Why is this JWST paper a cause for 'Panic'?

[Cerenkov]

TL;DR

https://arxiv.org/pdf/2207.09428.pdf
Panic! At the Disks: First Rest-frame Optical Observations of Galaxy Structure at z > 3 with JWST in the SMACS
0723 Field

Hello.

Could somebody please explain to me why the discovery of the unexpected number of spiral galaxies in this image is a cause for panic?

My naïve understanding is that this is at odds with the currently accepted model of galaxy formation in the early universe.

Any help give at a Basic level would be very much appreciated.

Thank you,

Cerenkov.

 

[Drakkith]

There's no panic, it's just a play on the band name, "Panic! At the Disco".

My naïve understanding is that this is at odds with the currently accepted model of galaxy formation in the early universe.

I'm not much more knowledgeable about this than you. According to the paper:

Thus, in this paper we explore the morphological properties of the earliest galaxies through an approach based on galaxy classification and measurement. We demonstrate that these early galaxies have a more normal morphology than expected, with classifications showing that disk galaxies are much more common than previous observations suggested (e.g., Conselice et al. 2005; Margalef-Bentabol et al. 2022). Overall, we argue that the formation of the Hubble sequence appears to be ongoing much earlier than we had anticipated based on HST observations.

In other words, we expected galaxies in the early universe to have a certain proportion of different shapes/morphology. But JWST has apparently demonstrated that our expectations were not correct, that the actual morphology proportions are very different from our expectations. This helps our understanding of the early universe and how galaxies evolved over time to what they look like today.

 

[Cerenkov]

Thank you Drakkith.

Could you please tell me what proportion of galaxy shapes/morphologies was expected?

Or direct me to where I can read about this?

My naïve understanding is that as it looked back farther in time the JWST should have revealed a greater proportion of primitive and unevolved galaxies rather than a greater proportion of these spirals.

Here I am (rightly or wrongly) assuming that these spirals should be the products of the Hierarchical Model of Galaxy Formation, which requires a long period of evolution.

And, given that the further we look back, the closer we come to the expected Cosmic Dark Ages, doesn't this require these newly-observed spirals to have formed more quickly than the Hierarchical Model allows for?

If anyone can correct or improve my understanding of these matters I look forward to such guidance.

Thank you,

Cerenkov.

 

[Drakkith]

Could you please tell me what proportion of galaxy shapes/morphologies was expected?

Or direct me to where I can read about this?

I wish I could, but I don't know enough about this subject. If I find out anything in the near future I'll post it here though.

 

[Cerenkov]

Thank you Drakkith!

I appreciate your help.

I suppose that what I'm trying to find out is if these newly-discovered spiral galaxies pose a similar problem to the stars that were apparently older than the universe.

https://www.forbes.com/sites/starts...pear-older-than-the-universe/?sh=7752c4633c44

My logic, such as it is, runs like this. It's my current understanding that spiral galaxies assemble slowly over billions of years. But the further back the JWST looks, the less time there is available for this assemblage to take place. Less time meaning from the Dark Ages, when such structures could not have existed.

Anyway, thanks again.

Cerenkov.

 

[ohwilleke]

The "Panic!" part is the stark disparity between LambdaCDM predictions for galaxy formation and what is actually seen. JWST isn't the first to see this. Several other pre-JWST searches have seen the same thing. But the JWST data makes the evidence that this problem is real much more definitive.

direct me to where I can read about this?

If you want to do research on the issue, one of the common names for what the JWST is observing with great frequency is the "Impossible Early Galaxies Problem" discussed for example, in a 2015 preprint that was subsequently published in 2016 in The Astrophysical Journal. The abstract of this paper states:

The current hierarchical merging paradigm and ΛCDM predict that the z∼4−8 universe should be a time in which the most massive galaxies are transitioning from their initial halo assembly to the later baryonic evolution seen in star-forming galaxies and quasars. However, no evidence of this transition has been found in many high redshift galaxy surveys including CFHTLS, CANDELS and SPLASH, the first studies to probe the high-mass end at these redshifts. Indeed, if halo mass to stellar mass ratios estimated at lower-redshift continue to z∼6−8, CANDELS and SPLASH report several orders of magnitude more M∼10¹²⁻¹³M⊙ halos than are possible to have formed by those redshifts, implying these massive galaxies formed impossibly early. We consider various systematics in the stellar synthesis models used to estimate physical parameters and possible galaxy formation scenarios in an effort to reconcile observation with theory. Although known uncertainties can greatly reduce the disparity between recent observations and cold dark matter merger simulations, even taking the most conservative view of the observations, there remains considerable tension with current theory.

Another paper discussing the subject in 2018 is:

To understand the formation and evolution of galaxies at redshifts z < 10, one must invariably introduce specific models (e.g., for the star formation) in order to fully interpret the data. Unfortunately, this tends to render the analysis compliant to the theory and its assumptions, so consensus is still somewhat elusive.

