"X" Marks Puzzling Galactic Bulge
Written by Nancy Atkinson
Looking at a galaxy edge-on provides astronomers the opportunity to study different aspects of galaxies than a face-on view offers. This Hubble image of NGC 4710 is part of a survey conducted to provide more information about the puzzling bulges that form around the middle of some galaxies. Have these galaxies been "eating" too much, or is it just part of a "middle-age spread" similar to what humans experience? Astronomers aren't sure why bulges evolve and become a substantial component of most spiral galaxies.
This image was taken by the Advanced Camera for Surveys in 2006, before the recent Hubble Servicing Mission.
A faint, ethereal "X"-shaped structure is also visible. Such a feature, which astronomers call a "boxy" or "peanut-shaped" bulge, is due to the vertical motions of the stars in the galaxy's bar and is only evident when the galaxy is seen edge-on. This curiously shaped puff is often observed in spiral galaxies with small bulges and open arms, but is less common in spirals with arms tightly wrapped around a more prominent bulge, such as NGC 4710.
Click here to watch a movie zooming into this galaxy.
When targeting spiral galaxy bulges, astronomers often seek edge-on galaxies, as their bulges are more easily distinguishable from the disc. This exceptionally detailed edge-on view of NGC 4710 taken by the Advanced Camera for Surveys (ACS) aboard Hubble reveals the galaxy's bulge in the brightly coloured centre. The luminous, elongated white plane that runs through the bulge is the galaxy disc. The disc and bulge are surrounded by eerie-looking dust lanes.
A wide-field image of the region around NGC 4710 constructed from Digitized Sky Survey 2 data. The field of view is approximately 2.8 degrees x 2.9 degrees. Credit: NASA, ESA and Digitized Sky Survey 2. Acknowledgment: Davide De Martin (ESA/Hubble)
NGC 4710 is a member of the giant Virgo Cluster of galaxies and lies in the northern constellation of Coma Berenices (the Hair of Queen Berenice). It is not one of the brightest members of the cluster, but can easily be seen as a dim elongated smudge on a dark night with a medium-sized amateur telescope. In the 1780s, William Herschel discovered the galaxy and noted it simply as a "faint nebula". It lies about 60 million light-years from the Earth and is an example of a lenticular or S0-type galaxy – a type that seems to have some characteristics of both spiral and elliptical galaxies.
Astronomers are scrutinizing these systems to determine how many globular clusters they host. Globular clusters are thought to represent an indication of the processes that can build bulges. Two quite different processes are believed to be at play regarding the formation of bulges in spiral galaxies: either they formed rather rapidly in the early Universe, before the spiral disc and arms formed; or they built up from material accumulating from the disc during a slow and long evolution. In this case of NGC 4710, researchers have spotted very few globular clusters associated with the bulge, indicating that its assembly mainly involved relatively slow processes.
Source: STSci
Tags: galaxies, Hubble Space TelescopeRelated stories on Universe Today
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November 18th, 2009 at 12:02 pm
Err… Nancy, at the end of the penultimate paragraph, you left out the words "elliptical galaxies".
You can delete this after you've made the necessary correction.
November 18th, 2009 at 12:25 pm
Really nice view of an edge on galaxy in the Virgo Cluster
AFAIU, most of these boxy, "X"-shaped galaxies are indicative of barred structure seen edge on. Due to viewing geometry, these "X"-shapes may or may not be centered on the nucleus of the galaxy. Computer modeling of these systems reveals that stars in these 'cross sections' form a distinct population separate from the disk or bulge.
November 18th, 2009 at 2:14 pm
IVAN3MAN- we're having a little glitch in our software where sometimes words that have links disappear from view. Working on it….
November 18th, 2009 at 2:19 pm
Knowing that this image is actually of a three-dimentional object, the "X" shape (which can be seen in the image — great) is likely two hyperbolic cones placed small end to small end at the center of the galaxy. This would provide a "X" appearance from any "edge" on view 360 degrees around the galaxy (or could it be referred to as an "hourglass").
This raises interesting possibilities…
November 18th, 2009 at 3:01 pm
@ Anaconda,
Like, er… what would that be, as if I didn't know already?
November 18th, 2009 at 3:26 pm
So _that's_ how a bar looks side-wise! Frankly, I had no idea. The dynamic processes in these galaxies are astounding.
