APOD: The Eyes in Markarian's Galaxy... (2024 Mar 20)

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APOD: The Eyes in Markarian's Galaxy... (2024 Mar 20)

Post by APOD Robot » Wed Mar 20, 2024 4:06 am

Image The Eyes in Markarian's Galaxy Chain

Explanation: Across the heart of the Virgo Galaxy Cluster lies a string of galaxies known as Markarian's Chain. Prominent in Markarian's Chain are these two interacting galaxies, NGC 4438 (left) and NGC 4435 - also known as The Eyes. About 50 million light-years away, the two galaxies appear to be about 100,000 light-years apart in this sharp close-up, but have likely approached to within an estimated 16,000 light-years of each other in their cosmic past. Gravitational tides from the close encounter have ripped away at their stars, gas, and dust. The more massive NGC 4438 managed to hold on to much of the material torn out in the collision, while material from the smaller NGC 4435 was more easily lost. The remarkably deep image of this crowded region of the universe also includes many more distant background galaxies.

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Re: APOD: The Eyes in Markarian's Galaxy... (2024 Mar 20)

Post by Ann » Wed Mar 20, 2024 7:45 am

Yes, I like it! :D The colors are so deep and rich that they almost remind me of a 19th century landscape painting!


So yes, I could almost frame this image and put it on my wall! I must say, however, that the resolution of the picture isn't that great. Because of that, it's not always immediately obvious if those little lights in the background are galaxies or stars.

Compare the resolution of the background objects in the APOD with the resolution of the background objects in this Hubble image (of course, it's never fair to compare an amateur image with picture taken by Hubble!):


But you know what? The center of the smaller galaxy, NGC 4435, is so much better resolved in the APOD than it is in the Hubble image! Woohoo! Way to go, Mike Selby! :thumb_up:

(And look how "dead" the Hubble image colors are.)


But the APOD made me pay attention to something in NGC 4438 that I've never paid attention before:

APOD 20 March 2024 annotated detail.png

That fuzzy blob of light sure looks like a small galaxy superimposed on NGC 4438, or else it looks like a Virgo Cluster galaxy seen right behind NGC 4438. Cool!


One thing that Hubble has revealed, that is not visible in the APOD, is that the black hole of NGC 4438 is blowing bubbles:



Like a kid chewing gum! Fancy that!

Let's change the subject a little.
APOD Robot wrote about NGC 4438 and NGC 4435:
The more massive NGC 4438 managed to hold on to much of the material torn out in the collision, while material from the smaller NGC 4435 was more easily lost.

I think the gaseous material of NGC 4435 may have been lost even before its close encounter with NGC 4438. Members of fairly dense galaxy clusters easily lose their gas over time, so NGC 4435 may well have been "barren" before it almost collided with NGC 4438. Just look at the central feature of the Virgo Cluster known as Markarian's Chain, which NGC 4435/NGC 4438 are members of. Most galaxies in Markarian's Chain are either elliptical galaxies or lenticulars, both of which are poor in gas.


And NGC 4438, which has held on to some of its gas, is in the process of losing it:

A deep new image of part of the Virgo cluster has revealed monumental tendrils of ionized hydrogen gas 400,000 light-years long connecting the elliptical galaxy M86 (right) and the disturbed spiral galaxy NGC 4438 (left). Taken with the wide-field Mosaic imager on the National Science Foundation’s Mayall 4-meter telescope at Kitt Peak National Observatory using a filter that reveals the light from Hydrogen-alpha emission, the image and related spectroscopic measurements of the filament provide striking evidence of a previously unsuspected high-speed collision between the two galaxies. The red filaments in the image show H-alpha emission with low velocities (similar to the velocities of the two colliding galaxies M86 and NGC 4438). The green filaments seen near the edge-on spiral galaxy in the lower right (NGC 4388) show H-alpha emission with much higher velocities, suggesting that this galaxy might not be related to M86. Credit: Tomer Tal and Jeffrey Kenney/Yale University and NOAO/AURA/NSF


Isn't Mark Hanson's picture of M86 and NGC 4438 gorgeous? It seems to suggest that the entire giant elliptical galaxy M86 is aglow with red hydrogen alpha light. I'm not sure that this effect is real, because I haven't seen it in any other pictures, but clearly gas is streaming from NGC 4438 onto elliptical galaxy M86.

So eventually, NGC 4438 will be as barren and devoid of gas as its hapless partner, NGC 4435. But for now, let's enjoy the funny shape of this cosmic Eye in the Sky!

Ann
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Re: APOD: The Eyes in Markarian's Galaxy... (2024 Mar 20)

Post by AVAO » Wed Mar 20, 2024 6:57 pm

ThanX Ann

Great comments.

If you ask me for my personal opinion, I do not live in the "bubble model". To me, we clearly see loop-like filament strands and not bubbles that were created from a pressure wave. (The same applies to the radio bubble model of our own milky way galaxy.)

Jac

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Re: APOD: The Eyes in Markarian's Galaxy... (2024 Mar 20)

Post by Roy » Wed Mar 20, 2024 9:30 pm

It appears to me M86 has ejected NGC4438. NGC4435 appears to be in the background. The “colliding galaxies” mantra is overused, as is the word “likely”.

