Cygnus X-3: Its Little Friend’s Counterpart, the Distance to Cygnus X-3, and Outflows/Jets

McCollough, Michael L.; Corrales, Lía; Dunham, Michael

doi:10.3847/2041-8205/830/2/l36

Cited by 37 publications

(26 citation statements)

References 25 publications

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“…(b) The following distance estimates have been used: GRS 1915+105: 8.6 +2.0 −1.6 kpc (Reid et al 2014), Cyg X-3: 7. The interstellar absorption for Cyg X-3 is relatively high as a result of its location in the plane of the Galaxy, and likely because it is located behind two spiral arms and the Cygnus X star-forming region (McCollough et al 2016). We fixed the lower limit of the hydrogen column to 3.5 × 10 22 atoms cm −2 , which is approximately the value found in studies where instruments with softer X-ray response were used (Koljonen et al 2018;Kallman et al 2019).…”

Section: Cyg X-3mentioning

confidence: 99%

“…The dash marks components that are not part of the spectral model in a particular data set. (a) The following distance estimates have been used: GRS 1915+105: 8.6 +2.0 −1.6 kpc (Reid et al 2014), Cyg X-3: 7.4 ± 1.1 kpc (McCollough et al 2016), V4641 Sgr: 6.2 ± 0.7 kpc (MacDonald et al 2014). (b) The following mass estimates have been used: GRS 1915+105: 12.…”

Section: Cyg X-3mentioning

confidence: 99%

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The obscured X-ray binaries V404 Cyg, Cyg X–3, V4641 Sgr, and GRS 1915+105

Koljonen

Tomsick

2020

A&A

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Aims. V404 Cyg, Cyg X–3, V4641 Sgr, and GRS 1915+105 are among the brightest X-ray binaries and display complex behavior in their multiwavelength emission. Except for Cyg X–3, the other three sources have large accretion disks, and there is evidence of a high orbital inclination. Therefore, any large-scale geometrical change in the accretion disk can cause local obscuration events. On the other hand, Cyg X–3 orbits its Wolf-Rayet companion star inside the heavy stellar wind obscuring the X-ray source. We study here whether the peculiar X-ray spectra observed from all four sources can be explained by local obscuration events. Methods. We used spectra obtained with the Nuclear Spectroscopic Telescope Array and Rossi X-ray Timing Explorer to study the spectral evolution of the four luminous hard X-ray sources. We fit the time-averaged spectra, and also time-resolved spectra in case of V404 Cyg, with two physically motivated models describing either a scenario where all the intrinsic emission is reprocessed in the surrounding matter or where the emitter is surrounded by a thick torus with variable opening angle. Results. We show that the X-ray spectra during specific times are very similar in all four sources, likely arising from the high-density environments where they are embedded. The fitted models suggest that a low-luminosity phase preceding an intense flaring episode in the 2015 outburst of V404 Cyg is heavily obscured, but intrinsically very bright (super-Eddington) accretion state. Similar spectral evolution to that of V404 Cyg is observed from the recent X-ray state of GRS 1915+105 that presented unusually low luminosity. The modeling results point to a geometry change in the (outflowing) obscuring matter in V404 Cyg and GRS 1915+105, which is also linked to the radio (jet) evolution. Within the framework of the models, all sources display obscured X-ray emission, but with different intrinsic luminosities ranging from lower than 1% of the Eddington luminosity up to the Eddington limit. This indicates that different factors cause the obscuration. This work highlights the importance of taking the reprocessing of the X-ray emission in the surrounding medium into account in modeling the X-ray spectra. This may well take place in other sources as well.

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Section: Cyg X-3mentioning

confidence: 99%

Section: Cyg X-3mentioning

confidence: 99%

The obscured X-ray binaries V404 Cyg, Cyg X–3, V4641 Sgr, and GRS 1915+105

Koljonen

Tomsick

2020

A&A

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“…It is a persistent, bright source at radio and X-ray wavelengths, featuring radio flux density levels around 100 mJy (e.g., Waltman et al 1994) and 2−8 × 10 −8 erg cm −2 s −1 bolometric Xray flux (e.g., Hjalmarsdotter et al 2008) ∼50% of the time. For a distance estimate of 7.4 kpc (McCollough et al 2016) these correspond to luminosities 10 31 -10 32 erg s −1 and 1-5 × 10 38 erg s −1 , respectively; for the second best distance solution of 10.2 kpc the luminosities are a factor of two higher (see McCollough et al 2016 for details on the distance estimation). Occasionally, Cyg X-3 undergoes giant radio outbursts, during which the radio flux density levels can reach 20 Jy (Waltman et al 1996) making Cyg X-3 the brightest Galactic radio source.…”

