z=14 galaxies have arrived

[mikehelland]

JWST/MIRI photometric detection at 7.7 μm of the stellar continuum and nebular emission in a galaxy at z>14

The James Webb Space Telescope (JWST) has spectroscopically confirmed numerous galaxies at z>10. While weak rest-ultraviolet emission lines have only been seen in a handful of sources, the stronger rest-optical emission lines are highly diagnostic and accessible at mid-infrared wavelengths with the Mid-Infrared Instrument (MIRI) of JWST. We report the photometric detection of the most distant spectroscopically confirmed galaxy JADES-GS-z14-0 at z=14.32+0.08−0.20 with MIRI at 7.7 μm. The most plausible solution for the stellar population properties is that this galaxy contains half a billion solar masses in stars with a strong burst of star formation in the most recent few million years. For this model, at least one-third of the flux at 7.7 μm comes from the rest-optical emission lines Hβ and/or [OIII]λλ4959,5007. The inferred properties of JADES-GS-z14-0 suggest rapid mass assembly and metal enrichment during the earliest phases of galaxy formation.

https://arxiv.org/abs/2405.18462

A shining cosmic dawn: spectroscopic confirmation of two luminous galaxies at z∼14

The discovery by JWST of an abundance of luminous galaxies in the very early Universe suggests that galaxies developed rapidly, in apparent tension with many standard models. However, most of these galaxies lack spectroscopic confirmation, so their distances and properties are uncertain. We present JADES JWST/NIRSpec spectroscopic confirmation of two luminous galaxies at redshifts of z=14.32+0.08−0.20 and z=13.90±0.17. The spectra reveal ultraviolet continua with prominent Lyman-α breaks but no detected emission lines. This discovery proves that luminous galaxies were already in place 300 million years after the Big Bang and are more common than what was expected before JWST. The most distant of the two galaxies is unexpectedly luminous (Muv=−20.81±0.16) and is spatially resolved with a radius of 260 parsecs. Considering also the steep ultraviolet slope of the second galaxy (β=−2.71±0.19), we conclude that both are dominated by stellar continuum emission, showing that the excess of luminous galaxies in the early Universe cannot be entirely explained by accretion onto black holes. Galaxy formation models will need to address the existence of such large and luminous galaxies so early in cosmic history.

https://arxiv.org/abs/2405.18485

[mikehelland]

I'll just tack this paper on here (rather than a different thread):

Do high redshift QSOs and GRBs corroborate JWST?

The James Webb Space Telescope (JWST) is reporting unexpectedly massive high redshift galaxies that appear challenging from the ΛCDM perspective. Interpreted as a problem of cosmological origin, this necessitates Planck underestimating either matter density Ωm or physical matter density Ωmh2 at higher redshifts. Through standard frequentist profile likelihoods, we identify corroborating quasar (QSO) and gamma-ray burst (GRB) data sets where Ωm increases with effective redshift zeff, with Ωm remaining anomalously large at higher redshifts. While the variation of Ωm with zeff is at odds with the ΛCDM model, demarcating frequentist confidence intervals through differences in χ2 in profile likelihoods, the prevailing technique in the literature, points to 3.9σ and 7.9σ tensions between GRBs and QSOs, respectively, and Planck-ΛCDM. We explain the approximations inherent in the existing profile likelihood literature, and highlight fresh methodology that generalises the prescription. We show that alternative methods, including Bayesian approaches, lead to similar tensions.

https://arxiv.org/abs/2405.19953

[LifeIsStrange]

"One finds that the Planck
value is disfavoured at 99.9999999999994% confidence level or ∼ 7.8σ."
This sentence is hilarious.

BTW dear researchers, I believe there is one huge missed opportunity here!

quasars (QSOs) are standardisable through
a non-linear UV, X-ray flux relation popularised by Risal-
iti & Lusso [70]. This begets an anomaly, whereby the re-
sulting QSO data set [71, 72] favours smaller luminosity dis-
tances than Planck-ΛCDM [57],

This new extremely promising cosmological probe needs Xrays and as explain the original author(s) of the concept:
"A few thousands SDSS quasars already have serendipitous X-ray observations with Chandra or XMM-Newton, and at least 100,000 quasars with UV and X-ray data will be available from the eROSITA all-sky survey in a few years."

This recent 2024 paper still uses a low quality and 100 times smaller Xray sample via chandra (2022) despite eROSITA DR1 being released since 4 months!!
It appears nobody has yet rebuilt the Hubble diagram of quasars with eROSITA!
The closest thing I can find is a pre-analysis a week before the data release
https://arxiv.org/abs/2401.12860

(you can see a list of most eROSITA related papers here
https://erosita.mpe.mpg.de/publications/ )
As such if any of you could do such an analysis, you would automatically produce a high value, highly cited paper with record high constraints on LCDM, however there probably is someone else working on it at the moment (but it has been 4 months)
Personally I won't do it since I am not technically a researcher.
Note that there is also the related ART-XC telescope (that is often forgotten despite being useful) about that one, probably no one is working on its data for an augmented hubble diagram (because it is russian/politics)
https://arxiv.org/abs/2405.09184
there is also https://www.srg.cosmos.ru/publications/155/show
https://www.srg.cosmos.ru/publications/

