APOD: The Colliding Spiral Galaxies of Arp 274 (2023 Jan 23)

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APOD: The Colliding Spiral Galaxies of Arp 274 (2023 Jan 23)

Post by APOD Robot » Mon Jan 23, 2023 5:05 am

Image The Colliding Spiral Galaxies of Arp 274

Explanation: Two galaxies are squaring off in Virgo and here are the latest pictures. When two galaxies collide, the stars that compose them usually do not. This is because galaxies are mostly empty space and, however bright, stars only take up only a small fraction of that space. But during the collision, one galaxy can rip the other apart gravitationally, and dust and gas common to both galaxies does collide. If the two galaxies merge, black holes that likely resided in each galaxy center may eventually merge. Because the distances are so large, the whole thing takes place in slow motion -- over hundreds of millions of years. Besides the two large spiral galaxies, a smaller third galaxy is visible on the far left of the featured image of Arp 274, also known as NGC 5679. Arp 274 spans about 200,000 light years across and lies about 400 million light years away toward the constellation of Virgo.

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Ann
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Re: APOD: The Colliding Spiral Galaxies of Arp 274 (2023 Jan 23)

Post by Ann » Mon Jan 23, 2023 6:43 am

Let's look at what processing does to an astronomical image, by comparing Mehmet Hakan Özsaraç's version of Arp 274 with the original NASA image!


As you can see, Mehmet Hakan Özsaraç has "shed more light" on the galaxies of Arp 274 than the original NASA image. The galaxies look brighter in Özsaraç's image, and we see more of the faint old population in each galaxy, as well as more details in the centers of the two larger galaxies. So in short, we get a more generous slice of galactic helping, with more cream and perhaps a cherry on top! 🍰 :D

But as a Color Commentator, I'm somewhat critical of the pink color of the center of the large spiral in Özsaraç's image. In RGB+Hα pictures of galaxies, like today's APOD, the pink color signals high levels of hydrogen alpha and high levels of star formation. All the little pink dots that follow the spiral arms of the two spirals of Arp 274 are indeed bright pink nebulas whose color is due to hot young stars whose ultraviolet light ionizes the birth clouds of these stars and makes clouds glow pink.

But we don't normally see galaxies with bright pink centers. It happens, of course, like in NGC 4194. But almost all reasonably large and well-behaved spiral galaxies have yellow centers.


So I have some issues with the pink color of the center of the largest galaxy of Arp 274, which suggests the presence of an explosive starforming event that isn't there.

Then again, the galaxies of Arp 274 will merge in the future. So if the center of the largest spiral of Arp 274 looks like the center of NGC 1512 today (or, in the words of Tom Lehrer, and with a nod to DL MARTIN, as far as the news has come to Harvard), in the future the center of the merger product of these three galaxies may well look like NGC 4194.

Ann
Last edited by Ann on Tue Jan 24, 2023 5:31 am, edited 1 time in total.
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Re: APOD: The Colliding Spiral Galaxies of Arp 274 (2023 Jan 23)

Post by ill » Mon Jan 23, 2023 11:53 am

How bright would the night sky be for people living on NGC 5679 if facing those two merging monsters

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Re: APOD: The Colliding Spiral Galaxies of Arp 274 (2023 Jan 23)

Post by Cousin Ricky » Mon Jan 23, 2023 1:10 pm

Ann wrote: Mon Jan 23, 2023 6:43 am But as a Color Commentator, I'm somewhat critical of the pink color of the center of the large spiral in Özsaraç's image. In RGB+Hα pictures of galaxies, like today's APOD, the pink color signals high level of hydrogen alpha and high levels of star formation. All the little pink dots that follow the spiral arms of the two spirals of Arp 274 are indeed bright pink nebulas whose color is due to hot young stars whose ultraviolet light ionizes the birth clouds of these stars and makes clouds glow pink.
The center galaxy has a higher redshift than the other two. Could this explain it?

