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Scientists Discover Mysterious New X-Ray Objects 'Unlike Any They Have Seen Before' (space.com) 17

An anonymous reader quotes a report from Space.com: NASA's Chandra X-ray Observatory has found a brand new type of an otherwise familiar object -- compact binary systems that steal gas from other stars, but which do so while emitting very low-energy X-rays but copious amounts of ultraviolet. Chandra spotted 84 suspicious object emitting very low-energy X-rays in six galaxies -- four evolved ellipticals and two spirals, namely our near-neighbor the Andromeda Galaxy (M31) and the Pinwheel Galaxy (M101). "We've never encountered a group of objects that act like this," said Mustafa Muhibullah of the University of Alabama in a statement.

Compact objects, in the form of black holes, neutron stars and white dwarfs, are the remains of stars that have died. Their small size and powerful gravity means that they're adept at getting close to orbiting companion stars and ripping the stars' outer layers of gas away. The gas swirls around the compact object, falling onto its surface, and this accretionary process usually produces torrents of high-energy X-rays because the stolen gas becomes superheated by the compact object's gravitational vice-like grip.

Because of their weak X-rays, Muhibullah's team refer to them as 'hypersoft X-ray sources'. Since low-energy X-rays and ultraviolet light are next to each other on the electromagnetic spectrum, Muhibullah and his team suspect that the low-energy X-rays are spillover from objects emitting prodigious amounts of ultraviolet. Moreover, they think that these objects are lower-level compact binaries. They're hard to find though, because the interstellar medium of hydrogen and helium gas between the stars absorbs ultraviolet light. This could be why we have yet to find any hypersoft X-ray sources in our own galaxy, because we have to look through the interstellar medium through the plane of the Milky Way. Consequently, there could be a large population of hypersoft X-ray sources that remain undiscovered and they could have an important effect on the universe around them.
The findings have been published in the journal Nature Astronomy.

Scientists Discover Mysterious New X-Ray Objects 'Unlike Any They Have Seen Before'

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  • Has anybody checked for encrypted messages distributed across the objects?

  • The finding simply means that there are accreting objects where the accreted matter is heated up less, i.e. it is somewhat cooler. This results in the Boltzmann spectrum being shifted towards longer wavelenghts. These are harder to detect because X-Ray sensors are only that sensitive, and there are many other UV sources around. That's all.
    • I think you answered your own question...

      What's so peculiar about this?

      ...harder to detect because...

  • Where does hypersoft X-ray end and just UV begin? Are our eyes actually just sensitive to ultrahypersoft xray sources? Or hyperhard infrared sources?

    Less snarky question: would an astronomer using a UV telescope look at this and just say it's a bright UV source?

    Not that it makes it any less interesting of an object, it's still unexpected and worth exploring.

    • Less snarky question: would an astronomer using a UV telescope look at this and just say it's a bright UV source?

      They might if anyone had an appropriate telescope. The have only been a couple of satellites that worked in the wavelength range of interest here and they observed in the 1990s. While I appreciate your jokes, spectral range naming has always been pretty arbitrary. Since I usually work in energy units, I usually think of UV as 3eV-10eV, EUV (or sometimes called VUV - vacuum UV) as 10eV-100eV, soft x-rays as 100eV-1KeV but others would probably disagree with me.

      Scanning the paper it looks like they

  • ...are always "never seen before."

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