[LifeIsStrange]

This is historic
note: haven't read your third paper yet.
The first paper gives an age of the galaxy at z=14.32 of 290 millions years (when the galaxy is observed, not when it was formed.
The compagnon papers gives it an age of 280 millions years it seems like they did not agree on the datation.
Actually, both are "wrong" because as a reminder the age of the universe is dependent on cosmic parameters, which are in tension
They have conveniently taken the CMB/BAO hubble constant but the most tested hubble constant measurement (both in the large number of "independent" probes and quantitatively) is of ~73.3. (within 1% statistical error)
Using the famous (but maybe not state of the art) cosmic calculator,
with the reference Pantheon+ values + SHOES,
of Omega M = 0.337
H0 = 73.3
Z= 14.32
The age of the galaxy (as tested via Hubble, JWST, etc) is actually of only 254 millions years.
One might believe the difference is small but at this point only a few dozen millions might make LCDM 100% untenable.
Add to that, that said galaxy is one of the most luminous and massive of all measured by JWST (700 IIRC), and that there is a signal of oxygen which indicate multiple stars generations.
Each time the date is broken the question stands: Is this a fatal definite blow for LCDM?
And the fact that I can't answer this with certainty is both symptomatic of my ignorance but most importantly of the very low falsifiability standards of LCDM, there is a fundamental minimum age limit for massive/luminous galaxy formation, but what is it?
This value should be known in advance, in fact it should be known and stable since decades.
NASA itself (not credible) says galaxies start forming after 400 millions years and ressources pre JWST required 800 million+ years.
I understand there is a difference between what is estimated to be plausible/likely for our astrophysical models and for the fundamental physical limit.
I am not asking for what is plausible (we are already far past that) but for what is possible without a 5th force.
This limit should be deriveable via maximal gas cooling efficiency and accretion speed cf the well known Eddington limit.
Note that the smaller the universe the lower the accretion efficiency (because the warmer the gas), add to that, that dark matter halos were not mature to catalyze gravity (how long do they take?) and that by design, dark energy was negligible (cf matter dominated era) hence weaker cooling too.
In this recent but already obscolete paper:
Researchers consider massive galaxies at z=8.2 ~600 million years old,

This result conflicts with the inferred ages of these galaxies, however, which were on average between 0.9 and 2.4 Gyr old within 95% CL. Given the sequence of star formation and galaxy assembly in the standard model, these galaxies should instead be even younger than 290 Myr on average, for which our analysis assigns a probability of only <3×10−4 (≳3.6σ tension)

They says, on average that those galaxies were estimated by current astrophysical models to be born at minimum, between 300 to 1800 millions years before the big bang.
Now since our new galaxy is 350 million years younger, and since it is, reportedly, one of the most luminous and massive, then if we pessimistically assume this galaxy would be "average" versus the quoted sample, then this new galaxy is at minimum (since I underestimate mass and luminosity), between 650 to 2150 millions years older than the big bang.
If you see an error in my intuitive reasoning or if you actually do the math to rank this galaxy proportionately as their sample, please tell me.
What is never discussed though is the metaprobability, they says 3.6 sigma but their other, unquoted method has 4+ sigma.
Moreover I am sure the astrophysical models can be altered, beyond plausible but without breaking the laws of physics too obviously.
However there was a blog post on tritonstation stating models were already at the limit with "100%" cooling/accretion efficiency but I can't find it back. He also talked about the possibility of top heavy IMF whatever that means, would that be sufficent?
related: https://tritonstation.com/2024/03/18/it-is-not-linear/
Is LCDM dead yet? I hope papers will soon properly address that question instead of perpetuating reality denial.
Also unfortunate that JWST hadn't a resolution capable of measuring Balmer breaks.

Note: I do not understand what takes JWST so long, the high redshift candidates were almost all, already discovered photometrically in 2022, many at Z=16, and even one at Z=20!!
They have spectroscopically verified some (a very low amount like <~20?) despite the paper showing that the total observation time was less than 24h. Is it bureaucracy? Is it because all the telescope time was allocated in a rigid manner years ago for low priority targets?
I don't get it, nor why they wouldn't start by spectroscopically identifying photometric candidates from the highest Z (20) in descending order...
They did show ~one? z=16 galaxy actually be a z=4 so there are photometric false positives but both their productivity and their prioritarization of targets seems abysmally low/deficient.

[mikehelland]

Note: I do not understand what takes JWST so long, the high redshift candidates were almost all, already discovered photometrically in 2022, many at Z=16, and even one at Z=20!!

I can think of a couple reasons.

A. Exoplanet research - there is as much interest in exoplanets/ETs as there is in the early universe
B. Spectroscopic confirmation is difficult/impossible for the highest redshifts using NIRSpec. I made this little graph to show where the visible range of the spectrum is at different redshifts:

https://mikehelland.github.io/hubbles-law/other/jwstir.htm

Between z=11 and z=12 the visible spectrum is out of NIRSpec's range. They're using the break in the UV range (in the rest frame) to make the determination of redshift.

