Another Hubble stunner

By Phil Plait | February 6, 2007 3:14 pm

Astronomers at Space Telescope Science Institute just released a new image, and it’s a beauty.

What you’re looking at is galaxy cluster Abell S0740. If galaxies are island universes, then clusters are archipelagos. Some are small, like this one, but others have hundreds or thousands of galaxies in them. In many of them, there is a central elliptical galaxy which dominates the cluster, and this cluster is no exception. The central galaxy grows through cannibalism, eating other galaxies and assimilating them. Sometimes the evidence for this is that the central galaxy has multiple cores — think of them as the undigested remains of its conquests — and sometimes the galaxy gets "puffed up" as the energy of the consumption is transferred to the stars in the galaxy. The central galaxy in this image has the look of the latter to me, but I’m not an expert. By the way, most of the little pinpricks of light you see surrounding the central galaxy are globular clusters. Cool.

The other galaxies in this cluster are a mess. This is expected. Imagine taking a hive of bees and compressing it. As the bees get jammed together, they get disturbed, right? Well, the same thing, kinda, is happening here. When you jam a few dozen galaxies into a small volume, their gravity starts to make a hash of things. They pass close by each other, disturbing their shapes. You get outright collisions as well.

That spiral above doesn’t look too happy to me. I think a few passing galaxies have distorted its shape. You can see blue regions in it as well, which are locations of star formation. This can get triggered when passing galaxies gravitationally poke gas clouds in a neighboring galaxy, slamming them together, which in turn makes them collapse and form stars.

Now look at this one:

This is what’s called a polar ring galaxy. If a small galaxy ploughs right through the center of a bigger galaxy, the bigger one can form a massive ring of stars surrounding a cylindrical mass in the center, like an axle on a wheel. We’re seeing this one nearly edge-on, and it looks a lot like a normal spiral galaxy seen edge-on. But if you look carefully, along the disk you can see a dark gap, which indicates this is really not a disk seen edge on, but a ring.

Then there’s this thing:

I have never seen a galaxy like this in my life. The press release says it’s another ring galaxy seen edge on, but man. That’s really weird.

I think what’s most interesting about this cluster is that according to the release, the central galaxy has a mass of about 100 billion times the Sun. But that’s about the same mass as our own Milky Way Galaxy! So in fact the galaxies in this cluster aren’t all that big. And I’m wondering just how many of the galaxies you see in the image really belong to the cluster; some of those much smaller spirals may be part of a different cluster farther away. Or I might be totally wrong, and they might just be dinky galaxies. It looks like I’ll have to find a paper on this cluster and do some reading. I love it when images from Hubble make me think, and I love it more when they make me rethink things I’ve already thought about!

Oh– don’t forget, I have more info on galaxies in my first ever episode of "Q & BA". And keep sending me questions!

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Comments (44)

  1. labtechpete

    One word…awesome!

  2. oldamatuerastronomer

    These pictures take my breath away!

    Galaxies were always my favorite targets when I went out observing, but these…

    WOW!!!!

  3. Tukla in Iowa

    You scared me. I thought another instrument had failed.

  4. Grand Lunar

    I heard of the Abell. Isn’t it also a gravitational lens?

    “The central galaxy grows through cannibalism, eating other galaxies and assimilating them.”

    Resistence is futile! :)

  5. wonderful post! i think about galaxies everyday and you certainly made me think….!! that last galaxy you show does look kinda strange. it has a severely “boxy” shape that kormendy uses to describe some cores, but it’s supposedly the whole disk! maybe a recent interaction disturbed and puffed it up, but then again it looks pretty orange/red… aka. not blue and young! cool stuff!

  6. Grand Lunar stole my comment! Boooooooooo!

  7. “I heard of the Abell. Isn’t it also a gravitational lens?”

    The Abell cluster catalog is just that: a catalog of galaxy clusters. Many of them are used for clustering studies. One of the most famous is Abell 1689:

    http://antwrp.gsfc.nasa.gov/apod/ap030109.html

    Which might be the one you are thinking of. I don’t see any obvious signs of lensing in this particular cluster, but it sure is pretty.

    Phil: if you find a followup paper on that, post it! I wonder how many of the apparent cluster members do they have redshifts for? I would agree that it looks like there is a second cluster much further back; upper right of the large red galaxy, just above the three bright stars…

    Also, I think that mass estimate is too low: go to the “fast facts” link and they have an image with a scale. The LRG is at least 50kpc across in the long dimension!

