big bang?

[roland]

After the discovery of galaxy HUDF-JD2 is the big bang theory to be revised?

[Garth]

Hi roland, and welcome to these Forums!
You didn't have to submit your thread twice! I expect you know that and only hit the 'submit' button twice by mistake.After the discovery of galaxy HUDF-JD2 is the big bang theory to be revised?
This has been discussed before here: Is there an Age Problem in the Mainstream Model? (http://physicsforums.com/showthread.php?t=94479). In that thread I said (refering to HUDF-JD2): but it is instructive to realise that already we have to reconcile the present observations by either modifying our stellar nucleosynthesis model or the cosmological model.
Does that answer your question?

Garth

[Nereid]

There's also the question "how certain are we of the distance and nature of this spot of fuzz?"

For starters, despite many hours with a VLT, a Keck, and a Gemini, no spectrum was detected (so the distance estimate remains a photometric one, and galaxy SED modeling not at all well constrained).

For seconds, if it is so young, who's to say that galaxy evolution models are particularly accurate? (I realise you can reverse the logic, but you still have just one data point).

And last (for now), is anyone brave enough to be confident about the selection effects?

Rumours of the danger posed by HUDF-JD2 to consensus cosmology models are greatly exaggerated.

[roland]

Rumours of the danger posed by HUDF-JD2 may be the tip of the iceberg. We must await the launch and deployment of JWST. However I shall never cease to be ammused. Merci Garth.

[Garth]

Rumours of the danger posed by HUDF-JD2 to consensus cosmology models are greatly exaggerated.
But we also have high-z quasars with significant iron abundances, and iron is the last element to be formed in fusion processes. In particular there is: APM 08279+5255 (http://arxiv.org/abs/astro-ph/0509212)at z = 3.91 whose age is 2.1 Gyr when the universe was only 1.6 Gyrs old (according to LCDM model expansion).

This age estimate is consistent with Cosmological implications of APM 08279+5255, an old quasar at z= 3.91 (http://www.ingentaconnect.com/content/bsc/mnr/2003/00000340/00000004/art00002) Alcaniz J.S.; Lima J.A.S.; Cunha J.V, Monthly Notices of the Royal Astronomical Society, Volume 340, Number 4, April 2003, pp. L39-L42(1)

But these age estimates are not consistent with the LCDM age of the universe at z = 3.91.

This point is emphasised by Drs. Norbert Schartel, Fred Jansen and Prof. Guenther Hasinger in their ESA web-page article Is the universe older than expected? (http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=30255)

There are other examples of early iron high abundances: at z = 3.104,
The First XMM-Newton spectrum of a high redshift quasar - PKS 0537 ( http://xmm.vilspa.esa.es/external/xmm_science/1st_results/pdf/xmm11.pdf),
(Oct 2000).

And six quasars at z>4
Restless quasar activity: from BeppoSAX to Chandra and XMM-Newton (http://www.sron.nl/saxsymp/papers/vignali.ps)
(2004)

Garth

[Nereid]

Two things (for Garth and roland):

I was responding to the OP (Rumours of the danger posed by HUDF-JD2 to consensus cosmology models) - your reply Garth (a good one) says nothing of HUDF-JD2, and the caveats I made about interpreting the meagre data we have on it.

Quasars are not galaxies; despite decades of intense scrutiny, much remains to be learned about quasars, esp what's really going on in the central engine, and just what the accretion disk (and jet) can, and cannot, produce in the way of nucleosynthesis.

And since we're on the subject, another (more recent) mystery is the formation of the SMBH which lie at the heart of quasars (and the nuclei of - most? all?? - galaxies) - which begat what? Was there only one formation mechanism? Are the all alike anyway??

To be sure, it's a very exciting time to doing astronomy; and an even more exciting time to be doing observational cosmology, a field that's what, less than 50 years old (if you don't count Olbers and the Hubble relationship)? At the same time, it's also frustrating; I doubt that any of us will live to see some of today's central questions in cosmology resolved, let alone the answer to David Hilbert's sixth problem (http://mathworld.wolfram.com/HilbertsProblems.html) ("Can physics be axiomatized?" - this is one of only what, three (of 23) that remain, today, unsolved).

[Garth]

Hi Nereid.
I was responding to the OP (Rumours of the danger posed by HUDF-JD2 to consensus cosmology models) - your reply Garth (a good one) says nothing of HUDF-JD2, and the caveats I made about interpreting the meagre data we have on it.
I was expanding on roland's point above and I think the age problems are related. I discussed HUDF-JD2 in the former thread linked to above.

The point is that there are now several observations, I have referred to nine, in which old features, particularly high iron content, are observed at (mostly unambiguous) high red shift.

It takes time to synthesise iron and, as I quoted myself saying in post #2 above, we may have to revise our nucleosynthesis models, however, these observations may also be indications that the universe is older than we expect (http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=30255). One possible explanation is that something is wrong with the way astronomers measure the age of objects in the Universe. The almost-holy red shift-distance-age conversion would therefore be wrong. Fred Jansen, ESA's project scientist for XMM-Newton, explains that this would mean rewriting the textbooks. "If you study the evolution of the Universe, one of the basic rules is that we can tie redshift to age. One distinct possibility to explain these observations is that, at the redshift we are looking at, the Universe is older than we think."
If the older-Universe interpretation is wrong, there is only one other, stranger possibility, according to Jansen. Somewhere in the early Universe there must be undiscovered 'iron factories', producing the metal by unknown physical means. Understandably, Jansen is cautious about this, saying, "This is the less likely solution in my opinion."
That observational fact (old features in an early universe) has to be flagged up when critically accepting the standard theoretical cosmological model.

Garth