APOD: Stripping ESO 137-001 (2018 Aug 25)

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APOD: Stripping ESO 137-001 (2018 Aug 25)

Post by APOD Robot » Sat Aug 25, 2018 4:06 am

Image Stripping ESO 137-001

Explanation: Spiral galaxy ESO 137-001 hurtles through massive galaxy cluster Abell 3627 some 220 million light years away. The distant galaxy is seen in this colorful Hubble/Chandra composite image through a foreground of the Milky Way's stars toward the southern constellation Triangulum Australe. As the spiral speeds along at nearly 7 million kilometers per hour, its gas and dust are stripped away when ram pressure with the cluster's own hot, tenuous intracluster medium overcomes the galaxy's gravity. Evident in Hubble's near visible light data, bright star clusters have formed in the stripped material along the short, trailing blue streaks. Chandra's X-ray data shows off the enormous extent of the heated, stripped gas as diffuse, darker blue trails stretching over 400,000 light-years toward the bottom right. The significant loss of dust and gas will make new star formation difficult for this galaxy. A yellowish elliptical galaxy, lacking in star forming dust and gas, is just to the right of ESO 137-001 in the frame.

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Re: APOD: Stripping ESO 137-001 (2018 Aug 25)

Post by Ann » Sat Aug 25, 2018 4:40 am

This APOD is a golden oldie, I think. The image is hugely interesting and sheds light on the fact that galaxies in populous galaxy clusters typically display little to no star formation. Their starmaking material has been spread and scattered in the intergalactic medium, instead of staying inside the galaxies where it can be used to make more stars.

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Re: APOD: Stripping ESO 137-001 (2018 Aug 25)

Post by heehaw » Sat Aug 25, 2018 9:32 am

I remember seeing a similar photo of, I think, another galaxy. The thing that impresses me most about this is seeing star formation in the stripped material. These are stars that formed in the stripped material AFTER the material was stripped. Now I think that the question of exactly how and why star formation occurs in galaxies is still open: density, pressure, whatever factors. This (or these) stripped-material star-forming regions are dramatically different from traditional regions of star formation inside galaxies. I'd like to hear some discussion on this, and on what it means!

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Re: APOD: Stripping ESO 137-001 (2018 Aug 25)

Post by Ann » Sat Aug 25, 2018 11:47 am

heehaw wrote:
Sat Aug 25, 2018 9:32 am
I remember seeing a similar photo of, I think, another galaxy. The thing that impresses me most about this is seeing star formation in the stripped material. These are stars that formed in the stripped material AFTER the material was stripped. Now I think that the question of exactly how and why star formation occurs in galaxies is still open: density, pressure, whatever factors. This (or these) stripped-material star-forming regions are dramatically different from traditional regions of star formation inside galaxies. I'd like to hear some discussion on this, and on what it means!

Obviously stars are forming in chains in the gassy tail left by ESO 137-001, and my amateur understanding suggests to me that the reason for the chain-like structures might be that gas is leaving this galaxy almost like heavy rainfall. Heavy rain can sometimes fall as long "chains" of water. In the picture at left, it would seem that the chains are formed when the rain hits the car. It may be the "bumpiness" of the car that turns the relatively smooth and evenly distributed rain into chains of water. Slightly similar chains may form as gas leaves a galaxy and hits concentrations of objects in the galaxy, for example star clusters and thick dust clouds.




















In the "chains" of gas (and, presumably, dust) leaving ESO 137-001, temperatures may fall and ideal conditions for star formation may be created. It is known from the Milky Way that star formation often takes place in elongated dusty tendrils.

As you can see in the picture at left, the serpentine cosmic tendril known as "The Snake" is hatching a massive star in its belly and a smaller one in its snout. (Do visit the page where I found the picture, because there are more images there and you can find more facts.) My point, however, is that if stars can form in dusty tendrils in the Milky Way, why shouldn't stars be able to form in long chains of gas and dust that have been pushed out of ESO 137-001?

If you check out today's APOD, you can see that the chains of stars only stretch so far below the disk of ESO-137-001. The longest chains seem to be about equal in length to the diameter of the visible disk of the galaxy. Note, in the APOD, that the longest chains of new stars emanate from the rightmost part of the galaxy, where Chandra didn't detect any really strong X-ray signals. My interpretation is that these chains are the oldest, and that the gas in this part of the galaxy may already be mostly used up.