If you look at the spectrum of GS-z14 in the paper (2nd one in the original post), Fig 1:

That's what they are working with. it's creeping away from reliable information. In my spectrum/redshift graph, the Lyman-α 121.6 nm (dashed line) is still detectable by NIRSpec out to z=40, but the amount of information you're getting out of it is probably highly degraded.

NOTE, I'm a layman, so this is just my working knowledge of what they do and how they do it. I'm quite open to corrections on these points.

[mikehelland]

https://arxiv.org/abs/2405.21054

The First Billion Years, According to JWST

With stunning clarity, JWST has revealed the Universe's first billion years. The scientific community is analyzing a wealth of JWST imaging and spectroscopic data from that era, and is in the process of rewriting the astronomy textbooks. Here, 1.5 years into the JWST science mission, we provide a snapshot of the great progress made towards understanding the initial chapters of our cosmic history. We highlight discoveries and breakthroughs, topics and issues that are not yet understood, and questions that will be addressed in the coming years, as JWST continues its revolutionary observations of the Early Universe.

[budrap00]

The scientific community... is in the process of rewriting the astronomy textbooks.

Which is to say the theorists are (once again) rejiggering their model to fit new data that the model (once again) failed to predict. As has been said, cosmologists are often wrong but never in doubt.

You have to appreciate too the way they spread the blame for this mess to the "scientific community" as if biologists and chemists, etc. have a hand in it.

[RedshiftDrift]

@LifeIsStrange

I do not understand what takes JWST so long, the high redshift candidates were almost all, already discovered photometrically in 2022, many at Z=16, and even one at Z=20!!

In addition to @mikehelland's reasons, 'Exoplanet research' and 'Spectroscopic confirmation is difficult', what makes it a slow process is that spectroscopic confirmations use emission lines but also the overall shape of the spectrum to fit star populations. The spectra of galaxies at z = 14 are fitted to spectra of galaxies at z = 13 with some changes to account for evolution. Astronomers don't understand the evolution of galaxies, so they must proceed incrementally from low redshift to high redshift, hence the sequential discovery of galaxies at higher and higher redshifts instead of a direct confirmation of the redshift of a z = 20 candidate.

This paper contains twenty candidates at z >20, even some at z = 22! See pages 54-56.

[HanDeBruijn]

The maximally possible redshift in the observable universe is 28.5, according to (my version of) the Variable Mass Theory.
I'm breathlessly awaiting.

[LifeIsStrange]

First paper about GS-z14-0 (Z= 14.32)
https://arxiv.org/abs/2405.20370
critics or validations are welcome as I don't know yet how to interpret this paper.

[LifeIsStrange]

Not as important as my last comment but new paper on the topic:
https://arxiv.org/abs/2406.02672

[RedshiftDrift]

I wonder why no one has made a tolman test or distance duality test based on quasars?

As I said, quasars have a large "intrinsic redshift", so the "distance redshift" is unreliable and a Tolman test is not possible (despite what everybody else thinks... https://github.com/orgs/a-cosmology-group/discussions/215#discussioncomment-9727719)

[mikehelland]

@RedshiftDrift, how large is the intrinsic redshift?

There's this example quasar I've been using:

https://en.wikipedia.org/wiki/3C_273

It has a redshift of 0.1583. If the intrinsic redshift was something like a gravitational redshift from the quasar's surface, I would think it would be somewhat universal. All quasars have an intrinsic redshift that's a function of their mass, not their distance. So at most, it would have to be less than what's reasonable for 3C 273. Maybe something like 0.05?

But to answer @LifeIsStrange 's question, quasars are quasi-stellar, point-like. Not much surface area to a point. At least that's my understanding.

[RedshiftDrift]

@mikehelland the scatter is huge. At a given luminosity the redshift is scattered over $\Delta z &gt; \pm 1$! (e.g. at $10^{33}$ erg/s/Hz in the radio bands, the redshifts are scattered over $0.5 &lt; z &lt; 3$. See sample image below)

[sahil5d]

despite what everybody else thinks

If you're slant writing about me, please reread what I wrote in that thread you linked that tags me. My point about quasar distance was that it is known with near-certainty that the quasars are very very far away, way beyond the local supercluster.

At a given luminosity

How reliable is the chart's "given luminosity"? The chart caption says, "To obtain the [luminosity], we use the luminosity distance obtained from the redshift and the standard cosmology and the standard K-correction." It doesn't seem reliable to base a luminosity distance on a quasar redshift.

A better chart would plot [quasar distance as estimated by the quasar's associated galaxy's redshift] vs the quasar's redshift. Also, a better chart would replace 'z' with the freq_obs/freq_emit, or λ_emit/λ_obs.

[budrap00]

Assuming that quasars evolve from higher to lower intrinsic redshift and from RL to RQ then the large scatter in the RL quasars will be greatly reduced when their intrinsic redshift is accounted for. It also follows that since the RQ-lower intrinsic redshift galaxies have overestimated luminosities also the lower bound line should be lower overall and perhaps flatten somewhat?