[As are the geometric fancies of EU religionists. How vertical motions of stars in a bar happen to form hyperbolic structures, even less rotational symmetric ones, boggles the mind and statistical probabilities both. Oh, the insanity! :-/]
November 18th, 2009 at 4:37 pm
@ Larsson:
It's not likely to be a "bar" shaped object.
As the post states: "This curiously shaped puff [the "X" shape] is often observed in spiral galaxies with small bulges and open arms…"
It is unlikely that galaxies of this sort would "often" line up so that observers from Earth's direction would see the "X" if it was bar shaped.
More likely, it's as I've already stated, a structure that appears as an "X" no matter which way the galaxy is viewed as long as it's viewed "edge" on.
And could that be a result of intergalactic plasma flows? You know, like "beads on a string".
From Astronomy.com:
"Astronomers have known since the early 1990s that galaxies cluster in filaments and sheets surrounding vast voids in space. Now, an international team of astronomers has found that spiral galaxies, like the Milky Way, line up like beads on a string, with their spin axes aligned with the filaments that outline voids."
http://www.astronomy.com/asy/default.aspx?c=a&id=4215
So this "X" structure could be related to the fact that galaxies are lined up like "beads on a string" with filaments connecting the galaxies, no less.
What would be interesting to know is if there are nearby galaxies that line up with this galaxy's spin axis?
November 18th, 2009 at 5:02 pm
Galaxies feed on material around them, including other dwarf galaxies. I would say this X is probably similar to material, dust and gas, which has been found (as I understand) onto the Milky Way.
LC
November 19th, 2009 at 12:42 am
@ Anaconda,
Firstly, thanks for the link to that Astronomty article — I had completely missed that one!
Secondly, true to your usual form, you took the above quote out of context; that article also mentions (missing section emphasized) in the 1st paragraph:
Also, further down, in the fifth paragraph, which you obviously just happened to overlook, the article states that tidal torque theory is probably responsible:
So, you were saying…?
November 19th, 2009 at 12:46 am
Where the bloody hell that extra "t" in "Astronomy" come from?!
November 19th, 2009 at 1:53 am
@Anaconda: have you heard of the Galaxy Zoo project?
It involves serving up images of galaxies, taken in the SDSS survey, to interested members of the public, and asking them to classify the galaxies, based solely on what they see.
Over a million galaxies have been classified, each dozens of times (no one gets to classify the same galaxy twice).
The classifications have been studied quite a bit, and the statistical biases are well understood.
Why am I asking you this?
Because of this; yet another personal theory:
May I ask if you've downloaded the Galaxy Zoo data, and performed your own analyses?
Or are you simply making a wild guess, based on nothing more than your fervent wishes?
November 19th, 2009 at 1:59 am
@ Ivan3Man:
I linked the article, there was no hiding the ball.
But think about it…Is Astronomy.com going to say, "This is evidence for Plasma Cosmology…" Laugh out loud
Interesting when you think about it: An "X" configuration is common in space plasma, in "magnetic reconnection", aka electric 'double layers', there is an "X" configuration, in many cylindrical nebulas there is an "X" configuration (See linked image and notice the same "X" configuration around the central star, labelled "pinch"):
http://www.holoscience.com/news/img/Planetary%20nebula%20M2-9.jpg
And, here, in the instant post we see an "X" configuration around the galactic nucleus.
Gee, "X" configurations at three levels of cosmic scale. At the first level we know about the "X" configuration in high resolution, it's electrical in nature, in the second and third, they are images for which are there are alternative explanations.
But it makes you wonder…
November 19th, 2009 at 2:17 am
Regarding galaxy spin alignments …
Indeed there isn't …
That's what you wrote earlier, Anaconda, and you cited an Astronomy article.
Unfortunately, a more recent study, based on far more data (from the Galaxy Zoo project), failed to reproduce (or, if you prefer, verify) the Trujillo, Carretero, and Patiri finding (you can find the Solsar and White paper in arXiv: "Alignment of galaxy spins in the vicinity of voids").
This particular one? I don't know.
However, another Galaxy Zoo paper would seem to be saying that such alignments would be random only (see Slosar et al. "Galaxy Zoo: chiral correlation function of galaxy spins"; note that this paper reports some evidence for the tidal torque theory).