The Chandra X-ray data extend far beyond the chains of new stars. I take that to mean that at this distance from the galaxy, any dusty chains have been disintegrated and turned into a hot smooth soup of turbulent gas. This is an environment that is very hostile to star formation.





Dwarf galaxies forming in the southern tidal tail
of colliding galaxies NGC 4038 and 4039.
Source: https://www.cv.nrao.edu/~jhibbard/n4038 ... 038uv.html




















What will happen to the newly hatched star clusters forming from the chains of gas and dust being stripped from ESO 137-001? My guess is that they will form tiny dwarf galaxies, and then these dwarf galaxies will age, fade, disintegrate and disappear. In the end, what remains may be a number of old red stars floating freely in the intergalactic medium of galaxy cluster Abell 3627.

Dwarf galaxies are formed by other means too, not just through "ram stripping" as is the case in today's APOD. Take a look at the picture at left of star clusters forming in the longest tidal tail of the Antennae, the colliding galaxies NGC 4038 and 4039. Gas has been flung out in a long tidal stream from the gas-rich NGC 4038, and the gas has kept flowing out until it hit a bump of some sort, perhaps an intergalactic dust cloud, that stopped the outflowing gas in its tracks. Now the stalled gas has been concentrated and is forming quite a lot of new stars. The new star clusters will turn into dwarf galaxies (in fact they have already done so), and then they will fade over time. They may not necessarily disintegrate, since they don't sit in a massive cluster where tidal forces are pulling at them from all directions.

But they will become very faint in the end.

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Re: APOD: Stripping ESO 137-001 (2018 Aug 25)

Post by neufer » Sat Aug 25, 2018 12:31 pm

Click to play embedded YouTube video.
APOD Robot wrote:
Sat Aug 25, 2018 4:06 am

Explanation: Spiral galaxy ESO 137-001 hurtles through massive galaxy cluster Abell 3627. As the spiral speeds along at nearly 0.65% the speed of light, its gas and dust are stripped away when ram pressure with the cluster's own hot, tenuous intracluster medium overcomes the galaxy's gravity. Evident in Hubble's near visible light data, bright star clusters have formed in the stripped material along the short, trailing blue streaks. Chandra's X-ray data shows off the enormous extent of the heated, stripped gas as diffuse, darker blue trails stretching over 400,000 light-years. The significant loss of dust and gas will make new star formation difficult for this galaxy.
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Re: APOD: Stripping ESO 137-001 (2018 Aug 25)

Post by BDanielMayfield » Sat Aug 25, 2018 2:21 pm

Ann wrote:
Sat Aug 25, 2018 11:47 am
heehaw wrote:
Sat Aug 25, 2018 9:32 am
I remember seeing a similar photo of, I think, another galaxy. The thing that impresses me most about this is seeing star formation in the stripped material. These are stars that formed in the stripped material AFTER the material was stripped. Now I think that the question of exactly how and why star formation occurs in galaxies is still open: density, pressure, whatever factors. This (or these) stripped-material star-forming regions are dramatically different from traditional regions of star formation inside galaxies. I'd like to hear some discussion on this, and on what it means!

Obviously stars are forming in chains in the gassy tail left by ESO 137-001, and my amateur understanding suggests to me that the reason for the chain-like structures might be that gas is leaving this galaxy almost like heavy rainfall. Heavy rain can sometimes fall as long "chains" of water. In the picture at left, it would seem that the chains are formed when the rain hits the car. It may be the "bumpiness" of the car that turns the relatively smooth and evenly distributed rain into chains of water. Slightly similar chains may form as gas leaves a galaxy and hits concentrations of objects in the galaxy, for example star clusters and thick dust clouds.


In the "chains" of gas (and, presumably, dust) leaving ESO 137-001, temperatures may fall and ideal conditions for star formation may be created. It is known from the Milky Way that star formation often takes place in elongated dusty tendrils.

As you can see in the picture at left, the serpentine cosmic tendril known as "The Snake" is hatching a massive star in its belly and a smaller one in its snout. (Do visit the page where I found the picture, because there are more images there and you can find more facts.) My point, however, is that if stars can form in dusty tendrils in the Milky Way, why shouldn't stars be able to form in long chains of gas and dust that have been pushed out of ESO 137-001?

