Unknown Structure in Galaxy

                 Artist's impression of a giant galaxy with a high-energy jet. 

Credit: ALMA (ESO/NAOJ/NRAO)

As a result of achieving high imaging dynamic range, a team of astronomers in Japan has discovered for the first time a faint radio emission covering a giant galaxy with an energetic black hole at its center. 

The radio emission is released from gas created directly by the central black hole. The team expects to understand how a black hole interacts with its host galaxy by applying the same technique to other quasars.

3C273, which lies at a distance of 2.4 billion light-years from Earth, is a quasar. A quasar is the nucleus of a galaxy believed to house a massive black hole at its center, which swallows its surrounding material, giving off enormous radiation. 

Contrary to its bland name, 3C273 is the first quasar ever discovered, the brightest, and the best studied. It is one of the most frequently observed sources with telescopes because it can be used as a standard of position in the sky: in other words, 3C273 is a radio lighthouse.

When you see a car's headlight, the dazzling brightness makes it challenging to see the darker surroundings. The same thing happens to telescopes when you observe bright objects. Dynamic range is the contrast between the most brilliant and darkest tones in an image. 

You need a high dynamic range to reveal both the bright and dark parts in a telescope's single shot. ALMA can regularly attain imaging dynamic ranges up to around 100, but commercially available digital cameras would typically have a dynamic range of several thousands. Radio telescopes aren't very good at seeing objects with significant contrast.  READ MORE...