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antoniseb
2004-Apr-28, 04:03 PM
There are a number members of this forum that are proponents of theories that dispute cosmological expansion as the cause of the red shift observed to distant light sources [galaxies and quasars mostly].

If the red shift is not due to cosmological expansion, then the universe could very well be much older than 13.7 billion years, and the state of the universe seven to twelve billion light-years away and seven to twelve billion years ago should pretty much the same as what we see [more easily] within only a few hundred million light-years.

If differences are observed that can't be disputed, this will cause some difficulty and need for modification to these theories. If no difference is observed when one should be, this will be difficult for the Big Bang cosmology to handle.

Note that there have been some surprises in the chemical maturity of the early universe. This may not be a slam dunk for either side.

I'm looking for observations and pointers to on-line papers and research.

Tim Thompson
2004-Apr-29, 01:59 AM
I think one has to understand the idea of surprises in context. When the first extrasolar planets were discovered, and found to be both (a) giant, and (b) really close to their parent stars, the astronomical community was genuinely surprised. Everyone had assumed that such proximity to the star would blow away the atmosphere of any gas giant planet very quickly. But noone had ever actually run a model, or done a calculation, they just assumed that it should be so, that it made sense. But once such surprising planets were found, there was a flurry of activity running models and calculating atmosphere erosion rates, and all the results quickly showed that noone should have been surprised. Had they done the calculations first, they would not have been surprised. The atmospheres are in fact far more robust than guessed.

The state of affairs concerning the chemical maturity of the early universe is quite the same, except that there is little in the way of models to run. It is far more difficult to model galaxy formation than it is to model atmospheric erosion. So the surprise is based purely on intuition, a guess, that galaxies should evolve "slowly". But in fact, nobody really knows enough about how galaxies form, in order to know enough to think they should be surprised. People who don't like big bang cosmology like to use the idea of surprise to suggest that there is a real problem here for big bang cosmology. But the reality is that rapid galactic evolution in the early universe, in big bang cosmology, won't be a problem until there is a real model, in the context of which the problem can be seen quantitatively. For the time being, it's enough to know that galaxies evidently formed very quickly, and to try to understand how that happened, and through that understanding, discover if it really is a real problem.

One must also not lose sight of the salient fact that galaxies in the early universe do not look like galaxies in our current universe. Morphological evolution is most obvious, as illustrated by images from the venerable Hubble Space Telescope:
Hubble Identifies Primeval Galaxies, Uncovers New Clues to the Universe's Evolution (http://hubblesite.org/newscenter/newsdesk/archive/releases/1994/52/), December 6, 1994.
Hubble Sheds Light on the "Faint Blue Galaxy" Mystery (http://hubblesite.org/newscenter/newsdesk/archive/releases/1995/08/), July 25, 1995, an observation that the early universe was dominated by galaxies that were physically smaller than is typical in the current universe.
Hubble Sees Early Building Blocks of Today's Galaxies (http://hubblesite.org/newscenter/newsdesk/archive/releases/1996/29/), September 4, 1996, especially the reference to faint blue sub-galactic clumps (http://hubblesite.org/newscenter/newsdesk/archive/releases/1996/29/image/b), reinforcing my earlier comment.
The Secret Lives of Galaxies Unveiled in Deep Survey (http://hubblesite.org/newscenter/newsdesk/archive/releases/2003/18/), June 19, 2003, a reference to the GOODS survey (http://www.stsci.edu/science/goods/) that then included HST (http://www.stsci.edu/hst/) & Chandra (http://cxc.harvard.edu/), and will now include the Spitzer Space Telescope (http://www.spitzer.caltech.edu/); results thus far are consistent with the hierarchical model of galaxies being built from smaller sub-galaxies or dwarf galaxies.
Hubble's Deepest View Ever of the Universe Unveils Earliest Galaxies (http://hubblesite.org/newscenter/newsdesk/archive/releases/2004/07/), March 9, 2004, the Ultra Deep Field, too soon for much analysis, but look for this to figure in the study of early galaxies.

I don't have time to try to summarize the literature now. But I can tell you that there is a great deal of evidence to show real galactic evolution (i.e., despite some claims to the contrary, galaxies "today" do not look like galaxies in the early universe). There is also much work on galaxy formation. The major stumbling block has been a lack of computational power. Newer, faster computers, and new methods for solving gravitational million-body (http://www.ids.ias.edu/~piet/act/astro/million/index.html) and trillion-body (http://www.ids.ias.edu/~piet/act/astro/trillion/index.html) problems, are fast making real models of real galaxy formation something that we can expect in the next decade, if not sooner.

Cambo
2004-Apr-29, 06:34 AM
Hooray at last a post by Tim Thompson I can actually understand!
Must be getting something through osmosis. Gosh reading is good for you!

Now to follow the links and see if I can understand further.

antoniseb
2004-Apr-29, 11:25 AM
Originally posted by Tim Thompson@Apr 29 2004, 01:59 AM
galaxies in the early universe do not look like galaxies in our current universe.
Thanks Tim,

I've seen most of these already, and I personally start assuming that this is correct. I made a statement about this in another thread recently and was called on it. Madman pointed to this site http://www.gemini.edu/project/announcement...ess/2004-1.html (http://www.gemini.edu/project/announcements/press/2004-1.html), and quoted a section that says that we are seeing lots of star burst galaxies in the most distant images, but that there is an observational bias that we would ONLY see starburst galaxies at that distance and redshift unless we took MUCH deeper images. The source seemed reputable.

The question came up about density of galaxies in the early universe compared to currently. For z=6, all other things being equal [they aren't] there should be about 50 times as many galaxies per cubic megaparsec as we see locally, but none of us could tell what kind of density we were seeing in the HUDF.

GOURDHEAD
2004-Apr-29, 01:33 PM
Because I choose to believe that nature opposes "infinite density" as strongly as it does a vacuum and because I choke on the concept of "something from nothing" I am being converted to bigbangism at something less than glacial speed. In an attempt to delude myself that I have an open mind on the subject, I try to think as if the big bang really happened. So much for my bias.

Can the ratio of hydrogen to the other elements as observed spectroscopically from 12 billion years ago until now be a help in sorting this out? Is our technology currently up to the task at a sufficiently accurate quantitative level? If star formation was initiated early and due to the much higher density (same mass smaller volume) it seems reasonable that the collapse from protostellar coulds into stars would have generated a high ratio of stars with masses and lives commensurate with supernova formation hence a more rapid production of second generation clouds from which stars of high metalicity and life supporting planets might have formed.

Immediately after the big bang the universe is believed to have been mostly hydrogen and helium (80/20 or so). If there were a large number of element factories in the first 2 billion years the ratio of helium and hydrogen to the heavier elements should be measurably different as a function of time assuming spectral analysis of the starlight from the 11-billion year old galaxies is doable. This may be an easier measurement than that of counting the number of galaxies per unit volume since some of them may be obscured or too faint.

How accurately have we assessed the content of the space between the galaxies at the present time?

In another part of my brain I brainstorm for a method by which the magnetism of black holes assists the escape of high energy photons along the magnetic poles which decay into particles and anti-particles thus recycling hydrogen. If true this would corrupt the hydrogen ratio characterization of the history of the universe.