If you check out today's APOD, you can see that the chains of stars only stretch so far below the disk of ESO-137-001. The longest chains seem to be about equal in length to the diameter of the visible disk of the galaxy. Note, in the APOD, that the longest chains of new stars emanate from the rightmost part of the galaxy, where Chandra didn't detect any really strong X-ray signals. My interpretation is that these chains are the oldest, and that the gas in this part of the galaxy may already be mostly used up.

The Chandra X-ray data extend far beyond the chains of new stars. I take that to mean that at this distance from the galaxy, any dusty chains have been disintegrated and turned into a hot smooth soup of turbulent gas. This is an environment that is very hostile to star formation.





Dwarf galaxies forming in the southern tidal tail
of colliding galaxies NGC 4038 and 4039.
Source: https://www.cv.nrao.edu/~jhibbard/n4038 ... 038uv.html


What will happen to the newly hatched star clusters forming from the chains of gas and dust being stripped from ESO 137-001? My guess is that they will form tiny dwarf galaxies, and then these dwarf galaxies will age, fade, disintegrate and disappear. In the end, what remains may be a number of old red stars floating freely in the intergalactic medium of galaxy cluster Abell 3627.

Dwarf galaxies are formed by other means too, not just through "ram stripping" as is the case in today's APOD. Take a look at the picture at left of star clusters forming in the longest tidal tail of the Antennae, the colliding galaxies NGC 4038 and 4039. Gas has been flung out in a long tidal stream from the gas-rich NGC 4038, and the gas has kept flowing out until it hit a bump of some sort, perhaps an intergalactic dust cloud, that stopped the outflowing gas in its tracks. Now the stalled gas has been concentrated and is forming quite a lot of new stars. The new star clusters will turn into dwarf galaxies (in fact they have already done so), and then they will fade over time. They may not necessarily disintegrate, since they don't sit in a massive cluster where tidal forces are pulling at them from all directions.

But they will become very faint in the end.

Ann

You would have to give Ann an A+ for that answer, wouldn't you professor?

Nice assignment heehaw. I think her answer nailed it. The only quibble I would have with Ann's excellent posting would be how she used the photo of the car behind the rainwater. This photo doesn't show rain falling in chains; I think it is showing puddled water being sprayed up by a passing car's tires. The tiretread channels water out away from in front of the tire.

Still, this car in the rain photo is a reasonable analogy for galaxy ram pressure stripping. The weight of the passing car provides presure to spray water away from the roadway. In the case of the galaxy being stripped of its gas, the gas and dust must be being consentrated into areas of greater density for star formation to commence, like the water in Ann's photo is being consentrated into streams of water by the passing tires.

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Last edited by BDanielMayfield on Sat Aug 25, 2018 2:36 pm, edited 2 times in total.
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Re: APOD: Stripping ESO 137-001 (2018 Aug 25)

Post by dumbnewbie » Sat Aug 25, 2018 2:22 pm

Why is ESO 137-001 speeding through the galaxy cluster at nearly 0.65 the speed of light and why are the other galaxies in the same cluster seemingly unaffected by whatever that is? :?

heehaw

Re: APOD: Stripping ESO 137-001 (2018 Aug 25)

Post by heehaw » Sat Aug 25, 2018 2:23 pm

Great discussion!

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Re: APOD: Stripping ESO 137-001 (2018 Aug 25)

Post by Chris Peterson » Sat Aug 25, 2018 2:37 pm

dumbnewbie wrote:
Sat Aug 25, 2018 2:22 pm
Why is ESO 137-001 speeding through the galaxy cluster at nearly 0.65 the speed of light and why are the other galaxies in the same cluster seemingly unaffected by whatever that is? :?
7 million kilometers per hour is 0.006 times the speed of light.
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Re: APOD: Stripping ESO 137-001 (2018 Aug 25)

Post by BDanielMayfield » Sat Aug 25, 2018 2:50 pm

dumbnewbie wrote:
Sat Aug 25, 2018 2:22 pm
Why is ESO 137-001 speeding through the galaxy cluster at nearly 0.65 the speed of light and why are the other galaxies in the same cluster seemingly unaffected by whatever that is? :?
Those are definitely NOT dumb questions. It makes me want to check your math though...

