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Researchers Using Hubble and Keck Telescopes Find Farthest Known Galaxy in the Universe
Caltech News Release
Embargoed for Release at 9 a.m. PST, Sunday, February 15, 2004 Researchers Using Hubble and Keck Telescopes Find Farthest Known Galaxy in the Universe PASADENA, California--The farthest known object in the universe may have been discovered by a team of astrophysicists using the Keck and Hubble telescopes. The object, a galaxy behind the Abell 2218 cluster, may be so far from Earth that its light would have left when the universe was just 750 million years old. The discovery demonstrates again that the technique known as gravitational lensing is a powerful tool for better understanding the origin of the universe. Via further applications of this remarkable technique, astrophysicists may be able to better understand the mystery of how the so-called "Dark Ages" came to an end. According to California Institute of Technology astronomer Jean-Paul Kneib, who is the lead author reporting the discovery in a forthcoming article in the Astrophysical Journal, the galaxy is most likely the first detected close to a redshift of 7.0, meaning that it is rushing away from Earth at an extremely high speed due to the expansion of the universe. The distance is so great that the galaxy's ultraviolet light has been stretched to the point of being observed at infrared wavelengths. The team first detected the new galaxy in a long exposure of the Abell 2218 cluster taken with the Hubble Space Telescope's Advanced Camera for Surveys. Analysis of a sequence of Hubble images indicate a redshift of at least 6.6, but additional work with the Keck Observatory's 10-meter telescopes suggests that the astronomers have found an object whose redshift is close to 7.0. Redshift is a measure of the factor by which the wavelength of light is stretched by the expansion of the universe. The greater the shift, the more distant the object and the earlier it is being seen in cosmic history. "As we were searching for distant galaxies magnified by Abell 2218, we detected a pair of strikingly similar images whose arrangement and color indicated a very distant object," said Kneib. "The existence of two images of the same object indicated that the phenomenon of gravitational lensing was at work." The key to the new discovery is the effect the Abell 2218 cluster's gigantic mass has on light passing by it. As a consequence of Einstein's theory of relativity, light is bent and can be focused in a predictable way due to the warpage of space-time near massive objects. In this case the phenomenon actually magnifies and produces multiple images of the same source. The new source in Abell 2218 is magnified by a factor of 25. The role of gravitational lensing as a useful phenomenon in cosmology was first pointed out by the Caltech astronomer Fritz Zwicky in 1937, who even suggested it could be used to discover distant galaxies that would otherwise be too faint to be seen. "The galaxy we have discovered is extremely faint, and verifying its distance has been an extraordinarily challenging adventure," Kneib added. "Without the magnification of 25 afforded by the foreground cluster, this early object could simply not have been identified or studied in any detail with presently available telescopes. Indeed, even with aid of the cosmic lens, our study has only been possible by pushing our current observatories to the limits of their capabilities." Using the unique combination of the high resolution of Hubble and the magnification of the cosmic lens, the researchers estimate that the galaxy is small--perhaps measuring only 2,000 light-years across-but forming stars at an extremely high rate. An intriguing property of the new galaxy is the apparent lack of the typically bright hydrogen emission seen in many distant objects. Also, its intense ultraviolet signal is much stronger than that seen in later star-forming galaxies, suggesting that the galaxy may be composed primarily of massive stars. "The unusual properties of this distant source are very tantalizing because, if verified by further study, they could represent those expected for young stellar systems that ended the dark ages," said Richard Ellis, Steele Family Professor of Astronomy, and a coauthor of the article. The term "Dark Ages" was coined by the British astronomer Sir Martin Rees to signify the period in cosmic history when hydrogen atoms first formed but stars had not yet had the opportunity to condense and ignite. Nobody is quite clear how long this phase lasted, and the detailed study of the cosmic sources that brought this period to an end is a major goal of modern cosmology. The team plans to continue the search for additional extremely distant galaxies by looking through other cosmic lenses in the sky. "Estimating the abundance and characteristic properties of sources at early times is particularly important in understanding how the Dark Ages came to an end," said Mike Santos, a former Caltech graduate student involved in the discovery and now a postdoctoral researcher at the Institute of Astronomy in Cambridge, England. "We are eager to learn more