It's interesting that the paper mentions quasar evolution:

... we have found that the radio luminosity evolves at a different rate than the optical luminosity, with the consequence that their ratio is a function of redshift.

Additionally, the luminosity evolution found for the optical only dataset matches that found for the combined radio-optical dataset...

So the data shows quasar evolution but they interpret it as epochal population evolution of course.

[LifeIsStrange]

Discovery of a black hole disc "fully ‘mature’ less than 760 Myr after the Big Bang."
https://phys.org/news/2024-06-black-hole-inexplicable-mass-jwst.html
https://www.nature.com/articles/s41550-024-02273-0

I don't believe ? this is the same black hole as the recently discovered z=10 quasar
https://arxiv.org/abs/2305.15458

here what is new is that not only the black hole, but its halo is resolved and considered mature.
I don't know what the theoretical time needed is but seems clearly longer.

The new observations described here provide strong evidence against some proposed explanations, notably against an "ultra-effective feeding mode" for the earliest black holes.
The bad news for those whose preferred solution to the massive early black holes lies in alternative quick modes of growth: The torus, and by extension the feeding mechanism in this very early quasar, appear to be the same as for its more modern counterparts. The only difference is one that no model of quick early quasar growth predicted: a somewhat higher dust temperature around a hundred Kelvin warmer than the 1300 K found for the hottest dust in less distant quasars.
Arguments that maybe we are merely overestimating early black hole masses because of additional dust are not the solution either.
Early quasars 'shockingly normal'
By almost all the properties that can be deduced from the spectrum, J1120+0641 is no different from quasars at later times.
(note that this is also corroborated by the exhaustive spectroscopic analysis of all highest z quasars (45) I previously listed)

So basically this is a falsification of all fast growth models except maybe the direct collapse ? If so the age of the universe is falsified.
btw can anyone send me the pdf? Since when are papers in cosmology not open access... (not yet on libstc.cc either)

see also anomalously early spiral galaxies
https://skyandtelescope.org/astronomy-news/spirals-galaxies-may-be-a-dime-a-dozen-in-the-early-universe/

[mikehelland]

From the arxiv article:

This mass is comparable to the inferred stellar mass of its host galaxy, in contrast to what is found in the local Universe wherein the BH mass is ∼0.1% of the host galaxy's stellar mass.

Can you find anywhere the size of the galaxy is estimated? As in arcseconds?

The big bang and its singularity require something very odd, that the size of objects as they appear on the sky start to get bigger after z=1.6. This is the angular diameter turnaround.

This assumption is why all high redshift galaxies are perplexingly compact. They don't look as big as the theory says, so they must be tiny.

If you figure out their actual size without that bizarre assumption, they're actually probably exactly like they are at z~0. If the size is being underestimated by orders of magnitude, then so are the masses (usually derived from SED fitting).

[LifeIsStrange]

Sorry I don't know the size of this galaxy.
IIRC the size and estimated mass of JADES-GS-z14-0 is published in https://arxiv.org/pdf/2405.18485 ? (figure 3 maybe)
Nobody has yet done a tolman test and distance duality test based on those record high Z galaxies hence it seems like a low hanging fruit to further obviously rule out LCDM.
https://arxiv.org/abs/2212.06575 see figure 5
the study is from 2022 so they is clearly better data nowadays, but their scale isn't clear, it seems they go up to z=15~ so I suppose they didn't require spectroscopic redshift to measure the angular distance, if so there are photometrics redshifts above z=20 they could use, otherwise z=14.32 is a major advance.
Since the deviation increase with redshift, the higher we go the more, non linearly, LCDM is falsified, this will also allow to falsify Gupta's hybrid (the last expandist bastion along with maybe, rh=ct).

This assumption is why all high redshift galaxies are perplexingly compact. They don't look as big as the theory says, so they must be tiny.

Honestly I have always wondered about this, I am aware of the differing angular distance bias based on an expanding universe, but still there are other biases that might makes the corrected galactic size and mass evolve with redshift, basically the time since the universe start (if it had a start) as the first objects have gradually grown in size, conversely at late time in some aging models, size should decrease I suppose as matter in a non homeostatic universe, would be gradually ireversibly converted into light. Moreover regardless of thoses, biases including malmquist and increasing cosmic dust opacification would alter the angular distance even in a static universe.
Actually if we make the assumption that the universe is static and that the real size of galaxies is constant over redshift then this assumption might allow to better empirically constrain the degree of opacity of the universe, which is currently one of the biggest open questions (and has implications for e.g. the CMB)

So I'm not sure how consistently in the litterature, the size of galaxies falsely is said to be smaller over redshift because of the expanding effect, is this effect systematically applied? Since it is empirically refuted since decades I'm not sure how consistently the zoom factor is applied. If you could prove the size and mass appears constant over redshift, that would be a huge result. I speculate that distant objects truly appears smaller than their local counterparts, because of dust opacification. If so, could the tolman test and distance duality tests truly be considered refutations of the big bang? Couldn't they simply assume there is more dust opacification than expected? Tolman is also constrained by the luminosity distance in addition to the angular distance so maybe it is possible to do better inferences than I do.

