A Tour of SPT 0346-52

Narrator (April Hobart, CXC): Astronomers have used NASA's Chandra X-ray Observatory and other telescopes to show that a very distant galaxy is undergoing an extraordinary boom of stellar construction. The galaxy is 12.7 billion light years from Earth, which means it is at a critical stage in the evolution of galaxies about a billion years after the Big Bang.

After astronomers discovered the galaxy, known as SPT 0346-52, with the South Pole Telescope, they observed it with several space and other ground-based telescopes. Data from the Atacama Large Millimeter/submillimeter Array revealed this galaxy was giving off tremendous amounts of infrared light.

This excess infrared light could be explaining by a huge burst of star formation. However, there was another possibility: What if the infrared emission was instead caused by a rapidly growing supermassive black hole at the galaxy's center? Gas falling towards the black hole would become much hotter and brighter, causing surrounding dust and gas to glow in infrared light.

To explore this possibility, researchers used Chandra and the Australia Telescope Compact Array, a radio telescope. If there was a massive, growing black hole in the middle of SPT0346-52, it should give off enough X-rays and radio waves for these telescopes to detect.

The result was that neither Chandra nor the Australia Telescope Compact Array saw emission coming from SPT0346-52. The absence of X-rays and radio waves let astronomers rule out a growing black hole being responsible for most of the bright infrared light.

Instead of this galaxy containing a gorging black hole, astronomers know it is shining brightly with the light from newborn stars. This gives scientists information about how galaxies and the stars within them evolve during some of the earliest times in the Universe.