APOD: The Fornax Cluster of Galaxies (2023 Nov 02)

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APOD: The Fornax Cluster of Galaxies (2023 Nov 02)

Post by APOD Robot » Thu Nov 02, 2023 4:08 am

Image The Fornax Cluster of Galaxies

Explanation: Named for the southern constellation toward which most of its galaxies can be found, the Fornax Cluster is one of the closest clusters of galaxies. About 62 million light-years away, it's over 20 times more distant than our neighboring Andromeda Galaxy, but only about 10 percent farther along than the better known and more populated Virgo Galaxy Cluster. Seen across this three degree wide field-of-view, almost every yellowish splotch on the image is an elliptical galaxy in the Fornax cluster. Elliptical galaxies NGC 1399 and NGC 1404 are the dominant, bright cluster members toward the bottom center. A standout, large barred spiral galaxy, NGC 1365, is visible on the upper right as a prominent Fornax cluster member.

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Re: APOD: The Fornax Cluster of Galaxies (2023 Nov 02)

Post by Ann » Thu Nov 02, 2023 6:58 am


It is hard not to be struck by the contrast between all the yellow blobs of elliptical galaxies in the Fornax cluster and the large, majestic, gorgeously shaped blue barred spiral galaxy of NGC 1365. This magnificent spiral looks so large compared with all the yellow blobs of the other galaxies that it is hard not to think that NGC 1365 is a foreground object. But it would really seem that it is not, because there was a type Ia supernova in NGC 1365 in 2012, and that should be enough to pin down the distance to NGC 1365 with a reasonable amount of certainty.


And you have to watch Judy's, Geckzilla's, fantastic animation of the core of NGC 1365. Go to this page and find a link to the animation.


NGC 1365 is a huge galaxy, with a diameter of some 300,000 light-years. That makes it three times the size of the Milky Way! And different parts of NGC 1365 orbit at different speeds in a complicated way. Read about it here!


There are two other interesting galaxies in the Fornax Cluster, and they are NGC 1399 and NGC 1427A. NGC 1399 is the largest elliptical galaxy of the Fornax Cluster, or the cD (central dominant) galaxy of the cluster.


I recommend that you look at the 780 KB version of the picture of NGC 1399, which is here. And if you are adventurous, I think you should look at the 22 MB version of the picture. If you do, you will see what looks like a rich sprinkling of round white salt flakes all over the image. These are globular clusters. NHC 1399 has a huge number of globular clusters, between 5700 and 6500 of them! Bear in mind that the Milky Way is estimated to only have some 200 globulars!


Another hugely interesting galaxy of the Fornax Cluster is just barely seen in today's APOD, as a tiny arc-shaped blue little thing at the very bottom edge of the APOD, slightly to the right of center. This is NGC 1427A. You can see it a bit better here, at about 9 o'clock:


Actually, NGC 1427A is a small and gas-rich galaxy helplessly falling into the Fornax Cluster, setting up a firestorm of star formation and almost burning up in the process!


I guess that if the Earth is the Pale Blue Dot, then NGC 1427A is the Poor Blue Blob. It is a hard life out there in the large galaxy clusters!

Ann
Last edited by Ann on Thu Nov 02, 2023 5:49 pm, edited 1 time in total.
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Re: APOD: The Fornax Cluster of Galaxies (2023 Nov 02)

Post by Roy » Thu Nov 02, 2023 5:12 pm

Ann’s explication seems to highlight several galaxy/cluster principal organization modes. Globe mode, spiral/rotational mode, and disorganized mode. Why is the cosmos organized thusly, as far as we can see?

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Re: APOD: The Fornax Cluster of Galaxies (2023 Nov 02)

Post by Chris Peterson » Thu Nov 02, 2023 6:53 pm

Roy wrote: Thu Nov 02, 2023 5:12 pm Ann’s explication seems to highlight several galaxy/cluster principal organization modes. Globe mode, spiral/rotational mode, and disorganized mode. Why is the cosmos organized thusly, as far as we can see?
Keep in mind that we're not seeing static structures, but bodies in complex orbits around each other. How they appear to our brief snapshot view is not representative of any real structure. It's transient. Come back in a few hundred million years and these clusters will look very different, with very different apparent structures.
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Re: APOD: The Fornax Cluster of Galaxies (2023 Nov 02)