  8. John Schroeder

    Is it possible to see differences in the arms of galaxies between pictures say a 100 years apart, even cooler would be a time lapse showing the bands moving like a hurricane

  9. Apparently, the center of this galaxy is acting as a strong gravitational lens!

    http://hubblesite.org/newscenter/archive/releases/2007/08/image/b/

    That’s what I get for not looking at the other press release images…

    *hangs head in shame*

  10. skeptigirl

    OK, here’s a fantasy hypothesis:

    The center of galaxies contain massive black holes which pull everything inward. The center of galaxy clusters have something even more massive pulling the galaxies in.

    So, could galaxy clusters be falling into something even more massive which is too far away to have been detected which explains the increased rate of expansion?

    Maybe this object is so large that not only does light not escape, gravity cannot escape either and ….. well I’m trying to think of how it might have so far escaped detection. I’ll go back with distance.

    While we can see 14 billion light years back in time in all directions, (or whatever the latest more precise figure is), is there anything precluding some matter having been flung faster than the speed of light in those first few fractions of a second when the amount of energy was so great that its properties are not yet fully known?

    Or perhaps the Universe is actually expanding into something after all and we are in a cluster of universes with a central attractive mass?

    Well, that’s the end of my naive speculation for the moment. I suppose there are enough things known that I don’t know which make my hypothesis already ruled out. But for whatever reason, I must contemplate the Universe from time to time. Thank you all for indulging me. :)

  11. skeptigirl

    About that last image in the blog, there are 2 lobes in that galaxy which looks similar in shape to exploding stars and other single bodies with bilateral explosive pulses shooting out.

  12. Chip

    The details are fantastic in the big spiral that’s spiraling out of the lower right corner! Notice also the dark streak running across its core. Wild.

  13. wright

    Yeah, the photo of that last galaxy… those opposed “lobes” aren’t an optical effect? If so, what forces would be needed to form such an usual (for galaxies) shape? The mind boggles…

    And great job on the first “Q & BA”, Phil. Informative and concise. Your enthusiasm for your field is evident, and contagious. :)

  14. Wow–and I’m glad I came across this site.

  15. CR

    Fantastic!
    I love looking at all the other galaxies in that pic… I noticed the one which Phil says doesn’t look very “happy” and speculated the same thing about it. Did anyone notice what appears to be a Sombrero Galaxy in the upper right corner? It’s “standing on end” near the top of the frame.
    While the ‘never before seen’ types interest me, I also think the ones that are similar to familiar ones are just as intriguing; they show that in certain conditions, repetition occurs. There’s something cool about that.

  16. CR

    Just to specify the “Sombrero” one a little better: it’s yellowish-orange in color, and is just above a nearly spherical eliptical galaxy and below & to the right of a bright blue-white star. That whole ‘group’ is in the upper right corner of the pic, near the top of the frame.

  17. Kevin Conod

    Wow!! Fantastic image!!

    Skeptigirl — I do believe you are confusing the expansion of the Universe with local motions of galaxies in clusters.

    Also you’re assuming the galaxies are falling inwards, whereas in all likelyhood the galaxies in this cluster are moving too fast to remain in the cluster. Over time one would expect the cluster to fall apart.

  18. Kullat Nunu

    Can’t believe that at all. Giant elliptical galaxies in the center of galaxy clusters are far more massive than the Milky Way. For example Messier 87 in the Virgo Cluster weights as much as 2.6 trillion (10^12) Suns within 32 kpc from the center. In comparison, Milky Way’s mass is 5.8 x 10^11 Suns.

    It should be obvious when you compare the volumes of Milky Way and M87. Milky Way is shaped like a compact disk except for the central bulge; M87 is only a slightly wider, but it is roughly spherical: therefore its volume (and number of stars) is much larger. I don’t know how large M87’s dark matter halo is so the total mass may be higher. The mass given for Milky Way includes the dark matter halo so the discrepancy may be higher.

    One should note that Messier 87 is far from being the largest known giant elliptical. The two galaxies in the center of the Coma Cluster are both much larger, and the largest ones–giant diffuse galaxies–can be millions of light years in diameter (though I have no idea how massive they actually are).

  19. Kullat Nunu

    There really should be a preview option.

    I was commenting the 100 billion solar mass claim, but the quote apparently disappeared.

  20. (HEARTS)

    Alien lifeforms to me seem like a necessity when imagining the number of solar systems out there. We may never find out, but I can only laugh at those who claim that we’re alone.

    Fantastic Images!

  21. Ausrick

    You’re right Hearts, The universe seems so huge it makes you wonder by the shear majesty of it what all can be out there! I love contemplating what could exist… and dangit Einsteinian Reletivity, it seems impossible to go there and find out!

