Astronomers detect the farthest galaxy yet with Keck telescope

September 4, 2015 by Rod Pyle
Astronomers detect the farthest galaxy yet with Keck telescope
Galaxy EGS8p7, as seen from the Hubble Space Telescope (wide and top right) and Spitzer Space Telescope (inset, bottom right), taken in infrared. Credit: I. Labbé (Leiden University), NASA/ESA/JPL-Caltech

A team of Caltech researchers that has spent years searching for the earliest objects in the universe now reports the detection of what may be the most distant galaxy ever found. In an article published August 28, 2015 in Astrophysical Journal Letters, Adi Zitrin, a NASA Hubble postdoctoral scholar in astronomy, and Richard Ellis—who recently retired after 15 years on the Caltech faculty and is now a professor of astrophysics at University College, London—describe evidence for a galaxy called EGS8p7 that is more than 13.2 billion years old. The universe itself is about 13.8 billion years old.

Earlier this year, EGS8p7 had been identified as a candidate for further investigation based on data gathered by NASA's Hubble Space Telescope and the Spitzer Space Telescope. Using the multi-object spectrometer for infrared exploration (MOSFIRE) at the W.M. Keck Observatory in Hawaii, the researchers performed a spectrographic analysis of the galaxy to determine its redshift. Redshift results from the Doppler effect, the same phenomenon that causes the siren on a fire truck to drop in pitch as the truck passes. With celestial objects, however, it is light that is being "stretched" rather than sound; instead of an audible drop in tone, there is a shift from the actual color to redder wavelengths.

Redshift is traditionally used to measure distance to galaxies, but is difficult to determine when looking at the 's most distant—and thus earliest—objects. Immediately after the Big Bang, the universe was a soup of charged particles—electrons and protons—and light (photons). Because these photons were scattered by free electrons, the could not transmit light. By 380,000 years after the Big Bang, the universe had cooled enough for and protons to combine into atoms that filled the universe, allowing light to travel through the cosmos. Then, when the universe was just a half-billion to a billion years old, the first galaxies turned on and reionized the neutral gas. The universe remains ionized today.

Prior to reionization, however, clouds of neutral would have absorbed certain radiation emitted by young, newly forming galaxies—including the so-called Lyman-alpha line, the spectral signature of hot hydrogen gas that has been heated by ultraviolet emission from new stars, and a commonly used indicator of star formation.

Because of this absorption, it should not, in theory, have been possible to observe a Lyman-alpha line from EGS8p7.

"If you look at the galaxies in the early universe, there is a lot of neutral hydrogen that is not transparent to this emission," says Zitrin. "We expect that most of the radiation from this galaxy would be absorbed by the hydrogen in the intervening space. Yet still we see Lyman-alpha from this galaxy."

They detected it using the MOSFIRE spectrometer, which captures the chemical signatures of everything from stars to the distant galaxies at near-infrared wavelengths (0.97-2.45 microns, or millionths of a meter).

"The surprising aspect about the present discovery is that we have detected this Lyman-alpha line in an apparently faint galaxy at a redshift of 8.68, corresponding to a time when the universe should be full of absorbing hydrogen clouds," Ellis says. Prior to their discovery, the farthest detected galaxy had a redshift of 7.73.

One possible reason the object may be visible despite the hydrogen-absorbing clouds, the researchers say, is that hydrogen reionization did not occur in a uniform manner. "Evidence from several observations indicate that the reionization process probably is patchy," Zitrin says. "Some objects are so bright that they form a bubble of ionized hydrogen. But the process is not coherent in all directions."

"The galaxy we have observed, EGS8p7, which is unusually luminous, may be powered by a population of unusually hot stars, and it may have special properties that enabled it to create a large bubble of ionized hydrogen much earlier than is possible for more typical at these times," says Sirio Belli, a Caltech graduate student who worked on the project.

"We are currently calculating more thoroughly the exact chances of finding this galaxy and seeing this emission from it, and to understand whether we need to revise the timeline of the reionization, which is one of the major key questions to answer in our understanding of the evolution of the universe," Zitrin says.

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Tuxford
1.9 / 5 (13) Sep 04, 2015
"We are currently calculating more thoroughly the exact chances of finding this galaxy and seeing this emission from it, and to understand whether we need to revise the timeline of the reionization, which is one of the major key questions to answer in our understanding of the evolution of the universe," Zitrin says.