More later on the statistical probabilities of higher element generation shortly after the end of the inflationary period prior to star formation.

madman
2004-Apr-30, 12:13 AM
i agree with Tim on a few points...surprises are just new data that usually fits with general/standard theory...if they don't, then it means "new science" to explore, and new lessons about the workings of the universe (something to get excited about..not distressed by). you should only worry if someone is trying to annex new (or any) information to bolster some bodgy theory.

i'm not here to push any big bang or steady state theory.. and i'm not interested in being part of an argument thats based on a competition between 2 defined competitors.
i posted the link to the gemini deep deep survey results, partly because it appeared to qualify the statement put by antoniseb. "it is very easy to show that distant galaxies have a greater likelyhood of being smaller, in a merger, having an AGN, and in having starburst behavior"
(it also addresses the data Tim has posted as i'll explain later)

the authors themselves raised the issue of the unexpected (by theory) results. Tim agrees with them, that theory might need to be tweaked to accommodate the changes necessary for the data to fit hierarchical models....big bang cosmology was sort of "painted into a corner" by the pronouncement of 13.7 billion years from the wmap results. but now the wmap data is under revue over concerns of contamination, and who knows..the goalpost of 13.7 bly might even be moved to a greater distance and iron out any problems about evolution/time?..anything could happen.


Tim said
"People who don't like big bang cosmology like to use the idea of surprise to suggest that there is a real problem here for big bang cosmology"

please don't equate the presentation of information as a product and proof that the presenter has a specific agenda to promote..ie: you surprised us! therefore you must be an anti big bang nut (who are the only ones that "try to suggest that there is a real problem for big bang cosmology").
sorry Tim, i didn't put the words in the authors' mouths...i just passed the story along.

the authors of the article surprised me too..am i supposed to think that they are bad, nuts or really anti big bang/steady state theorists in disguise?
they say, that the data shows objects that shouldn't be there (according to big bang evolutionary theory)...it's their "surprise" that is being promoted by them in the article..shouldn't we empathise with their concerns rather than lump them in (by association) with the "steady state nuts" and think of them as losers for not realising "everything's okay...it's not the end of the world".

i presented the article in the same way the gemini team did....neither i, nor they declared.."aha!..steady state wins!"
their data did not dovetail with standard big bang evolution, for them (and as a situation that they project upon their peers) it seems problematic......they even wonder if they need a new model?...the "surprise (that shouldn't be a surprise)" apparently strains credibility of their models ("It is unclear if we need to tweak the existing models or develop a new one in order to understand this finding,")
but, the accepted evidence still appears to lean more heavily in the favour of a big bang, so, attempts will be made to correlate the data...that's it (for the big bang hierarchical modellers), as you've also concluded.

but that still leaves the main point i raised in the other thread...that if "the team" is out trying to square their model with reality, then there is still no closure on the subject.



sorry to use harsh thoughts in reply, but you set the level of perception as one of "a bad guy(steady state nut) just rode into town, looks like trouble".

there's no trouble, so, relax.

************************************************** *******************

Tim, the hst might seem to be the best tool to apply to this problem, but it isn't....yes, it is above the atmosphere, bypassing problems of atmospheric distortion and obscuration of wavelengths... and has made the deepest and most detailed detections (within inherent limits).

but this does not help it do a better job than gemini in deep imaging and spectroscopic surveys.

hubble (like all telescopes/detectors) is limited by the frequencies it can obtain...but however distant/redshifted an object is, will determine what portion of it's energetic components will shift into the observable range of hubble...(nicmos does extend this range into the near infrared...but not as far as gemini).

a few years back there was some concern amongst the hst crew about this predicament. that the farther away an object is, the further it's light will be redshifted (uv shifted into optical..optical shifted into near ir..near ir shifted into mid ir). and depending on the structure of the galaxy viewed, different morphologies will be seen by hst.

http://hubblesite.org/newscenter/newsdesk/...2001/04/image/a (http://hubblesite.org/newscenter/newsdesk/archive/releases/2001/04/image/a)

************************************************** ******************

hubbles' (including nicmos') range does not extend as far as gemini(north) into the infrared.

range of hst (with nicmos) = 1150 - 25000 angstroms = 115 - 2500 nanometres = 0.115 - 2.5 microns
range of Gemini = 10000 - 55000 angstroms = 1000 - 5500 nanometres = 1 - 5.5 microns
************************************************** **************************

http://www.nrc-cnrc.gc.ca/newsroom/news/al...altair03_e.html (http://www.nrc-cnrc.gc.ca/newsroom/news/altair03_e.html)

quote from the article:
"One of the big questions facing the international astronomy community today is how stars and galaxies form. While the Hubble Space Telescope (HST) provides excellent high-resolution images, Gemini coupled with Altair will be able to capture infrared images of fainter, hence more distant, galaxies with three times the resolution. Astronomers also need to study the spectra of distant galaxies to understand what is happening within them.

The Gemini Observatory's light gathering power (10 times that of the HST) combined with the extra resolution provided by the Canadian-built Altair, will allow Gemini's infrared spectrographs to study the inner workings of galaxies in depth.

"So now Hubble becomes our finding chart, and Gemini does the physics on what Hubble sees," says Dr. Matt Mountain, Director of the Gemini Observatory."

************************************************** *************************

at high redshifts, optical components will shift towards infrared.
redshifted ultraviolet/blue components/objects will be most easily seen by hst.
redshifted red components/objects will be better seen by gemini.

to present hst images as evidence of:

1) "true forms at high redshift" ....is incorrect...they are instead the bright/high energy components of the objects. (ie: "it is very easy to show that distant galaxies have a greater likelyhood of being smaller, in a merger, having an AGN, and in having starburst behavior")

2) "the whole menagerie" ..is incorrect...red objects have shifted into near infrared/mid infrared and are not represented well.

you should have a new catch cry "no science without representation!"


a better solution to the problem of observing highly redshifted objects will be covered by the jwst.

************************************************** *****************

antoniseb
2004-Apr-30, 12:41 PM
Originally posted by madman@Apr 30 2004, 12:13 AM
please don't equate the presentation of information as a product and proof that the presenter has a specific agenda to promote
Thanks for a solid contribution to the topic. I've read my post over and don't see how it did anything to interpret which side of this topic you were on. I am thankful for your having pointed out the possible hole.

i'm not interested in being part of an argument thats based on a competition between 2 defined competitors.
Sorry if that's the way this comes across. I was interested in knowing what evidence is out there that can resolve this question. I am interested in the question because it appears to be a strong argument for the expanding universe cosmologies. I also feel that it is important to challenge accepted models, but the new model must not fail to explain what is observed, or it is not really a challenge. I see this sort of thread as giving more credence to alternative theories than silence, and at the same time, it helps winnow out the really junky theories pretty quickly.

madman
2004-Apr-30, 01:21 PM
maybe there is no viable alternative theory at the moment...there might be some important factor that we have not discovered yet..and might not discover for years/decades/etc?

antoniseb
2004-Apr-30, 01:39 PM
Originally posted by madman@Apr 30 2004, 01:21 PM
maybe there is no viable alternative theory at the moment
Yes, but we can't know if alternative theories are impossible, or simply constrained by observations without exploring them. Most of these theories aren't terribly well expressed or worked out with all phenomena in mind. I'm interested in trying to know what the proponent actually means. If a theory starts off seeming too bodgy, you don't need to explore them.

madman
2004-May-03, 05:56 AM
here's a qualification for the statement that hubble cannot see red objects in deep surveys, and gemini can. (corrected version)

the deep field observations relate to the search for hierarchical or evolutionary objects at redshifts higher than 1, which equates to distances greater than 8 billion light years (see redshift/distance image).
************************************************** ************************
in the hierarchical model image supplied by the gemini crew you can see 3 groupings defining expected evolutionary forms in an area spanning 8-11.75 bly (billion light years).

in the area 8 - 9.65 bly (z = 1 - 1.575), nearly formed galaxies exist.
between 9.65 - 10.8 bly (z = 1.575 - 2.35) galaxies are barely half formed.
between 10.8 - 11.75 bly (z = 2.35 - 3.55) there are only proto-galactic building blocks.

considering that we can see "building blocks" (dwarf galaxies) in our local area of the universe it would be best not to infer anything specific by observing them in association with larger and more developed galaxies in the distant past...it would be preferable to see these building blocks by themselves and so the area to study would be the zone where only they should reside...ie: at redshift z > 2.35.

