Chandra Image May Rival July 4th Fireworks

by Shannon Hall on July 4, 2014

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A new composite of NGC 4258 features X-rays from Chandra (blue), radio waves from the VLA (purple), optical data from Hubble (yellow and blue), and infrared with Spitzer (red). Image Credit: Chandra

A new composite of NGC 4258 features X-rays from Chandra (blue), radio waves from the VLA (purple), optical data from Hubble (yellow and blue), and infrared with Spitzer (red).

While Fourth of July festivities tonight may bring brilliant colors blazing across the night sky, only 23 million light-years away is another immense cosmic display, complete with a supermassive black hole, shock waves, and vast reservoirs of gas.

The night sky never ceases to amaze. And NGC 4258, also known as Messier 106, is a sight to be seen. A new image from NASA’s Chandra X-ray Observatory is shedding light on one of the galaxy’s most startling features: instead of two spiral arms, typical for any massive spiral galaxy, it appears to have four (imaged above in blue and purple).

Although the second pair of arms can be seen in visible light images as ghostly wisps of gas, they are prominent in images outside the visible spectrum, such as those using X-ray or radio waves. Unlike normal arms, they are made up of hot gas rather than stars, and their origin has remained a mystery.

Astronomers now think the arms — so-called anomalous for their atypical features — are indirectly caused by the supermassive black hole at NGC 4258’s heart.

Images from multiple telescopes help paint a complete picture. Radio data taken with the Very Large Array show that the supermassive black hole is producing powerful jets. As these jets travel through the galactic matter, they disrupt the surrounding gas and generate shock waves. These shock waves, seen by NASA’s Spitzer Space Telescope, heat the anomalous arms — composed of reservoirs of gas as massive as about 10 million Suns — to thousands of degrees.

Finally, the recent Chandra X-ray image also reveals huge bubbles of hot gas above and below the plane of the galaxy. These bubbles indicate that although much of the gas was originally in the disk of the galaxy, it was heated to such high temperatures that it was ejected into the outer regions by the jets from the supermassive black hole.

The results provide drastic implications for the fate of the galaxy. Most of the gas in the disk of the galaxy has been ejected, causing stars to form at a rate ten times slower than the Milky Way. Further, astronomers estimate that all of the remaining gas will be ejected within the next 300 million years.

Although NGC 4258 is currently a sight to be seen in any small telescope, like the best fireworks display followed by smoke, its death is inescapable.

The results were published in The Astrophysical Journal Letters and are available online.

About 

Shannon Hall is a freelance science journalist. She holds two B.A.'s from Whitman College in physics-astronomy and philosophy, and an M.S. in astronomy from the University of Wyoming. Currently, she is working toward a second M.S. from NYU's Science, Health and Environmental Reporting program.

philw1776 July 4, 2014 at 9:55 AM

Visible in modest telescopes in Canes Venatici tonight.
http://www.constellation-guide.com/constellation-list/canes-venatici-constellation/

A member of the “nearby” M51 group of galaxies

Aqua4U July 4, 2014 at 11:10 AM

I’ll wager that we eventually find that the jets from NGC 4258′s massive black hole ARE tilted almost parallel to the plane of the galaxy, Later the jets synchronize with the gravitational pull of the arms, and assume or re-orient themselves as in a typical spiral galaxy with the jets central and perpendicular to the arms. Now, all we’ve got to do to see if I’m right, is wait a couple hundred million to a billion years or so…. sheesh.

Addendum: Those clouds look similar to the gamma ray ‘lobes’ discovered on our galaxy’s polar axis… cept leaning over like a decelerating (OR accelerating) spinning top?

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