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Most Accurate X-ray Map Of The Sky To Date

X-ray astronomers have produced the most detailed X-ray map of the entire sky with the help of the Russian space observatory Spektr RG and the German eROSITA telescope. This was by the Russian Academy of Sciences.

Scientists created the most precise X-ray mapping of the whole sky.
Scientists created the most precise X-ray mapping of the whole sky.

The observatory was launched into space in July 2019. In October, Spektr-RG reached the point of commissioning at a distance of 1.5 million kilometers from Earth.

"Already the first survey of the sky with the Spektr-RG satellite has enabled the eROSITA telescope to generate a map that contains almost ten times more sources and is four times more sensitive than the map of the German Rosat satellite from 1990, which was considered the best so far," said the Academy's Space Research Institute in a statement.

This new map of the hot, high-energy universe contains more than one million objects - roughly doubling the number of known X-ray sources discovered in the 60-year history of X-ray astronomy to date.

"This map allows us to see how hundreds of flashes of supernovae and possibly also the supermassive black hole that becomes active from time to time in the centre of the galaxy cause erupting ejections of hot gas with a temperature of up to ten million degrees".

Three quarters of all objects on the map are distant quasars and centres of active galaxies, i.e. supermassive black holes.
According to the Institute, these objects are located hundreds of millions and billions of light years away from Earth, far outside the Milky Way.

Most detailed map expected in five years

It is planned that Spektr-RG start a second survey of the sky in a few days, which will last until the end of the year. A total of eight X-ray maps are to be generated. The most accurate will be a composition of the previous eight maps and will be published around 2025.

Spectrum RG

The observatory Spektr-RG was built by the space company NPO S. A. Lavotshkin near Moscow. The mission uses two telescopes: In addition to eROSITA, built by the Max Planck Institute for Extraterrestrial Physics (MPE) in Germany, the high-energy X-ray telescope ART-XC is also used. 

This instrument was built under the leadership of the Space Research Institute thanks to a cooperation between the Russian Research Institute for Experimental Physics in Sarov (central Russian region of Nizhny Novgorod) and the Marshall Space Flight Center (MSFC) in Huntsville (US state of Alabama).

Instruments owned by the Spektr-RG observatory

Max Planck Institute for Extraterrestrial Physics IKI / VNIIEF
Telescope type
Wolter Wolter
810 kg
350 kg
Sensitivity range
0.3 - 10 keVolts
6 - 30 keVolts
Angle of view
1 degree
30 minutes
Angular resolution
15 seconds
45 seconds
Sensor area
2,400 cm2 / 1 keVolts
450 cm2 / 8 keVolts