Starship Asterisk*

The Cartwheel Galaxy from Webb

Explanation: To some, it looks like a wheel of a cart. In fact, because of its outward appearance, the presence of a central galaxy, and its connection with what looks like the spokes of a wheel, the galaxy on the right is known as the Cartwheel Galaxy. To others, however, it looks like a complicated interaction between galaxies awaiting explanation. Along with the two galaxies on the left, the Cartwheel is part of a group of galaxies about 500 million light years away in the constellation Sculptor. The large galaxy's rim spans over 100,000 light years and is composed of star forming regions filled with extremely bright and massive stars. The Cartwheel's ring-like shape is the result of gravitational disruption caused by a smaller galaxy passing through a large one, compressing the interstellar gas and dust and causing a star formation wave to move out like a ripple across the surface of a pond. The featured recent image of the Cartwheel Galaxy by the Webb Space Telescope reveals new details not only about where stars are forming, but also about activity near the galaxy's central black hole.

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Fitting
visual near IR mid-IR

hovering visual over near IR hovering near IR over mid-IR Stars do drift between Hubble and Webb

VictorBorun wrote: ↑Wed Aug 24, 2022 7:44 am hovering visual over near IR

Click to view full size image 1 or image 2

hovering near IR over mid-IR

Click to view full size image 1 or image 2

Stars do drift between Hubble and Webb

Thank you for your hover images, Victor!

Ann

The cart wheel sorta reminds me of a Farris wheel very unique galaxy! I really like this picture! Kitty is watching!

orin stepanek wrote: ↑Wed Aug 24, 2022 12:03 pm reminds me of a Farris wheel

do you mean Ferris Wheel

VictorBorun wrote: ↑Wed Aug 24, 2022 12:16 pm

orin stepanek wrote: ↑Wed Aug 24, 2022 12:03 pm reminds me of a Farris wheel

do you mean Ferris Wheel

I used Spell check! had Ferris wheel at first and it red lined me!

orin stepanek wrote: ↑Wed Aug 24, 2022 12:23 pm I used Spell check! had Ferris wheel at first and it red lined me!

Ferris at night

APOD Robot wrote: ↑Wed Aug 24, 2022 4:05 am The featured recent image of the Cartwheel Galaxy by the Webb Space Telescope reveals new details not only about where stars are forming, but also about activity near the galaxy's central black hole.

Why would the Cartwheel Galaxy have a black hole in the middle when CHANDRA absolutely can't see it in the x-ray?


Credit: NASA/CXC/A.Wolter & G.Trinchieri et al.


(Credit: NASA/STScI/CXC/A.Wolter & G.Trinchieri et al.

AVAO wrote: ↑Wed Aug 24, 2022 5:51 pm

APOD Robot wrote: ↑Wed Aug 24, 2022 4:05 am The featured recent image of the Cartwheel Galaxy by the Webb Space Telescope reveals new details not only about where stars are forming, but also about activity near the galaxy's central black hole.

Why would the Cartwheel Galaxy have a black hole in the middle when CHANDRA absolutely can't see it in the x-ray?


Credit: NASA/CXC/A.Wolter & G.Trinchieri et al.


(Credit: NASA/STScI/CXC/A.Wolter & G.Trinchieri et al.

We see no signs of a bright accretion disk in the MIRI image. If it was there, it would look like a bright star with six characteristic JWST diffraction spikes in the center of the Cartwheel galaxy. There may be a black hole there, of course - in fact, there probably is - but it doesn't appear to be active.

Ann

VictorBorun wrote: ↑Wed Aug 24, 2022 7:44 am ...

Stars do drift between Hubble and Webb

Drift? I'm not seeing any stars changing position between the HST images and the Webb images. Only a lot more stars and other background galaxies in the Webb pics than in the Hubble pic. ......Ok, maybe that one bright star (in the MW) on the far right shifts a little. Is that what you are referring to?

Wait, is this saying the the smaller bright central disk is really a separate galaxy that is still "plowing through" the center of the larger "ringed" galaxy?

johnnydeep wrote: ↑Wed Aug 24, 2022 8:57 pm

VictorBorun wrote: ↑Wed Aug 24, 2022 7:44 am ...

