August 13, 2001

1 min read

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Chandra Reveals Long-Sought Source of X-Rays Behind the Milky Way

By Kate Wong

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Astronomers have long wondered where the mysterious x-ray glow in the Milky Way plane comes from. Now new evidence, described in the current issue of the journal Science, may help to settle the matter. According to the report, researchers using NASA's Chandra X-Ray Observatory have traced the emission to a hot, diffuse gas.

Ken Ebisawa of the NASA Goddard Space Flight Center and his colleagues focused on a small sector of the galactic plane in the constellation Scutum. Probing what is known as the zone of avoidance¿a region of space so-named because no optical observations have been made of it¿Chandra detected a diffuse emission, as opposed to x-ray point sources. This, the researchers explain, indicates the x-ray glow comes from tremendously hot plasma gas concentrated along the galactic plane.

The team also detected 36 new distant x-ray point sources beyond the plane. These, they believe, are active galaxies located millions of light-years behind our own.

Kate Wong is an award-winning science writer and senior editor for features at Scientific American, where she has focused on evolution, ecology, anthropology, archaeology, paleontology and animal behavior. She is fascinated by human origins, which she has covered for nearly 30 years. Recently she has become obsessed with birds. Her reporting has taken her to caves in France and Croatia that Neandertals once called home to the shores of Kenya’s Lake Turkana in search of the oldest stone tools in the world, as well as to Madagascar on an expedition to unearth ancient mammals and dinosaurs, the icy waters of Antarctica, where humpback whales feast on krill, and a “Big Day” race around the state of Connecticut to find as many bird species as possible in 24 hours. Wong is co-author, with Donald Johanson, of Lucy’s Legacy: The Quest for Human Origins. She holds a bachelor of science degree in biological anthropology and zoology from the University of Michigan. Follow her on Bluesky @katewong.bsky.social

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