While as I said, going with higher Z galaxies is key to solve the conundrum, orthogonally, few people seems to know that the most accurate angular distance measurements are currently made by the Cherenkov telescopes.
https://arxiv.org/abs/1904.06324
Cherenkov telescopes are very bad optical telescopes but they are also the largest optical telescopes to exists, which seems (layman) to be the single most important limiting factor for angular distance measurements.
This use is even more useful IMHO than their classical use for transient astronomy/gamma rays detection.
While the VERITAS has paved the way, the soon to be operational CTA telescope should considerably increase the amount of SOTA angular size measurements.
https://en.wikipedia.org/wiki/Cherenkov_Telescope_Array
We should be able to get even better measurements via the soon to be operational E-ELT.
The veritas paper says:

direct measurement of the occulted stars' angular diameter at the ≤0.1 milliarcsecond scale.
This is a resolution never achieved before with optical measurements and represents an order of magnitude improvement over the equivalent lunar occultation method. We compare the resulting stellar radius with empirically derived estimates from temperature and brightness measurements, confirming the latter can be biased for stars with ambiguous stellar classifications.

See figure 4, the angular size measured seems considerably smaller than usually assessed (I would have expected the opposite)
I'm not sure those measurements allow a tolman/distance duality test since those are stars, not galaxies and at relatively short distances, but it should at least inform us that our models to infer angular distances clearly artificially inflate the real size.

regarding JADES-GS-z14-0 (figure 3 top row) I don't really understand how to interpret the data, the size isn't given as a number but as a function, between normalized surface brightness and arcseconds, where the radius goes from 0 to 0.4 arcseconds (or 1.25 kiloparsecs).
Regardless google says:

Most galaxies are 1,000 to 100,000 parsecs in diameter

so the upper? bound of 1250 parsecs puts JADES-GS-z14-0 within the minimum value (but one, I am probably badly understanding the data, and two I have not corrected for the expandist zoom factor I suppose (not sure) they have applied. I hope you will compute its proper size.

[mikehelland]

Here's an example:

https://iopscience.iop.org/article/1...7#apjlacfe07t1

Both UNCOVER-z12 and UNCOVER-z13 are clearly resolved with measured half-light radii of 4.35 pixels and 3.95 pixels, respectively, with a pixel scale of 0''.04 per pixel.

If, hypothetically, z12 and z13 were the same physical size, z13 should appear larger than z12; farther objects should appear larger due to the angular diameter turnaround.

With an angular diameter distance of 2.37 Gly, a galaxy at z=13.07 should appear the same size on the sky as a similarly sized galaxy at z=0.21.

If it's ~4 pixels, and 0.04 arcseconds per pixel, then that's 0.16 arcseconds, or 7.757e-7 radians.

If we're talking z=13 and 2.37 Gly, that's 726.645 Mpc.

Diameter D = distance d * angle, so, in LCDM, the z13 galaxy has an effective radius of 0.56 kpc.

In a nonexpanding universe, and no angular diameter turnaround, the distance is d = 3.9 Gpc, d * a = 3.05 kpc.

That's pretty close to the Milky Way:

Because of uncertainty in the current measurement of the Milky Way’s size (Methods), we adopt a range of effective radii of 3.4–6.7 kpc

https://www.nature.com/articles/s41550-023-01977-z

[LifeIsStrange]

Bound star clusters observed in a lensed galaxy 460 Myr after the Big Bang (at z=10.2)
https://arxiv.org/abs/2401.03224
https://jwstfeed.com/PostView/FeedPost?ci=1719241506_weic2418b
https://esawebb.org/news/weic2418/?lang

Those are I believe the earliest observed globular star clusters (thanks to lensing)
I wonder what was the earliest assumed age of GCs previously.

ages younger than 50 Myr and intrinsic masses of ∼106 M
Not sure wether their age are valid inferences or LCDM expectations.
Their lensing-corrected sizes are approximately 1 pc, resulting in stellar surface densities near 105~M⊙/pc2, three orders of magnitude higher than typical young star clusters in the local universe.

I wonder if their record high density is merely a product of them applying the expandist universe angular distance zoom factor, would be nice to compute @mikehelland and to check wether a static universe assumption leads to density close to local globular clusters.
I'm not sure at all I understand the axis scale of objects at Z=10 (cf figure 5 https://arxiv.org/pdf/2212.06575)
But the angular diameter at Z=10 seems to be around 0.3 arcseconds for TL/empirical data versus ~3 arcseconds for LCDM. Does that means objects should be 10 times smaller in reality and hence the infered density is one order of magnitude lower? (hence still two order of magnitude denser than local ones? rest might be because of gravitational lensing model inaccuracies?)
I don't understand, even so why would they (do they?) apply wrongly the lcdm scale factor when the same JWST data is used in figure 5 to find the true value... So maybe they don't apply the LCDM zoom, I have no idea.

[HanDeBruijn]

@RedshiftDrift writes something that I do not understand:

About ten times larger because $z \simeq 10$

???? Please explain, Louis!