Stars do drift between Hubble and Webb

Drift? I'm not seeing any stars changing position between the HST images and the Webb images. Only a lot more stars and other background galaxies in the Webb pics than in the Hubble pic. ......Ok, maybe that one bright star (in the MW) on the far right shifts a little. Is that what you are referring to?

I mean these 5 dots:

The largest drift, #2 is 1.8 arc seconds (if 100,000 ly line is drawn according to 500 million ly distance assumption and is 41.3 arc seconds).
The drift is too large for a parallax by Earth's orbital movement, but can it be a parallax by Sun's relative movement during the years between those snapshots (on October 16, 1994 by Hubble and 28 years later by Webb)?

johnnydeep wrote: ↑Wed Aug 24, 2022 8:58 pm Wait, is this saying the the smaller bright central disk is really a separate galaxy that is still "plowing through" the center of the larger "ringed" galaxy?

No, that is not the case. The Cartwheel Galaxy wouldn't have acquired its full cartwheel shape, spokes and all, if the intruding galaxy had still been in the process of plowing into the very center of the spiral galaxy that would become the Cartwheel.

The intruder has been identified, and it has left the Cartwheel behind:

ESA wrote:
The galaxy's unusual configuration was created by a nearly head-on collision with a smaller galaxy about 200 million years ago.

Ann

Ann wrote: ↑Thu Aug 25, 2022 3:40 am

ESA wrote:
The galaxy's unusual configuration was created by a nearly head-on collision with a smaller galaxy about 200 million years ago.

Ann

"These two rings expand outwards from the center of the collision, like ripples in a pond after a stone is tossed into it."
https://www.nasa.gov/feature/goddard/20 ... eel-galaxy

In WEBB's MIRI images, it is clear that the spokes go all the way to the center. In addition, the inner and outer rings spread outwards together. This means that if a collision had taken place, it would have to have taken place precisely in the center or at least inside the inner ring. But since the size of the potentially invading galaxy is probably larger than the inner ring, the hypothesis is nothing more than one of many possible hypotheses for me, and not a fact. However, the possibility that some form of interaction took place between the galaxies is certainly very realistic, but not necessarily the cause of the unusual cartwheel shape.


https://live.staticflickr.com/65535/523 ... 072f_o.jpg
jac berne (flickr)

VictorBorun wrote: ↑Thu Aug 25, 2022 2:28 am

Click to view full size image 1 or image 2

The largest drift, #2 is 1.8 arc seconds (if 100,000 ly line is drawn according to 500 million ly distance assumption and is 41.3 arc seconds).
The drift is too large for a parallax by Earth's orbital movement, but can it be a parallax by Sun's relative movement during the years between those snapshots (on October 16, 1994 by Hubble and 28 years later by Webb)?

Thanks! And also for your previous post. You're certainly much more observant than I am, though at least I can see those stars shifting now that you've pointed them out for me. It seems I'd make a terrible observational astronomer.

AVAO wrote: ↑Thu Aug 25, 2022 4:54 am

Ann wrote: ↑Thu Aug 25, 2022 3:40 am

ESA wrote:
The galaxy's unusual configuration was created by a nearly head-on collision with a smaller galaxy about 200 million years ago.

Ann

"These two rings expand outwards from the center of the collision, like ripples in a pond after a stone is tossed into it."
https://www.nasa.gov/feature/goddard/20 ... eel-galaxy

In WEBB's MIRI images, it is clear that the spokes go all the way to the center. In addition, the inner and outer rings spread outwards together. This means that if a collision had taken place, it would have to have taken place precisely in the center or at least inside the inner ring. But since the size of the potentially invading galaxy is probably larger than the inner ring, the hypothesis is nothing more than one of many possible hypotheses for me, and not a fact. However, the possibility that some form of interaction took place between the galaxies is certainly very realistic, but not necessarily the cause of the unusual cartwheel shape.

...

I had indeed read the statement about a head-on collision 200 My ago, but what threw me was this statement in the APOD description:

"because of its outward appearance, the presence of a central galaxy, and its connection with what looks like the spokes of a wheel, the galaxy on the right is known as the Cartwheel Galaxy."

That seemed to be implying that the central disc structure was a separate galaxy. Poor wording I now suppose.