by finding further examples, although it will no doubt be challenging." The Caltech team reporting on the discovery consists of Kneib, Ellis, Santos, and Johan Richard. Kneib and Richard are also affiliated with the Observatoire Midi-Pyrenees of Toulouse, France. Santos is also at the Institute of Astronomy, in Cambridge. The research was funded in part by NASA. The W. M. Keck Observatory is managed by the California Association for Research in Astronomy, a scientific partnership between the California Institute of Technology, the University of California, and NASA. For more information, visit the observatory online at www.keckobservatory.org. ### Image and further information: http://www.astro.caltech.edu/~kneib/z7/ Contacts:Robert Tindol (626) 395-3631 Jean-Paul Kneib (626) 395 5927 Richard Ellis (626) 395 2598 (626) 676 5530 (cell) |
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Dear Ron:
"Ron" wrote in message om... .... According to California Institute of Technology astronomer Jean-Paul Kneib, who is the lead author reporting the discovery in a forthcoming article in the Astrophysical Journal, the galaxy is most likely the first detected close to a redshift of 7.0, meaning that it is rushing away from Earth at an extremely high speed due to the expansion of the universe. The distance is so great that the I wish they wouldn't say it like this. Expansion is not a bunch of individual objects "rushing away"... and a z (or even z+1) is not a Doppler shift. Maybe its just too easy to present it this way. David A. Smith |
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"N:dlzc D:aol T:com (dlzc)" wrote:
Dear Ron: "Ron" wrote in message om... ... According to California Institute of Technology astronomer Jean-Paul Kneib, who is the lead author reporting the discovery in a forthcoming article in the Astrophysical Journal, the galaxy is most likely the first detected close to a redshift of 7.0, meaning that it is rushing away from Earth at an extremely high speed due to the expansion of the universe. The distance is so great that the I wish they wouldn't say it like this. Expansion is not a bunch of individual objects "rushing away"... and a z (or even z+1) is not a Doppler shift. Maybe its just too easy to present it this way. David A. Smith But "rushing away" does cause a Doppler shift, does it not? db |
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"db" ha scritto nel messaggio
... ... According to California Institute of Technology astronomer Jean-Paul Kneib, who is the lead author reporting the discovery in a forthcoming article in the Astrophysical Journal, the galaxy is most likely the first detected close to a redshift of 7.0, meaning that it is rushing away from Earth at an extremely high speed due to the expansion of the universe. The distance is so great that the I wish they wouldn't say it like this. Expansion is not a bunch of individual objects "rushing away"... and a z (or even z+1) is not a Doppler shift. Maybe its just too easy to present it this way. David A. Smith But "rushing away" does cause a Doppler shift, does it not? In the standard big bang theory Doppler shift is the reason for "rushing away". In other less popular theories this is not so sure... But big bang is so fascinating that almost noone has doubts about strange facts as a galaxy formed only 750 millions years after the big bang (a bit too young)... seen using gravitational lens... some sort of great illusionism like dark everything (matter, energy, holes, etc.) that we discover day after day... But if I can believe Italian politicians I can believe everything... Luigi Caselli |
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Luigi Caselli wrote:
"db" ha scritto nel messaggio ... ... According to California Institute of Technology astronomer Jean-Paul Kneib, who is the lead author reporting the discovery in a forthcoming article in the Astrophysical Journal, the galaxy is most likely the first detected close to a redshift of 7.0, meaning that it is rushing away from Earth at an extremely high speed due to the expansion of the universe. The distance is so great that the I wish they wouldn't say it like this. Expansion is not a bunch of individual objects "rushing away"... and a z (or even z+1) is not a Doppler shift. Maybe its just too easy to present it this way. David A. Smith But "rushing away" does cause a Doppler shift, does it not? In the standard big bang theory Doppler shift is the reason for "rushing away". Sorry, but this makes no sense. Did you want to say: "In the standard big bang theory 'rushing away' is the reason for Doppler shift"? If yes: that would make sense, but would be wrong nevertheless.. In other less popular theories this is not so sure... But big bang is so fascinating that almost noone has doubts about strange facts as a galaxy formed only 750 millions years after the big bang (a bit too young)... This is, AFAIK, consistent with the current view on galaxy formation. Not a trouble for the current hypotheses. seen using gravitational lens... Yes. So what? some sort of great illusionism like dark everything (matter, energy, holes, etc.) that we discover day after day... What's your problem with those? But if I can believe Italian politicians I can believe everything... One should never "believe" a physical theory. One should study it and accept its validity based on the evidence. Bye, Bjoern |
