A binary star system containing a massive star and what is likely a black hole, which together are a source of intense X-rays, has been shown to be a smaller-scale example of some of the brightest quasars in the world. the universe.
The new findings, from an international team that used NASA‘S Imaging X-ray Polarimetry Explorer spacecraft (IXPE), describe how a binary X-ray system located approximately 24,000 light years away in our Milky Way amplifies the X-rays in a funnel-shaped cavity surrounding the probable black hole.
The system, Cygnus speed of light. The radio transmission from these jets lasts for a few days before being turned off and then turned back on again.
The origins of the jets were mysterious at the time. The system was described as an “astronomical puzzle”, not helped by the fact that we can’t even see Cygnus X-3 in visible light; it is blocked by thick dust in the plane of our galaxy. In the 1970s, radio astronomers at observatories around the world coordinated by telephone to try to catch Cygnus X-3 turning on or off.
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Over the years, further observations in radio, infrared and X-ray wavelengths have allowed astronomers to figure out that Cygnus X-3 is a binary X-ray system involving matter being transferred between a massive star and a compact object orbiting a common center. by gravity. The compact object is either a neutron star or, more likely, a black hole with a mass about five times its mass mass of our sun. The massive star is a Wolf-Rayet star – a rare phase supergiant stars during which they radiate powerful stellar winds that begin to lift large parts of their outer shell inward room. It is the material carried by the winds of this Wolf-Rayet star and fuels an accretion disk that orbits the compact object.
However, Cygnus X-3s Brightness is hardly credible. The flow of matter into a compact object such as a black hole is controlled by a property known as the Eddington limit. If the accretion rate is high enough, the accretion disk becomes a liability: the matter is backed up, the disk becomes compact and so hot that the amount of radiation flowing out can stop the influx of fresh material. In this way, black holes can regulate their own growth and some of the material is spewed back into the radio beams.
However, some of the most luminous quasars – galaxies with extremely active ones supermassive black holes at their heart – seem to break the Eddington limit, in that their brightness is extremely high, yet they still seem to attract matter. And Cygnus X-3 seems to fall into this category, albeit on a smaller scale.
Now, a team led by Alexandra Veledina from the University of Turku in Finland has used IXPE to measure the degree of polarization in the X-ray light coming from Cygnus X-3. They found that the degree of polarization is so high that it can only be explained by the X-rays scattered from the inside of a funnel-shaped cavity at the heart of the accretion disk.
“We discovered that the compact object is surrounded by a shell of dense, opaque matter,” Veledina said in an article rack. “The light we observe is a reflection from the inner funnel walls formed by the surrounding gas, and resembles a cup with a mirror on the inside.”
An opaque envelope raised by a funnel-shaped cavity is typical of quasars described as ‘ULXs’ — ultra-luminous X-ray sources. The scale of enhancement due to the X-rays scattered from the inside of the funnel cavity is also analogous to ULXs.
“ULXs are typically observed as bright spots in the images of distant galaxies, with their emissions amplified by the focusing effects of the compact object’s surrounding funnel, resembling a megaphone,” says Juri Poutanen, a member of the research team from the University of Turku. “However, due to the large distances to these sources, they appear relatively faint to X-ray telescopes.”
Learning about ULXs in quasars has therefore proven difficult, but astronomers can now use the much closer Cygnus X-3 as a model to better understand those distant ULXs.
“Our discovery has now revealed a bright counterpart to these distant ULXs found in our own Milky Way,” says Poutanen.
Cygnus IXPE could see that when Cygnus . . This suggests that the structure of the funnel changes in response to greater or lesser amounts of fouling. If accretion gets too low, the funnel could collapse completely, only to rebuild itself when accretion picks up again, Veledina’s team predicts.
The team now plans to conduct further observations to detect this collapse. This collapse could be heralded by a near-zero polarization. This indicates that the X-rays come directly from the hot gas on the surface of the accretion disk and not indirectly via scattering in the funnel.
The findings were published in the journal on June 21 Nature Astronomy.