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Post Info TOPIC: Microquasar Cyg X-3


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WR 145a
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ATel 10109: Enhanced high-energy gamma-ray emission from the microquasar Cygnus X-3 detected by Fermi/LAT



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Cygnus X-3
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Cyg X-3's Little Friend: A Stellar Circle of Life

In 2003, astronomers presented results using Chandra's high-resolution vision in X-rays to identify a mysterious source of X-ray emission located very close to Cygnus X-3 on the sky (smaller white object to the upper left). The separation of these two sources is equivalent to the width of a penny about 800 feet away. A decade later, astronomers reported the new source is a cloud of gas and dust. In astronomical terms, this cloud is rather small - about 0.7 light years in diameter or under the distance between the Sun and Pluto's orbit.
Astronomers realized that this nearby cloud was acting as a mirror, reflecting some of the X-rays generated by Cygnus X-3 towards Earth. They nicknamed this object the "Little Friend" due to its close proximity to Cygnus X-3 on the sky and because it also demonstrated the same 4.8-hour variability in X-rays seen in the X-ray binary.

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V1521 Cygni
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ATel 9501: The predicted giant flare of Cyg X-3 occurs 



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RE: Cygnus X-3
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Title: Cygnus X-3's Little Friend
Authors: Michael L. McCollough, Randall K. Smith, Lynne Valencic

Using the unique X-ray imaging capabilities of the Chandra observatory, a 2006 observation of Cygnus X-3 has provided insight into a singular feature associated with this well-known microquasar. This extended emission, located ~16 arcseconds from Cygnus X-3, varies in flux and orbital phase (shifted by 0.56 in phase) with Cygnus X-3, acting like a celestial X-ray "mirror". The feature's spectrum, flux and time variations allow us to determine the location, size, density, and mass of the scatterer. We find that the scatterer is a Bok globule located along our line of sight, and discuss its relationship to Cygnus X-3. This is the first time such a feature has been identified with the Chandra X-ray Observatory.

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RE: Microquasar Cyg X-3
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Title: Cyg X-3: a Galactic double black hole or black hole-neutron star progenitor
Authors: Krzysztof Belczynski, Tomasz Bulik, Ilya Mandel, B.S. Sathyaprakash, Andrzej Zdziarski, Joanna Mikolajewska

There are no known double black hole (BH-BH) or black hole-neutron star (BH-NS) systems. We argue that Cyg X-3 is a very likely BH-BH or BH-NS progenitor. This Galactic X-ray binary consists of a compact object, wind-fed by a Wolf-Rayet (WR) type companion. Based on a comprehensive analysis of observational data, it was recently argued that Cyg X-3 harbours a 2-4.5 solar masses BH and a 7.5-14.2 solar masses WR companion. We find that the fate of such a binary leads to the prompt (13 solar masses). For the low- to mid-mass range of the WR star (M_WR=7-10 solar masses) Cyg X-3 is most likely (probability 70%) disrupted when WR ends up as a supernova. However, with smaller probability, it may form a wide (15%) or a close (15%) BH-NS system. The advanced LIGO/VIRGO detection rate for mergers of BH-BH systems from the Cyg X-3 formation channel is 10 per year, while it drops down to 0.1 per year for BH-NS systems. If Cyg X-3 in fact hosts a low mass BH and massive WR star, it lends additional support for the existence of BH-BH/BH-NS systems.

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RE: Cygnus X-3
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Title: New Evidence for a Black Hole in the Compact Binary Cygnus X-3
Authors: Chris Shrader, Lev Titarchuk, Nikolai Shaposhnikov

The bright and highly variable X-ray and radio source known as Cygnus X-3 was among the first X-ray sources discovered, yet it remains in many ways an enigma. Its known to consist of a massive, Wolf-Rayet primary in an extremely tight orbit with a compact object. Yet one of the most basic of parameters - the mass of the compact object - is not known. Nor is it even clear whether its is a neutron star or a black hole. In this Paper we present our analysis of the broad-band high-energy continua covering a substantial range in luminosity and spectral morphology. We apply these results to a recently identified scaling relationship which has been demonstrated to provide reliable estimates of the compact object mass in a number of accretion powered binaries. This analysis leads us to conclude that the compact object in Cygnus X-3 has a mass greater than 4.2 solar masses thus clearly indicative of a black hole and as such resolving a long-standing issue. The full range of uncertainty in our analysis and from using a range of recently published distance estimates constrains the compact object mass to lie between 4.2 solar masses and 14.4 solar masses. Our favoured estimate, based on a 9.0 kpc distance estimate is ~ 10 solar masses with the error margin of 3.2 solar masses. This result may thus pose challenges to shared-envelope evolutionary models of compact binaries, as well as establishing Cygnus X-3 as the first confirmed accretion-powered galactic gamma-ray source.

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NASA's Fermi Gamma-ray Space Telescope successfully made the first clear detection of high-energy gamma-rays from Cygnus X-3, one of the stronger binary systems in the sky. Located some 37 000 light years away, Cygnus X-3 pairs a hot, massive star with a compact object that blasts twin radio-emitting jets of matter into space at the speed of light. The findings will offer scientists new insight into the acceleration and movement of high-energy particles. The research, published in the journal Science, is part of the 'GAMMARAYBINARIES' project, which received almost EUR 750 000 in funding under the Ideas Theme of the EU's Seventh Framework Programme (FP7).
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cygx3.jpg
Expand (527kb, 1500 x 1500)
Credit: NASA/DOE/Fermi LAT Collaboration


Brighter colours indicate greater numbers of gamma rays detected in this Fermi LAT view of a region centred on the position of Cygnus X-3 (circled). The brightest sources are pulsars.

Position(2000): RA 20 32 25.78, Dec +40 57 27.9

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Energetic gamma rays spotted from 'microquasar'
After decades of searching, astronomers have confirmed that a gluttonous stellar remnant that glows brightly in X-rays can create high-energy gamma rays as well. The tiny powerhouse could serve as a nearby laboratory to study how particles are accelerated in the universe's biggest black holes.
Cygnus X-3, a pair of objects that sit some 30,000 light years from Earth, has long been a puzzle. The system is thought to contain the dense remnant of a star - either a black hole or a neutron star - that is feeding on a disc of material stolen from a companion star.


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NASA's Fermi Gamma-ray Space Telescope has made the first unambiguous detection of high-energy gamma-rays from an enigmatic binary system known as Cygnus X-3. The system pairs a hot, massive star with a compact object -- either a neutron star or a black hole -- that blasts twin radio-emitting jets of matter into space at more than half the speed of light.
Astronomers call these systems microquasars. Their properties -- strong emission across a broad range of wavelengths, rapid brightness changes, and radio jets -- resemble miniature versions of distant galaxies (called quasars and blazars) whose emissions are thought to be powered by enormous black holes.

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