Post by johnnydeep » Thu Nov 02, 2023 9:13 pm

Chris Peterson wrote: Thu Nov 02, 2023 6:53 pm
Roy wrote: Thu Nov 02, 2023 5:12 pm Ann’s explication seems to highlight several galaxy/cluster principal organization modes. Globe mode, spiral/rotational mode, and disorganized mode. Why is the cosmos organized thusly, as far as we can see?
Keep in mind that we're not seeing static structures, but bodies in complex orbits around each other. How they appear to our brief snapshot view is not representative of any real structure. It's transient. Come back in a few hundred million years and these clusters will look very different, with very different apparent structures.
Do elliptical, spiral and irregular galaxies morph into each other over time? Merging spirals can form ellipticals I think, but are there other transformations? Irregulars growing into either spirals or ellipticals?
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Re: APOD: The Fornax Cluster of Galaxies (2023 Nov 02)

Post by johnnydeep » Thu Nov 02, 2023 9:17 pm

Besides the nice galaxies Ann pointed out above, this odd looking "three bead" galaxy caught my eye:

odd looking galaxy in the fornax cluster - three beads.png
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Re: APOD: The Fornax Cluster of Galaxies (2023 Nov 02)

Post by Chris Peterson » Thu Nov 02, 2023 9:23 pm

johnnydeep wrote: Thu Nov 02, 2023 9:13 pm
Chris Peterson wrote: Thu Nov 02, 2023 6:53 pm
Roy wrote: Thu Nov 02, 2023 5:12 pm Ann’s explication seems to highlight several galaxy/cluster principal organization modes. Globe mode, spiral/rotational mode, and disorganized mode. Why is the cosmos organized thusly, as far as we can see?
Keep in mind that we're not seeing static structures, but bodies in complex orbits around each other. How they appear to our brief snapshot view is not representative of any real structure. It's transient. Come back in a few hundred million years and these clusters will look very different, with very different apparent structures.
Do elliptical, spiral and irregular galaxies morph into each other over time? Merging spirals can form ellipticals I think, but are there other transformations? Irregulars growing into either spirals or ellipticals?
There's a lot that isn't known about galaxy formation. But broadly, I don't think anything morphs into a spiral (unless it's a process very early in galaxy formation). It's possible that some non-spiral galaxies formed that way, but when a spiral is tidally disrupted, it commonly becomes an elliptical or irregular galaxy.
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Re: APOD: The Fornax Cluster of Galaxies (2023 Nov 02)

Post by Pastorian » Thu Nov 02, 2023 10:28 pm

johnnydeep wrote: Thu Nov 02, 2023 9:17 pm Besides the nice galaxies Ann pointed out above, this odd looking "three bead" galaxy caught my eye:

odd looking galaxy in the fornax cluster - three beads.png
I browsed the CDS Portal - I'm fairly sure the galaxy you're referring to is NGC 1380, position: 03 36 27.828 -34 58 33.85. The cause of the beaded appearance becomes more clear in this excellent HST image: Another intriguing find from today's thread is the face-on spiral to the 10 o'clock of NGC 1427A in the HST image that Ann posted:
Ann wrote: Thu Nov 02, 2023 6:58 am Another hugely interesting galaxy of the Fornax Cluster is just barely seen in today's APOD, as a tiny arc-shaped blue little thing at the very bottom edge of the APOD, slightly to the right of center. This is NGC 1427A. You can see it a bit better here, at about 9 o'clock:
Browsing the CDS Portal, it appears to be designated as 2MASX J03400430-3536514, and I would expect that it is not a part of the Fornax Cluster. Not sure yet how to determine distances from the data on the portal.

PS: CDS Portal (http://cdsportal.u-strasbg.fr/) is next level, bringing a whole interactive aspect for this armchair astronomer. Glad to have read about it on these boards a while back.

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Re: APOD: The Fornax Cluster of Galaxies (2023 Nov 02)

Post by johnnydeep » Thu Nov 02, 2023 10:56 pm

Pastorian wrote: Thu Nov 02, 2023 10:28 pm
johnnydeep wrote: Thu Nov 02, 2023 9:17 pm Besides the nice galaxies Ann pointed out above, this odd looking "three bead" galaxy caught my eye:

odd looking galaxy in the fornax cluster - three beads.png
I browsed the CDS Portal - I'm fairly sure the galaxy you're referring to is NGC 1380, position: 03 36 27.828 -34 58 33.85. The cause of the beaded appearance becomes more clear in this excellent HST image:
Yup, that's it alright, but it looks completely different in that center region closeup!
Another intriguing find from today's thread is the face-on spiral to the 10 o'clock of NGC 1427A in the HST image that Ann posted:

'''

Browsing the CDS Portal, it appears to be designated as 2MASX J03400430-3536514, and I would expect that it is not a part of the Fornax Cluster. Not sure yet how to determine distances from the data on the portal.
Yup, that's a nice one!
PS: CDS Portal (http://cdsportal.u-strasbg.fr/) is next level, bringing a whole interactive aspect for this armchair astronomer. Glad to have read about it on these boards a while back.
Nice. I'll save a link.

