by Ann » Fri Apr 28, 2017 2:26 pm
Thanks for chiming in, Roberto!
My interest in the red "whisker" is limited, although, who knows, it might be something shed by the Cheshire cat.
The APOD is superb, and the colors are splendid and so revealing. Both galaxies are highly distorted, and to me, their disks look like a pair of spoons, attached to long, bent handles. Both have obvious, bright yellow nuclei, and both have long bluish tails. But there are very obvious differences, too.
Yellowish bread shovel, or NGC 4039?
Let's consider the differences! NGC 4038, at right in the APOD, has a bright blue (and pink) border of brilliant clusters, making it look like a piece of jewelery. NGC 4039, on the other hand, is rather yellow and featureless, somewhat like a bread shovel. The two galaxy disks are different because of them, NGC 4038, is gas-rich and brilliantly starforming, whereas the other galaxy is gas-poor and full of old stars.
Where the two galaxies meet there is a humongous brown and pink train wreck-splash of galactic proportions. The brown splash is dark dust, and the pink stuff is brilliant hydrogen emission from new star formation.
Note that the tail that emanates from gas-rich NGC 4038 is very long and full of kinks of star formation. The tail that emanates from NGC 4039 is shorter and quite smooth.
Great image!
Ann
Thanks for chiming in, Roberto! :D
My interest in the red "whisker" is limited, although, who knows, it might be something shed by the Cheshire cat.
[float=left][img2]https://thumbs.dreamstime.com/x/two-crossed-party-spoons-4655319.jpg[/img2][c][size=85]Two spoons with bent handles.
Source: https://www.dreamstime.com/royalty-free-stock-images-two-crossed-party-spoons-image4655319[/size][/c][/float]The APOD is superb, and the colors are splendid and so revealing. Both galaxies are highly distorted, and to me, their disks look like a pair of spoons, attached to long, bent handles. Both have obvious, bright yellow nuclei, and both have long bluish tails. But there are very obvious differences, too.
[float=right][img2]http://www.mahnajewellers.com/wp-content/uploads/2016/05/bluetopaz1-300x300.jpg[/img2][c][size=85]Blue topaz, or NGC 4038?
Source: http://www.mahnajewellers.com/product-category/gemstone-jewellery/blue-topaz/[/size][/c][/float] [float=left][img2]http://2.bp.blogspot.com/-03pHWD22POI/Vf1_eXl-vyI/AAAAAAAAIgo/TQAs3bCZTxw/s1600/20150919_170523.jpg[/img2][c][size=85]Yellowish bread shovel, or NGC 4039?[/size][/c][/float]
Let's consider the differences! NGC 4038, at right in the APOD, has a bright blue (and pink) border of brilliant clusters, making it look like a piece of jewelery. NGC 4039, on the other hand, is rather yellow and featureless, somewhat like a bread shovel. The two galaxy disks are different because of them, NGC 4038, is gas-rich and brilliantly starforming, whereas the other galaxy is gas-poor and full of old stars.
Where the two galaxies meet there is a humongous brown and pink train wreck-splash of galactic proportions. The brown splash is dark dust, and the pink stuff is brilliant hydrogen emission from new star formation.
Note that the tail that emanates from gas-rich NGC 4038 is very long and full of kinks of star formation. The tail that emanates from NGC 4039 is shorter and quite smooth.
Great image! :D
Ann