Thread: Ngc 3621
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Old 01-04-2015, 11:36 AM
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madbadgalaxyman (Robert)
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Hi there Rog,

Thanks for an interesting image of this challenging object.

Gee those arms look like they are of very low surface brightness.
I didn't even think of this fact when I was trying to characterize this galaxy in this thread: (within the third post)
http://www.iceinspace.com.au/forum/s...d.php?t=133011

I should have had a look at the surface brightness, which would have modified my "theoretical" conclusions about the size of this galaxy's OB star population, which arose as a result of navigating the numerical data in the galaxy catalogs!
The moral of this story is "take your mind off the data and actually have a look!"

The disk/spiral component of this galaxy is very very interesting;
- it is not planar
- it is extremely extremely extended, far beyond the borders of your jpg
- this may be a case of an 'unevolved' galaxy, where the outer arms and disk are still in the process of formation.

cheers,
Robert

These faint and very very extended disks are pretty hot in the current literature, as the GALEX ultraviolet images bring them up to a bright level of visibility.
Some people call them "XUV" disks, which is short for "extended ultraviolet disks"

e.g. Mr Sidonio has made a nice image of the extended disk of NGC 1512:
http://www.flickr.com/photos/strongman/15614965059/

Last edited by madbadgalaxyman; 01-04-2015 at 12:00 PM.
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