2MASX J03400430-3536514 at cdsportal.jpg
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Re: APOD: The Fornax Cluster of Galaxies (2023 Nov 02)

Post by orin stepanek » Thu Nov 02, 2023 11:35 pm

ClusterFornax1024.jpg
NGC1365; What a beauty! Upper Right!
Andromeda_on_the_rocksFattinnanzi950.jpg
Not seeing Andromeda here!
STScI-01GS812ZSR75EFTHTY2TP8YA5F.png
Ah! NGC1365 from JWST; so beautiful
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Re: APOD: The Fornax Cluster of Galaxies (2023 Nov 02)

Post by Ann » Fri Nov 03, 2023 5:59 am

johnnydeep wrote: Thu Nov 02, 2023 9:17 pm Besides the nice galaxies Ann pointed out above, this odd looking "three bead" galaxy caught my eye:

I'll reserve judgement on whether or not the "three bead galaxy" really is NGC 1380. Admittedly it could be, although it does look quite different in the picture posted by Pastorian. It is true that some lenticular galaxies, which otherwise lack dust or star formation, may have a small dust ring near their cores.


But often, when we see a "three-bead" galaxy, we are seeing what I would call a former barred spiral galaxy that has lost its ability to form new stars. All its stars have grown old and yellow, and the galaxy has lost its spiral arms and its dust lanes.

But a three-bead galaxy may have started out like this:

NGC 1300 ESA Hubble annotated.png
Galaxy NGC 1300. You can see its core, its bar and its bar-end enhancement.
These are found where the bar-ends meet the spiral arms. They typically
contain a high amount of star formation.
When the galaxy grows old, the bar-end enhancements may remain bright.

NGC 936 VLT ESO annotated.png
We can still see the bar and the bar-end enhancements.

I'd say that NGC 936 is a good example of a real three-bead galaxy.

Ann
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Re: APOD: The Fornax Cluster of Galaxies (2023 Nov 02)

Post by Ann » Fri Nov 03, 2023 6:46 am

orin stepanek wrote: Thu Nov 02, 2023 11:35 pm
NGC1365; What a beauty! Upper Right!

Not seeing Andromeda here!

Here it is, Orin! :D

APOD 27 September 2013 annotated.png

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Re: APOD: The Fornax Cluster of Galaxies (2023 Nov 02)

Post by johnnydeep » Fri Nov 03, 2023 1:47 pm

Chris Peterson wrote: Thu Nov 02, 2023 9:23 pm
johnnydeep wrote: Thu Nov 02, 2023 9:13 pm
Chris Peterson wrote: Thu Nov 02, 2023 6:53 pm

Keep in mind that we're not seeing static structures, but bodies in complex orbits around each other. How they appear to our brief snapshot view is not representative of any real structure. It's transient. Come back in a few hundred million years and these clusters will look very different, with very different apparent structures.
Do elliptical, spiral and irregular galaxies morph into each other over time? Merging spirals can form ellipticals I think, but are there other transformations? Irregulars growing into either spirals or ellipticals?
There's a lot that isn't known about galaxy formation. But broadly, I don't think anything morphs into a spiral (unless it's a process very early in galaxy formation). It's possible that some non-spiral galaxies formed that way, but when a spiral is tidally disrupted, it commonly becomes an elliptical or irregular galaxy.
Which way?
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Re: APOD: The Fornax Cluster of Galaxies (2023 Nov 02)

Post by Chris Peterson » Fri Nov 03, 2023 1:50 pm

johnnydeep wrote: Fri Nov 03, 2023 1:47 pm
Chris Peterson wrote: Thu Nov 02, 2023 9:23 pm
johnnydeep wrote: Thu Nov 02, 2023 9:13 pm

Do elliptical, spiral and irregular galaxies morph into each other over time? Merging spirals can form ellipticals I think, but are there other transformations? Irregulars growing into either spirals or ellipticals?
There's a lot that isn't known about galaxy formation. But broadly, I don't think anything morphs into a spiral (unless it's a process very early in galaxy formation). It's possible that some non-spiral galaxies formed that way, but when a spiral is tidally disrupted, it commonly becomes an elliptical or irregular galaxy.
Which way?
The way they are... as ellipticals or irregulars.
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Re: APOD: The Fornax Cluster of Galaxies (2023 Nov 02)

