Supergiant gas plumes revealed in nearby galaxy

17 Jun 2002

Astronomers have captured a spectacular image of a nearby galaxy, complete with huge filaments, loops and "bubbles" of ionized hydrogen gas that extend thousands of light years from the plane of the galaxy. The observations were made in September 1994 and September 1995 by researchers at Johns Hopkins University and University of Wisconsin-Madison. The astronomers used a 1.5-meter telescope at the Cerro Tololo Inter-American Observatory in Chile.

The galaxy, NGC 55, is an irregular galaxy similar to the Large Magellanic Cloud, a companion to the Milky Way. It resides in a group of galaxies, known as the Sculptor Group, located about 5 million light years from Earth. NGC 55 is seen nearly edge-on from Earth, providing a much different perspective than the Large Magellanic Cloud, which presents a more face-on view.

Astronomers aren't certain what the structures are, but a popular theory is that material flowing out from massive stars as they evolve shapes the hydrogen gas surrounding the stars. The stars, which are more than ten times the mass of the sun, spew out material in stellar winds and from their explosive deaths, known as supernovas. JHU graduate student Annette Ferguson presented a paper on her observations during a recent meeting of the American Astronomical Society.