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CeeBee: Do the entities that comprise the universe also increase in size proportionately with the "expanding fabric" of space? If so, why? If not, why not? Ralph Hertle [ quotation included: ] CeeBee wrote: db wrote in sci.astro: But "rushing away" does cause a Doppler shift, does it not? (by db) You probably guessed he wass referring to the common notion of people not familiar with cosmology that the galaxy mentioned above is rushing away from us "through space", while in reality it is the expanding fabric of space itself creating the separation - as well as the "speed" of the separation. For Doppler shift the result is indeed the same. |
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"Bjoern Feuerbacher" ha scritto nel
messaggio ... Luigi Caselli wrote: But "rushing away" does cause a Doppler shift, does it not? In the standard big bang theory Doppler shift is the reason for "rushing away". Sorry, but this makes no sense. Did you want to say: "In the standard big bang theory 'rushing away' is the reason for Doppler shift"? If yes: that would make sense, but would be wrong nevertheless.. You're right (is the "rushing away" that creates Doppler shift), but why is wrong? In other less popular theories this is not so sure... But big bang is so fascinating that almost noone has doubts about strange facts as a galaxy formed only 750 millions years after the big bang (a bit too young)... This is, AFAIK, consistent with the current view on galaxy formation. Not a trouble for the current hypotheses. I'm not so sure. See for example http://www.cnn.com/2004/TECH/space/0...ind/index.html Noone seems to have answer to a young galaxy supercluster like this one. If there are problems to explain galaxies of 10,8 billion years ago how can explain a so young galaxy (13 billions years ago). Maybe superultraspeed inflation? seen using gravitational lens... Yes. So what? No problem, only it's a bit funny to see multiple copies of the same object due to gravitational lens... some sort of great illusionism like dark everything (matter, energy, holes, etc.) that we discover day after day... What's your problem with those? I don't like claiming forces from nowhere to save any theory. But if I can believe Italian politicians I can believe everything... One should never "believe" a physical theory. One should study it and accept its validity based on the evidence. There's no more evidence in cosmology, only indirect effects that you can explain as you like... For example: Strange galaxy rotation? Introduce dark matter of the right quantity to justify it (very easy). Ultraspeed galaxy "rushing away"? Introduce dark energy of the right quantity to justify it (very easy). Search some less dark solutions? Too difficult and risky... Luigi Caselli |
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"Luigi Caselli" wrote in message ... I'm not so sure. See for example http://www.cnn.com/2004/TECH/space/0...ind/index.html Noone seems to have answer to a young galaxy supercluster like this one. If there are problems to explain galaxies of 10,8 billion years ago how can explain a so young galaxy (13 billions years ago). I think the difficulty with the galactic supercluster is that it is SO big when the universe itself was then so small. The COBE survey should have set limits to the unevenness of the early universe and its hard to see how such a large structure could have developed that early. In itself there is no really major problem with galaxy creation well within the first billion years - at 750Million years old, the universe was 6000x denser than at present, so one can imagine a rapid gas cloud collapse without stretching credulity too much. There's no more evidence in cosmology, only indirect effects that you can explain as you like... For example: Strange galaxy rotation? Introduce dark matter of the right quantity to justify it (very easy). Ultraspeed galaxy "rushing away"? Introduce dark energy of the right quantity to justify it (very easy). Search some less dark solutions? Too difficult and risky... Luigi Caselli Yup, broadly you're right; I don't think anyone is pretending that the current model is in any sense complete, and we're at a stage of understanding where the observational material from the very early universe is beginning to outstrip the theory once again. However, we're not ready to chuck out the whole theory quite yet. Owen |
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Dear db:
