NGC 1313

NGC1313 (RA 3h18m, Dec -66.5) is a pretty but strange barred spiral galaxy. It is about 15 million light years from us (to give some scale, our galaxy is a tad over 100,000 light years across) and as you can see from the picture below, it has lots of stars being formed in its spiral arms.

NGC 1313
The central parts of the starburst galaxy NGC 1313 obtained with the FORS1 instrument on the European Southern Observatory's Very Large Telescope CREDIT: Henri Boffin (ESO) and ESO
The reason I say it is strange is for a couple of reasons. Firstly, the centre of the galaxy (the point around which everything

rotates) doesn't actually correspond to the bar as you might expect. The second aspect of its strangeness refers to all the new stars that are forming in it. Most galaxies with lots of new star formation (starburst galaxies) have a reason for the starburst to occur. This is often because two galaxies have got close to each other and the gravitational interaction (or physical interaction) causes huge clouds of gas to be squashed or compressed and so trigger the birth of new stars at their cores. However, according to the ESO press release, NGC 1313 doesn't appear to have any neighbouring galaxies. A quick look at a combined UK Schmidt plate image (put your mouse over that image) shows that the outer parts of this galaxy are very disturbed with huge streams of gas that don't seem to correspond to the spiral arms in the image above. So, something has happened to this galaxy but nobody seems to be sure what. Whatever is causing the starburst it sure does look nice!

As if all this wasn't interesting enough, there are also two ultra-luminous X-ray objects in this galaxy. These have been seen by XMM-Newton, and measurements of them imply that they are both black holes with masses between 100 and 1000 times that of our Sun.

The image is available as wallpapers for your desktop at a variety of resolutions from the European Southern Observatory's website.

Posted in astro blog by Stuart on Friday 24th Nov 2006 (10:16 CET) | Permalink
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