In other words, "We are working furiously on another patch to the Huge Bang Fantasy," said the committed merger maniac.
docile
Sep 04, 2015
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viko_mx
Sep 04, 2015
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viko_mx
1.4 / 5 (9) Sep 04, 2015
The accuracy of their measuring methods can not be checked when we are observing the universe only from one point in cosmic space. Кnowledge of type sand tower.
Steve 200mph Cruiz
4.5 / 5 (15) Sep 04, 2015
No tuxford,
It's called checking your data because these people aren't freaking idiots
matt_s
4.7 / 5 (14) Sep 04, 2015
Aw how sad, the first theory viko suggests has been disproved. The other is cute speculation. Please present a link to prove the concept you suggest is viable and would result in what we see as redshift. I'm guessing you can't.

You can read all about your first theory here....
https://en.wikipe...ed_light

"Serious scientists?" Sounding like JVK now.
matt_s
4.6 / 5 (11) Sep 04, 2015
"Additionally, the surface brightness of galaxies evolving with time, time dilation of cosmological sources, and a thermal spectrum of the cosmic microwave background have been observed — these effects should not be present if the cosmological redshift was due to ANY tired light scattering mechanism."

matt_s
4.6 / 5 (11) Sep 04, 2015
" but this is only hypothesis which can not be proved by physical experiments"

So apparently the Pound–Rebka experiment never happened?
Tuxford
1.7 / 5 (11) Sep 04, 2015
"Additionally, the surface brightness of galaxies evolving with time, time dilation of cosmological sources, and a thermal spectrum of the cosmic microwave background have been observed — these effects should not be present if the cosmological redshift was due to ANY tired light scattering mechanism."


Oh like the observed non-time-dilation in otherwise observed time dilating quasars. Matt, don't be so gullible, or you might fall for the Huge Bang Fantasy.

http://phys.org/n...ies.html
viko_mx
1.6 / 5 (7) Sep 05, 2015
@ matt_s

Let see what kind of evidence is the experiment of Pound–Rebka. After you see the wikipedia as the source of reliable information I quote the part of article that explain this experiment:

"The Pound–Rebka experiment is a well known experiment to test Albert Einstein's theory of general relativity. It was proposed by Robert Pound and his graduate student Glen A. Rebka Jr. in 1959,[1] and was the last of the classical tests of general relativity to be verified (in the same year). It is a gravitational redshift experiment, which measures the redshift of light moving in a gravitational field, or, equivalently, a test of the general relativity prediction that clocks should run at different rates at different places in a gravitational field. It is considered to be the experiment that ushered in an era of precision tests of general relativity."

viko_mx
1.6 / 5 (7) Sep 05, 2015
"This experiment is based on the _principle_ that when an atom transitions from an excited state to a ground state, it emits a photon with a characteristic frequency and energy. Conversely, when an atom of the same species, in its ground state, encounters a photon with the same characteristic frequency and energy, it will absorb the photon and transition to the excited state. If the photon's frequency and energy is different by even a small amount, the atom _cannot_ absorb it (this is the basis of Quantum mechanics). "

Here is the catch. The author speaks about atoms as emitters of photons (electromagnetic energy), but what exactly in atoms? They are made up of various elementary particles which can emit photons with discrete values ​​of energy. Electrons, protons, neutrons. Energy state of the photon is a discrete positive value or sum of any possible discrete values ​​of energy that can receive. Any physical impact on it does not change this fact.
viko_mx
1.5 / 5 (8) Sep 05, 2015
The photon can be received by the electrons energy orbiting in the upper orbits and excess part is radiated back by these electrons and can be absorbed by nucleus or transformed in mechanical momentum of atom atomic nucleus gets gets additional momentum.
Benni
2.6 / 5 (5) Sep 05, 2015
"It is a gravitational redshift experiment, which measures the redshift of light moving in a gravitational field, or, equivalently, a test of the general relativity prediction that clocks should run at different rates at different places in a gravitational field. It is considered to be the experiment that ushered in an era of precision tests of general relativity."


