On the left, an optical image from the Digitized Sky Survey shows Cygnus X-1, outlined in a red box. Cygnus X-1 is located near large active regions of star formation in the Milky Way, as seen in this image that spans some 700 light years across. An artist's illustration on the right depicts what astronomers think is happening within the Cygnus X-1 system. Cygnus X-1 is a so-called stellar-mass black hole, a class of black holes that comes from the collapse of a massive star. The black hole pulls material from a massive, blue companion star toward it. This material forms a disk (shown in red and orange) that rotates around the black hole before falling into it or being redirected away from the black hole in the form of powerful jets.

The star-forming region, 30 Doradus, is one of the largest located close to the Milky Way and is found in the neighboring galaxy Large Magellanic Cloud. About 2,400 massive stars in the center of 30 Doradus, also known as the Tarantula Nebula, are producing intense radiation and powerful winds as they blow off material.

An era of space exploration ended on July 21, 2011 when Space Shuttle Atlantis touched down before dawn at Kennedy Space Center. The shuttle flights excited our imaginations and tragically revealed the dangers of space travel as mankind dipped its toes into the cosmic ocean. One of the most enduring legacies of the shuttle was established in the 1990's, when the shuttle delivered three of NASA's Great Observatories – Hubble Space Telescope, Compton Gamma Ray Observatory, and the Chandra X-ray Observatory – into space.

Last week, the German Aerospace Center (DLR) issued this statement:

"On 23 October 2011 at 03:50 CEST, the German research satellite ROSAT re-entered the atmosphere over the Bay of Bengal; it is not known whether any parts of the satellite reached Earth's surface. Determination of the time and location of re-entry was based on the evaluation of data provided by international partners, including the USA."

View the most recent updates to the Chandra image collection at Flickr Commons, a forum created by Flickr for cultural institutions to share their photographic collections with the public. For more on the new additions to the Chandra collection, visit the Smithsonian's Bigger Picture blog: https://siarchives.si.edu/blog/new-chandra-x-ray-images-flickr-commons

-Kim Arcand, Chandra EPO

This image combines data from four different space telescopes to create a multi-wavelength view of all that remains of the oldest documented example of a supernova, called RCW 86. The Chinese witnessed the event in 185 A.D., documenting a mysterious "guest star" that remained in the sky for eight months. X-ray images from NASA's Chandra X-ray Observatory and the European Space Agency's XMM-Newton Observatory are combined to form the blue and green colors in the image. The X-rays show the interstellar gas that has been heated to millions of degrees by the passage of the shock wave from the supernova.

Astronomers have used a large survey to test a prediction that close encounters between galaxies can trigger the rapid growth of supermassive black holes. Key to this work was Chandra's unique ability to pinpoint actively growing black holes through the X-rays they generate.

The researchers looked at 562 pairs of galaxies ranging in distances from about 3 billion to 8 billion light years from Earth. They found that the galaxies in the early stages of an encounter with another were more likely than isolated, or "lonelier" galaxies to have actively growing black holes in their cores.

October is American Archives Month—a time to celebrate the importance of archives across the country. In honor of Archives Month, we're participating in a pan-Smithsonian blogathon. Throughout October we, and other blogs from across the Smithsonian, will be blogging about Chandra's rich archive of astronomical data, issues, and behind-the-scenes projects.

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Concluding our series of Archives Month blog posts, we thought we'd shift our focus towards the future of Chandra's digital legacy. Although the modern marvel of engineering that is the Chandra X-ray Observatory will not last forever, its lasting gift to humanity will be its archive of data. Long after the last bits of X-ray light have found their way to Chandra's detectors, scientists and curious amateurs will still be pouring over Chandra's archival data looking for their particular X-ray needle in the digital haystack.

Aneta Siemiginowska is an astrophysicist at the Chandra X-ray Center. In addition to her responsibilities for Chandra’s Science Data System group, she is actively involved is exploring the Universe, particularly its black holes and galaxies.