[HanDeBruijn]

@mikehelland . OK, I'll bite too.
According to this reply: In a flat and static cosmology, the radial distance $d$ is equal to the angular distance $d_A$. And in (my version of) the Variable Mass Theory we have the same relationship between redshift and distance as in tired light models:

$$ d = \frac{c}{H}\ln(1+z) $$

Calculation:

ArcSec := 0.02;
radians := 2*Pi*ArcSec/(360*3600);
Mpc := 3.08567758*10^22;
H := 73.4; # Riess
H := H*1000/Mpc;
c := 299792458;
z := 10.2;
d_A := c/H*ln(1+z);
diameter := evalf(d_A*radians);
diameter := diameter/Mpc*1000*1000; # parsec

                       diameter := 956.7774609

That is $\approx 957\mbox{ pc}$. Ah, now I understand the factor (*1000) in your formula for the diameter.

[mikehelland]

FWIW, using the LCDM best for $H_0$ to the supernovae data is not the best fit for Hubble's constant in a static model. Here's H = 74:

The best fit (using sum of squared errors) is 70.5 km/s/Mpc. You can see for yourself using these tools:

https://mikehelland.github.io/hubbles-law/other/supernovae.htm
https://mikehelland.github.io/hubbles-law/other/sse.htm
https://github.com/mikehelland/hubbles-law/blob/master/other/python/sse.ipynb

[mikehelland]

Yeah, the *1000 just converts Mpc to kpc.

[RedshiftDrift]

About ten times larger because $z \simeq 10$

???? Please explain, Louis!

@HanDeBruijn the ratio between the $\Lambda\mbox{CDM}$ equation and the STz equation for angular distance is about $(1+z)$. This makes Big Bang cosmologists hallucinate and see objects (1+z) times smaller than they really are.

[LifeIsStrange]

The case for a younger universe

I have always thought that the idea that the universe is in equilibrium and recycling, is albeit complex and requiring some new physics, more credible than the idea our universe drift towards its eternal non viability.

One argument for this is to consider we are a random statistical sample, e.g. it is well understood that the idea that we live in a very highly preferential place spatially (geocentrism) is unlikely and unparcimonous.
What is considerably underappreciated is that the same argument holds for where we are placed in time, meaning that LCDM suppose the universe will remain habitable for trillion of years IIRC (albeit new star formation should stop in a few billion years?) Cf wiki Timeline of the universe
The idea that taken at random within the habitable period, we were to exist this early in the universe has a likelihood of 1/trillions chances.(well the exact calculation should model the number of habitable planets per epoch but that shouldn't change the order of magnitude of the argument too much)
Hence it appears from this simple argument, that the idea we exist that early is fringe given how ineptly unlikely statistically, it would be. (unless assumptions about future habitability or about doing statistics in time are wrong)
There are besides many observations like the impossibly early galaxies, other coincidence problems such as what is literally called the coincidence problem, regarding the current value of dark energy.

While I believed the universe is eternal or at least older than LCDM, there is one extremely potent argument that makes me consider having a younger universe than LCDM more likely.
The argument is simply, where are the others?
Where are the aliens?
You might alter the drake equation as much as you'd like to make life appearance (Abiogenesis or spermatogenesis) as unlikely as you wish.
I do believe life appearance and survival is considerably more unlikely and brittle than we appreciate.
For example only a few tens of thousands years ago, a nearby star passed through the oort clouds!
We have many paradoxes to explain, e.g the current physical almost impossibility of spontaneous life appearance and sustainment.
The faint young sun paradox, the fact that we currently live in an under-dense region, etc.

The thing that most cosmologists don't realize is that however unlikely you believe life appearance is, if the universe is eternal in time or infinite in space, in both scenarios it is an absolute certainty that an infinite number of intelligent aliens will have existed. Literally infinite independently of the base probability, that a basic and absolutely certain consequence when you have infinite iterations (time) or parallelism.

So since we assume an infinite number of aliens, however how distant in space and time from us, some of them might not want to expand and conquer the universe, for philosophical, economical or military reasons (e.g the idea they are hiding from each others to avoid being invaded).
But however small the subset of aliens that would be maximalists expansionists exists, any subset of infinite, is itself infinite.
So those arguments, in fact all possible arguments have zero impact.
The only way to beat the basic and absolute certainty that aliens should have made contact with us are:
To have a Great Filter, a law that prevent alien exploration of the universe with absolute certainty, a 100% blockade. If it is 99.9% there will be an infinite amount. If it is 100% there will be zero.
So whatever the scientific level, within this universe, if it is eternal (and to a lesser extent infinite) it has to be strictly impossible to expand past a certain area.
Is it impossible to escape your stellar system?
Is it impossible to escape your galaxy? (escape velocity, radiations because of no magnetic field)
Is it impossible to reach another galaxy? (millions of light years)
Is it impossible to exit your local group?
Your cluster?
Your supercluster?
Your "filament"?
A consequence of eternality is that the most unlikely events that are possible will always happen with certainty.