It is the relative strength of one gravity field compared to another that determines the differences in rate at clocks will run when comparing them to one another. This is the same effect that creates redshifting when photons enter & exit gravity fields of any strength also creating gravitational lensing effects.
docile
Sep 05, 2015
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viko_mx
1.7 / 5 (6) Sep 05, 2015
In fact the prerequisites and assumptions for this experiment are wrong. "The main problem with this explanation lies in the conceptualization of a physical process by which mass, momentum and energy could be either added to or subtracted from a photon without changing its velocity or angular momentum. Such a mechanism has never been proposed except for a mathematical description of a four-dimensional substance called a "space-time continuum." This is a non-Doppler explanation of the shifts in which both source, observer and all photons are in the same inertial reference frame and the photons move at exactly C relative to both source and observer."
docile
Sep 05, 2015
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docile
Sep 05, 2015
This comment has been removed by a moderator.
docile
Sep 05, 2015
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AGreatWhopper
4.3 / 5 (12) Sep 05, 2015
We're getting there. Except for Steve and Matt's brief comments it's good to see people letting the mentally ill babble amongst themselves without dignifying it with a response.

That is the one thing that might change PO's mendacious policies that lead to the incredible load of trolls and mental cases posting. If it gets so that every article only has troll babble, they will be forced to change. It would be nice to attempt some decent discussion every now and then, but better to hold off until they reform their trolling policy, lest you get into something interesting only to be interrupted by returners/benni or someone like tuxford saying, "Hey! Look at this dingle berry I just dug out of my butt. I think it's composed of anti-matter. That fits my theory of everything in that...".
Benni
2.1 / 5 (7) Sep 06, 2015
We're getting there. Except for Steve and Matt's brief comments it's good to see people letting the mentally ill babble amongst themselves without dignifying it with a response.


......the very reason I don't Comment on anything you post or on which to take the bother giving you so much as a 1 Star, you never post anything about science worth reading about, just your persistent psychobabble about who should be classified as trolls & who shouldn't be so classified.

You've already demonstrated how little you know about the effects of gravity in creating redshifting when you gave me a 1 Star vote above, with that being in evidence as to how little you comprehend the Einstein Field Equations, why should those of us whose life's endeavors are totally invested in science believe that you yourself are anything other than what you complain about? Yeah, just one more "troll".

Captain Stumpy
4.5 / 5 (8) Sep 06, 2015
If it gets so that every article only has troll babble, they will be forced to change
@Whopper
doubtful... if history is any indication, then they thrive on the troll posts because it givens the impression of public support for articles... the more the posts, the more advertising they can get, the more money then cay charge per advert because the more popular the site is

the only way they will get rid of trolls like benni and others is to actually moderate the comments: this is demonstrated most effectively in sites like SciForums and Sapo's Joint... moderated and perma-banned is the only solution

even current bans on PO are not effective: see docile/zephir above
he has dozens of sock puppets

problem is: if they moderate, they lose all the floods of posts that pad the count, which then affects the bottom line in $$$$

they will not change until it pays to moderate!
mytwocts
4.5 / 5 (8) Sep 06, 2015
@Benni
"those of us whose life's endeavors are totally invested in science"
That does not include you. You are incapable of science.
Your sanctimonious credo should not fool anyone.
Egleton
2.6 / 5 (5) Sep 06, 2015
I suppose that psyorg could retreat into a self referential, ivory tower where the ultra sophisticated go to preen each other's egos' and stab each other in the back in sterile genteelness, but then it would be just another peer reviewed journal.
And I don't trust peer review because of the cowardly fear that the peers have of losing their place at the table and censor any evidence that might raise an eyebrow of their august colleagues.
I love psyorg just the way it is. Warts and all. Although I do wish some would reign in their egos. Remember it is not all about you, but about the thoughts and evidence you bring to bear.

I have a delightfully devastating bit of evidence. The aether exists. And has a measurable sidereal component.
https://www.dropb...txt?dl=0
Captain Stumpy
5 / 5 (6) Sep 07, 2015
And I don't trust peer review because of the cowardly fear that the peers have of losing their place at the table and censor any evidence that might raise an eyebrow of their august colleagues
@eglet
there is noting better, though, and you suggest nothing superior to the peer review system

even with the retractions that have made news, the statistics still show that the best and most accurate system is the peer review in place today
evidence. The aether exists
that was HILARIOUS
thanks

of course... the scientific method is about replication and validation, you know

considering the date of your "link" and the credibility of the link, and the lack of validation.... it is no different than me claiming "i am a toyota" because i stood in a garage once and took a pic of it
antialias_physorg
5 / 5 (7) Sep 07, 2015
And I don't trust peer review because of the cowardly fear that the peers have of losing their place at the table and censor any evidence that might raise an eyebrow of their august colleagues.

It's pretty obvious that
a) you don't know who does peer review
b) you don't know what the relation of the area of research of the author and those of the peer reviewers are
c) who actually writes scientific paper
d) how peer review actually works

Please try to look up these things and you will notice how very wrong you are.

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