************************************************** ************************
the visible light range is considered to lie between 400 - 700 nanometres (nm).
the redshift denominator "z" is a multiplier that is applied to wavelengths to determine the amount of "redshifting"...(plus 1 * the wavelength).

*****************************
lyman alpha ultraviolet (added for reference...see antoniseb's post below)

z=0 120nm
z=1 240nm
z=2 360nm
z=3 480nm
z=4 600nm
z=5 720nm
z=6 840nm
z=7 960nm

*****************************
400nm violet

z=0 400nm
z=1 800nm
z=2 1200nm
z=3 1600nm
z=4 2000nm
z=5 2400nm
z=6 2800nm
z=7 3200nm

*****************************
550nm yellow/green

z=0 550nm
z=1 1100nm
z=2 1650nm
z=3 2200nm
z=4 2750nm
z=5 3300nm
z=6 3850nm
z=7 4400nm
*****************************
700nm red

z=0 700nm
z=1 1400nm
z=2 2100nm
z=3 2800nm
z=4 3500nm
z=5 4200nm
z=6 4900nm
z=7 5600nm
*****************************

range:

hst(wfpc2) 115 - 1100nm
hst(nicmos) 800 - 2500nm
gemini 2000 - 5500nm

at z > 2.575, nicmos cannot see red objects
at z > 3.55, nicmos cannot see yellow/green objects
at z > 5.25, nicmos cannot see blue/violet objects

whereas, gemini can see all these colours up to z = 6.85

************************************************** *******

during the period describing the investigation of blue building blocks exhibited by Tim (1994 - 1996), nicmos was not yet installed....and so the range of hst(wfpc2) did not exceed 1100nm.

at z > 0.56...hst cannot see red objects
at z > 1...hst cannot see yellow/green objects
at z > 1.75...hst cannot see blue/violet objects

hst alone is unable to view the visible components or objects residing in the area assigned to building blocks (z > 2.35). the best it could do is see ultraviolet emissions which are the product of high energy events...ie: agn, starburst activity, etc.

in the area assigned to half formed galaxies (z = 1.575 - 2.35), hst cannot see red or yellow objects and blue/violet objects are very poorly represented.

in the area where nearly formed galaxies reside (z = 1 - 1.575), hst can only see blue/violet objects (or higher..ie: uv).


and so hst with or without nicmos** is not a robust enough tool to apply to this problem...hence the importance of gemini, which very adequately is...especially regarding the crucial area of proof expected to lie at z > 2.35.

************************************************** ********

**through the building block area of:
z = 2.35 - 2.575, nicmos loses red frequency.
z = 2.575 - 3.55, nicmos loses yellow frequency

z = 3.55 is the cut off point for building blocks?..ie: even they don't exist beyond this distance? not really correct since we supposedly now see objects out to z = 10.
a higher hubble constant of 70 or 75 pushes the redshift scale up to cover this range, but also means that the visible wavelengths pass beyond hst(wfpc2 and nicmos) earlier as well.

************************************************** ********

the following graphic was used for the z = distance relationship (green lines)

http://hometown.aol.com.au/Profnim/zdrnew.jpg

taken from this site..

http://nedwww.ipac.caltech.edu/level5/Marc...d/Spinrad1.html (http://nedwww.ipac.caltech.edu/level5/March03/Spinrad/Spinrad1.html)

copyright credits to Curtis Manning and Mr Spinrad?...of caltech.

antoniseb
2004-May-03, 09:50 PM
Thanks madman,

That's a useful chart and tabulation on the redshifted colors.

I think it is also useful to take a look at the Lyman Alpha [120nm] and Lyman continuum [around 90nm] colors, Hubble can see these colors out to z=8 or 9 fairly easily.

Yes this only shows us star-forming regions and AGNs, but we can see the same locally as well with FUSE and other instruments.

I'm not sure if your wonderful overlay technique could be used to show a comparison like this since we are not comparing the same piece of sky at the same magnification for this question.

antoniseb
2004-May-04, 01:21 PM
I saw a paper on arXive today that looks at this subject:
Galaxy Evolution Paper (http://www.arxiv.org/PS_cache/astro-ph/pdf/0405/0405001.pdf)

This paper makes it clear that there is obivous, observed galactic evolution going on correlated to redshift. Naturally the details are complex, but the short version points out that currently we have about 75% spiral galaxies, 23% elliptical galaxies, and 2% peculiar [merging] galaxies. At z=1.5 the number of peculiars was equal to the number of the others. This result takes into account the less regular appearance of galaxies seen in UV light.

One main thrust of the paper is the historic development of mass fraction of the universe that is in luminous bodies [stars] at various z-values. It points out that if you look at galaxies before the main star forming period 5-8Gyears ago, there are fewer galaxies visible. At z=3 about 10% as much matter was in luminous bodies as now.

Note that when you download this paper, it says that it is 36 pages, but the actual text part is only about 9 pages.

VanderL
2004-May-04, 05:11 PM
I guess I'll just add this to the discussion: if redshift is not related to distance but a measure of it's youth (as Arp has proposed) than we would also expect high redshift objects to be morphologically different from the mature, low-redshift galaxies. The real problem is that it is difficult to distinguish between these options.

Cheers.

antoniseb
2004-May-04, 05:41 PM
Originally posted by VanderL@May 4 2004, 05:11 PM
if redshift is not related to distance but a measure of it's youth (as Arp has proposed) than we would also expect high redshift objects to be morphologically different from the mature, low-redshift galaxies.
Yes, it is difficult to distinguish between the two. The evolution of the cosmos [if demonstrated] pretty much elimintates the steady state ideas, and also confirms the age of the universe [perhaps with less certainty than the WMAP team claims].

I haven't read a lot of Halton C. Arp's recent work. I remember thinking that his catalog of peculiar galaxies was pretty cool. I understand that right now he's a proponant of theories that the cosmological redshift isn't connected to unversal expansion. But I can't discuss his ideas just yet.

madman
2004-May-04, 08:08 PM
i consider both to be probable/real...ie: distance redshifting and intrinsic redshifting.

in that nuclear jet shot, you can see:

1) an acceptable style of intrinsic redshifting (redshifting along the length of the jet)
2) bizarre blue/red-shifting (due to a helical flow?)
and
3) a possible extrapolation that's in line with Arp ie:

if the blob fully separates and maintains it's integrity (it is 1000 ly long)...it might stay swaddled in redshifted radio emitting material for a while.....spark star formation near it's centre...and end up looking like a highly redshifted (and high energy) object to radio telescopes.

whether or not the last 2 scenarios are or could be true, i'm not sure, but it doesn't hurt to log any idea (no matter how wacky it is) to memory...if it fits with reality later..great...if not..there shouldn't be a problem anyway.

antoniseb
2004-May-04, 09:08 PM
Originally posted by madman@May 4 2004, 08:08 PM
it doesn't hurt to log any idea (no matter how wacky it is) to memory...if it fits with reality later..great...if not..there shouldn't be a problem anyway.
I agree. I am inclined to put wacky [or even somewhat non-standard] models to the test of as many observed phenomena as I can find that seem relevant. If a different model passes these tests, I tuck it away in a very special place.