    From a statisticians point of view, what I’ve been reading seems a little more lonely–that chances of other habitable planets occuring seem to diminish with every new discovery. :( The last paper I read had quoted something like there being 202 parameters that need to fall within very specific guidlines to form a habitable planet (another paper only said 120, but I think it was written earlier). It seems that everthing from the metal content of the star to where and when gas giants form and what type of orbit they have seems to have an effect on planetary formation models. and they quoted the statistical probability of another habitable planet occurring as 1 in 10^140. I also heard by comparison that there are supposedly only about 10^76 protons in the universe. (this last one is hearsay, I’ve seen it a number of places, but not in a scientific journal and have no idea the context… I’m sure the amount of protons estimated in 1970 would probably be different than the amount estimated today.)

    Now I admit, these numbers seem out of whack to me, but to be honest my mind can’t truly conceptualize them anyway… and with every advance or discovery they change as do the models that seem to generate them. So I see how some one could say they would tend to believe we are alone and I can easily see why someone would say the opposite.

    I’m really only qualified to say the universe is awe inspiring and humbling… and I think that galaxy on the lower right side of the picture is pretty :) Oh, and to echo that it makes you think about things like this to begin with… before seeing this picture I was only concerned with where I sat my Mountain Dew. 😉 Thanks Phil!

  22. Mark

    Kevin Conod:

    You said, “whereas in all likelyhood the galaxies in this cluster are moving too fast to remain in the cluster. Over time one would expect the cluster to fall apart.”

    If they are moving too fast to remain in the cluster, then that means they aren’t gravitationally bound, doesn’t it? If they aren’t gravitationally bound, then how did they come to be a cluster in the first place? Maybe you or Phil could explain this.

  23. ioresult

    Mark and Kevin Conod:
    Galaxies in clusters are moving too fast to remain in the cluster if we only take into account the visible matter. Dark matter contributes to the gravitational pull of the whole cluster on itself so the galaxies are really just orbiting around each other.

    Skeptigirl:
    The universe is pulling away from us at the same speed and acceleration whichever direction we look. According to your idea, that would mean we should be surrounded by black hole matter further than 14 billion light years away in every direction. This can’t be: the gravitational field inside a massive hollow sphere is flat, there is no pull in whatever direction. So even if there were black hole matter all around us, it wouldn’t affect the universe’s expantion. That puts us back at thinking about the cosmological constant, or the quintessence, or dark energy (however you may want to call this thing that ir ripping the universe appart).

  24. ioresult

    Mmh the comment thing doesn’t like web links too much. So I’ll post dirfferently.

    Gravity inside a hollow sphere. Do this google search: “gravity inside hollow sphere”. It sould yeld a couple of interesting texts.

    About the universe’s quintessence: type “Quintessence (physics)” in wikipedia.

  25. skeptigirl

    Kevin Conod Says:
    Skeptigirl — I do believe you are confusing the expansion of the Universe with local motions of galaxies in clusters.

    Also you’re assuming the galaxies are falling inwards, whereas in all likelyhood the galaxies in this cluster are moving too fast to remain in the cluster. Over time one would expect the cluster to fall apart.

    ioresult Says:
    Skeptigirl: The universe is pulling away from us at the same speed and acceleration whichever direction we look. According to your idea, that would mean we should be surrounded by black hole matter further than 14 billion light years away in every direction. This can’t be: the gravitational field inside a massive hollow sphere is flat, there is no pull in whatever direction. So even if there were black hole matter all around us, it wouldn’t affect the universe’s expantion. That puts us back at thinking about the cosmological constant, or the quintessence, or dark energy (however you may want to call this thing that ir ripping the universe appart).

    I’m aware of the dif in expansion and movement. I told you it was naive speculation. I suppose I wasn’t taking into account the fact redshifts don’t suggest any gravitational point of attraction. Back to contemplating…. :)

  26. cope

    The galaxy in the lower right…do we know what its distance relative to the more central globular and “disturbed” spiral is? It is quite a beautiful spiral.

    Just curious.

  27. Troy

    I’m not a deep sky guy, BUT my impression was always that the Milky Way while not a huge galaxy is actually quite large. Now if you want a small galaxy we have two satellite galaxies called the large and small Magellinic clouds (not generally visible in the Northern hemisphere) those are puny galaxies, but the Milky Way is a big boy. M31 the galaxy in Andromeda is quite a bit bigger. And contrary to previous posts; on the level of galaxies the universe can indeed cease its expansion and clump together. The tendancy is red shift but blue shift is possible, and M31 and the milky way will someday collide forming a huge super galaxy.

    Nice picture, it seems Hera’s breast has many heirs.

