compact object orbiting around a Wolf-Rayet star. It has been detected at radio frequencies and up to high-energy γ rays (above 100 MeV). However, many models also predict a very high energy (VHE) emission (above hundreds of GeV) when the source displays relativistic persistent jets or transient ejections. Therefore, detecting such emission would improve the understanding of the jet physics. The imaging atmospheric Cherenkov telescope MAGIC observed Cygnus X-3 for about 70 hr between 2006 March 843 844 ALEKSIĆ ET AL.Vol. 721and 2009 August in different X-ray/radio spectral states and also during a period of enhanced γ -ray emission. MAGIC found no evidence for a VHE signal from the direction of the microquasar. An upper limit to the integral flux for energies higher than 250 GeV has been set to 2.2 × 10 −12 photons cm −2 s −1 (95% confidence level). This is the best limit so far to the VHE emission from this source. The non-detection of a VHE signal during the period of activity in the high-energy band sheds light on the location of the possible VHE radiation favoring the emission from the innermost region of the jets, where absorption is significant. The current and future generations of Cherenkov telescopes may detect a signal under precise spectral conditions.

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“…During 2006-2009 Cyg X-3 showed similar dependencies between soft (RXTE ASM), hard (Swift/BAT) X-rays and radio emission ( [1,6,[8][9][10]). Gamma-ray emission was detected during the flaring states ( [11,12]).…”

Section: Monitoring Program Of Microquasars With the Ratan-600 Telescopementioning

confidence: 88%

“…The giant flares have been detected in the GBI two-frequency monitoring program, and [6] have detected that flares occur after the 'quenched state', when radio fluxes decrease to 10-30 mJy at 2-8 GHz. McCollough et al [7] found that radio fluxes were anti-correlated with the hard (BATSE) X-ray fluxes during the hard state and switched to correlation in the flaring state.…”

Section: Monitoring Program Of Microquasars With the Ratan-600 Telescopementioning

confidence: 99%

The Giant Flares of the Microquasar Cygnus X-3: X-Rays States and Jets

et al. 2017

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Abstract:We report on two giant radio flares of the X-ray binary microquasar Cyg X-3, consisting of a Wolf-Rayet star and probably a black hole. The first flare occurred on 13 September 2016, 2000 days after a previous giant flare in February 2011, as the RATAN-600 radio telescope daily monitoring showed. After 200 days on 1 April 2017, we detected a second giant flare. Both flares are characterized by the increase of the fluxes by almost 2000-times (from 5-10 to 17,000 mJy at 4-11 GHz) during 2-7 days, indicating relativistic bulk motions from the central region of the accretion disk around a black hole. The flaring light curves and spectral evolution of the synchrotron radiation indicate the formation of two relativistic collimated jets from the binaries. Both flares occurred when the source went from hypersoft X-ray states to soft ones, i.e. hard fluxes (Swift/BAT 15-50 keV data) dropped to zero, the soft X-ray fluxes (MAXI 2-10 keV data) staying high, and then later, the binary came back to a hard state. Both similar giant flares indicated the unchanged mechanism of the jets' formation in Cyg X-3, probably in conditions of strong stellar wind and powerful accretion onto a black hole.

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The quiescent level of Cygnus X-3 at 2.25 and 8.3 GHz: 1988-1992

Cited by 70 publications

References 0 publications

Vlbi Observation of Microquasar Cyg X-3 During an X-Ray State Transition From Soft to Hard in the 2007 May-June Flare

Vlbi Observation of Microquasar Cyg X-3 During an X-Ray State Transition From Soft to Hard in the 2007 May-June Flare

MAGIC CONSTRAINTS ON Γ-Ray EMISSION FROM CYGNUS X-3

The Giant Flares of the Microquasar Cygnus X-3: X-Rays States and Jets

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