NGC 1365 is a very interesting and impressive galaxy, and JWST's MIRI image sheds new light on it.
A striking aspect of the inner core is the "eye shape" that is created by the dust lanes above and below the core. The central round yellowish light source between the dust lanes in the MIRI image could represent the pupil of an eye, and the dust lanes the eyelids.
The "eyelids" look extremely bright in far infrared light. The center of NGC 1365 also looks both bright and star-filled in an optical and infrared composite image from ESO and TIMER, but the dust lanes look quite different than in the JWST image (because the infrared filter used for the ESO/TIMER image did not detect MIRI's far infrared wavelengths at all):
The dust lanes, which are so bright in the MIRI image, are dark in the ESO/TIMER picture. On the other hand, dozens of bright white knots are seen that could be young star clusters. But are they?
In the GALEX image, blue represents hot ultraviolet stars, and yellow represents cooler stars. As you can see, the core of NGC 1365 is not bright blue at all, and there really does not appear to be very many new stars there.
There are two possible reasons for the apparent lack of young ultraviolet stars in the core of NGC 1365. One is that the dust lanes there simply don't form new stars at all. Not all dust lanes do. Consider the overlapping galaxy pair known as AM 1316-241:
Another possibility is that new star clusters are indeed forming in the bright dust lanes surrounding the core of NGC 1365, but the clusters are hidden by dust. On the whole, I find that unlikely. The formation of new star clusters in the dust lanes should disturb the dust and make it look "irregular", but we see no signs of any such disturbances.
Let's take a closer look at the core as seen by MIRI:
Let's look at the objects in the core. The one farthest to the left is a round yellowish thing, that actually looks as if it could be the galactic core. Yes, but look at the red rays that appear to emerge from another location in the galactic center. They don't come from the yellowish knot at left. And since
NGC 1365 is a Seyfert galaxy with an active core, I expect any light rays and jets from the central region to come from the core. That's why I surmised that the small bright knot to the lower left of the yellow knot is the actual core of the galaxy, and the yellowish object to the left of it would be a star cluster. Maybe a globular cluster?
Then again... the picture that AVAO, Jac, posted above does indeed suggest that what I called "the yellowish knot at left" is indeed the core of NGC 1365:
So I guess that the "red rays" seen in the MIRI image come from an intensely bright far infrared source. Perhaps a hidden cluster?
Finally, you can see a bright "swelling" at the end of one of the central dust lanes that in my opinion must be a relatively newborn star cluster.
To close, I want to show you a picture of NGC 1365 that shows the "true" brightness distribution of NGC 1365, where the brightest parts of the galaxy are the core and the inner bar:
If you have trouble seeing the inner bar of NGC 1365 (and not just the long bar between the spiral arms), here it is:
Finally, I want to remind everyone that I am a complete amateur. I love galaxies, and I love to try to understand why they are the way they are, and I love to compare them with other galaxies. I really do my best to try to understand what is going on, as long as I can understand it in a non-mathematical way.
But I am not a scientist and certainly not a researcher, and what I write here is not the gospel truth. Always remember that.
Ann
Barred Spiral Galaxy NGC 1365 from Webb