  28. biosparite

    Ausrick said, “From a statisticians point of view, what I’ve been reading seems a little more lonely–that chances of other habitable planets occuring seem to diminish with every new discovery. The last paper I read had quoted something like there being 202 parameters that need to fall within very specific guidlines to form a habitable planet (another paper only said 120, but I think it was written earlier). ”

    Ausrick, before you get too discouraged, remember JBS Haldane’s comment after a lecture on the habitable zone around stars: “But what if they (alien life) look like bloody stones?”

  29. Dave Kary

    The whole question of “habitability” is a still has way too many variables to get even the right order of magnitude on estimating the likelihood. We certainly know now that among metal-rich stars (which dominate disks of spiral galaxies) like the ones around us, planets are at least 10%, and quite probably more than that.

    But beyond that, we still don’t know whether terrestrial planets are common, or how many are on sufficiently circular orbits to give a fairly stable climate, or what the real habitablity range is for those kinds of planets (since atmospheric greenhouse feedback relations can stabilize a temperature over a wide range of distances from the star).

    We also don’t know if you need a terrestrial planet? How about a jovian moon? How about the atmosphere of a jovian planet itself? Both of these are at least worth considering as places for life to develop.

    Lastly, we don’t know even know if you really need liquid water conditions for life. There are some lovely liquid methane lakes on Titan (see today’s Astronomy Picture of the Day) that look pretty inviting, provided you don’t mind a temperature of 93K.

    I think that we will have a much better idea of the likelihood of life elsewhere once we have more thoroughly explored the solar system. If there really isn’t any life in the oceans of Europa or the lakes of Titan, and there really aren’t any fossils in the sedimentary beds on Mars, then maybe we can say that life is rare. On the other hand, if life developed just one more place in our solar system, then I’d bet it is common throughout the universe. After all, if you get it twice in one little solar system, it be easy to get the right conditions.

  30. Mark

    ioresult, Thanks for the answer!

    Is this the primary evidence for the existance of dark matter?

  31. Hmmm, not that it really makes a difference, but why is APOD’s posting of this photo rotated 90 degrees CW from the BA’s?
    http://apod.nasa.gov/apod/ap070208.html

  32. Buzz Parsec

    The talk about dark matter and the missing mass problem reminds me just how incredibly *cool* it was that my astronomy classmate Judy’s mom had just discovered that 90% of the universe had gone missing!

  33. Mark

    Hey Buzz,

    Whoa, your class mate’s mom discovered dark matter? That’s another thing that’s been puzzling me lately… It’s my understanding is that astronomers first realized back in the 30’s that galaxies didn’t have enough mass to behave the way they were behaving. My impression is that this problem remained in the forefront right up to today. So my question is, what event constituted the “discovery” of dark matter?

  34. Dave Kary

    There certainly were indications of a problem all of the way back to the 30’s, but it didn’t really move to the forefront until the 70’s (if I remember right) when Vera Rubin did some detailed studies on the Milky Way and found that the rotation curve is flat, indicating that we weren’t seeing most of the mass of the galaxy (since most of the light comes from the bulge). That’s when “dark matter” became one of the big problems in astronomy.

    I just checked with my wife, (who is a historian of astronomy), and she confirmed that Vera Rubin does have a daughter named Judy, so I’m guessing that’s who Buzz went to school with.

  35. ioresult

    Mark: dark matter is only matter that hasn’t been observed directly yet. Neptune was one of the first such examples. It was discovered by its gravitational influence on Uranus in 1846. So before being observed, during a short time when it was known that Neptune existed, it was effectively “dark matter”.

    Right now, if I’m not mistaken, about 5% of the universe’s total energy has been observed by its influence on photons. 25% more can be accounted for only by its gravitational influence, so that’s the actual current amount of “dark matter”. 70% is dark energy (the mysterious thing that’s responsible for the expansion’s acceleration).

  36. SF Reader

    And the only foreground objects (our galaxy? our cluster?) are the ones with the diffraction spikes (from the legs supporting the secondary mirror?).

    Just getting the scale straight in my head, so I can explain it all to my 9-year-old!

  37. Mark

    Dave and everyone, Thanks for the answers!

  38. Is the Abell Cluster one of the clusters that leaves a shadow on the CMB due to the Sunyaev-Zeldovich Effect, or one that doesn’t because the gas and dust in the cluster emits at 2.72 K. We do know that it is closer to us than the surface of last scattering, true? pete

  39. Buzz Parsec

    Mark – the web strikes again :-)

  40. Are you sure that your PC not by and other *hit?Are you protected from PC-spy?TAKE A LOOK HERE AND SCAN YOUR PC HERE AT OUR SITE!
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  41. Angel Elf

    What is the name of that beautiful spiral in the lower right hand corner of the image above?

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