| 7th of February 2015 |
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| The vast, distorted gas disk of NGC 300 |
| by Tobias Westmeier (UWA/ICRAR) |
| This colourful picture of NGC 300, a
medium-sized spiral galaxy in the nearby Sculptor Group, combines two separate
data sets: an optical image (from the Digitized Sky Survey) showing mainly
young, blue stars along the galaxy's spiral arms, and a radio image from the
Australia Telescope Compact Array (ATCA) that shows the galaxy's extended neutral hydrogen disc (shown in red). The gas disc is significantly more extended than the stellar disk and - surprisingly - appears to have a different orientation. Such conspicuous warping of the gas disc is thought to be the result of a recent encounter with a companion galaxy whose gravitational forces would have distorted the outer parts of the disc. A closer inspection of the deep radio image also reveals an asymmetry in the morphology of the outer gas disc itself, suggesting that the gas is affected by ram-pressure forces as NGC 300 moves through the intergalactic medium of the Sculptor Group in an approximately south-easterly direction (lower-left in the image). --- The results of the analysis of the radio data have been published by Westmeier, Braun & Koribalski. |