November 19th, 2009 at 4:29 am
Actually, quite a large body of work exists (going back to at least the 1980's) regarding the relationship between boxy-peanut shaped bulges and barred spiral galaxies. Research on these types of galaxies is now mainly on the formation and evolution of these features in the bulge and how the strength of the bar (or other variables regarding bar structure) relates to features commonly observed in boxy bulge galaxies.
A recent study of a number of these objects( including NGC 4710) also has a good review of the evidence linking boxy-peanut shaped galaxies and barred spirals ( K-band Observations of Boxy Bulges by Bureau et al http://arxiv.org/PS_cache/astro-ph/pdf/0606/0606056v1.pdf ).
On a related note, any theories regarding these galaxies must account for so-called "off-centered X" features seen in some galaxies (where the ridges of the X-shaped feature do not cross the center of the galaxy but stop short of it). The paper I linked above describes this and other features and how they relate to the bigger picture in boxy-bulge galaxies.
@Nereid2, thanks for mentioning Galaxy Zoo (from a die hard Zooite
)
November 19th, 2009 at 4:55 am
The Electric Universe "theory" is a lot of twaddle. I use the word in inverted commas to emphasize that it isn't on par with, say, the Theory of Relativity or the theory of evolution; you know, like real science.
EU supporters like to show up after a surprising result is obtained by real scientists doing actual real science, and then claim that EU can explain it. Any scientific enigma can be dragged under the umbrella of the EU crackpottery with some inappropriately applied buzzwords and a total lack of scientific rigour.
When the EU people predict some discoveries BEFORE they're made, then I might take it more seriously. But that's not going to happen because to make detailed and specific predictions you need to have a detailed and specific model, and EU doesn't have that.
November 19th, 2009 at 4:55 am
@ Anaconda,
The stellar object that you provided a link to, above, is the bipolar planetary nebula Minkowski 2-9 (abbreviated M2-9), also known as the "Minkowski's Butterfly", the "Wings of a Butterfly Nebula", and the "Twin Jet Nebula".
Astronomers are not sure about the cause of its peculiar shape, but the current hypothesis is that the primary component of this binary is the hot core of a star that reached the end of its main-sequence life cycle, ejected most of its outer layers and then became a red giant, and is now contracting into a white dwarf. It is assumed to have been a sun-like star early in its life. The second, smaller star of the binary orbits very closely and may even have been engulfed by the other's expanding stellar atmosphere with the resulting interaction creating the nebula. Astronomers hypothesize that the gravity of one star pulls some of the gas from the surface of the other and flings it into a thin, dense disk extending into space. Such a disc can successfully account for the jet-exhaust-like appearance of M2-9.
However, you seem to be absolutely certain that it's all due to some kind of magical "Z-pinch" according to "Holoscience" — an appropriate name, considering that the 'evidence' offered on their website is full of holes!
Can you tell me why the Z-pinch has, so far, failed to achieve fusion in the laboratory?
November 19th, 2009 at 5:04 am
Nereid:
Yeah, just like friggin' psychics after the event!
November 19th, 2009 at 5:43 am
Houston, we have a problem! I have no particular idea what this X shape is in this galaxy. I might offer possibilities, but frankly I don't know for sure. Anaconda appears pretty sure he understands, with various buzz words being thrown about, Z-pinch, electric double layers, magnetic reconnection and so forth. HSB Crumb might not salvage the situation by taking on the EU people, particularly Anaconda, head on, but the intention is understandable.
This is similar to what is found on other blogsites involving science. If things are permitted to be a free for all these are rubbished up by quasi-scientific types. In physics there is a literal pantheon of these people, from free energy to aether theory and perpetual motion, they are there and they show up. In biology there are the creationists, in geology there are hollow Earth wogs and so forth. This blog site is afflicted with plasma universe people, who will haunt here unless moderated off the site. Otherwise they will continue to rubbish things up here — and we may end up with a lot more of them.
LC
November 19th, 2009 at 6:18 am
For those interested in a brief (one page) overview of both theory and observational evidence regarding boxy bulge galaxies and bar structure in galaxies, check out: http://www.oamp.fr/dynamique/pap/peanut.html .Some great images of computer simulations vs. observations (including morphology and spectroscopy) with links to published papers included. This page should get most here up to speed with current research on boxy/peanut bulges and bars. No Z-pinches need apply
November 19th, 2009 at 6:27 am
Let's see now …
A garden sprinkler produces a spiral shape, as does milk which you stir into your coffee.
