A new image of the center of our galaxy reveals details in dust swirling into the central black hole. Scientists said the picture is the highest resolution ever gained in mid-infrared wavelengths.
The mid-infrared part of the electromagnetic spectrum comprises the wavelengths at which room temperature objects glow most brightly. People, plant and even the atmosphere emit a bright glow in the mid-infrared. Seeing celestial objects though this glow is like trying to see stars during daylight, however, so special techniques are needed to tease the stars from this glow to build a recognizable picture, said the astronomers.
The image was taken by a team led by Dr. Mark Morris of the University of California, Los Angeles, at the Keck II telescope in Hawaii, with an infrared camera called the Mid-Infrared Large-Well Imager, or Mirlin. The camera was built at NASA's Jet Propulsion Laboratory in Pasadena, Calif.
At the center of the Milky Way is a black hole thought to contain the mass of roughly 3 million suns. It can't be seen, but astronomers infer its existence by noting the motions of stars, gas and dust near the black hole.
A veil of dust absorbs the visible light emitted by most of the stars near the Galactic Center. The light warms the dust, which then radiates in the infrared and becomes visible to the mid-infrared camera.
The image shows this dusty material spiraling toward the black hole.
When this material eventually falls into the black hole, it will release energy that affects everything in its vicinity. This event, which astronomers are certain has happened many times in the history of the Milky Way, may trigger the formation of a new generation of stars by causing other nearby dust clouds to collapse, or it may actually inhibit the formation of new stars if the released energy destroys those clouds.
The black hole continues to grow larger as new material falls into it.
Astronomers know that the stars in this image are all very luminous, because less luminous stars appear very faint to a mid-infrared camera. A massive star nearing the last stages of its life, the red supergiant IRS7, is visible in this image as the smallish, bright spot just above the center. IRS7 is simply so luminous -- more than 100,000 times as bright as our Sun -- that its starlight can be seen directly.
A small cavity in the center is a bubble has apparently been evacuated of dust and gas, according to a statement issued by JPL. A star located at the center of the mini-cavity (not visible in the image) apparently blows this bubble with its powerful stellar wind. A bullet-like structure is a mysterious, fast-moving feature pointing roughly away from the mini-cavity, just below and to the right of the center. It may be a jet composed of gas and dust.
Researchers have published some of their findings based on this image in the Astrophysical Journal.
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