The best tentative explanation is to consider that while the universe is eternal, we are not. And the planet earth might be relatively recent.
IIRC around 5 billion years.
So there isn't an infinite amount of infinitely developed aliens that have specifically looked for us yet, but I assume the time to explore and conqueer planets is much smaller than the time it takes for planetary creation as such aliens should have reached a steady state we're they can conqueer faster than planets are created.
5 billion years is a lot of time that is extremely hard to explain in an eternal universe that has countless neighboring optimal aliens. Especially since they must have optimal telescopes (don't know if the scaling laws have limits but e.g. a planetary wide mirror)
I do not believe the theory that aliens have not yet had enough time to reach us.
Therefore either there is an absolute great filter, either there is a periodic great reset (the universe would become globally inhabitable each n time), either aliens always discover that life is meaningless (unlikely given the qualia/knowledge dichotomy), either the earth is much younger than we believe it is (Cf Tesla measurements), either the universe (or our local space) is much younger than we understand.
Even within the LCDM timeline there is enough time for aliens to reach us with near certainty.
So any timeline longer than LCDM is almost ruled out unless aforementioned hyper costly hypothesises, and most likely the universe must be significantly younger than our current estimate (e.g. < 6 billion years).

While believe it or not, this is the strongest argument in cosmology, there has been a lack of empirical evidence for a younger universe. It goes without saying that a younger universe to explain observed formation history would require an altered dust attenuation model and mechanisms that catalyze star formation (MOND, super Eddington, altered IMF, etc)

The situation has recently changed via two groundbreaking studies that indicate a younger universe (except maybe via some new physics)
Galaxy Group Ellipticity Confirms a Younger Cosmos
https://arxiv.org/abs/2406.19612
Galaxy groups have considerably higher ellipticities than expected.

And the motions of satellite galaxies match a younger universe
https://arxiv.org/abs/2401.10342

[HanDeBruijn]

I think we might be alone.

I think not. Two references and a picture.

• Stefan Denaerde

• 

• UFO CONTACT FROM PLANET IARGA

[RedshiftDrift]

Since we don't see anybody else, this tells us that the value of the Drake equation is very small, i.e. $N \ll 1$. An indefinitly long time duration doesn't make a difference, the finite lifetime of our civilization is the "filter".

[LifeIsStrange]

@RedshiftDrift sorry for the delay

the finite lifetime of our civilization is the "filter"

Since we don't see anybody else, this tells us that the value of the Drake equation is very small

I disagree, in an eternal universe, the value of the drake equation must necessarily be zero given the old age of earth (5 billion years)
The argument is very simple yet irrefutable,
The task for the aliens (conquering the universe) is a simple computer science task of exhaustive dynamical graph exploration.
At first, (an infinite or trillions of years ago) aliens had a low amount of parallelism (number of spacecrafts sent simultaneously) and discovered planets at a rate slower than planets formed. If their space exploration had remained slower than planetary formation, then either instantaneously or after a long time, an infinite number of new planets would have remained unexplored.
However because aliens must necessarily, eventually, have reached a point of steady state where they explore planets on average faster than new planets forms.
Once such a threshold in the universe is passed, which is only a matter of time given exponential growth and spacecraft parallelism, it is by design only a matter of time before the total share of unexplored planets in the universe starts to shrink.
By design after N time, the number of unexplored old planets becomes zero. Though there is always an influx of new planets being created, this planetary creation rate is ridiculously small over the total number of preexisting planets, meaning that aliens should find new planets exhaustively and have only this task remaining given they already had time to explore all old planets.
The time it takes to reach the milky way is ~ a billion years from the local group, the milky way appears to be as old as the observable universe, though except some signals, for a weird reason almost all stars seems to be younger than 13 billion years old (unless they rejuvenate without leaving a chemical abundance signature..)
Meaning aliens had at least 13 billions years to reach the milky way, once you're in the milky way, distances are much smaller, via a nearest neighbor search and gigantic space telescopes it should be trivial to find most earth like planets in the milky way. Reaching them takes orders of magnitudes less than 5 billions years.
To assume the age of earth is the filter, require the milky way to be not older than 13 billion years old AND require aliens to be greedy and do a "low" amount of parallelism in terms of spacecrafts (despite having not much observational limits (telescopes))
In that scenario earth could still be left to discover, but in such scenario, aliens must still have massively populated the milky way meaning they would send visible biosignatures (radio waves, etc) and I don't see why we couldn't see such signatures.
Besides previous aforementioned possible great filters like worldwide extinction events caused by new physics, and greed in terms of exploratory parallelism, the only other explanation that remains would be that planetary formation follow a curve that is always higher than alien exploratory parallelism.
Since parallelism is expected to be nearly exponential, it follows that new planets must forms more than exponentially.
In such a scenario the percentage of explored planets will always be near 0% but in order to preserve observed matter density, it would require a steady state universe with space expansion and constant matter density, even such a scenario is already highly constrained obseevationally in terms of speed.

[RedshiftDrift]

The age of a "civilization" is the filter, not the age of Earth.

The limit is imposed by the exponential growth of a population ($e^t$ ) which quickly consumes all available resources within a volume (which cannot grow faster than $t^3$ ). Since $A e^t &lt; B t^3$ and $A$ and $B$ are bound by the laws of physics, the maximum possible value of $t$ is a logarithmic function which never reaches the scales involved in the scenario described above.

