Scientific American - USA (2019-12)

December 2019, ScientificAmerican.com 71

SWIRLING SPIRALS

TWO MERGING GALAXIES, collectively known as M51, or the

Whirlpool, show the beautiful arms characteristic of spiral galaxies.

About 400 x-ray sources, most of them binary stars, are visible

here, primarily located near regions of star formation. Scientists

speculate that the interaction between the two galaxies is trigger-

ing a wave of star formation that results in the large number of

x-ray binaries in this system. Pulsations from one x-ray binary imply

that the compact companion is a neutron star that must be accret-

ing huge amounts of material from its companion to generate its

unusually high luminosity.

The main image ( 1 ) is a composite of Chandra’s x-ray data ( 2 )

and optical light ( 3 ) captured by the Hubble Space Telescope.

Combining data from various telescopes allows astronomers to

create fuller, multiwavelength pictures that reveal cosmic phenom-

ena visible in different ranges of the electromag netic spectrum.

(^1) X-RAY: NASA, CXC, WESLEYAN UNIV. AND R. KILGARD ET AL.; OPTICAL: NASA AND STSCI
2
3
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