M33 from Spitzer

M33 as seen by Spitzer. Click for a larger and annotated version. Image credit: NASA/JPL-Caltech/Univ. of Ariz.

This is a naked eye galaxy with dark skies, can’t prove it by me, but I know for sure it can be seen with binoculars. At the moment M-33 isn’t really easy to see because it is following the Sun and is close to setting itself by the time it gets dark enough so it don’t really make any difference.

Of course Spitzer makes the difference, producing an image that includes infrared. That’s what threw me off. Cool Cosmos has a nice page featuring on of my favorite galaxies the Sombrero galaxy (M-104), showing the difference looking at multiple wavelengths can make.

If you want larger versions of the image click the link to the Spitzer site below.

Here’s the press release from the Spitzer site:

One of our closest galactic neighbors shows its awesome beauty in this new image from NASA’s Spitzer Space Telescope. M33, also known as the Triangulum Galaxy, is a member of what’s known as our Local Group of galaxies. Along with our own Milky Way, this group travels together in the universe, as they are gravitationally bound. In fact, M33 is one of the few galaxies that is moving toward the Milky Way despite the fact that space itself is expanding, causing most galaxies in the universe to grow farther and farther apart.

When viewed with Spitzer’s infrared eyes, this elegant spiral galaxy sparkles with color and detail. Stars appear as glistening blue gems (several of which are actually foreground stars in our own galaxy), while dust rich in organic molecules glows green. The diffuse orange-red glowing areas indicate star-forming regions, while small red flecks outside the spiral disk of M33 are most likely distant background galaxies.

But not only is this new image beautiful, it also shows M33 to be surprising large - bigger than its visible-light appearance would suggest. With its ability to detect cold, dark dust, Spitzer can see emission from cooler material well beyond the visible range of M33’s disk. Exactly how this cold material moved outward from the galaxy is still a mystery, but winds from giant stars or supernovas may be responsible.

M33 is located about 2.9 million light-years away in the constellation Triangulum. This is a three-color composite image showing infrared observations from two of Spitzer instruments. Blue represents combined 3.6- and 4.5-micron light and green shows light of 8 microns, both captured by Spitzer’s infrared array camera. Red is 24-micron light detected by Spitzer’s multiband imaging photometer.