VanderL
2004-May-05, 08:46 PM
but it doesn't hurt to log any idea (no matter how wacky it is) to memory...if it fits with reality later..great...if not..there shouldn't be a problem anyway.

Funny though that a lot of people are not even prepared to consider novel ideas, they just seem to be looking for a reason to strike out at people proposing these new ideas. I've seen a number of dicussions where the proposer is really attacked, it seems that not everyone thinks wacky ideas are not a problem. But it's great to hear you expressing this attitude, and I can only say that I fully agree with this stance.

There are several reasons for intrinsic redshift to be likely; besides connecting bridges between high- and low-redshift objects and the grouping of quasars around mature elliptical galaxies (Arp), the latest surveys (wich have sampled a large number of objects) show that the redshift distribution of QSO's (quasi stellar objects) show distinct peaks (Burbidge et al.), which would be a problem when only cosmological (expansion) redshift is considered.

Cheers.

antoniseb
2004-May-05, 08:56 PM
Originally posted by VanderL@May 5 2004, 08:46 PM
I've seen a number of dicussions where the proposer is really attacked, it seems that not everyone thinks wacky ideas are not a problem.
There are some ideas proposed by people desparate to get their thoughts out, but they just don't have a solid connection to known science [exhale for example]. I didn't go after her theories because there was nothing to prove or disprove. It was like arguing with an impolite creationist.

At the opposite end of the spectrum, I haven't said anything about the Electric Universe stuff because I simply don't yet understand the proposal in a mathematical enough way. He may have something. I just don't know.

None the less, if an idea can explain everything it touches, there's no reason to reject it. But there is every reason to subject it to scrutiny, to see if it really does explain things.

VanderL
2004-May-05, 09:42 PM
Antoniseb,

I didn't mean to say that the ideas shouldn't be scrutinized, it's just that sometimes the discussion is not about the proposed idea. The Exhale example is a good one, if ideas are not backed up by evidence or reasoning they are just ideas and should be treated without insulting people. It's best not to respond to insulting behaviour (for both sides of an argument) and it seems people are unable to do this. The Electric model discussion was, imo, an ok discussion, whenever it became heated it was still possible to discuss, although admittedly sometimes close to the line.
As you stated these ideas can be kept in mind and whenever evidence is pointing in that direction they can be discussed again (as for example the electric dust devils on Mars).


I haven't said anything about the Electric Universe stuff because I simply don't yet understand the proposal in a mathematical enough way

Well, that's possibly one of the reasons why this model is difficult; plasmas are very hard to approach mathematically. I never realised this, it could explain why it is hard to predict what plasmas will do.


None the less, if an idea can explain everything it touches, there's no reason to reject it. But there is every reason to subject it to scrutiny, to see if it really does explain things.

Now that's openminded and I think that's the best attitude,
Thanks Antoniseb,

Cheers.

madman
2004-May-06, 01:21 PM
in regards to that pdf...to me it seems to be an heroic attempt to feel around in the dark and try to tell us they know what's out there.

gemini is the first to apply the correct tool for the job.

the results they have turned up aren't going to go away, but will more than likely be confirmed and extended upon by other surveys using similar methods.

antoniseb
2004-May-06, 02:51 PM
Originally posted by madman@May 6 2004, 01:21 PM
the results they have turned up aren't going to go away, but will more than likely be confirmed and extended upon by other surveys using similar methods.
There is no question that better instuments and more data will help to clarify the situation. Certainly the James Webb Space Telescope [if the mission is successful] will go a long way in this direction.

One thing I'd like to see is a survey that looks at the Lyman wavelengths adjusted for redshift for each galaxy viewed. I predict that such a survey would clearly show the evolution described in this paper. Such a survey would be a lot of effort to do.

Concerning the PDF file I pointed to a few days ago, it certainly goes against the opinion cited by the scientists from Gemini, yet this paper drew its conclusions looking back only to z=1.5, which doesn't require Gemini's wonderful infrared capabilities, so I would dismiss this paper so quickly either.

madman
2004-May-06, 06:11 PM
there are 2 problems with that paper

1) yes, it only goes back to z=1.5..that is still within the area where galaxies would look close to normal in any model.
2) all the ground based imaging took place before the "nod and shuffle" technique..so they had buckleys' chance of gathering the redshifted infrared data.

i've pointed out before that hst is not able to see the visible components of galaxies at high redshift.

to really perform a controlled experiment, you must make sure that you are checking for all colour components that galaxies emit at whatever frequency - v - redshift they are being viewed at.

using hst and blinkered ground based scopes does not reach that standard of quality control.

this is why the gemini team start their article with the strong statement that "Until now, astronomers have been nearly blind when looking back in time to survey an era when most stars in the Universe were expected to have formed."

antoniseb said:
"One thing I'd like to see is a survey that looks at the Lyman wavelengths adjusted for redshift for each galaxy viewed. I predict that such a survey would clearly show the evolution described in this paper"

only if you checked for the other possible galactic components too and found that they were not present (see above note for controlled experiment conditions)

your experiment would be similar to the authors of the pdf paper..except they were checking the b-band (440nm)

in both cases only one possible component of (preferentially) "active" type galaxies is being considered...the attempt is therefore biased from the beginning...and circular reasoning because you are assuming evolution as "a given".

this is not objective science.

you will find what you are looking for because these objects do exist, but because you do not check that they are not merely components..you will never know that you only have part of the story and your conclusions are only partly correct.

you will prove hierarchy on false premises.




if hierarchy/evolution is true, it should be proven conclusively.

VanderL
2004-May-06, 07:11 PM
you will find what you are looking for because these objects do exist, but because you do not check that they are not merely components..you will never know that you only have part of the story and your conclusions are only partly correct.

you will prove hierarchy on false premises.


if hierarchy/evolution is true, it should be proven conclusively.


Yes, Madman, this is called a "confirmatory bias" and is seen throughout science. Being aware that is exists means we have to be careful about interpretations and always look for control tests. As example there should have been a deep field image (with whatever telescope we use) in a "crowded" area as well, to get a complete picture.

Cheers.

madman
2004-May-06, 07:39 PM
many apologies to antoniseb.....i see it as a product of the cost in resources.
big science costs a lot of money. scientists/astronomers attempt to focus experiments onto logical lynchpins of proof....so they can bring their maximum resources to bear on the experiment in the most economical way.

it's easy to be objective when the cost is not coming out of your pocket :blink:

VanderL said:
"we have to be careful about interpretations and always look for control tests"

yes, but sometimes the capability isn't there for all controls on an experiment. gemini is the first to have it "all in one"...maybe spitzer too.

antoniseb
2004-May-06, 08:08 PM
Originally posted by madman@May 6 2004, 07:39 PM
many apologies to antoniseb.....i see it as a product of the cost in resources.
Apologies aren't needed here. As good as Gemini is, it will be superceded by OWL [if they ever build it] and to a lesser degree JWST. We are talking about a topic on the cutting edge of observational astronomy. Naturally it is useful to discuss where we are, and what experiments could get us to a more knowledgeable place.

Personally, I am not taking the bravado of the Gemini scientists as gospell just yet, but I don't refute it either. I am thankful to you for championing a non-standard position. We learn nothing if we are not aware of what is in doubt.

VanderL
2004-May-06, 08:10 PM
sometimes the capability isn't there for all controls on an experiment.

Then that is reason to be very careful in our publications. Whenever we have interpreted a set of data, we need to include comments of caution whenever some tests couldn't be performed (for whatever reason).