Hurricanes (or typhoons) also have spiral shapes.
Around the (Milky Way) galactic centre there is a mini-spiral.
And of course we all know about spiral galaxies.
Gee, spiral shapes at FOUR levels of cosmic scale. At the first level we know about the spiral shape in high resolution, it's watery in nature; in the second, well, it's also watery in nature; the third and fourth they are images for which are there are alternative explanations.
But it makes you wonder…
November 19th, 2009 at 7:12 am
Nexus:
"The Electric Universe "theory" is a lot of twaddle. I use the word in inverted commas to emphasize that it isn't on par with, say, the Theory of Relativity or the theory of evolution; you know, like real science.
EU supporters like to show up after a surprising result is obtained by real scientists doing actual real science, and then claim that EU can explain it. Any scientific enigma can be dragged under the umbrella of the EU crackpottery with some inappropriately applied buzzwords and a total lack of scientific rigour.
When the EU people predict some discoveries BEFORE they're made, then I might take it more seriously. But that's not going to happen because to make detailed and specific predictions you need to have a detailed and specific model, and EU doesn't have that."
In the comic industry, this is known as "retconning".
November 19th, 2009 at 8:16 am
The EU or PU or "E-what ever" is electromagnetic – plasma hype. When I posed to Anaconda a rather elementary question on the impedance of free space, something a senior physics student should be able to at least address, he had no apparent idea of where to begin. This EU stuff is pure balderdash wrapped up in jargon and buzzwords borrowed from physics.
It is also interesting how virtually everthing appears to be electric layers, Birckland currents, magnetic reconnections, Z-pinch and so forth. In other words everything is filtered or transformed in a way which makes it EU. Of course there are no actual calculations which manage to show up. This is of course similar to other pseudo-sciences, such as the creationist will see the Noachian flood in sedimentary rocks, or the free energy guru sees it in ball lightning and so forth. It is an almost autistic perception of the scientific view of the world.
LC
November 19th, 2009 at 12:39 pm
EU is indeed a religion same pattern as creationists.
They rely on spamming.
They rely on brainwashing.
They use the evidences that fit their view but ignore the tens of thousands other evidences that show they are wrong.
Using hype buzzwords hoping that people will not check if what they say is all true.
ZERO mathematical models that could show it could work. Only none related events where they create a pseudoscience story around it so it sounds plausible.
Siting resources out of context and forgetting to add the next paragraph.
You discover real scientists when they say "We don't know what it is really but we do know that this and this and this happens and confirms this this and this observations so it is very probable that we think is the best explanation".
Compare this with the EU and religion groups: "Scientists cannot explain what gravity is so they are wrong and we are right! "
What I still do not understand is WHY they keep on promoting this because some are clearly intelligent enough to realize that they are saying BS. Is it the negative attention? Or is it to safe face so people won't laugh at them. And what is very weird is why on science sites where they get caught with their pants down in seconds by real scientists?
But I do like the real science explanations here by people as response that clearly know their stuff.
November 19th, 2009 at 12:47 pm
What I am wondering is, could there exist some gravitational interaction that somehow changes the stars orbit to a tilted orientation so they all start orbiting under a 45 degree?
Would these distributions be in a cone like apparency or something like 2 times a 45 degree angle tilted orbits ring that happen to be where the bars are located. Viewed from a nother angle it would just show some ring or disk not a X.
November 19th, 2009 at 12:55 pm
@ Nereid2:
Thank you for the paper which fails to reproduce the earlier finding of Trujillo.
@ Nexus: Hannes Alfven predicted in 1950 that deep-space would have filamentary structure. This has been confirmed.
@ Jon Hanford, thank you for the "peanut" link. I will study.
@ Ivan3Man:
Ivan3Man wrote: "…magical 'Z-pinch'…"
No, it's a well documented phenomenon in high energy plasma physics.
Ivan3Man wrote: "Can you tell me why the Z-pinch has, so far, failed to achieve fusion in the laboratory?"
Eric Lerner is working on sustained fusion. Apparently, the tokamak hasn't had success, either.
