Feb 12, 2013

Amateur Astronomers Help Find Galaxy's Arms

Even a familiar night sky object can hold some interesting surprises. This is especially true when looked at with a fresh set of eyes. Or telescopes.

The image above is of Messier 106, a galaxy with an active supermassive black hole at its center. The image was composed of data from the Hubble Space Telescope, reprocessed by Robert Gendler for the Hubble Hidden Treasures competition. He included in the mosaic astrophotography from his own telescope and from that of fellow astroimager Jay GaBany to fill in the places where there were no Hubble data.

Though the galaxy’s structure is dominated by two large spiral arms, there are two fainter arms that can be seen in this image in red. These arms are not made of bright, newly formed stars like the other, but of very hot gas expelled from the region surrounding the supermassive black hole at the center. They are comprised of hot gas seen in infrared and in Hydrogen alpha emission.

When you look at M106 is non-visible wavelengths, this activity is even more obvious.

Another name for this galaxy is NGC4258, and this is also well known for the masers (or microwave lasers) found near the supermassive black hole in the center. These spots of water vapor that act like lasers have been tracked with exquisite precision by astronomers using the Very Long Baseline Array, giving an accurate measure of the distance to this galaxy at 24 million light years away, and the mass of its black hole at 40 million times the mass of the sun.

The supermassive black hole at the center is pulling material onto it, but not all that material can make it into the black hole at once. As a result, there is a disk of hot glowing material that powers a number of phenomena, including the small radio jets perpendicular to the disk and the water megamasers in the accretion disk. It also powers the wispy red gas forming the two newly seen spiral arms in the disk of the galaxy.

Read more at Discovery News

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