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Re: APOD: The Eyes in Markarian's Galaxy... (2024 Mar 20)

Post by johnnydeep » Wed Mar 20, 2024 10:15 pm

Roy wrote: Wed Mar 20, 2024 9:30 pm It appears to me M86 has ejected NGC4438. NGC4435 appears to be in the background. The “colliding galaxies” mantra is overused, as is the word “likely”.
I don't believe there is any known mechanism for a galaxy to "eject" or spawn another galaxy all on its own.
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Re: APOD: The Eyes in Markarian's Galaxy... (2024 Mar 20)

Post by Chris Peterson » Thu Mar 21, 2024 12:39 am

johnnydeep wrote: Wed Mar 20, 2024 10:15 pm
Roy wrote: Wed Mar 20, 2024 9:30 pm It appears to me M86 has ejected NGC4438. NGC4435 appears to be in the background. The “colliding galaxies” mantra is overused, as is the word “likely”.
I don't believe there is any known mechanism for a galaxy to "eject" or spawn another galaxy all on its own.
Correct. Not only is there no known mechanism, there's not even a remotely hypothesized one. Such a thing would violate well understood and accepted laws of nature. On the other hand, it is completely understandable how galaxies interact gravitationally, including collisions when their paths intersect.
Chris

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Re: APOD: The Eyes in Markarian's Galaxy... (2024 Mar 20)

Post by johnnydeep » Thu Mar 21, 2024 1:19 pm

Chris Peterson wrote: Thu Mar 21, 2024 12:39 am
johnnydeep wrote: Wed Mar 20, 2024 10:15 pm
Roy wrote: Wed Mar 20, 2024 9:30 pm It appears to me M86 has ejected NGC4438. NGC4435 appears to be in the background. The “colliding galaxies” mantra is overused, as is the word “likely”.
I don't believe there is any known mechanism for a galaxy to "eject" or spawn another galaxy all on its own.
Correct. Not only is there no known mechanism, there's not even a remotely hypothesized one. Such a thing would violate well understood and accepted laws of nature. On the other hand, it is completely understandable how galaxies interact gravitationally, including collisions when their paths intersect.
Thanks. I had first not included the word "known" in my post, but decided to be a little less certain about it than you. However, "ejecting" a child galaxy would at least involve a prodigious amount of energy. Is a quasar even that profligate? ...Perhaps? Quasars are powered by billion solar mass black holes at the centers of galaxies, and the brightest one discovered so far has 4 trillion times the Sun's output:
https://en.wikipedia.org/wiki/Quasar#Properties:~:text=is%2C%20therefore%2C%20about-,4%C2%A0trillion,-(4%C3%9710 wrote: Although quasars appear faint when viewed from Earth, they are visible from extreme distances, being the most luminous objects in the known universe. The brightest quasar in the sky is 3C 273 in the constellation of Virgo. It has an average apparent magnitude of 12.8 (bright enough to be seen through a medium-size amateur telescope), but it has an absolute magnitude of −26.7.[55] From a distance of about 33 light-years, this object would shine in the sky about as brightly as the Sun. This quasar's luminosity is, therefore, about 4 trillion (4×1012) times that of the Sun, or about 100 times that of the total light of giant galaxies like the Milky Way.[55] This assumes that the quasar is radiating energy in all directions, but the active galactic nucleus is believed to be radiating preferentially in the direction of its jet. In a universe containing hundreds of billions of galaxies, most of which had active nuclei billions of years ago but only seen today, it is statistically certain that thousands of energy jets should be pointed toward the Earth, some more directly than others. In many cases it is likely that the brighter the quasar, the more directly its jet is aimed at the Earth. Such quasars are called blazars.
So, maybe the energy could be available to do it, but any mechanism as you say, for ejecting several billion solar masses of stars in galaxy formation intact, would not be at all plausible. 😊
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Re: APOD: The Eyes in Markarian's Galaxy... (2024 Mar 20)

Post by Chris Peterson » Thu Mar 21, 2024 1:27 pm

johnnydeep wrote: Thu Mar 21, 2024 1:19 pm
Chris Peterson wrote: Thu Mar 21, 2024 12:39 am
johnnydeep wrote: Wed Mar 20, 2024 10:15 pm

I don't believe there is any known mechanism for a galaxy to "eject" or spawn another galaxy all on its own.
Correct. Not only is there no known mechanism, there's not even a remotely hypothesized one. Such a thing would violate well understood and accepted laws of nature. On the other hand, it is completely understandable how galaxies interact gravitationally, including collisions when their paths intersect.
Thanks. I had first not included the word "known" in my post, but decided to be a little less certain about it than you. However, "ejecting" a child galaxy would at least involve a prodigious amount of energy. Is a quasar even that profligate? ...Perhaps? Quasars are powered by billion solar mass black holes at the centers of galaxies, and the brightest one discovered so far has 4 trillion times the Sun's output:
https://en.wikipedia.org/wiki/Quasar#Properties:~:text=is%2C%20therefore%2C%20about-,4%C2%A0trillion,-(4%C3%9710 wrote: Although quasars appear faint when viewed from Earth, they are visible from extreme distances, being the most luminous objects in the known universe. The brightest quasar in the sky is 3C 273 in the constellation of Virgo. It has an average apparent magnitude of 12.8 (bright enough to be seen through a medium-size amateur telescope), but it has an absolute magnitude of −26.7.[55] From a distance of about 33 light-years, this object would shine in the sky about as brightly as the Sun. This quasar's luminosity is, therefore, about 4 trillion (4×1012) times that of the Sun, or about 100 times that of the total light of giant galaxies like the Milky Way.[55] This assumes that the quasar is radiating energy in all directions, but the active galactic nucleus is believed to be radiating preferentially in the direction of its jet. In a universe containing hundreds of billions of galaxies, most of which had active nuclei billions of years ago but only seen today, it is statistically certain that thousands of energy jets should be pointed toward the Earth, some more directly than others. In many cases it is likely that the brighter the quasar, the more directly its jet is aimed at the Earth. Such quasars are called blazars.
So, maybe the energy could be available to do it, but any mechanism as you say, for ejecting several billion solar masses of stars in galaxy formation intact, would not be at all plausible. 😊
Yeah. You'd expect just a big clump or stream of stars. Not some Mini Me version of the "parent".
Chris

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