Ah, I see Chris already did. Nevermind.

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Re: APOD: Stripping ESO 137-001 (2018 Aug 25)

Post by Ann » Sat Aug 25, 2018 2:55 pm

BDanielMayfield wrote:
Sat Aug 25, 2018 2:21 pm

Nice assignment heehaw. I think her answer nailed it. The only quibble I would have with Ann's excellent posting would be how she used the photo of the car behind the rainwater. This photo doesn't show rain falling in chains; I think it is showing puddled water being sprayed up by a passing car's tires. The tiretread channels water out away from in front of the tire.
You're right! :oops:
Still, this car in the rain photo is a reasonable analogy for galaxy ram pressure stripping. The weight of the passing car provides presure to spray water away from the roadway. In the case of the galaxy being stripped of its gas, the gas and dust must be being consentrated into areas of greater density for star formation to commence, like the water in Ann's photo is being consentrated into streams of water by the passing tires.

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Re: APOD: Stripping ESO 137-001 (2018 Aug 25)

Post by Ann » Sat Aug 25, 2018 3:18 pm

dumbnewbie wrote:
Sat Aug 25, 2018 2:22 pm
Why is ESO 137-001 speeding through the galaxy cluster at nearly 0.65 the speed of light and why are the other galaxies in the same cluster seemingly unaffected by whatever that is? :?

As Chris pointed out, ESO 137-001 is falling through the cluster Abell 3627 at 0.006 times the speed of light.

But in any case, I believe we can think of the the other galaxies of the cluster as if they are orbiting the center of gravity of the cluster in a more or less orderly way.

But ESO 137-001 is a newcomer, entering the cluster from outside. It is falling headlong towards the center of gravity of the cluster, picking up speed as it goes. I think there are some similarities between a comet falling towards the Sun from the Kuiper Belt and ESO 137-001 falling towards the center of gravity of Abell 3627.

Click to play embedded YouTube video.
You must bear in mind, too, that all the inner galaxies of Abell 3627 have likely already lost all their gas, so there is nothing more for them to lose. They can't leave any gaseous trails behind.















Interestingly, we see the effects of ram stripping in a the closest large galaxy cluster as well, namely the Virgo cluster. NGC 4388 is falling through the cluster, and gas, seen as red in the picture at right, is driven out of it.

Another galaxy in the Virgo cluster experiencing ram pressure and losing gas because of it is NGC 4402. Check it out here, in a picture from NASA/ESA and Wikisky.

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Re: APOD: Stripping ESO 137-001 (2018 Aug 25)

Post by BDanielMayfield » Sat Aug 25, 2018 3:25 pm

Ann wrote:
Sat Aug 25, 2018 2:55 pm
BDanielMayfield wrote:
Sat Aug 25, 2018 2:21 pm

Nice assignment heehaw. I think her answer nailed it. The only quibble I would have with Ann's excellent posting would be how she used the photo of the car behind the rainwater. This photo doesn't show rain falling in chains; I think it is showing puddled water being sprayed up by a passing car's tires. The tiretread channels water out away from in front of the tire.
You're right! :oops:
Still, this car in the rain photo is a reasonable analogy for galaxy ram pressure stripping. The weight of the passing car provides presure to spray water away from the roadway. In the case of the galaxy being stripped of its gas, the gas and dust must be being consentrated into areas of greater density for star formation to commence, like the water in Ann's photo is being consentrated into streams of water by the passing tires.

Bruce
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Ann
You're very welcome. The rest of your post was awesome though.

This example of star formation in stripped gas and dust makes me doubt the conventional wisdom that protostars must have cool dust for gravitational collapse to begin. Afterall, look at how hot the gas streaming out of this galaxy is ... its glowing in X-rays it's so hot! And the gas is still doing so for, what, many millions of years after it's been stripped :!: (Bassed on the great length of the blue gas tendrils.)

Conjecture: If the mass and density are high enough, even hot gas can collapse into stars. I think this APOD proves it.

