The transitory nature of a spiral structure at that epoch could explain why Law and his colleagues found just one spiral in their galactic survey. In fact, BX 442 may have evolved into a different shape in the billions of years since it emitted the light now reaching Earth. "It's impossible to say what happened to that spiral galaxy," Conselice says. "It's not like the galaxy types are set in stone."
BX 442 could also have generated its own spiral structure without a nudge from its neighbor, Elmegreen notes. Clumps of stars and gas within a galaxy can cause spirals to form, and BX 442 appears to contain at least one large clump along one of its spiral arms. "They perturb everything around them, and each clump sort of makes its own tidal tail," Elmegreen says. "That's a rather easy way to get three spiral arms, and this galaxy has three arms."
It may be that numerous different mechanisms can shape a spiral galaxy. Many more examples should be accessible for study once next-generation observatories, such as NASA's James Webb Space Telescope, come online. Until then, astronomers will have to rely on unique specimens such as BX 442 to help clear up which are the dominant forces creating spiral structure at different times in the universe's history. "We don't really have a good explanation for how the spiral arms exist," Conselice says. "There's a lot of questions that we just haven't answered."
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Add CommentThe article states:
Reply | Report Abuse | Link to this"A study last year showed that the Sagittarius Dwarf Galaxy, a satellite of the Milky Way, could be responsible for some of the spiral structure of our own galaxy. As Sagittarius fell inward and passed through the plane of the larger galaxy, its impact would have been strong enough to disrupt a uniform disk of stars and morph it into a familiar spiral. A similar process could explain the atypical spiral nature of BX 442."
Have any galaxies with "a uniform disk of stars" been observed? The suggested mechanism for a small satellite galaxy to perturb an unobserved 'uniform disk' galaxy and produce a spiral galaxy seems wildly speculative unless uniform galaxies have been widely observed.
Perhaps in the much greater expansion of the early universe (even an accelerating universe is not thought to be currently expanding at a rate greater than the early universe), when two fuzzy blob galaxies did interact gravitationally, they began by orbiting each other in an increasingly tighter spin, two black holes dominating tails of trailing gasses and stars as the galactic nuclei eventually merged. This general mechanism should naturally produce a planar disk of spiral arms.
Have any galaxies with "a uniform disk of stars" been observed? The suggested mechanism for a small satellite galaxy to perturb an unobserved 'uniform disk' galaxy and produce a spiral galaxy seems wildly speculative unless uniform galaxies have been widely observed.
Reply | Report Abuse | Link to thisRight in the article it says:
"It's been known for awhile that there are disks at these redshifts. Disks are not surprising, and usually when there are disks locally there are spirals in the disks," he adds. "But at these redshifts spirals have not been seen, and that had been a puzzle."
So I guess the answer to your question would be - yes.
If this article is your only source of information, your guess might be quite reasonable, at least based on the one paragraph you mention. But then that was a quote from a Bruce Elmegreen of IBM's T. J. Watson Research Center in Yorktown Heights, N.Y. Interestingly, he was refernced in http://news.sciencemag.org/sciencenow/2012/07/hubble-spots-the-farthest-spiral.html?ref=hp
Reply | Report Abuse | Link to thisregarding the idea that the small companion galaxy produced the spiral structure:
"However, Elmegreen questions this idea, noting that most spirals stirred up by companion galaxies have two arms, not three. Instead, he says the large amount of gas in the galaxy may be responsible. Although the stars and gas clouds in the galaxy move fast relative to their neighbors, Elmegreen says the gravity of all the gas may overwhelm the high velocity dispersion and mold a spiral pattern."
There is no mention of the term 'uniform discs' in this article except in the suggested mechanism for producing spiral galaxies. A web search indicates that the terms 'uniform disk' are most often used in relation to galaxies to refer to an idealized model of any disk galaxy.
As this article also states:
"Instead of orderly swirls, astronomers see lumpy, blobby galaxies going through the cosmic equivalent of an awkward phase. "At these redshifts, the galaxy population if you look with Hubble mostly looks irregular and peculiar," says astrophysicist Christopher Conselice of the University of Nottingham. "Most of those galaxies are probably undergoing mergers, smashing together." And their stars are not usually confined to a flat, thin, evenly rotating disk."
To jtdwyer
Reply | Report Abuse | Link to thisYou posed the question "Have any galaxies with "a uniform disk of stars" been observed?"
you also stated " when two fuzzy blob galaxies did interact gravitationally, they began by orbiting each other in an increasingly tighter spin,"
Now I pose the same question : Have any fuzzy blob galaxies orbiting in tight intrinsic spins been observed?
obviously, evolution of spirals in large galaxies is subject to lot of speculations ranging from interaction from some satellite galaxy to presence of some large clumps within galaxy. It may be the products of a variety of intrinsic (within galaxy) and extrinsic factors which might have shaped spirals in a galaxy
Author of this article is also stating "It may be that numerous different mechanisms can shape a spiral galaxy. Many more examples should be accessible for study once next-generation observatories, such as NASA's James Webb Space Telescope, come online"
@jtdwyer - Yes, type S0 galaxies are flattened disks without noticeable arms. They can still have clumpy gas clouds in some cases. Here is an example:
Reply | Report Abuse | Link to thishttp://bama.ua.edu/~rbuta/nearirs0/plate014c.jpg
Typology of galaxy shapes predates detailed study of their internal motions, and groups them into 3 general classes, ellipticals (E type), spirals (S type), and barred spirals (SB type). S0 is at the junction of the types, flattened but without arms:
http://www.astr.ua.edu/keel/galaxies/tunfork.gif
DaniEder - yes, I should have been more specific and asked about the specified 'uniform disk' galaxies at the distance of the observed early spiral galaxy.