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Re: APOD: The Colliding Spiral Galaxies of Arp 274 (2023 Jan 23)

Post by Chris Peterson » Mon Jan 23, 2023 2:01 pm

ill wrote: Mon Jan 23, 2023 11:53 am How bright would the night sky be for people living on NGC 5679 if facing those two merging monsters
The brightness would be similar to how the Milky Way appears to us in our night sky. Depending on distance, it would just be more spread out, covering more sky.
Chris

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Re: APOD: The Colliding Spiral Galaxies of Arp 274 (2023 Jan 23)

Post by Chris Peterson » Mon Jan 23, 2023 2:03 pm

Cousin Ricky wrote: Mon Jan 23, 2023 1:10 pm
Ann wrote: Mon Jan 23, 2023 6:43 am But as a Color Commentator, I'm somewhat critical of the pink color of the center of the large spiral in Özsaraç's image. In RGB+Hα pictures of galaxies, like today's APOD, the pink color signals high level of hydrogen alpha and high levels of star formation. All the little pink dots that follow the spiral arms of the two spirals of Arp 274 are indeed bright pink nebulas whose color is due to hot young stars whose ultraviolet light ionizes the birth clouds of these stars and makes clouds glow pink.
The center galaxy has a higher redshift than the other two. Could this explain it?
The redshifts involved are too small to visually impact the color.
Chris

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thecolomb77

Re: APOD: The Colliding Spiral Galaxies of Arp 274 (2023 Jan 23)

Post by thecolomb77 » Mon Jan 23, 2023 2:34 pm

Ann wrote: Mon Jan 23, 2023 6:43 am Let's look at what processing does to an astronomical image, by comparing Mehmet Hakan Özsaraç's version of Arp 274 with the original NASA image!


As you can see, Mehmet Hakan Özsaraç has "shed more light" on the galaxies of Arp 274 than the original NASA image. The galaxies look brighter in Özsaraç's image, and we see more of the faint old population in each galaxy, as well as more details in the centers of the two larger galaxies. So in short, we get a more generous slice of galactic helping, with more cream and perhaps a cherry on top! 🍰 :D

But as a Color Commentator, I'm somewhat critical of the pink color of the center of the large spiral in Özsaraç's image. In RGB+Hα pictures of galaxies, like today's APOD, the pink color signals high level of hydrogen alpha and high levels of star formation. All the little pink dots that follow the spiral arms of the two spirals of Arp 274 are indeed bright pink nebulas whose color is due to hot young stars whose ultraviolet light ionizes the birth clouds of these stars and makes clouds glow pink.

But we don't normally see galaxies with bright pink centers. It happens, of course, like in NGC 4194. But almost all reasonably large and well-behaved spiral galaxies have yellow centers.


So I have some issues with the pink color of the center of the largest galaxy of Arp 274, which suggests the presence of an explosive starforming event that isn't there.

Then again, the galaxies of Arp 274 will merge in the future. So if the center of the largest spiral of Arp 274 looks like the center of NGC 1512 today (or, in the words of Tom Lehrer, and with a nod to DL MARTIN, as far as the news has come to Harvard), in the future the center of the merger product of these three galaxies may well look like NGC 4194.

Ann
Hi Ann,
the RGB of this image is completely unbalanced.
You can see it from the histogram. You can see it just looking at the image using a calibrated device where you'll perceive a very strong pink/red dominant.
In addition to this point, there's a too strong usage of denoise that can't allow anymore to distinguish what are real details and what are artifacts.

IMHO, the featured image is steps below the image processed by the Heritage Team.

Best regards.

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Re: APOD: The Colliding Spiral Galaxies of Arp 274 (2023 Jan 23)

Post by orin stepanek » Mon Jan 23, 2023 4:20 pm

Arp274_HubbleOzsarac_1080.jpg
Beautiful; photo of galaxy merger! I hope some future family
member gets to see in reality! 8-)
ac21cdb998ded047b5d7e0e2280e0d48.jpg
Kitty; you need to take a nap! :mrgreen:
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Re: APOD: The Colliding Spiral Galaxies of Arp 274 (2023 Jan 23)

Post by Dardanelles » Mon Jan 23, 2023 4:41 pm

So is there any advantage for beings living on a planet orbiting a star of being in a galaxy? If our galaxy was in the midst of colliding with another, would there be any important difference from life in the non-colliding milky way?

