A binary system containing a massive star and possibly a black hole, together being a source of intense X-rays, has been shown to be a smaller-scale example of some of the brightest quasars on Earth. Universe.
New findings from an international team used NASA‘S Imaging X-ray Polarimetry Explorer spacecraft (IXPE), approximately 24,000 images of an X-ray binary system light years away from us Milky Way galaxy It enhances the X-ray emission in a funnel-shaped cavity surrounding the prospective area. black hole.
The Cygnus X-3 system was discovered in the early 1970s when radio telescopes detected powerful jets emanating from almost the same distance. speed of lightThe radio emission from these jets lasts for a few days, then turns off and then turns on again.
At the time, the origins of jets were mysterious. The system has been described as an “astronomical puzzle”, and it’s not helped by the fact that we can’t even see Cygnus X-3 in visible light; is blocked by thick dust in the plane of our galaxy. In the 1970s, radio astronomers at observatories around the world were coordinating by telephone to try to capture Cygnus X-3 as it was turning on or off.
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Over the years, more observations in radio, infrared, and X-ray wavelengths allowed astronomers to understand that Cygnus . gravity.A compact object is either a neutron star or, more likely, a black hole with a mass about five times greater than itself. mass of our sun. The giant star is a Wolf-Rayet star; It is a rare stage. super giant stars They emit strong stellar winds that begin to lift large pieces of their outer envelope upwards. space. Wind-blown material from this Wolf-Rayet star feeds an accretion disk that spirals around the compact object.
However, Cygnus X-3 brightness It’s unbelievable. The flow of matter into a compact object like 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 congestion — matter starts to recoil, the disk becomes denser, and it gets so hot that the amount of radiation flowing out can stop the flow of fresh matter. In this way, black holes can regulate their own growth, and some of the matter is ejected back in radio-emitting jets.
But some of the brightest quasars — extremely active galaxies supermassive black holes at their hearts – they appear to exceed the Eddington Limit, as their luminosity is extremely high but they still appear to accumulate matter. And the 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 X-ray light from Cygnus X-3. They found that the amount of polarization was so high that it could only be explained by X-rays scattered from the interior of the funnel-shaped cavity at the heart of the accretion disk.
“We discovered that the compact object is surrounded by a dense, opaque envelope of matter,” Veledina said. expression. “The light we observe is the reflection of the inner walls of the funnel formed by the surrounding gas and resembles a glass with a mirror inside.”
An opaque envelope raised by a funnel-shaped cavity is typical of quasars, described as ”.ULXs—ultraluminous X-ray sourcesThe scale of amplification as a result of X-rays emitted from the interior of the funnel cavity is also similar to ULXs.
“ULXs are often observed as bright spots in images of distant galaxies, their emissions amplified by the focusing effects of the compact object funneling around it, acting similar to a megaphone,” said study team member Juri Poutanen from the University of Turku. “However, due to the great 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 distant ULXs.
“Our discovery has now revealed a bright analogue of these distant ULXs found in our own galaxy,” said Poutanen.
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Cygnus This means that time is getting closer and more material is falling into the possible black hole in the wind. IXPE was able to see that the degree of polarization reached 24.9% when the Cygnus . This suggests that the structure of the funnel changes in response to greater or lesser accumulation. If the accumulation rate falls too low, the funnel could collapse completely, but could rebuild itself when accumulation restarts, Veledina’s team said.
The team now plans to make more observations to try to catch this collapse, which can be signaled by polarization dropping to almost zero; This suggests that the X-ray emission comes directly from the hot gas at the surface of the accretion disk, rather than indirectly. by scattering in the funnel.
The findings were published June 21 in the journal. Nature Astronomy.