Bruce
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Re: APOD: Stripping ESO 137-001 (2018 Aug 25)

Post by rleever » Sat Aug 25, 2018 5:55 pm

Since every galaxy is like 70 percent dark matter, I would presume that the dark matter in this galaxy is moving right along with the visible components of this galaxy. Since dark matter does not react to ordinary matter it CAN NOT be being stripped away.
Therefore (sorry, math major) this galaxy with more and more of it's ordinary matter stripped away must be getting richer and richer in dark matter. Shouldn't the speed of rotation of the stars currently in THIS galaxy be increasing? Has anyone thought to check this out?
Do you suppose that there could be HUGE galaxies composed primarily of dark matter with only a few very old ordinary stars be zipping
about. If this galaxy 'stripping' is a frequent occurrence one would suppose that there should be quite a few of these almost completely dark galaxies shooting thru space. So there should be lots of gravitational lenses around without any observable 'galaxies' doing the lensing. Has any one detected these inexplicable lens features anywhere? There should be at least a few places where this is occurring in the millions and millions of observable galaxies.

Guest

Re: APOD: Stripping ESO 137-001 (2018 Aug 25)

Post by Guest » Sat Aug 25, 2018 6:08 pm

Ann wrote:
Sat Aug 25, 2018 3:18 pm


As Chris pointed out, ESO 137-001 is falling through the cluster Abell 3627 at 0.006 times the speed of light.

But in any case, I believe we can think of the the other galaxies of the cluster as if they are orbiting the center of gravity of the cluster in a more or less orderly way.

But ESO 137-001 is a newcomer, entering the cluster from outside. It is falling headlong towards the center of gravity of the cluster, picking up speed as it goes. I think there are some similarities between a comet falling towards the Sun from the Kuiper Belt and ESO 137-001 falling towards the center of gravity of Abell 3627.

Click to play embedded YouTube video.
You must bear in mind, too, that all the inner galaxies of Abell 3627 have likely already lost all their gas, so there is nothing more for them to lose. They can't leave any gaseous trails behind.

Ann
OK Thanks everyone for the speed correction :D
But how do we know that it is going towards the centre of the cluster? And why there? because of dark matter/dark energy? ultra super super supermassive black hole? (Those soiund like cosmological ways of saying that "the devil made it do it.") And where did it come from? And why did it leave where it had been? And how often does this happen in the observed clusters?

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Re: APOD: Stripping ESO 137-001 (2018 Aug 25)

Post by Chris Peterson » Sat Aug 25, 2018 6:48 pm

rleever wrote:
Sat Aug 25, 2018 5:55 pm
Since every galaxy is like 70 percent dark matter, I would presume that the dark matter in this galaxy is moving right along with the visible components of this galaxy. Since dark matter does not react to ordinary matter it CAN NOT be being stripped away.
Dark matter does interact with ordinary matter. Just not via the electromagnetic force. The interaction is gravitational, and there are examples of galaxies which are dark matter poor, probably because it was stripped away in a collision.
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Re: APOD: Stripping ESO 137-001 (2018 Aug 25)

Post by BDanielMayfield » Sat Aug 25, 2018 7:08 pm

rleever wrote:
Sat Aug 25, 2018 5:55 pm
Since every galaxy is like 70 percent dark matter, I would presume that the dark matter in this galaxy is moving right along with the visible components of this galaxy. Since dark matter does not react to ordinary matter it CAN NOT be being stripped away.
Therefore (sorry, math major) this galaxy with more and more of it's ordinary matter stripped away must be getting richer and richer in dark matter. Shouldn't the speed of rotation of the stars currently in THIS galaxy be increasing? Has anyone thought to check this out?
Do you suppose that there could be HUGE galaxies composed primarily of dark matter with only a few very old ordinary stars be zipping
about. If this galaxy 'stripping' is a frequent occurrence one would suppose that there should be quite a few of these almost completely dark galaxies shooting thru space. So there should be lots of gravitational lenses around without any observable 'galaxies' doing the lensing. Has any one detected these inexplicable lens features anywhere? There should be at least a few places where this is occurring in the millions and millions of observable galaxies.
I think that you might be correct to assume that the ratio of dark to ordinary matter has gone up in this stripped galaxy rleever, but this wouldn't make the stars in the galaxy move faster. If anything, their orbital speeds would have to decrease somewhat because the total mass of the galaxy has been reduced.