Reply | Report Abuse | Link to thishttp://en.wikipedia.org/wiki/Disk_galaxy
Disc galaxy types include:
spiral galaxies
- barless spiral galaxies (type S, SA)
- barred spiral galaxies (type SB)
- intermediate barred spiral galaxies (type SAB)
lenticular galaxies (type E8, S0, SA0, SB0, SAB0)
http://en.wikipedia.org/wiki/Lenticular_galaxy
opens stating:
"Lenticular galaxies are disk galaxies (like spiral galaxies) which have used up or lost most of their interstellar matter and therefore have very little ongoing star formation."
This description of lenticular galaxies is not 'universally' accepted, but if it is correct then it's not likely that any 'uniform disk' lenticular galaxies existed in the early universe...
vinodkumarsehgal - You ask: "Have any fuzzy blob galaxies orbiting in tight intrinsic spins been observed?"
I suggest that this is one!
To repeat again, this article states:
"Instead of orderly swirls, astronomers see lumpy, blobby galaxies going through the cosmic equivalent of an awkward phase. "At these redshifts, the galaxy population if you look with Hubble mostly looks irregular and peculiar," says astrophysicist Christopher Conselice of the University of Nottingham. "Most of those galaxies are probably undergoing mergers, smashing together." And their stars are not usually confined to a flat, thin, evenly rotating disk."
If, as many now think, most if not all galaxies are dominated by a supermassive black hole, the merger of two or more galaxies would, at least for some period, necessarily produce the described orbiting supermassive black holes.
As stated in
http://en.wikipedia.org/wiki/Supermassive_black_hole#Supermassive_black_holes_outside_the_Milky_Way
"Some galaxies, such as Galaxy 0402+379, appear to have two supermassive black holes at their centers, forming a binary system. If they collided, the event would create strong gravitational waves. Binary supermassive black holes are believed to be a common consequence of galactic mergers. The binary pair in OJ 287, 3.5 billion light years away, contains the previous most massive black hole known (until the December 2011 discovery), with a mass estimated at 18 billion solar masses. A supermassive black hole was recently discovered in the dwarf galaxy Henize 2-10, which has no bulge. The precise implications for this discovery on black hole formation are unknown, but may indicate that black holes formed before bulges."
You actually exposed your address and password???
Reply | Report Abuse | Link to thisBig bang theory is wrong. Read re cyclic -re bounce theory of matter and antimatter universe on opposite entropy path producing dark energy at common boundary by annihilation and injected into our universe as five god particles--four for four forces and one for mass creation. Standard model is wrong beyond wrong assumption of quarks.
Reply | Report Abuse | Link to thisTo jtdwyer
Reply | Report Abuse | Link to thisDo two binary supermassive BHs in a galaxy always remain as binary pair or do they merge after some time to form a very very large massive BHs. Was SMBH, having mass of 18 billion solar masses, at the center of galaxy OJ 287 due to merger of binary pair of BHs? At the stage of merger of binary SMBHs, there could be emission of very very large violent burst of energies in form of high energy e.m radiations and gravitational force in Galaxy. This may be simply due to reasons that one SMBH shall devour very large mass of another SMBH. Even in case of normal single SMBH like Saggitarus A in case of MW, which has mass of 4 million solar masses, there is outburst of violent energies in form of gamma rays. Such a violent outburst of energies may disturb the entire structure of galaxy. There could also be chances that violent outburst of energies may tear apart the merged galaxy again in two galaxies particularly if merged galaxies is a dwarf one.
But here another issue arises. Why a very very massive BH shall form at the center of a dwarf galaxy? Should not be there some positive correlation between the mass of galaxy and total mass of galaxy? After all, matter in the formation of a central SMBH has to emerge from matter from within that galaxy only.
Since most if not all galaxies are thought to contain a SMBH and galaxies are thought to develop through mergers with other galaxies (with the exception of ancient, small discrete satellite galaxies captured by much larger galaxies), it seems that either SMBHs must merge (without destroying their galaxies) or one must be ejected.
Reply | Report Abuse | Link to thisIt was the authors of the research being reported here that seem to suggest that the companion dwarf galaxy caused the spiral structure to form in BX 442 - my suggestion is that BX 442 is the product of a merger of two (or three) larger galaxies, having nothing to do with the companion dwarf galaxy.
Checking the referenced research report abstract, Law et. al, (2012), "High velocity dispersion in a rare grand-design spiral galaxy at redshift z = 2.18", http://www.nature.com/nature/journal/v487/n7407/full/nature11256.html
- it states:
"Although grand-design spiral galaxies are relatively common in the local Universe, only one has been spectroscopically confirmed to lie at redshift z > 2 (HDFX 28; z = 2.011); and it may prove to be a major merger that simply resembles a spiral in projection."
This would seem to validate the suggestion that the apparent spiral galaxy may be the product of the merger of two (or three) larger galaxies.
The abstract goes on to say "Spectroscopy of ionized gas shows that the disk is dynamically hot, implying an uncertain origin for the spiral structure."
Most of your questions apply to the quotation from wikipedia and should be directed to its authors. Wikipedia entries include a 'Talk' view (select tab) which allows comments, suggestions and questions. If you refer to the wikipedia link provided, you will also find a number of references and additional links that may help you find the answers to your questions.
IMO, SMBH emissions are the product of processes that are applied to ingested matter at the event horizon. I think that the merger of two SMBHs that were not then active would not result in any EM emissions. According to general relativity they should produce gravitational waves, as mentioned in the wikipedia entry. There is no evidence that such mergers would tear the galaxy apart - I can't speak to predictions of any theory.
100 million years or so! It is very likely that I will not be around to see that.
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