The Chandra Observatory has released a series of composite images that combine different types of light. Among these images we find galaxies, stars, supernovae. And it’s absolutely beautiful.
The universe is sublime to look at, but part of its beauty is inaccessible to us with a single appearance. This is where telescopes come in to show us the cosmos in all its richness. By moving on the electromagnetic spectrum, one can look at all the different emitted lights. At each type of light looked at its relevant scientific information.
But what happens when you overlap multiple lights – that is, multiple images from another part of the spectrum? It is then a “composite image”, a fairly common technique in astronomy for combining several different recordings, and it often produces breathtaking sky images.
The Chandra Observatory gives us new and excellent examples of this in a new post, published on February 2, 2022. If Chandra specializes in detecting X-rays (convenient for detecting distant or small very energetic objects), these images are published by the Observatory combines this “layer” with images that originate mainly from optics or radio waves. ” This gallery shows examples of combinations of different types of light from ground-based and space-based telescopes », Introduces the observatory.
Galaxies, supernovae …
The image below shows Cassiopeia A, a supernova remnant. X-rays observed by Chandra show silicon (in red), sulfur (in yellow), calcium (in green) and iron (in light purple). Two layers have been added: one from radio wave data captured by Karl Jansky’s Very Large Array (dark purple, blue and white); the other is an optical recording from Hubble (orange).
” Like X-rays, radio waves can penetrate the thick clouds of gas and dust that lie between Earth and Cassiopeia A, providing more information about this famous star explosion. », Details of the observatory.
This is a composite image. If we observe the same celestial object under each of the mentioned lights, this gives the three images below (from left to right: X-ray, radio, optics).
Now here galaxy NGC 4490, which collides with another, smaller galaxy not present in the image. The composite image combines X-rays and an optical image. In violet these are X-rays, and in red, green and blue the optical spectrum. ” Some X-ray sources represent black holes with star mass and neutron stars in the galaxy », Explains the observatory.
Same combination for R Aquarii, below. This object is a pair of two objects: a white dwarf star, at a (relatively) cold temperature, and a red giant (very hot, but whose energy varies). ” The white dwarf orbits each other and attracts matter from the red giant to its surface. Over time, enough of this material builds up and triggers an explosion. The composite image combines X-rays with optics.
Abell 2597, in the images below, is a cluster of galaxies: this type of cluster represents the largest known “structure” of the universe, as it brings together several galaxies held together by gravity. There are individual galaxies, large amounts of hot gas, most likely dark matter … and a black hole in the center can affect the behavior of the cluster. ” In the galaxy cluster Abell 2597, a giant central supermassive black hole pushes gas out, creating bubbles or cavities inside. »
The composite image at the top left combines X-rays from the Chandra Observatory (in blue), optical recordings from the Digitalized Sky Survey (in orange), and a more specific light called H-Alpha (Hα): l emission of hydrogen atoms in optical light, captured of the Las Campanas Observatory in Chile (red).
It also helps to understand what a telescope like James Webb can be used for. The latter will not result in images that will seem visually revolutionary to you, but they will be infinitely valuable. They will bring their own information about the universe and they will also be combined with other footage.