Nonetheless, the surprisingly early appearance of massive galaxies challenges the standard model, and the halo mass function estimated from galaxy surveys at z > 4 appears to be inconsistent with the predictions of LCDM, giving rise to what has been termed "The Impossibly Early Galaxy Problem" by some workers in the field. A simple resolution to this question may not be forthcoming.

The situation with the halos themselves, however, is more straightforward and, in this paper, we use linear perturbation theory to derive the halo mass function over the redshift range z < 10 for the R_h=ct universe. We use this predicted halo distribution to demonstrate that both its dependence on mass and its very weak dependence on redshift are compatible with the data.

The difficulties with LCDM may eventually be overcome with refinements to the underlying theory of star formation and galaxy evolution within the halos. For now, however, we demonstrate that the unexpected early formation of structure may also simply be due to an incorrect choice of the cosmology, rather than to yet unknown astrophysical issues associated with the condensation of mass fluctuations and subsequent galaxy formation.

Manoj K. Yennapureddy, Fulvio Melia, "A Cosmological Solution to the Impossibly Early Galaxy Problem" (March 19, 2018).

Universe Today had an article on October 30, 2020 discussing the issue from an educated layman's perspective in reference primarily to the paper The ALPINE-ALMA [CII] survey: Survey strategy, observations and sample properties of 118 star-forming galaxies at 4<z<6. The "money chart" in the Universe Today article is this one (which demonstrates what theory expected and what the ALPINE-ALMA survey compared to the theoretical expectation):

The Impossible Early Galaxy problem with the LambdaCDM standard model of cosmology is intimately intertwined with the galaxy morphology problem, in which is explained this way at the link:

If galaxies grew hierarchically, then massive galaxies required many mergers. Major mergers inevitably create a classical bulge. On the contrary, about 80% of observed galaxies give evidence of no such bulges, and giant pure-disc galaxies are commonplace. The tension can be quantified by comparing the observed distribution of galaxy shapes today with predictions from high-resolution hydrodynamical cosmological simulations in the ΛCDM framework, revealing a highly significant problem that is unlikely to be solved by improving the resolution of the simulations. The high bulgeless fraction was nearly constant for 8 billion years.

This discussion cites in its support, the following three papers:

Kormendy, J.; Drory, N.; Bender, R.; Cornell, M.E. (2010). "Bulgeless giant galaxies challenge our picture of galaxy formation by hierarchical clustering". The Astrophysical Journal. 723 (1): 54–80. arXiv:1009.3015. Bibcode:2010ApJ...723...54K. doi:10.1088/0004-637X/723/1/54. S2CID 119303368.

Haslbauer, M; Banik, I; Kroupa, P; Wittenburg, N; Javanmardi, B (2022-02-01). "The High Fraction of Thin Disk Galaxies Continues to Challenge ΛCDM Cosmology". The Astrophysical Journal. 925 (2): 183. arXiv:2202.01221. Bibcode:2022ApJ...925..183H. doi:10.3847/1538-4357/ac46ac. ISSN 1538-4357.

Sachdeva, S.; Saha, K. (2016). "Survival of pure disk galaxies over the last 8 billion years". The Astrophysical Journal Letters. 820 (1): L4. arXiv:1602.08942. Bibcode:2016ApJ...820L...4S. doi:10.3847/2041-8205/820/1/L4. S2CID 14644377.

 

[Cerenkov]

Many thanks ohwilleke!

There's plenty of material there to keep me busy.

All the best,

Cerenkov.

 

[collinsmark]

New Sixty Symbols video on the subject:

 

[Cerenkov]

Thank you for this video, collinsmark.

Unfortunately, instead of easing my confusion about this issue, it's increased it.

The speaker explains that the HST is a visible light telescope and so the extremely distant galaxies appearing in its Deep Field images appear to be irregular in shape. Whereas, because the JWST is an infrared telescope, it gives us a more complete image, showing them to be disks. That's fine, I can understand that.

So, irregular-looking galaxies in the very early universe would seem to fit in with the hierarchical model of galaxy formation - where the large and well-behaved disk galaxies we see nearer to us are built up over time. Therefore, if the distant irregular HST galaxies are actually disk galaxies and the extremely distant galaxies in the JWST images are also disks, how could these well-behaved systems evolve so quickly?

Any help given to resolve my confusion would be very much appreciated?

Thank you,

Cerenkov.

 

[collinsmark]

Thank you for this video, collinsmark.

Unfortunately, instead of easing my confusion about this issue, it's increased it.

The speaker explains that the HST is a visible light telescope and so the extremely distant galaxies appearing in its Deep Field images appear to be irregular in shape. Whereas, because the JWST is an infrared telescope, it gives us a more complete image, showing them to be disks. That's fine, I can understand that.