Cheers.

madman
2004-May-07, 08:18 PM
here's that chart again, but with Ned Wright's correct? data (in blue) for the parameters.

http://hometown.aol.com.au/Profnim/ned+z3.jpg

******************************************

z / distance (billion light years)
**********************************
0.5 = 5.019
1.0 = 7.731
1.5 = 9.320
2.0 = 10.324
2.5 = 10.999
3.0 = 11.476
3.5 = 11.827
4.0 = 12.094
4.5 = 12.303
5.0 = 12.469
5.5 = 12.604
6.0 = 12.716
6.5 = 12.809
7.0 = 12.888
7.5 = 12.956
8.0 = 13.014
8.5 = 13.065
9.0 = 13.110
9.5 = 13.149
10.0 = 13.184

100 = 13.649

1000 = 13.665

*********************************
data copyright credits: curtis manning, mr spinrad and ned wright.

madman
2004-May-07, 10:33 PM
overlap of gemini "hierarchy survey" and hst "wall of galaxies"

http://hometown.aol.com.au/Profnim/hwv3.jpg

hst mystery (http://www.space.com/scienceastronomy/hubble_gap_040506.html)

the (aqua) area of the gemini deep deep field overlaps the wall of galaxies (yellow) found by the hst ultra deep field...beyond that is a void?

Tim Thompson
2004-May-08, 05:45 AM
I really do not understand what the point of the discussion is supposed to be at this point, so let me just follow up on my earlier mention of the HST images. They are not biased by starburst galaxies, because they are, for the most part, at redshifts too low to suffer from such a bias. Out to z ~2.5 the sample of galaxies is fairly unbiased. Beyond that, and certainly by z ~3, the bias swings towards starburst galaxies, because they are the brightest, and therefore most likely to be seen. But I get the impression from the discussion that there is a general belief that galactic evolution at redshifts < ~3 is not significant. This is not so, and indeed, significant evolution is seen at redshift < 2. These references should serve to make the point, only a few examples from many possible.



When did the Hubble sequence appear?: Morphology, color, and number-density evolution of the galaxies in the Hubble deep field north
M. Kajisawa & T. Yamada
Publications of the Astronomical Society of Japan 53(5): 833-852, 2001
Abstract:
Using the HST WFPC2 (http://www.stsci.edu/instruments/wfpc2/wfpc2_top.html)/NICMOS (http://www.stsci.edu/hst/nicmos) archival data of the Hubble Deep Field North (http://www.stsci.edu/ftp/science/hdf/hdf.html), we constructed a nearly complete sample of the M-V < -20 (similar to L* + 1) galaxies to z = 2, and investigate when the Hubble sequence (http://www.astro.soton.ac.uk/~crk/PH227/node25.html) appeared, namely, the evolution of the morphology, colors, and the comoving number density of the sample. Even if taking into account the uncertainty of the photometric redshift technique, the number density of relatively bright bulge-dominated galaxies in the HDF-N decreases significantly at z > 1, and their rest-frame U - V color distribution is wide-spread over 0.5 < z < 2. On the other hand, while the number density of both disk-dominated and irregular galaxies does not show a significant change at 0.5 < z < 2, their distribution of the rest-frame U - V color alters at z ~1.5; there are no relatively red (rest U - V > ~0.3) galaxies at z > 1.5, while a significant fraction of these red disk-dominated or irregular galaxies exist at z < 1.5. These results suggest that the significant evolution of the Hubble sequence, which is seen in the present Universe, occurs at 1 < z < 2.




Ten billion years of galaxy evolution
S. van den Bergh
Publications of the Astronomical Society of the Pacific 114(798): 797-802, August 2002
Abstract:
Observations in the Hubble Deep Fields have been used to study the evolution of galaxy morphology over time. The majority of galaxies with z < 1 are seen to be disklike, whereas most objects with z > 2 appear to be either chaotic or centrally concentrated "blobs." Such blobs might be the ancestral objects of ellipticals or of galaxy bulges. About 1/3 of objects with z > 2 appear to be in the process of merging. The region with 1 < z < 2 marks an important transition in the global history of star formation from a merger-dominated regime at z > 2 to one at z < 1 in which most star formation takes place in galactic disks. It is speculated that the break in the Madau plot (http://nedwww.ipac.caltech.edu/level5/Illingworth/Ill5.html) at z ~ 1.5 might be related to the transition from merger-dominated star formation at z > 2 to disk-dominated star formation at z < 1. The Hubble tuning-fork diagram provides a satisfactory framework only for galaxy classification at z <= 0.5. At z > 0.5, barred spirals become increasingly rare. Possibly very young disks are still too hot (chaotic) to become unstable in global barlike modes. Furthermore, it becomes increasingly difficult to shoehorn galaxies at z >= 0.5 into the Hubble classification sequence E-Sa-Sb-Sc. The fraction of "peculiar" spirals, i.e., those that do not fit naturally into the Hubble tuning-fork diagram, increases from 12% at z ~0.0 to 46% at 0.6 < z < 0.8. Early-type galaxies appear to approach their normal morphology faster than do late-type spirals. As a result, only ~5% of E-Sa-Sab galaxies are peculiar at z ~0.7, compared to 69% peculiars among objects of types Sbc-Sc. With increasing redshift, the spiral-arm pattern in late-type spirals is seen to become ever more chaotic. In early-type galaxies, the spiral arms appear to be less well developed at large redshifts than they are at z ~0. Finally, a very tentative, and entirely empirical, scheme is proposed for the classification of objects with z > 2.




On the global structure of distant galactic disks
V.P. Reshetnikov, R.J. Dettmar & F. Combes
Astronomy and Astrophysics 399(3): 879-887, March 2003
Abstract:
Radial and vertical profiles are determined for a sample of 34 edge-on disk galaxies in the HDFs, selected for their apparent diameter larger than 1.3" and their unperturbed morphology. The thickness and flatness of their galactic disks are determined and discussed with regard to evolution with redshift. We find that sub-L* spiral galaxies with z ~1 have a relative thickness or flatness (characterized by h(z)/h the scaleheight to scalelength ratio) globally similar to those in the local Universe. A slight trend is however apparent, with the h(z)/h flatness ratio larger by a factor of ~1.5 in distant galaxies if compared to local samples. In absolute value, the disks are smaller than in present-day galaxies. About half of the z ~1 spiral disks show a non-exponential surface brightness distribution.


Another approach to the problem is one I cannot find an illustration for on the web. So I can only refer you to my source, Cosmological Physics, John A. Peacock (http://www.roe.ac.uk/~jap/), Cambridge University Press 1999 (reprint 2002), page 409, figure 13.7. The figure is a plot of galaxy number counts per square degree, vs apparent magnitude, as a function of photometric band, B, R, I, and K, similar to the plots seen in Deep Galaxy Counts, Extragalactic Background Light, and the Stellar Baryon Budget (http://nedwww.ipac.caltech.edu/level5/Madau5/frames.html), by Madau & Pozzetti (follow the link to part 2). But Peacock&#39;s plot includes a comparison between observations and the "no evolution" model, which is arrived at by simply transporting the present universe galaxies to the appropriate redshift. The fact that the counts and the model disagree significantly is prima-facie evidence for evolution.

That&#39;s all I can do for now, I hope it&#39;s at least relevant to whatever you have in mind.

madman
2004-May-08, 07:03 AM
it&#39;s still about the differences between near and far galaxies...and the hst (ultra deep field) crew has just announced an over-density of galaxies in the area where proto-galaxies should be observed instead..(that&#39;s why i posted the last image to show the overlap area of supposed hierarchy -v- discovered galactic over-density).

quote:
"Strangely, though, there is an almost complete lack of galaxies around redshift 7 in the Hubble image. In addition, around redshifts of 2, 3 and 4, a "wall" of galaxies inexplicably appears, said Roger Thompson, a University of Arizona astronomer who led the study.

