M83 Through the Eye of a HAWK

Details, People!!

This image of the nearby galaxy Messier 83 was taken in the infrared part of the spectrum with the HAWK-I instrument on ESO’s Very Large Telescope. The very fine image quality of this camera, coupled with the huge light-collecting power of the VLT, reveals vast numbers of stars within the galaxy. The images were taken in three different parts of the infrared spectrum and the total exposure time was eight and a half hours, split into more than five hundred exposures of one minute each. The field of view is about 13 arcminutes across.

When astronomers look at a galaxy in fine detail, they want the highest resolution they can get. They want to look at it in as many wavelengths of light as possible.  They want to KNOW what’s in that galaxy.  Why?  For one thing, peering at a galaxy gives many clues about its past — what its rates of star formation have been, where it’s producing stars now, what’s in its core, and insight into the ages of its different populations of stars. Did it collide with another galaxy in the past?  Did smaller galaxies coalesce to make it?

Observers using the European Space Agency’s Very Large Telescope, outfitted with an infrared-sensitive instrument called HAWK-1, have gotten one of the clearest looks at a nearby galaxy called M83.  It lies some 15 million light-years away in the direction of the constellation Hydra, and gives astronomers a chance to look at a galaxy that is, in many ways, similar to our own Milky Way.  M83 has spiral arms, and if you look closely at the image, you can see reddish clouds that are the incubators of young stars.

M83 is also fascinating because it has a higher than normal number of supernovae occurring.  You get supernovae when massive, hot stars explode and spread their atmospheres and much of their mass to interstellar space. You get massive hot stars when a galaxy is boiling with star formation.  So, sometime in the past, M83 was a busy little star-producing factory.  Today when we look at it in optical light (the kind of light we see with our eyes), we see a lot of dust spread out around the galaxy.  To look through that dust, astronomers use instruments like HAWK-1, to get a clearer view of the details in the galaxy’s spiral arms and core.  Click on the image above and study the larger version. You’ll love what you see!

A Seagull (or is it a Lizard?) in Space

WISE Studies a Nebula

The Seagull Nebula as seen by the WISE spacecraft. Courtesy NASA/JPL-Caltech/WISE Team

I’ve talked about star formation many times in this blog. It’s a fascinating topic and there are many, many star-forming regions in our galaxy (and others) for astronomers to study!  The Wide-field Infrared Survey Explorer (WISE) released a very cool infrared image of a star-forming cloud near the constellations of Monoceros and Canis Major called IC 2177, nicknamed the Seagull Nebula. The image is a mosaic — meaning that it’s made from several smaller images.  Now, if this doesn’t look like a seagull, look at another orientation of the image.

Re-oriented to show the seagull.

Now, see the seagull? It’s a somewhat  fanciful vision of a very complex place where stars are forming as we speak. And, the infrared view reveals the sites of the stellar nurseries. For example, astronomers can tell that the pink, oval-shaped region near the seagull’s eye (or lizard’s hip) is one such nursery. It’s called NGC 2327, and it contains a cluster of stars born about 1.5 million years ago. The center of the eye is the brightest and hottest of the newborn stars in the entire nebula. Its intense heat and radiation are warming the dust in the surrounding cloud and causing it to glow in infrared light. Infrared light is not blocked by dust or gas, which makes it a very useful tool for peeking into starbirth nurseries to understand the processes by which all stars — including our Sun — come into being.