So, irregular-looking galaxies in the very early universe would seem to fit in with the hierarchical model of galaxy formation - where the large and well-behaved disk galaxies we see nearer to us are built up over time. Therefore, if the distant irregular HST galaxies are actually disk galaxies and the extremely distant galaxies in the JWST images are also disks, how could these well-behaved systems evolve so quickly?

Any help given to resolve my confusion would be very much appreciated?

Thank you,

Cerenkov.

Astrophysicists create their models based on the best data they have at the time.

If new evidence comes into being, the astrophysicists update their models.

Until recently, it thought, given the best data at the time, that well behaved galaxies came into existence around 2-3 billion years after the big bang. With JWST data, this looks more like 1.5 billion years after the big bang.

Before JWST's data, you could have asked the same questions that you're asking now. "How could these well-behaved systems evolve so quickly?" Or, you could have asked "why did it take so long for these well-behaved systems to evolve?"

The only difference now is that the timeframe is around 1.5 billion years instead of 2 or 3 billion years. Nothing else changes.

Jump to around 16:27 in the video below for Dr. Becky Smethurst's explanation.

 

[Cerenkov]

Hello collinsmark.

First off, thank you for the Dr. Becky video, which I listened to yesterday.

I'm beginning to see that part of my problem stems from not having a proper understanding of where (and when) these galaxies lie in relation to the Big Bang, the cosmic Dark Ages and the era of Reionization. Articles like this one, https://phys.org/news/2022-08-largest-image-james-webb-space.html , don't really help because the distances to various galaxies are given in two different ways.

Two interacting spirals galaxies are at redshift Z=0.7 but Maisie's galaxy formed within 290 million years of the Big Bang. One is a measurement of redshift and the other is a measurement of elapsed time.

So, is there a way of understanding how these two different scales compare to each other or better still, a way seeing their relationship presented graphically?

Thank you,

Cerenkov.

 

[collinsmark]

Two interacting spirals galaxies are at redshift Z=0.7 but Maisie's galaxy formed within 290 million years of the Big Bang. One is a measurement of redshift and the other is a measurement of elapsed time.

So, is there a way of understanding how these two different scales compare to each other or better still, a way seeing their relationship presented graphically?

The "Z" number represents the measured redshift. This is something that measured here on Earth, by the astronomers. As long as no mistakes are made, and the spectral lines are shifted correctly as part of the measurement, it's something everybody can agree on. As long as nobody makes a mistake, you can look at the data and determine the redshift, and that will agree with another astronomer's redshift result.

How that relates to elapsed time is a bit more complicated because the calculations assume cosmological parameters. So if you assume different cosmological models, you'll get different answers.

Astronomers like to discuss cosmological distances and times in terms of the "Z" redshift, because it makes the fewest assumptions and it's hopefully something that everybody can agree upon.

If you must convert that "z" number to distance or elapsed time, you'll first need to make some assumptions about the cosmos. You might want to google "cosmological redshift to time" for some ways to go about such conversions.

 

[Cerenkov]

I've done as you suggested collinsmark and found this. https://astro.ucla.edu/~wright/CosmoCalc.html So, thanks very much for pointing me in the right direction.

When it comes to using this calculator, let me see if I've got this right.

The Hubble constant (H₀) is set at 69.6.
The Critical Density (Omega_m) is set at 0.286
The Ratio of the density of the Universe to the Critical Density (Omega_vac) is set at 0.714
I can then enter a redshift value (z) and click on General to see the results displayed on the right.
I can toggle between an Open or a Flat universe should I choose to do so.
So, should I read an article where a galaxy's redshift is given, I can then input this value and calculate how many Gigayears have elapsed since the Big Bang.

Is that about right or have I overlooked/misinterpreted something?

Thank you,

Cerenkov.

 

[artis]

Once in a while I find something of interest in the news media.

So apparently the data from the JWST shows that there were already massive galaxies formed in the early universe (500 to 700 millions years)
So from the plasma cooldown state - aka recombination and the free release of the CMB radiation up until mature galaxies it took much less than we once thought.

https://www.nature.com/articles/s41586-023-05786-2
https://edition.cnn.com/2023/02/22/world/webb-telescope-massive-early-galaxies-scn/index.html

So this is a question as well as food for thought for those interested.
The question is this - what would it mean for our current understanding of the universe if eventually 100% verified?
How does this impact/change the Lambda/CDM model?

 

[member 673059]

Mike Boylan-Kolchin has a talk about this topic a few days ago:

 

[Jupiter60]

I have read somewhere where it was said that some of those galaxies could actually be smaller than they appear or be supermassive black holes. I watched a YouTube video where Michio Kaku was discussing the possibility of them.being supermassive black holes.

 

[Hornbein]

I have read somewhere where it was said that some of those galaxies could actually be smaller than they appear or be supermassive black holes. I watched a YouTube video where Michio Kaku was discussing the possibility of them.being supermassive black holes.

I once heard Michio discussing quantum computers. He didn't know the first thing about it.