November 19th, 2009 at 12:58 pm
@Olaf: Nancy, and ND, made a good point in another UT story comment section: Do not feed trolls.
——————————-
Have you seen any of the animations of galaxy collision simulations? If not, I'll see if I can find some examples on the web …
A quick answer to your question: a great many features found in many galaxies can be accounted for – quantitatively – by galaxy collision models. The simplest of these involve nothing more than a few thousand (or million) test particles interacting under their mutual gravitation, but they do a really good job of accounting for not only the structures, but also the mass distributions and velocity fields …
Bars are a particularly interesting structure, not only because they seem so simple, but also because they are so common. No surprise then that a lot of work has gone into studying them (and also no surprise that we now know quite a bit about them, how they form, what maintains them, how they dissipate, etc).
November 19th, 2009 at 1:08 pm
Nereid2,
I've shown Anaconda videos of sims of galaxy collisions dislaying results and galaxy shapes observed in the universe. He didn't have much to say about them. Funny that they fit his scientific approach of "if A it looks like B then B must be the phenomenon behind A".
November 19th, 2009 at 1:10 pm
@Anaconda: Alfvén's ideas on this have not yet lead to any convincing explanations, which is one reason why they are not part of mainstream astrophysics.
The 'confirmation' is of the same kind as my example of four levels of spiral structure …
I'm looking forward to reading your response to my last comments, in the V445 Pup UT story thread …
November 19th, 2009 at 1:12 pm
@ND: yeah … I wonder if Olaf has seen them (my comment was mainly for him)?
November 19th, 2009 at 1:59 pm
@ Olaf, your earlier post concerning the topology of the feature (possibly cone-shaped) would seem not to be the case, due to the complex orbits of stars perturbed by the bar. The paper I linked to earlier ( http://arxiv.org/PS_cache/astro-ph/pdf/0606/0606056v1.pdf ) points out that the appearance of the system would be dependent on our viewing angle to the bar in the galaxy. The bar seen from side-on (perpendicular to us) would appear as a box-shaped feature in the bulge. Seen at intermediate angles, the bar would appear as a peanut-shaped feature. And seen end-on (parallel to us) the bar would appear as a spherical feature in the bulge! Fig 5 on pg. 19 of the linked paper has a cartoon diagram depicting this relationship. Great question, though
The paper mentioned above has a gallery of over 20 of these galaxies, so you can get an idea of the variety of subtypes. The paper mentions that up to 45% of all edge-on galaxies exhibit some degree of boxy-peanut shaped features in their bulges( in line with known statistics on the total number of barred spirals).
November 19th, 2009 at 8:11 pm
Nereid wrote: "Alfvén's ideas [correct prediction of filamentary structure in deep-space] on this have not yet lead to any convincing explanations…"
In your opinion and the other interlocutors here, but not so for others.
Besides the question was whether any predictions had been made and confirmed.
The answer is yes.
Alfven's work on electric 'double layers' has been confirmed and that is widely hailed as the driving mechanism for the aurora and as potential mechanism for coronal mass ejections.
Also, while the spin axis alignment was not reproduced, it is known that galaxies tend to fall in lines with each other.
November 19th, 2009 at 9:25 pm
Alfven's ideas cannot be reconciled with the extreme evenness of the cosmic microwave background radiation. It should be far less isotropic if his ideas are right. So that's one correct prediction which is also predicted by regular old gravity, and two that are wrong. Sorry, but you'll have to do better than that.
November 19th, 2009 at 10:33 pm
Anaconda:
I am aware of that, but what I meant by "magical", when I referred to the "Z-pinch", was that, on this planet Earth, the Z-pinch requires some source of power: in lightning, it is convection currents building up a static charge in clouds; in the laboratory, it is from a generator and/or bank of capacitors — but what about in space…?
I suggest that you read this article, "The Con-Artist Physics of Ocean's Eleven", from which this extract (emphasis mine) is taken from:
The same principle of physics applies to the vacuum of space in the Universe.
Furthermore, since you did not answer my question, the reason why it's so bloody difficult, if not impossible, to achieve fusion with a Z-pinch is that the plasma within a Z-pinch quickly becomes unstable and breaks up before it can compressed to these levels, and applying the current more quickly, with a large bank of capacitors, simply makes it break up faster. The analogy is like trying to squeeze jelly in your clenched fist: the tighter your fingers — like the magnetic field lines — try to squeeze the jelly, the more it will squeeze out from between your fingers; it is the same problem with plasma, which is why it results in instability.