Section: Introductionmentioning

confidence: 97%

The hypersoft state of Cygnus X–3

Koljonen

Maccarone

McCollough

et al. 2018

A&A

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Context. Cygnus X–3 is a unique microquasar in the Galaxy hosting a Wolf-Rayet companion orbiting a compact object that most likely is a low-mass black hole. The unique source properties are likely due to the interaction of the compact object with the heavy stellar wind of the companion. Aim. In this paper, we concentrate on a very specific period of time prior to the massive outbursts observed from the source. During this period, Cygnus X–3 is in a so-called hypersoft state, in which the radio and hard X-ray fluxes are found to be at their lowest values (or non-detected), the soft X-ray flux is at its highest values, and sporadic γ-ray emission is observed. We use multiwavelength observations to study the nature of the hypersoft state. Methods. We observed Cygnus X–3 during the hypersoft state with Swift and NuSTAR in X-rays and SMA, AMI-LA, and RATAN-600 in the radio. We also considered X-ray monitoring data from MAXI and γ-ray monitoring data from AGILE and Fermi. Results. We found that the spectra and timing properties of the multiwavelength observations can be explained by a scenario in which the jet production is turned off or highly diminished in the hypersoft state and the missing jet pressure allows the wind to refill the region close to the black hole. The results provide proof of actual jet quenching in soft states of X-ray binaries.

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“…In this system the compact object is extremely close to its Wolf-Rayet companion (van Kerkwijk et al 1992;Koljonen & Maccarone 2017) rendering the system peculiar in many ways when compared to other XRBs with low companion mass, such as for example GX 339-4 or even the high-mass system Cyg X-1. It is situated at a distance of 7.4 ± 1.1 kpc (McCollough et al 2016) with an orbital period of 4.8 h (Parsignault et al 1972).…”

Section: Introductionmentioning

confidence: 99%

INTEGRAL discovery of a high-energy tail in the microquasar Cygnus X-3

Cangemi

Rodríguez

Grinberg

et al. 2021

A&A

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Context. The X-ray spectra of X-ray binaries are dominated by emission of either soft or hard X-rays which defines their soft and hard spectral states. While the generic picture is relatively well understood, little is known about the interplay of the various media at work, or about the reasons why some sources do not follow common behavior. Cygnus X-3 is amongst the list of X-ray binaries that show quite complex behavior, with various distinct spectral states not seen in other sources. These states have been characterized in many studies. Because of its softness and intrinsic low flux above typically 50 keV, very little is known about the hard X/soft gamma-ray (100-1000 keV) emission in Cygnus X-3. Aims. Using the whole INTEGRAL data base, we aim to explore the 3-1000 keV spectra of Cygnus X-3. This allows to probe this region with the highest sensitivity ever, and search for the potential signature of a high-energy non-thermal component as sometimes seen in other sources. Methods. Our work is based on state classification carried out in previous studies with data from the Rossi X-Ray Timing Explorer. We extend this classification to the whole INTEGRAL data set in order to perform a long-term state-resolved spectral analysis. Six stacked spectra were obtained using 16 years of data from JEM-X (3-25 keV), ISGRI (25-300 keV), and SPI (20-400 keV). Results. We extract stacked images in three different energy bands, and detect the source up to 200 keV. In the hardest states, our purely phenomenological approach clearly reveals the presence of an additonnal component > 50 keV in addition to the component usually interpreted as thermal Comptonization. We apply a more physical model of hybrid thermal/nonthermal corona (eqpair) to characterize this nonthermal component and compare our results with those of previous studies and analyses. Our modeling indicates a more efficient acceleration of electrons in states where major ejections are observed. We also evaluate and find a dependence of the photon index of the power law as a function of the strong orbital modulation of the source in the Flaring InterMediate (FIM) state. This dependence could be due to a higher absorption when Cygnus X-3 is behind its companion. However, the uncertainties on the density column prevent us from drawing any firm conclusions.

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Cygnus X-3: Its Little Friend’s Counterpart, the Distance to Cygnus X-3, and Outflows/Jets

Cited by 37 publications

References 25 publications

The obscured X-ray binaries V404 Cyg, Cyg X–3, V4641 Sgr, and GRS 1915+105

The obscured X-ray binaries V404 Cyg, Cyg X–3, V4641 Sgr, and GRS 1915+105

The hypersoft state of Cygnus X–3

INTEGRAL discovery of a high-energy tail in the microquasar Cygnus X-3

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