"The void at 7 really worries me," thompson said. "What worries me more is the excess at 2, 3, 4."

**********************

an average sized inter-cluster void of 150 million light years residing at 12.9 billion light years would produce a "redshift void" from z=6.5 - 7.5.

***********************

Tim said:
"But I get the impression from the discussion that there is a general belief that galactic evolution at redshifts < ~3 is not significant."

yes and no.

yes: redshifts 2 - 3 are very significant. in that area we are supposed to find definite evolutionary forms..ie: proto-galaxies...and only proto-galaxies.

no: conversely, finding intermingling and formative processes between mature galaxies and dwarf galaxies is common in the local universe...they prove ongoing interactions only&#33;

the proof of hierarchy can only be found by the observation of proto galaxies alone, in their domain and before the construction of larger forms....which is not seen.

gemini has found mature elliptical galaxies in that domain..and now (overlapping and beyond that area), hst finds a wall of galaxies.

madman
2004-May-09, 01:53 AM
Tim posted a link to a short description of the "hubble sequence" as a pointer to "evolution".

the author of the article himself doubts the veracity of the concept.

"Hubble suggested an evolutionary sequence from left to right in this diagram. This is most likely incorrect"

*****************************************

i have posted a multiwavelength composite image of the nuclear jet of the giant elliptical galaxy M87....it appears to be ejecting a substantial sized and cohesive blob of material.
this is not a commonly known or understood phenomena...it is new, and is opposed to the formal understanding of evolution in the universe which assumes that:
1) all building blocks were formed at the beginning.
2) most building blocks have merged to form galaxies by our time.
3) any building blocks left over will either contribute to this process or become their own "island universe" due to "expansion of the universe".

creation of "new building blocks" is a new discovery. it makes a hash of the supposed "evolution".

**********************************************

to be honest, if i did not have these pieces of evidence that i have been posting, i would not be here attempting to argue this alternative case.
my recent past experience as a coder/programmer forces me to accept these anomalous pieces of evidence and try to fit them into reality.
i am used to the fact that "a function returns a value"...ie: "evidence" or "the state of the situation". in programming there is no denying what a returned value is...it is what it is&#33;...and whatever theory you have that does not address the facts is wrong...no matter how strong the argument may seem.

there are now 3 pieces of evidence that do not dovetail with expected hierarchical/evolutionary theries.

1) creation of new "building blocks" in the present era. (M87)
2) spectroscopic and visual evidence of mature galaxies at a time when they should not exist. (gemini)
3) visual evidence of a "wall of galaxies" overlapping and extending beyond the area designated as the domain of building blocks. (hst)

************************************
apologies to Tim, the evidence you have presented would ordinarily be quite sufficient to assume evolution...but new evidence that contradicts that assumption should not be denied.

Tim Thompson
2004-May-09, 06:09 AM
madman: yes: redshifts 2 - 3 are very significant. in that area we are supposed to find definite evolutionary forms..ie: proto-galaxies...and only proto-galaxies.

Why do you say this. I would say it is a factually incorrect statement. It is not true that only proto-galaxies should exist in that redshift range.

madman: i have posted a multiwavelength composite image of the nuclear jet of the giant elliptical galaxy M87 ...

Posted it where?

madman: 1) creation of new "building blocks" in the present era. (M87)

Two objections. First, it&#39;s irrelevant to the issue. Even if "building blocks" are being generated in the universe today, that has no bearing on whether or not there were building blocks in the past. Second, the assertion that the jet from M87 is creating a "building block" is purely arbitrary. Why should we believe that&#39;s what it is? What&#39;s the physical basis for the claim?

madman: 2) spectroscopic and visual evidence of mature galaxies at a time when they should not exist. (gemini)

I claim the statement is false; it is not true that mature galaxies are being seen at a time when they "should not exist". In order for the statement to be true, there must be a theory of galaxy formation in place, by which to determine where mature galaxies "should" and "should not" be found, in theoretical context. But there is no such theory, so "should" is an arbitrary condition without physical foundations.

madman: 3) visual evidence of a "wall of galaxies" overlapping and extending beyond the area designated as the domain of building blocks. (hst)

This looks like a repeat of (2) above (mature galaxies where they "should not" be), and seems false to me for the same reason.

I am unconvinced, and find the "evidence" presented to be weak at best.

As for the Hubble Sequence, I never even thought of it as an evolutionary sequence, and I know that it is not so considered by today&#39;s cosmologists, even if Hubble himself thought of it that way (he never believed in an expanding universe - big bang cosmology anyway). I only considered it as a classification scheme, and meant to point out that there is observational evidence (referenced in the paper), that galaxies did not cleanly differentiate into their Hubble sequence forms until the redshift range 1-2.

The fact is that we see "mature" galaxies as far back as we can look, certainly redshift 6, and maybe as far as redshift 10. There is no strong theory of galaxy formation in place, so what "should" or "shoud not" happen are arbitrary considerations, no matter who says it. The goal is to find a theory that is consistent with observation, and observation indicates that galaxies form much faster than was previously thought. But that in no way falsifies the idea of galaxy formation from "building blocks", it only constrains and limits such theories.

madman
2004-May-09, 01:30 PM
************************************************** *****
"madman: yes: redshifts 2 - 3 are very significant. in that area we are supposed to find definite evolutionary forms..ie: proto-galaxies...and only proto-galaxies.

Why do you say this. I would say it is a factually incorrect statement. It is not true that only proto-galaxies should exist in that redshift range."
***************************

okay, proto-galaxies and half formed galaxies....and possibly very rare instances of mature galaxies...because z=2-3 is really halfway between proto-galaxies and half formed galaxies
(which is not what i think roger thompson is describing when he says "galaxies"...if he meant "half formed galaxies/building blocks, i&#39;m sure he would have clearly said so...remember, this "wall of galaxies" is the thing that worries him the most).
http://www.space.com/scienceastronomy/hubb...gap_040506.html (http://www.space.com/scienceastronomy/hubble_gap_040506.html)
************************************************** *****
************************************************** *****

************************************************** *****
************************************************** *****
"madman: i have posted a multiwavelength composite image of the nuclear jet of the giant elliptical galaxy M87 ...

Posted it where?"
***************************

http://www.universetoday.com/forum/index.p...?showtopic=2694 (http://www.universetoday.com/forum/index.php?showtopic=2694)
************************************************** *****
************************************************** *****


************************************************** *****
"madman: 1) creation of new "building blocks" in the present era. (M87)

Two objections.
First, it&#39;s irrelevant to the issue. Even if "building blocks" are being generated in the universe today, that has no bearing on whether or not there were building blocks in the past.