That's why I referred to the 'cosmic Z-pinch' as "magical"; how is it that this phenomenon can just occur spontaneously in space and 'power' the "Electric Sun" and stars, but controlled fusion cannot easily be achieved in perfectly controlled laboratory conditions here on Earth?
Nevertheless, you still expect us to buy your "he's not dead, he's 'resting'" parrot!
November 20th, 2009 at 7:28 am
I think the Atkinson advise "Don't feed the troll" is best. This discussion thread is being rubbished up here over EU stuff.
I don't know what to do about pseudo-science. The one purpose these people have is to tie things up and to dominate the stage. Even if in the end it amounts to creating noise, confusion and fighting they succeed in their cause. Creationists are very organized along these lines, and hamper schood districts and bring things into the courts. There is a long term worry they might in the future under an even more right winged political environment prevail in the education field. Plasma universe stuff is nowhere as big or organized, but there is a curious subculture around this. There are other quasi-physics things out there involving Tesla or free energy and so forth.
I am not sure what to advise, but I think arguing point by point with Anaconda and other EU wogs does not work. It ties things down into a mire of nonsense. I think a short disclaimer should be written, with the web address
http://en.wikipedia.org/wiki/Plasma_universe
and a quote from the second paragraph, "While during the late 1980s to early 1990s there was limited discussion of the merits of plasma cosmology, these ideas have generally been rejected by the mainstream cosmology community." If nothing else this might deter some of the uninformed from thinking there is really something behind this EU stuff.
Lawrence B. Crowell
November 20th, 2009 at 8:12 am
@LBC: I've been thinking over this a bit, and now (tentatively) consider two distinct things need to be distinguished:
* trollish behaviour, which should, indeed, be completely ignored
* promotion of pseudo-science (or, worse, anti-science), which should be robustly addressed.
I like your idea of a concise statement (or set of concise statements) summarising the key reasons why plasma cosmology/electric universe has no legs, and providing a link to a site where this is explained in more detail (my personal preference is for Tom Bridgman's blog, because it addresses every important claim, point by point, as well as PC/EU's underlying anti-science stance).
(to be continued)
November 20th, 2009 at 8:19 am
What do you think of compiling material, from undoubted EU/PC sources, which make the pseudo-science foundations crystal clear?
I have in mind such statements as Scott's, on the impossibility of knowing what changes have happened in a transmission channel if you can take measurements at only one end (i.e. all astronomy is bunk), and Lerner's to the effect that GR cannot be applied on cosmological scales, simply because he says so.
November 20th, 2009 at 8:23 am
Oh, and in general I don't like the idea of linking to Wikipedia entries, especially where there is controversy (PC proponents' efforts to grossly distort this very entry are a very pertinent case in point – see the history and discussion pages for evidence).
November 20th, 2009 at 11:28 am
Nereid2: I just did a bit of a search on the APS and AIP websites to see if there are any policy like statements about this. I never checked whether these sites had any policy statements about pseudoscientic stuff. There appears to be a bit of a vacuum when it comes to these matters. APS has a policy statement on creationism and that is about it. I am not really interested in going through EU/PU stuff. It would be good if somehow a quick reference were given in response to Anaconda and other PU people.
LC
November 20th, 2009 at 7:04 pm
Apparently, you all feel EU/PC is wrong.
I know Crowell is a big time AGW man.
Apparently, the high priests in AGW got caught with their fingers in the cookie jar:
http://bishophill.squarespace.com/blog/2009/11/20/climate-cuttings-33.html
"Phil Jones says he has use Mann's "Nature trick of adding in the real temps to each series"…to hide the decline".
(Above quote is tip of the iceberg.)
And remarks about putting pressure on peer-reviewed journals to not publish anything that contradicts AGW.
I think it's about time you guys seriously look in the mirror — if you can stand to.
November 21st, 2009 at 11:29 pm
@ Anaconda,
CLICK HERE. (Quick Time player required.)
November 22nd, 2009 at 7:28 pm
D'OH! Forget it, the link has been cut.