"db" wrote in message ... "N:dlzc D:aol T:com (dlzc)" wrote: Dear Ron: "Ron" wrote in message om... ... According to California Institute of Technology astronomer Jean-Paul Kneib, who is the lead author reporting the discovery in a forthcoming article in the Astrophysical Journal, the galaxy is most likely the first detected close to a redshift of 7.0, meaning that it is rushing away from Earth at an extremely high speed due to the expansion of the universe. The distance is so great that the I wish they wouldn't say it like this. Expansion is not a bunch of individual objects "rushing away"... and a z (or even z+1) is not a Doppler shift. Maybe its just too easy to present it this way. But "rushing away" does cause a Doppler shift, does it not? Events that occur on the surface of the Sun are red-shifted. They are red-shifted because the density of the space they occur in is higher than where the events are measured... namely on Earth. So to say that those events (on the Sun) are red-shifted because they are rushing away, is incorrect. The ancient Universe had a much higher density. The red shift we perceive of the ancient Universe as compared to the here&now is due primarily to the density of the two Universes. And yes, rushing away does provide a Doppler shift. And no, z+1 is not a Doppler shift, not entirely anyway. David A. Smith |
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Luigi Caselli wrote:
"Bjoern Feuerbacher" ha scritto nel messaggio ... Luigi Caselli wrote: But "rushing away" does cause a Doppler shift, does it not? In the standard big bang theory Doppler shift is the reason for "rushing away". Sorry, but this makes no sense. Did you want to say: "In the standard big bang theory 'rushing away' is the reason for Doppler shift"? If yes: that would make sense, but would be wrong nevertheless.. You're right (is the "rushing away" that creates Doppler shift), but why is wrong? That's a popular misconception about the cosmological red shift. It isn't called by galaxies actually moving - it is caused by the space between galaxies expanding. In other less popular theories this is not so sure... But big bang is so fascinating that almost noone has doubts about strange facts as a galaxy formed only 750 millions years after the big bang (a bit too young)... This is, AFAIK, consistent with the current view on galaxy formation. Not a trouble for the current hypotheses. I'm not so sure. See for example http://www.cnn.com/2004/TECH/space/0...ind/index.html Noone seems to have answer to a young galaxy supercluster like this one. The crucial word here is *supercluster*, not "galaxy". And IIRC, there was even an explanation for this find - the formation of such large clusters at such an early time is not impossible, simply very unlikely. We have found only one such big cluster so far at that early time - only time will tell if there are more like that one. Only *if* there are more, the current theories of galaxy and galaxy cluster formation will be in trouble. If there are problems to explain galaxies of 10,8 billion years ago how can explain a so young galaxy (13 billions years ago). The problem is not with explaining the galaxies. The problem is with explaining how a *cluster* of galaxies (a big structure) could have formed so early. Maybe superultraspeed inflation? No, that makes no sense. Are you sure you know what inflation means? seen using gravitational lens... Yes. So what? No problem, only it's a bit funny to see multiple copies of the same object due to gravitational lens... Yes, that's kind of funny. Sorry if I misunderstood you - it seemed to me if you thought this were some kind of problem. some sort of great illusionism like dark everything (matter, energy, holes, etc.) that we discover day after day... What's your problem with those? I don't like claiming forces from nowhere to save any theory. Dark Matter wasn't postulated simply because of cosmology - there were several lines of evidence for it (galactic rotation curves and galaxy clusters). For Dark Energy, there are two lines of evidence, too (supernovae and CMBR); additionally, it is expected to be there based on QFT. And Black Holes weren't ever postulated to save any theory, so why did you include them above? But if I can believe Italian politicians I can believe everything... One should never "believe" a physical theory. One should study it and accept its validity based on the evidence. There's no more evidence in cosmology, only indirect effects that you can explain as you like... Please present any other theory than the Big Bang which explains all the observations. *Quantitatively*. Not with some vague hand waving. For example: Strange galaxy rotation? Introduce dark matter of the right quantity to justify it (very easy). First, galaxy rotation has nothing to do with cosmology. Second, as mentioned above, there are several lines of evidence for the existence of dark matter - not just one, as you seem to propose here. Ultraspeed galaxy "rushing away"? Introduce dark energy of the right quantity to justify it (very easy). See above. Search some less dark solutions? Too difficult and risky... If you think this is possible, why don't you do it? Hint: not all cosmologists accept the Big Bang theory (there was Hoyle, there still is Narlikar, and so on). They have searched for alternatives. So far, they haven't succeeded in finding one which describes the observations so good as the BBT. The argument "The BBT looks strange to me, I don't like it - surely there is a better explanation somewhere, although I don't know which!" doesn't look very convincing... Bye, Bjoern |
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