Second, the assertion that the jet from M87 is creating a "building block" is purely arbitrary. Why should we believe that&#39;s what it is? What&#39;s the physical basis for the claim?"
*************************

first) i agree..it has no bearing on "whether or not there were building blocks in the past"...it has bearing on "what can be their method of creation".

second) the "blob" is approximately 1000 light years long, is emitting x rays (has a lot of energy...e=mc*2..energy=mass...right?)..and is in a "solid enough" material state to cause a *coanda effect upon the radio emitting material which therefore flows around it (check the vla image on page 2 of the thread i linked to above).
if it is involved in a merger at some time in it&#39;s future it would be fulfilling a function attributed to "building blocks".ie: small forms/bodies joining to make larger forms/bodies.
i&#39;m sorry the thing can&#39;t fulfill all these expectations at the same time, but that isn&#39;t feasible. it appears to be at the completion stage of creation, you could hardly expect it to be merging with another form so soon, just so it can prove it&#39;s really a building block.

i will qualify the concept by saying....it is a form that is too large to be a "will&#39;o the wisp"...but instead concrete enough to extrapolate possible futures for it ie: that it might spark star formation under gravitic collapse and could possibly merge with other forms.
************************************************** *****
************************************************** *****

************************************************** *****
************************************************** *****
madman: 2) spectroscopic and visual evidence of mature galaxies at a time when they should not exist. (gemini)

I claim the statement is false; it is not true that mature galaxies are being seen at a time when they "should not exist". In order for the statement to be true, there must be a theory of galaxy formation in place, by which to determine where mature galaxies "should" and "should not" be found, in theoretical context. But there is no such theory, so "should" is an arbitrary condition without physical foundations.
*************************

there is no theory of galaxy formation?
then why did the hst team get so excited about finding "blue building blocks" (their term) back in the 90&#39;s...and why did you post their results as a proof?&#33;

i&#39;m taking my calculations from the diagram supplied by the gemini team...we the public are presented with information by those who supposedly are the experts, do you think they are showing us lies, mistakes, crap they&#39;ve made up on a whim?
they are talking about their own field of work...showing us their accepted and accurate model..if they were mistaken, don&#39;t you think someone would point that out to them?
do you think they are stupid?...they knew exactly what was required to gather their data, and went to great pains to do it....so what do they then correlate their results with?...the broadly accepted model for hierarchical evolution...a model only you say doesn&#39;t exist.
maybe you should straighten them out....because, none of them seem to realise they are using a model that doesn&#39;t exist.
************************************************** *****
************************************************** *****

************************************************** *****
************************************************** *****
madman: 3) visual evidence of a "wall of galaxies" overlapping and extending beyond the area designated as the domain of building blocks. (hst)

This looks like a repeat of (2) above (mature galaxies where they "should not" be), and seems false to me for the same reason.
*************************

it&#39;s not a repeat...this is from an interview with roger thompson, the team leader of the nicmos portion of the hubble ultra deep field. he is commenting on their results. (results you pointed us to as being relevant enough to bring as witness to the debate)
i&#39;m sorry there is only the one example of this "comment on results"...but it is from the pertinent person.
http://www.space.com/scienceastronomy/hubb...gap_040506.html (http://www.space.com/scienceastronomy/hubble_gap_040506.html)
************************************************** *****
************************************************** *****


************************************************** *****
"I am unconvinced, and find the "evidence" presented to be weak at best."

i would agree that the evidence is small, and that it is evidence that goes against the accepted models of the gemini and hst crews...which is evident by their shock/worry...maybe you can convince them that it&#39;s nothing?
************************************************** *****


************************************************** *****
"As for the Hubble Sequence, I never even thought of it as an evolutionary sequence, and I know that it is not so considered by today&#39;s cosmologists,"

it appeared that you were presenting it as a model for evolution..thanks for confirming that it&#39;s not.
************************************************** *****


************************************************** *****
"even if Hubble himself thought of it that way (he never believed in an expanding universe - big bang cosmology anyway)."

i&#39;ve heard that "seemingly odd" story before..thanks for some straight confirmation.
personally, i don&#39;t really care either way if big bang or steady state is correct...i&#39;m just looking for the truth of the matter.
************************************************** *****


************************************************** *****
"I only considered it as a classification scheme, and meant to point out that there is observational evidence (referenced in the paper), that galaxies did not cleanly differentiate into their Hubble sequence forms until the redshift range 1-2."

i don&#39;t agree...we see all manner of forms within an area of 7.5 billion years (z<1), they have not all settled down into pure forms...if variants of types/forms are seen over an extended range of billions of years, then perhaps we are just confusing very large scale variations with proof of hierarchy.
there are now 2 famous "great walls"..one is 700 million light years long, the other 1.4 billion light years long. "differentiation into hubble sequence forms" might be expressed over similar dimensions.
************************************************** *****


************************************************** *****
"The fact is that we see "mature" galaxies as far back as we can look, certainly redshift 6, and maybe as far as redshift 10."


using wmap parameters
http://lambda.gsfc.nasa.gov/product/map/pu...arams_table.pdf (http://lambda.gsfc.nasa.gov/product/map/pub_papers/firstyear/basic/wmap_params_table.pdf)
if you are considering that mature galaxies are present:

at z=10?

(big bang) 13.700 -
(reionisation) 00.180
------
= 13.520
------

13.520 -
z=10 = 13.184
------
= 00.336 = 336 million years after reionisation

or

at z=6?

13.520 -
z=6 = 12.716
------
= 00.804 = 804 million years after reionisation

these are very short times for their formation.
elliptical galaxies supposedly take about 1 billion years to form.

i agree...the new time/evolution parameters enforced by the new data, constrains and limits the theories heavily....the gemini team wonders if they should tweak their model or throw it away and make a new one.
************************************************** *****


************************************************** *****
"There is no strong theory of galaxy formation in place, so what "should" or "shoud not" happen are arbitrary considerations, no matter who says it. The goal is to find a theory that is consistent with observation, and observation indicates that galaxies form much faster than was previously thought. But that in no way falsifies the idea of galaxy formation from "building blocks", it only constrains and limits such theories."

now you&#39;re saying there is an "idea" but no "strong theory" for galaxy formation from building blocks?...so, when you argue for hierarchy, it&#39;s just an idea, but not a strong theory?...so we shouldn&#39;t take much notice or think much of the idea?

you say "the goal is to find a theory that is consistent with observation"...but the "observations indicate that galaxies form much faster than was previously thought".

sounds like you&#39;re trying to do the reverse and fit the observations to a theory...or is that just an idea?
...sorry Tim, you can&#39;t on the one hand, deny the hierarchy model exists....
and then argue in favour of it ....you&#39;re not making sense.
************************************************** *********



*coanda effect...the property of a liquid or gas, such that it follows a curved surface.

GOURDHEAD
2004-May-09, 04:07 PM
Why isn&#39;t the metalicity revealed by light from the oldest know galaxies the ultimate resolver?

antoniseb
2004-May-09, 04:56 PM
Originally posted by GOURDHEAD@May 9 2004, 04:07 PM
Why isn&#39;t the metalicity revealed by light from the oldest know galaxies the ultimate resolver?
On the face of it, this is a good suggestion.

What&#39;s the dimmest galaxy we can get good metalicity data for? I bet it doesn&#39;t have a z-factor greater than 1.0. Bright z=1 galaxies probably have fairly mature metalicity.

Once the Over-Whelmingly Large Telescope [OWL] gets built, perhaps we can use your ultimate resolver on z=3 to 5 galaxies.

GOURDHEAD
2004-May-10, 11:56 AM
What&#39;s the dimmest galaxy we can get good metalicity data for? I bet it doesn&#39;t have a z-factor greater than 1.0. Bright z=1 galaxies probably have fairly mature metalicity

I have assumed that cosmological red shift was estimated from looking at the entire spectrum, or at least the detectable large chunk spanning from microwave up to gamma energies, where the spectrum as a whole is being shifted into the red region. Otherwise, how would anyone know what is being observed? Can you know the "Z" number without knowing enough information to compute the ratio of hydrogen to other elements? At what "Z" number would we expect to see only those lines specific to helium and hydrogen, the big bang products?

antoniseb
2004-May-10, 12:22 PM
Originally posted by GOURDHEAD@May 10 2004, 11:56 AM
Otherwise, how would anyone know what is being observed?
The reason that redshift is generaly given fairly imprecisely for the most distant galaxies is that it is measured making some assumptions about the what energy the peak luminosity is at, and seeing what bands pick up the light. For some galaxies, the image is created based only on thousands, or even hundreds of photons. This is not nearly enough to make a detailed spectrum from.

