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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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Researchers Using Hubble and Keck Telescopes Find Farthest Known Galaxy in the Universe
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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Researchers Using Hubble and Keck Telescopes Find Farthest KnownGalaxy in the Universe
"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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Researchers Using Hubble and Keck Telescopes Find Farthest Known Galaxy in the Universe
"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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Researchers Using Hubble and Keck Telescopes Find Farthest KnownGalaxy in the Universe
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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Researchers Using Hubble and Keck Telescopes Find Farthest KnownGalaxy in the Universe
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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Researchers Using Hubble and Keck Telescopes Find Farthest Known Galaxy in the Universe
"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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Researchers Using Hubble and Keck Telescopes Find FarthestKnownGalaxyin the Universe
Bart Mathias wrote:
Bjoern Feuerbacher wrote: Bart Mathias wrote: ... Back in my youth I read an analog of the expanding universe (might possibly have been in George Gamow's _One Two Three Infinity_) with dots on a balloon that was blown up. Yes, that's a common analogue. Unfortunately many people confuse this analogue with reality and thus take it too far... That analogy has space expanding but the "galaxies" expand as well. The analogy would be better if you wouldn't point dots on the balloon, but glue cent pieces to it. But then we're seemingly back to it being not space per se that is expanding, but we're getting more units of intergalactic space: Huh? Where do you see the difference between these concepts? the galaxies are moving apart and there are more light years between them. Or, alternatively, the space between the galaxies is expanding! Consider if a line representing a light year had been painted on the balloon. Doesn't work--you have to glue on a piece of thread. Yes, obviously. There's another common analogy that doesn't work, the one for visualizing curved space-time. You imagine a large ball on an elastic sheet, That makes the sheet curve down, so if you roll a small ball across the sheet it will roll down around the big ball. How would that work in the space station? According to the analogy, gravity is caused by gravity! Yes, that's another analogy I don't like very much, for precisely this reason. It can be improved of you don't take only one elastic sheet, but two, between which the small ball is "trapped". I think in this case, the small ball would roll around the big ball even without gravity pulling it down. Bye, Bjoern |
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Researchers Using Hubble and Keck Telescopes Find Farthest Known Galaxy in the Universe
"N:dlzc D:aol T:com (dlzc)" N: dlzc1 D:cox wrote in message news:z%yYb.1578$4K3.274@fed1read06... Dear OG: "OG" wrote in message ... "N:dlzc D:aol T:com (dlzc)" N: dlzc1 D:cox wrote in message news:0MeYb.435$C21.161@fed1read07... 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. Density of space ? What are the units of that then?? cubic metres per cubic metre??? Density of the Universe, like the density of anything else is typically mass/volume^3. So an ancient Universe that was only tens of light years in diameter (based on the CMBR), and the Universe today would have different densities. Assuming the amount of mass has not changed. 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. That seems a very odd thing to say. Surely if you were right, then the red shift of distant objects would go as the third power of distance, rather than linearly with distance as observed. Two things... Dark Matter was not evident at the time of the CMBR, and the relationship between "time rate" and density may not be linear. I find the simplified relationship: /\T/T = g/\R/c^2 at URL:http://www.pact.cpes.sussex.ac.uk/~markh/GR/node24.html Substituting... g = GM/R^2 /\T/T = G*M/c^2 * /\R/R^2 It's not third order in radius... Allowing rho = M/R^3 /\T/T = G*/\R*R/c^2 * rho It appears first order in density, but it leaves the extra R term as a nasty. David A. Smith Hi David, I've been away - otherwise I would have replied earlier. I think you are mistaken in talking about 'density' in respect of red shift - if by that you mean the density of the gas producing the spectral features. The spectral lines in the solar spectrum are created in the photosphere which is very much lower density than the earth's atmosphere. So in your model the spectral lines would be 'blue shifted' as they moved from the low density photosphere to practically zero density space between the sun and the earth and back into the 1300g/m^3 Earth's atmosphere. Now, maybe you meant something other than 'density', but that's what you said. Going back to the website you referred to; that gives an equation for calculating time dilation between two points in a radial gravitational field - I would be surprised if it can be straightforwardly applied to derive a 'cosmolological red shift' in the way you hope. For instance - the term R in the formula is used to give a distance from the centre of gravity, and I don't accept that it can be used to represent a scale size of the universe in the way you have done. If you can provide any good references I would be interested to read further about this. Owen |
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Researchers Using Hubble and Keck Telescopes Find Farthest Known Galaxy in the Universe
Dear OG:
"OG" wrote in message ... "N:dlzc D:aol T:com (dlzc)" N: dlzc1 D:cox wrote in message news:z%yYb.1578$4K3.274@fed1read06... Dear OG: "OG" wrote in message ... .... 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. That seems a very odd thing to say. Surely if you were right, then the red shift of distant objects would go as the third power of distance, rather than linearly with distance as observed. Two things... Dark Matter was not evident at the time of the CMBR, and the relationship between "time rate" and density may not be linear. I find the simplified relationship: /\T/T = g/\R/c^2 at URL:http://www.pact.cpes.sussex.ac.uk/~markh/GR/node24.html Substituting... g = GM/R^2 /\T/T = G*M/c^2 * /\R/R^2 It's not third order in radius... Allowing rho = M/R^3 /\T/T = G*/\R*R/c^2 * rho It appears first order in density, but it leaves the extra R term as a nasty. Hi David, I've been away - otherwise I would have replied earlier. No issues. I think you are mistaken in talking about 'density' in respect of red shift - if by that you mean the density of the gas producing the spectral features. The spectral lines in the solar spectrum are created in the photosphere which is very much lower density than the earth's atmosphere. So in your model the spectral lines would be 'blue shifted' as they moved from the low density photosphere to practically zero density space between the sun and the earth and back into the 1300g/m^3 Earth's atmosphere. Now, maybe you meant something other than 'density', but that's what you said. I refer to the density of the entire Universe, at two different times. The instant of emission occured in a Universe with a mass M_u, and a size R_u. Absorption occured in a Universe that is likely close to M_u, but R_u is now larger. So the "time base" for the absorbing Universe is short, compared to the "time base" at emission. Going back to the website you referred to; that gives an equation for calculating time dilation between two points in a radial gravitational field - I would be surprised if it can be straightforwardly applied to derive a 'cosmolological red shift' in the way you hope. For instance - the term R in the formula is used to give a distance from the centre of gravity, and I don't accept that it can be used to represent a scale size of the universe in the way you have done. It would be naive to think it could be that easy. And it would be a pretty boring Universe if everything were that easy. But my point was only that the time base might not have to vary by 1/r^3. I am not up to a reasonable attempt at what the quantitative relationship should be. If you can provide any good references I would be interested to read further about this. I do not find any web sites that have my "unique" interpretation of red shift. This one is always good: URL:http://www.astro.ucla.edu/~wright/cosmo_02.htm. Anyway, think Shapiro time delay, if you are concerned about light passing through empty space. I will only offer that we are moving at 200-300 km/sec wrt the Universe at large, and likely have done so since we were embedded in the CMBR. If "rushing away" from the ancient Universe is the correct terminology, then we do so along the time axis. I just don't think "rushing away" is the right terminology, which is why I was bitching. It has the baggage of describing "where did the energy come from" to make us "rush away", faster and faster. Are you OK with "rushing away" to describe the red shift? Maybe I'm just being too critical... David A. Smith |
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