Beneath the Spiral

M83
As seen through X-ray eyes, the spiral galaxy M83 is filled with diffuse hot glowing gas and pointlike binary star systems.
Courtesy NASA/CXC/R.Soria and K.Wu.
Buried deep within the spiral galaxy M83 is a dense and tumultuous star-making factory in a bagel-shaped volume around the galaxy's nucleus. The Chandra X-Ray Observatory captured this high-resolution image in an hour and a half exposure, also revealing a large population of X-ray binary stars and an envelope of scorching-hot ionized gas, say Roberto Soria (University College London) and Kinwah Wu (University of Sydney).

"Notice the never-before-seen hot gas along the spiral arms," says Soria. "In the starburst nucleus, the gas is even hotter." Chandra resolved the galaxy's X-ray emission in unprecedented detail, distinguishing point-source X-rays emitted by aging binary stars from diffuse X-ray glowing gas.

M83
These two images of M83 in visible light (left) and X-rays illustrate the power of multiwavelength surveys. The white box shows the area covered by the left image.
X-ray image courtesy NASA/CXC/R.Soria & K.Wu. Visible image courtesy European Southern Observatory.
X-ray binaries are dual star systems in which a black hole, neutron star, or white dwarf ravenously feeds off its companion star, diminishing the companion's mass. The gravitational attraction on the infalling material is so strong that when it hits the surface of the more dense object, it heats the spot to X-ray temperatures.

M83 holds an abundance of such binaries. Over time, the central zone of this 12-million-light-year distant galaxy became a mecca for black holes, neutron stars, and supernova explosions, spawning a thick gas cloud of carbon, silicon, neon, sulfur, and magnesium around itself. The gas cloud, observed for the first time in this image, is growing more chemically diverse as the nucleus ages and ejects other elements into it.

Color distributions representing differing X-ray wavelengths indicate that star formation first began in the southern portion of the nucleus 10 to 30 million years ago. The northernmost tip of the nucleus holds the youngest stars, at 5 million years old. This suggests that star formation is propagating outward.

M83 is located in Hydra and shines at magnitude 7.5.