October is designated as American Archive Month, to promote an awareness of the importance of historical records. While many think ‘archive’ may only apply to books and letters, there are other important archives. Archives are used for major telescopes and observatories, including NASA’s Chandra X-ray Observatory.

The primary role of the Chandra Data Archive (CDA) is to store and distribute data so the astronomical community, as well as the general public, have access to it. The CDA does this with the aid of powerful search engines. This archive collection will preserve the legacy of the Chandra mission for generations.

In celebration of American Archive Month, the Chandra team chose images from a group of eight objects in the CDA to be released to the public for the first time. These are but a few of the thousands of objects that Chandra’s archive has made permanently available to the public. 

G266.2-1.2

Chandra’s observation of this supernova remnant, located around 2,400 light years away in the constellation Vela, revealed extremely high-energy particles. These particles are produced as the shock wave from the explosion expands into interstellar space. The X-rays from Chandra (purple) have been combined with optical data from the Digitized Sky Survey (red, green, and blue).

3C353

This is a wide and double-lobed jet, generated by a supermassive black hole at the centre of a galaxy about 410 million light years away, in the constellation Ophiuchus. The jet itself is the tiny point in the centre while the giant plumes of radiation can be seen in X-rays from Chandra (purple) and radio data from the Very Large Array (orange).

NGC 3576

This nebula is located around 9,000 light years away from Earth, in the Sagittarius arm of the Milky Way galaxy. The scattered X-ray data detected by Chandra (blue) are probably due to the winds from young, massive stars blowing throughout the nebula. Optical data from ESO are shown in orange and yellow.

NGC 4945

This galaxy is similar in appearance to our own, but contains a much more active supermassive black hole within the white area near the top. NGC 4945 is only about 13 million light years from Earth, in the constellation Centaurus, and is seen edge-on. X-rays from Chandra (blue), have been overlaid on an optical image from the European Space Observatory to reveal the presence of the supermassive black hole at the centre of this galaxy.

IC 1396A

The nebula otherwise known as the Elephant Trunk Nebula is located about 2,800 light years away in the constellation of Cepheus. Radiation and winds from massive young stars seem to be triggering new generations of stars to form. X-rays from Chandra (purple) have been combined with optical (red, green, and blue) and infrared (orange and cyan) to give a more complete picture of this source.

3C 397 (G41.1-0.3)

Also known as G41.1-0.3, this is a Galactic supernova remnant with an unusual shape found around 33,000 light years away in the constellation Aquila. Its box-like shape is possibly produced as the heated remains of the exploded star interacts with the cooler gas enveloping it. The exploded star was detected by Chandra in X-rays (purple) and this composite of the area around 3C 397 also contains infrared emission from Spitzer (yellow) and optical data from the Digitized Sky Survey (red, green, and blue).

SNR B0049-73.6

This supernova is located approximately about 180,000 light years away in the constellation Tucana, within our neighbouring galaxy of the Small Magellanic Cloud. Observations of the dynamics as well as the composition of the debris from the explosion provide evidence that the explosion was produced by the collapse of the central core of a star. In this image, X-rays from Chandra (purple) are combined with infrared data from the 2MASS survey (red, green, and blue).

NGC 6946

Nicknamed the ‘Fireworks Galaxy’, this medium-sized, face-on spiral galaxy is found about 22 million light years away from Earth in the constellation Cygnus. Eight supernovae have been observed to explode in the arms of this galaxy in the last 100 years. Chandra observations (purple) have revealed three of the oldest supernovas ever detected in X-rays. This composite image also includes optical data from the Gemini Observatory in red, yellow, and cyan.