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Re: APOD: Stripping ESO 137-001 (2018 Aug 25)

Post by Ann » Sat Aug 25, 2018 7:18 pm

Guest wrote:
Sat Aug 25, 2018 6:08 pm

OK Thanks everyone for the speed correction :D
But how do we know that it is going towards the centre of the cluster? And why there? because of dark matter/dark energy? ultra super super supermassive black hole? (Those soiund like cosmological ways of saying that "the devil made it do it.") And where did it come from? And why did it leave where it had been? And how often does this happen in the observed clusters?
It is kind of complicated to explain, but I will do my best. Look at the video below of athletes throwing the hammer.

Click to play embedded YouTube video.
We can compare the athlete throwing the hammer to the Sun keeping the Earth in orbit around it. The hammer is circling the athlete because the athlete himself is moving in a circle, holding on the the hammer by a string of some sort. The faster the athlete is circling around, the faster the hammer is moving around him. When the athlete lets go of the hammer, it flies off in the tangent's direction.

The Earth is moving around the Sun because the Earth is moving at a certain speed, some 107,000 km/h (67,000 miles per hour). At every moment, the Earth tries to fly off in the tangent's direction at this exact speed. But the Sun's gravity is the "string" that holds the Earth in place, forcing the Earth to move around the Sun in an elliptical orbit.

Click to play embedded YouTube video.






Anything entering the Solar system and lacking a proper "sideways direction" is going to fall towards the Sun. Very occasionally objects, such as comets, may fall into the Sun and be destroyed. This, however, is unusual.



Click to play embedded YouTube video.





Many objects follow very elongated objects around a center of mass. A great example of this is a number of stars orbiting or galaxy's central supermassive black hole, Sagittarius A*, which contains some 4 million solar masses, unless my memory has let me down. I also seem to remember that Sagittarius A* has packed all this mass within a radius no bigger than the Solar system, which means that the gravity here is extreme. See how the stars move around Sagittarius A* in very elongated orbits, and see how they pick up speed when they get closer to the terrifying black hole. Note, however, that they don't fall in. They all move at exactly the proper speed and have exactly the necessary "sideways motion" to avoid falling into the black hole. (Of course, every ten million years or so a star falls in, I suppose.)

Now imagine ESO 137-001 entering galaxy cluster Abell 3627. ESO 137-001 has not adjusted its speed to follow a suitable orbit around the center of the galaxy cluster (because, you bet your boots, Abell 3627 does have a center of gravity). So it just falls in haplessly, picking up speed as it falls in.

More importantly, perhaps, ESO 137-001 has not suffered the wear and tear that characterizes all the other galaxies that have spent billions of years following orbits in the crowded environment of Abell 3627. Why do you think that the galaxies that are members of rich galaxy clusters are typically so yellow and fuzzy? It is because their interactions with each other over billions of years have squeezed most of the gas out of them and made the remaining gas hot and turbulent and unsuitable for star formation.

Take a look at that galaxy cluster Abell 1689 again. Can you see that one of the galaxies at upper center is surrounded by a huge amount of pale yellow fluff? I'd say that that is the dominant galaxy of Abell 1689. If you fell into Abell 1689 from outside, chances are that you would career straight at that fluff-enshrouded galaxy. And you might get swallowed too, because galactic mergers are not unusual at all.

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Re: APOD: Stripping ESO 137-001 (2018 Aug 25)

Post by BDanielMayfield » Sat Aug 25, 2018 8:23 pm

Guest wrote:
Sat Aug 25, 2018 6:08 pm
OK Thanks everyone for the speed correction :D
But how do we know that it is going towards the centre of the cluster? And why there? because of dark matter/dark energy? ultra super super supermassive black hole? (Those soiund like cosmological ways of saying that "the devil made it do it.") And where did it come from? And why did it leave where it had been? And how often does this happen in the observed clusters?
It probably isn't moving toward the exact center of the cluster (just as most comets don't fall directly into the sun. [but some do.]) And there's no magic or mystery involved; all matterial objects in the universe are always experiencing an apparent acelleration toward all other objects in the universe by a force aligned with the objects' centers of mass and proportional to the product of the two masses divided by the square of the distance between their centers. Easy as pi. :P

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Re: APOD: Stripping ESO 137-001 (2018 Aug 25)

Post by Boomer12k » Sat Aug 25, 2018 10:55 pm

My first thought was that of a "galactic comet"...but rather than a solar wind, the cluster medium...
it seems to be a passer through...like some comets...
Very interesting shot, and discussion.

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