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Re: APOD: The Colliding Spiral Galaxies of Arp 274 (2023 Jan 23)

Post by Chris Peterson » Mon Jan 23, 2023 5:02 pm

Dardanelles wrote: Mon Jan 23, 2023 4:41 pm So is there any advantage for beings living on a planet orbiting a star of being in a galaxy? If our galaxy was in the midst of colliding with another, would there be any important difference from life in the non-colliding milky way?
The problem is that if a couple of stars come within a light year or two of each other, their planetary systems can be perturbed. Which is why there are probably no planets with complex life in dense parts of galaxies, and why galaxy collisions probably disrupt millions of planetary systems in ways that would be catastrophic for any with life on them. The best place to be for long term stability is either outside of a galaxy completely, or in the lower density parts of galactic arms.
Chris

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Re: APOD: The Colliding Spiral Galaxies of Arp 274 (2023 Jan 23)

Post by Judy » Mon Jan 23, 2023 5:29 pm

Is the smaller galaxy on the left just originally not a spiral, or has it been deformed by the middle galaxy? I see a bot of a trail from the middle galaxy toward the small blobby one. ("Blobby" is a technical term meaning I don't have a word for that shape.)

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Re: APOD: The Colliding Spiral Galaxies of Arp 274 (2023 Jan 23)

Post by Ann » Mon Jan 23, 2023 7:18 pm

Judy wrote: Mon Jan 23, 2023 5:29 pm Is the smaller galaxy on the left just originally not a spiral, or has it been deformed by the middle galaxy? I see a bot of a trail from the middle galaxy toward the small blobby one. ("Blobby" is a technical term meaning I don't have a word for that shape.)
I don't think that anything is known about the original shape of the small galaxy at left in Arp 274.

It is a small galaxy, and small galaxies are less often spirals. But it happens. The Large Magellanic Cloud, whose diameter is only 14,000 light-years (way smaller than the diameter of the Milky Way, whose diameter is some 100,000 ly) is believed to have originally been a spiral.


The Large Magellanic Cloud is not considered to be a spiral galaxy, but it does display some spiral-like features. It very clearly has a bar (the long straight elongated yellowish feature) and it has bar-end enhancements that look like the beginnings of spiral arms. Compare the LMC with NGC 1073, which is considered a proper barred spiral galaxy:


You can see that there are similarities between the LMC and NGC 1073, but there are also clear differences. NGC 1073 has much clearer and much better defined spiral features than the LMC. Another difference is that NGC 1073 is much bigger than the LMC, some 80,000 ly in diameter vs. only some 14,000 ly for the LMC.

I think it is possible that the smallest galaxy of Arp 274 is (or used to be) similar to the LMC.

Ann
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Re: APOD: The Colliding Spiral Galaxies of Arp 274 (2023 Jan 23)

Post by AVAO » Mon Jan 23, 2023 10:02 pm

Judy wrote: Mon Jan 23, 2023 5:29 pm Is the smaller galaxy on the left just originally not a spiral, or has it been deformed by the middle galaxy? I see a bot of a trail from the middle galaxy toward the small blobby one. ("Blobby" is a technical term meaning I don't have a word for that shape.)
I like this little jellyfish galaxy too :content:

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Re: APOD: The Colliding Spiral Galaxies of Arp 274 (2023 Jan 23)

Post by So much violence » Mon Jan 23, 2023 10:51 pm

"Collide", then "rip apart". Boo. Is the universe really so mean? I see a billion-year-long high-five, at long last after more eons just getting there. Then they make lotsa stars, just one last time, two old galaxies long past the Cosmic High Noon when making stars was fashionable. OK, they lose the Grand Design and all that, but then they become One.

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Re: APOD: The Colliding Spiral Galaxies of Arp 274 (2023 Jan 23)

Post by Fred the Cat » Tue Jan 24, 2023 2:51 am

A flexible mind might see this trio as pig-headed. I guess the gravity of the situation can fool you. :ssmile:
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Re: APOD: The Colliding Spiral Galaxies of Arp 274 (2023 Jan 23)

Post by Ann » Tue Jan 24, 2023 5:46 am

So much violence wrote: Mon Jan 23, 2023 10:51 pm "Collide", then "rip apart". Boo. Is the universe really so mean? I see a billion-year-long high-five, at long last after more eons just getting there. Then they make lotsa stars, just one last time, two old galaxies long past the Cosmic High Noon when making stars was fashionable. OK, they lose the Grand Design and all that, but then they become One.
That's so funny! :lol2: :clap:

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