Post by johnnydeep » Fri Nov 03, 2023 1:58 pm

Chris Peterson wrote: Fri Nov 03, 2023 1:50 pm
johnnydeep wrote: Fri Nov 03, 2023 1:47 pm
Chris Peterson wrote: Thu Nov 02, 2023 9:23 pm
There's a lot that isn't known about galaxy formation. But broadly, I don't think anything morphs into a spiral (unless it's a process very early in galaxy formation). It's possible that some non-spiral galaxies formed that way, but when a spiral is tidally disrupted, it commonly becomes an elliptical or irregular galaxy.
Which way?
The way they are... as ellipticals or irregulars.
Ah - "Formed that way, not "formed that way"! D'oh!
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Re: APOD: The Fornax Cluster of Galaxies (2023 Nov 02)

Post by Chris Peterson » Fri Nov 03, 2023 2:41 pm

johnnydeep wrote: Fri Nov 03, 2023 1:58 pm
Chris Peterson wrote: Fri Nov 03, 2023 1:50 pm
johnnydeep wrote: Fri Nov 03, 2023 1:47 pm

Which way?
The way they are... as ellipticals or irregulars.
Ah - "Formed that way, not "formed that way"! D'oh!
English as she is spoke.
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Re: APOD: The Fornax Cluster of Galaxies (2023 Nov 02)

Post by johnnydeep » Fri Nov 03, 2023 3:14 pm

Chris Peterson wrote: Fri Nov 03, 2023 2:41 pm
johnnydeep wrote: Fri Nov 03, 2023 1:58 pm
Chris Peterson wrote: Fri Nov 03, 2023 1:50 pm
The way they are... as ellipticals or irregulars.
Ah - "Formed that way, not "formed that way"! D'oh!
English as she is spoken.
:ssmile:
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Re: APOD: The Fornax Cluster of Galaxies (2023 Nov 02)

Post by Chris Peterson » Fri Nov 03, 2023 3:23 pm

johnnydeep wrote: Fri Nov 03, 2023 3:14 pm
Chris Peterson wrote: Fri Nov 03, 2023 2:41 pm
johnnydeep wrote: Fri Nov 03, 2023 1:58 pm

Ah - "Formed that way, not "formed that way"! D'oh!
English as she is spoken.
:ssmile:
https://en.wikipedia.org/wiki/English_as_She_Is_Spoke
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Re: APOD: The Fornax Cluster of Galaxies (2023 Nov 02)

Post by johnnydeep » Fri Nov 03, 2023 3:41 pm

Chris Peterson wrote: Fri Nov 03, 2023 3:23 pm
johnnydeep wrote: Fri Nov 03, 2023 3:14 pm
Chris Peterson wrote: Fri Nov 03, 2023 2:41 pm

English as she is spoken.
:ssmile:
https://en.wikipedia.org/wiki/English_as_She_Is_Spoke
Thanks. I didn't get the reference.
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Re: APOD: The Fornax Cluster of Galaxies (2023 Nov 02)

Post by AVAO » Fri Nov 03, 2023 8:45 pm

johnnydeep wrote: Thu Nov 02, 2023 10:56 pm
Pastorian wrote: Thu Nov 02, 2023 10:28 pm
johnnydeep wrote: Thu Nov 02, 2023 9:17 pm Besides the nice galaxies Ann pointed out above, this odd looking "three bead" galaxy caught my eye:

odd looking galaxy in the fornax cluster - three beads.png
I browsed the CDS Portal - I'm fairly sure the galaxy you're referring to is NGC 1380, position: 03 36 27.828 -34 58 33.85. The cause of the beaded appearance becomes more clear in this excellent HST image:
Yup, that's it alright, but it looks completely different in that center region closeup!
The core region is very small compared to the galaxy's halo. jac berne (flickr)

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Re: APOD: The Fornax Cluster of Galaxies (2023 Nov 02)

Post by Ann » Sat Nov 04, 2023 5:52 am

AVAO wrote: Fri Nov 03, 2023 8:45 pm
johnnydeep wrote: Thu Nov 02, 2023 10:56 pm
Pastorian wrote: Thu Nov 02, 2023 10:28 pm

I browsed the CDS Portal - I'm fairly sure the galaxy you're referring to is NGC 1380, position: 03 36 27.828 -34 58 33.85. The cause of the beaded appearance becomes more clear in this excellent HST image:
Yup, that's it alright, but it looks completely different in that center region closeup!
The core region is very small compared to the galaxy's halo. jac berne (flickr)

Thanks, Jac! So NGC 1380 is another NGC 4526 after all!


