Christmas time means gathering together with friends and loved ones, usually in festive environments that involve some colorful lights. It turns out the same applies to galaxies.
Spiral galaxies NGC 2207 and IC 2163 both lie about 130 million light-years from Earth in the constellation Canis Major. Between the two of them, they have hosted three supernova explosions in the last three years. And recently, they were caught grazing one another. This close encounter has yielded a stunning sight of something called ultra luminous x-ray sources (ULXs) which is bright x-ray light.
Both NGC 2207 and IC 2163 are filled with star systems called as X-ray binaries, systems wherein a star tightly orbits a neutron star or a black hole. The strong gravity of the neutron star or black hole siphons matter from its companion star, heating it and generating X-rays that are far brighter than normal X-rays, which makes for some stunning images.
Our space telescopes see in different wavelengths. Hubble sees in visible light, that is, light that our eyes can see unaided. When Hubble looked at NGC 2207 and IC 2163, it saw this:
The Spitzer Space Telescope sees in infrared light, that is, light that is of too long a wavelength for our eyes to see. Spitzer’s view of NGC 2207 and IC 2163 looks like this:
It’s the Chandra Observatory that sees X-rays, including ULXs. When it looked at NGC 2207 and IC 2163, it revealed a total of 28 ULXs, twelve of which have varied over the last few years. Some seen today weren’t detectable at all seven years ago when they were in a “quiet” phase. Chandra’s view looks like this:
Together, the composite image of these three telescopes is stunning:
Galactic collisions are violent and produce more than their share of stellar and planetary casualties. But they sure are gorgeous from a safe distance.