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Researchers Using Hubble and Keck Telescopes Find Farthest Known Galaxy in the Universe



 
 
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  #1  
Old February 16th 04, 04:36 AM
Ron
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Default 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)

  #2  
Old February 16th 04, 05:28 AM
N:dlzc D:aol T:com \(dlzc\)
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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


  #3  
Old February 16th 04, 04:15 PM
db
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Default

"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
  #4  
Old February 16th 04, 05:10 PM
Luigi Caselli
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Posts: n/a
Default

"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


  #5  
Old February 16th 04, 05:49 PM
Bjoern Feuerbacher
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Posts: n/a
Default

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
  #6  
Old February 16th 04, 08:33 PM
Ralph Hertle
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Posts: n/a
Default


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.



  #7  
Old February 16th 04, 10:36 PM
Luigi Caselli
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Posts: n/a
Default

"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


  #8  
Old February 17th 04, 12:38 AM
OG
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Posts: n/a
Default


"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



  #9  
Old February 17th 04, 03:12 AM
N:dlzc D:aol T:com \(dlzc\)
external usenet poster
 
Posts: n/a
Default

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


  #10  
Old February 17th 04, 10:47 AM
Bjoern Feuerbacher
external usenet poster
 
Posts: n/a
Default

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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