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Re: APOD: The Fornax Cluster of Galaxies (2023 Nov 02)

Post by johnnydeep » Sat Nov 04, 2023 12:33 pm

Ann wrote: Sat Nov 04, 2023 5:52 am
AVAO wrote: Fri Nov 03, 2023 8:45 pm
johnnydeep wrote: Thu Nov 02, 2023 10:56 pm

Yup, that's it alright, but it looks completely different in that center region closeup!
The core region is very small compared to the galaxy's halo. jac berne (flickr)

Thanks, Jac! So NGC 1380 is another NGC 4526 after all!


Ann
And just to be clear, that diffuse white "fog" of a halo surrounding the galaxy cores in these images is composed of stars, not just gas, correct?
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Re: APOD: The Fornax Cluster of Galaxies (2023 Nov 02)

Post by Ann » Sun Nov 05, 2023 5:51 am

johnnydeep wrote: Sat Nov 04, 2023 12:33 pm
Ann wrote: Sat Nov 04, 2023 5:52 am
AVAO wrote: Fri Nov 03, 2023 8:45 pm

The core region is very small compared to the galaxy's halo. jac berne (flickr)

Thanks, Jac! So NGC 1380 is another NGC 4526 after all!


Ann
And just to be clear, that diffuse white "fog" of a halo surrounding the galaxy cores in these images is composed of stars, not just gas, correct?
Since these images are visible-light images, the white stuff surrounding the galaxy cores are most definitely stars. Because gas doesn't glow at visible wavelengths unless it's being ionized and made to emit light at visible wavelengths. And there is nothing here that could create that sort of large-scale ionization.

There might, for all I know, be a ubiquitous glow of extremely faint hydrogen alpha emission all over and inside this galaxy. But it would be way, way, way too faint to show up here. But it is far, far from certain that there is any appreciable amount of any such hydrogen alpha surrounding these elliptical and lenticular galaxies at all. Take a look at this LRGB + H-alpha picture of Markarian's Chain in the Virgo Cluster:

Virgo Cluster in LRGB and 33 hours of H alpha Jakob Sahner.png
The Virgo Cluster of galaxies in LRGB and 33 hours of H-alpha.
Note the red tendril between disturbed spiral NGC 4438 and elliptical M86.
Credit: Jakob Sahner.

You can see that, apart from the bridge of ionized hydrogen between NGC 4438 and M86, there isn't a lot of visible red gas in the Virgo Cluster. Not in a 33 hours of H-alpha exposure image, at least.


However, there may be million-degree gas surrounding NGC 1380. There exists no Chandra X-ray telescope image showing us NGC 1380, but there is a Chandra X-ray picture of the central massive elliptical galaxy, NGC 1399, and two other elliptical galaxies close to it:


But this million-degree gas is only visible to telescopes like Chandra. So, conclusion, the white stuff we can see in the images you asked about is stars, and stars only.

Ann
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Re: APOD: The Fornax Cluster of Galaxies (2023 Nov 02)

Post by johnnydeep » Sun Nov 05, 2023 2:29 pm

Ann said:
So, conclusion, the white stuff we can see in the images you asked about is stars, and stars only.
Thanks. And yes, I am always amazed by this fact. Stars, stars, oh so many blazing stars!


Or, "My god, it's full of stars!"

Click to play embedded YouTube video.
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Re: APOD: The Fornax Cluster of Galaxies (2023 Nov 02)

Post by johnnydeep » Sun Nov 05, 2023 3:11 pm

Oh, one more question. How far apart do you suppose the stars are in the halo, at, say, the location of the two Xs below?

NGC 1380 in the Fornax Cluster.jpg

And would it be similar to the separation of the stars near the Sun?

stars within 20 lightyears.png
a census of stars withing 20 lightyears.png

PS - why can't I create a picture link to this gif:
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"To B̬̻̋̚o̞̮̚̚l̘̲̀᷾d̫͓᷅ͩḷ̯᷁ͮȳ͙᷊͠ Go......Beyond The F͇̤i̙̖e̤̟l̡͓d͈̹s̙͚ We Know."{ʲₒʰₙNYᵈₑᵉₚ}