If there were one individual galaxy that was extremely interesting [say if it had a type 1A supernova], they could use lots of telescope time with the giant mirrors, and get a spectrum, but even then it wouldn&#39;t be nearly as detailed as the one we get from the sun or nearby stars. In addition, galaxies are amalgams of many objects who&#39;s velocity relative to us varies over a 50,000 m/sec range, and so the over-all spectrum may have a redshift, but the emission and absorbsion lines are less distinct anyway.

GOURDHEAD
2004-May-12, 02:36 PM
The reason that redshift is generaly given fairly imprecisely for the most distant galaxies is that it is measured making some assumptions about the what energy the peak luminosity is at, and seeing what bands pick up the light

Thanks. I understand how this would work; however, the imprecision is overwhelming. I&#39;m no longer impressed with 13.7 billion years as the age of the universe. Does anyone know how many photons would produce a spectrum with decent diagnostic properties or how many hours it would take to collect them?

madman
2004-May-17, 07:50 AM
http://hometown.aol.com.au/Profnim/evo6.jpg



the *diagram displays a summary of galactic theory and data relative to the first "third" of the universe.

redshift is shown at the top in red...at the bottom is distance in billions of light years.

reionisation takes place at 13.520 billion light years...or 180 million light years after the big bang.

the 3 segments h1, h2, h3....are the 3 areas of galactic evolution detailed in the gemini hierarchy model.
h1 = proto galaxies
h2 = semi formed galaxies
h3 = nearly formed galaxies (extends beyond the diagram to 8bly, z1.1)

their search into these "areas of hierarchy" returned a result that they did not expect.

quote from the article:

"What is arguably the dominant galactic evolution theory postulates that the population of galaxies at this early stage should have been dominated by evolutionary building blocks. Aptly called the Hierarchical Model, it predicts that normal to large galaxies, like those studied in this work, would not yet exist and would instead be forming from local beehives of activity where big galaxies grew. The GDDS reveals that this might not be the case."


following on and confirming this situation is the recent data from the hst ultra deep field.
an "over-density" or "wall" of galaxies exists between z 2 to 4...which extends across and beyond the areas designated as harboring semi and proto galaxies.


neither of these teams have stated or confirmed the finding of "galaxies forming from local beehives of activity"....or "hierarchical objects"....they instead use terms such as: "galaxies", "normal galaxies" and "large galaxies" or "mature ellipticals".

************************************************** ***************************************

at the bottom of the diagram is a white line bordered in red that roughly represents a galaxy count...numbers of observed galaxies reduces as the distance and difficulty of observation increases (white and yellow circles bordered in red).

Tim suggests that we have seen mature galaxies all the way to z = 6.....at 1bly after the big bang, this coincides with the amount of time it would take for an elliptical galaxy to form.
perhaps a dozen more galaxies and quasars have been seen beyond z6 (yellow circles)...though some of them have been termed by their discoverers as semi formed or proto galactic.

above them is an oval stretching across an area of 1bly....it represents hierarchical evolution along a normal timeline....showing that the hierarchical theory is still possible (which is the point Tim was really trying to make).

also added is a dark circle representing a 150 mly intercluster void as a possible answer for the redshift void around z = 7 found by the hst udf crew.



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* wmap parameters used for timeline and redshift data.

antoniseb
2004-May-17, 11:11 AM
Thanks Madman,

That&#39;s a nice diagram, and does a good job of showing current mainstream astronomy&#39;s take on the data that&#39;s been seen. Thanks also for your clear commentary.

VanderL
2004-May-17, 07:35 PM
Thanks madman,

Here http://tedrusk.50megs.com is a plot from Ted Rusk&#39;s webpage, showing the result of QSO&#39;s plotted against redshift (from the SDSS data). As can be seen there are distinct peaks at specific redshifts, confirming Burbidge/Napier (regarding periodocities and intrinsic redshifts ).
In your plot the "walls" and "voids" of galaxies might correspond to the QSO&#39;s, I guess. As Burbidge and Napier conclude, these data hint at intrinsic redshifts.

Cheers.

antoniseb
2004-May-17, 07:50 PM
Thanks VanderL,

That&#39;s a pretty nice find too. Some of the things I notice from these graphs are:

Some Quasars have redshifts under z=0.05, which means any "intrinsic redshift" associated with quasars must be very small compared to the cosmological redshifts.

There is a distinct set of redshifts for which there are many quasars, [such as around z=3.7] but clearly the a simple observational bias can not be used to say that the number of quasars at any given epoch has been constant.

VanderL
2004-May-17, 09:34 PM
Some Quasars have redshifts under z=0.05, which means any "intrinsic redshift" associated with quasars must be very small compared to the cosmological redshifts.

If redshifts are not cosmological (as hypothesized in the CREIL topic and stated in Arp&#39;s work), they could have any value, depending on the specific properties of the object and it&#39;s immediate surroundings. Furthermore if the redshifts have specific values that are quantised, as the peaks seem to suggest, in Big Bang cosmology these results must be considered walls (or shells) around the Earth, or epochs of galaxy formation, which to me goes against the principle of parsimony; we shouldn&#39;t be at a special place and time in the Universe.

Cheers.

StarLab
2004-May-17, 10:53 PM
we shouldn&#39;t be at a special place and time in the Universe.
Oh, really :angry: ...why shouldn&#39;t we? :o :rolleyes:

madman
2004-May-18, 09:48 AM
VanderL....sorry to say the galaxy count section of the diagram i made is not usefull for determining if there is any periodicity to redshifts.
it is simplified...and really, we don&#39;t have enough data at the extreme edge of the universe to attempt that sort of accuracy.

the yellow circles represent galaxies...(there are no quasars included)

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StarLab...i don&#39;t think there is any good reason why we should have a special place in the universe...or that our "visible universe" should be in a special section of the universe as a whole.

GOURDHEAD
2004-May-20, 02:25 AM
Does anyone know how many photons would produce a spectrum with decent diagnostic properties or how many hours it would take to collect them?

Continuing with the thought implied by this question, when photon counts get this low, do they become a distance determinant considered with respect to the inverse square law?

madman
2004-Jun-01, 02:24 PM
total photon count...as in , for all wavelengths?....then it would sound reasonable.

************************************************** **********

here&#39;s an article on classification of galaxies using infrared observations...

Spitzer Dissects True Nature Of Galaxies (http://www.space.com/scienceastronomy/aas_galaxies_040531.html)

madman
2004-Jun-24, 08:19 PM
ghost galaxy

http://astro.ph.unimelb.edu.au/~mdrinkwa/f...io/ngc2915.html (http://astro.ph.unimelb.edu.au/~mdrinkwa/fornax/radio/ngc2915.html)

madman
2004-Jun-27, 01:04 PM
m81 group

http://hometown.aol.com.au/Profnim/m81groupa.jpg

http://hometown.aol.com.au/Profnim/m81groupb.jpg

http://hometown.aol.com.au/Profnim/m81groupc.jpg

http://hometown.aol.com.au/Profnim/m81groupd.jpg

image 1 is an rgb composite of xray, optical and radio images (m81 is the large galaxy at the bottom and m82 is at the top)
image 2 is a new ultra violet image by Galex.

image 3 is a wider angle view in visible light (which also shows ngc3077 in the bottom left)
image 4 is the same optical shot with 21cm neutral hydrogen added.

VanderL
2004-Jun-27, 02:11 PM
Incredible&#33; The last shot shows how much connection exists between all the components.
Madman, you&#39;ve been posting many images highlighting the need for integration of all the different wavelength images. Maybe you have a website where all the images can be viewed? If not it might be a good idea.

Cheers.