Here are two images of NGC 253, not exactly in registration, but close enough to enable comparison between them.
The first is a visible-wavelengths image,
and the second is from the 4.1 metre VISTA telescope in the near-infrared
[[ The infrared image is composite of Z and Y bands (0.88 and 1.02 micrometers) and also the Ks and J bands (2.15 micrometers and 1.25 microns), possibly with a narrowband filter image also added to it. ]]
The highly-foreshortened bar structure and the two primary spiral arms are much more evident in the near-infrared, and it is consistent with the morphology of the largest-scale features that the bar structure sits within a ring structure.
Another interesting aspect of the NIR image from the VISTA telescope is that we can make a more informed hypothesis as to what parts of the heavy and rather-chaotic dust distribution (which is so very evident at visible wavelengths) are associated with major structural features in this galaxy (e.g. the bar, spiral arms, etc.) and what parts are not;
This sort of analysis may give some further insight into the structure of this galaxy, e.g. what is the nature of the unsettled-looking dust streamers on the right side of this galaxy that look like they could be rising above the principal plane of this galaxy?
The observed overall dust asymmetry & entropy would, considered as an isolated fact, probably
not be interesting, because many other galaxies which have a high Current time-rate of formation of New Stars
can also have this sort of heavy and semi-chaotic dust distribution, BUT........
I am also currently contemplating the nature of
some other interesting peculiarities in NGC 253;
- its asymmetric outer halo.
- the unusual outermost distribution of the HI (neutral atomic hydrogen gas) in this galaxy, which is perhaps a sign of a gas inflow or outflow.
- the notably compact disk of HI, which is truncated (absent outside of the bright optical portions of this galaxy), something which is, under normal circumstances, the signature of a galaxy which has undergone multiple interactions in a dense Galaxy Cluster environment.
So, given that NGC 253 actually has
several different peculiarities and anomalies, perhaps there is some correlation between all of these interesting facts??!???
