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Old 21-11-2013, 06:02 PM
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madbadgalaxyman (Robert)
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Join Date: Mar 2011
Location: Brisbane
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And while I am at it, here are some "pretty pictures" of the WLM

"Ooooh....look at that cute little galaxy!"
(a very un-madbadgalaxyman-like comment.....)

Click image for larger version

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Name:	WLM_B band__(w. Hall 1.07m)_de Vaucouleurs Atlas)(assigns IAB(s)m ).jpg
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I don't think that WLM is actually an irregular galaxy!
The apparent (as observed) symmetry is greater than that of the LMC.
Maybe this galaxy is as early in the Hubble Sequence as Hubble class Sdm??!?
My hunch is that what we are seeing here is a fairly regular disk of stars, but seen in a rather edge-on orientation. I also think that there could be some incipient spiral structure evident, especially if this galaxy were viewed from a more face-on orientation.

The authors of The de Vaucouleurs Atlas of Galaxies (Buta ; Corwin ; Odewahn) classify WLM as being an irregular galaxy that has a weak bar structure, which to me is something of a contradiction in terms.
A lot of the galaxies that these authors include in the "irregular" morphological class have rather strong symmetry......so I can't understand how these could be true irregular galaxies!
However, I do agree with this atlas that there is a significant probability of the existence of a weak bar structure and that there is some evidence for a spiral arm opening.

Another Image, added in later edit
:

Here is the far-ultraviolet (1500 Angstrom) + near-ultraviolet composite image from GALEX.
The far-ultraviolet band, displayed as blue, is very sensitive to the light from OB stars.

Click image for larger version

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Near-ultraviolet is displayed as yellow; this bandpass (filter) includes light from the older stars in this galaxy, so it corresponds to the shape of the galaxy as seen in the visual regime.

Last edited by madbadgalaxyman; 21-11-2013 at 10:57 PM.
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