Any civilization will eventually suffocate, fight for resources and destroy itself. Even a civilization that is a billion times larger will have a history that is merely 20 times longer. There are many studies (this is a gory one) and there are plenty of natural examples of that on Earth.

[HanDeBruijn]

@RedshiftDrift writes:

Any civilization will eventually suffocate, fight for resources and destroy itself.

This is a very pessimistic view and it is exremely unwise to agree with it. I urge everybody read the two references given in my above reply, especially the last one.

Just a quote from chapter 2. It's about what is needed for a civilization to reach eternal life. Nothing new actually: every major religion on earth (communism included) has preached (approximately) the same, in theory, for centuries. I admit that practice is another matter.

"Just this, that unselfishness makes an intelligent race immortal. But before you can understand this, you will first have to climb the ladder with Us to the misty heights of comic integration."

[LifeIsStrange]

Highest (?) redshift balmer break found and empirical evidence for a rejuvenation mechanism of galaxies
https://arxiv.org/abs/2407.07937
First concomittant finding of a balmer break with emission lines

While the presence of a Balmer break can be taken as evidence
of an old stellar population, its absence cannot be used to imply a
lack of one. The effects of stochastic SFHs will act to drown out the
optical continuum of old stellar populations and hence will bias us
towards underestimating the age and stellar mass of these galaxies in
the very early Universe.

https://arxiv.org/abs/2407.07769

https://news.ycombinator.com/item?id=40948202

[LifeIsStrange]

tripling the number of spectroscopically confirmed galaxies with a BB (balmer break) at z >7.
https://arxiv.org/abs/2407.17410

[LifeIsStrange]

slope of the stellar profile discards the UFDs (ultra faint dwarfs) to reside in a CDM (cold dark matter) potential at a > 97% confidence level.
The stellar distribution in ultra-faint dwarf galaxies suggests deviations from the collision-less cold dark matter paradigm
https://arxiv.org/abs/2407.16755

[LifeIsStrange]

https://academic.oup.com/mnras/article/534/1/325/7756422?searchresult=1

[LifeIsStrange]

Paper about how to optimally design a JWST survey to break the Z=15 "barrier" and find the highest possible redshift galaxies (mostly via selective gravitational lenses targeting)
Be sure that this will be ignored by the JWST teams..
https://iopscience.iop.org/article/10.3847/1538-4357/ad639d

Btw here are some recent interesting jwst related studies https://arxiv.org/abs/2407.15279
https://arxiv.org/abs/2409.18086
https://arxiv.org/abs/2409.16347
https://arxiv.org/abs/2409.15453
https://arxiv.org/abs/2408.00073
https://arxiv.org/abs/2407.15279

[LifeIsStrange]

The largest ever JWST survey has been released: PANORAMIC, which is twice as large as the previous best.
However it seems to prioritize wideness over depth so its ability to break the redshift barrier is unclear, though it should allows many major discoveries
https://arxiv.org/abs/2410.01875
among the stated science goals:

The primary motivation for PANORAMIC are two-
fold: to reveal statistical samples of (1) luminous galax-
ies at z > 9, and (2) the most massive, red sources at
3 < z < 9. Since the abundances of these populations
are critical constraints on galaxy formation models, the
pure parallel strategy has a strong advantage in lower-
ing the uncertainties due to cosmic variance.

[LifeIsStrange]

Evidence for the milky way being older than 13 billions years
https://www.nature.com/articles/s41550-024-02382-w

[HanDeBruijn]

Let $H=$ Hubble parameter, $c=$ speed of light, $R_O=$ radius of our Observable universe, $W=3.383634283$ a pure number and the Hubble time $=1/H$ . From the G. de Vaucouleurs section at my webite the following is inferred for the maximal age of stars at the edge of our Observable universe. In the Atomic time frame $t$ we have

$$ H t = -(H/c)R_O = -(H/c)W(c/H) = -W \quad \Longrightarrow \quad \mbox{age}_t \approx {\bf 3.38} \times \mbox{(Hubble time)} $$

According to Narlikar's Law, in the Orbital time frame $T$ we have

$$ \left[1+\frac{1}{2}H T\right]^2 = e^{H t} $$

And so, for $T = -T_O$ at the rim of our Observable universe

$$ 1-\frac{1}{2}H T_O = \sqrt{e^{-W}} \quad ; \quad T_O = 2\left(1-e^{-W/2}\right)\times\frac{1}{H} \quad \Longrightarrow \quad \mbox{age}_T \approx {\bf 1.63} \times \mbox{(Hubble time)} $$

The age of the "whole" Universe in atomic time $t=-\infty$ is simply eternal. Consequently, in the orbital time frame for $T=-T_U$ :

$$ \left[1-\frac{1}{2}H T_U\right]^2 = e^{H(-\infty)} = 0 \quad \Longrightarrow \quad T_U = \frac{2}{H} $$

With the Variable Mass Theory, the age of the (whole) universe in orbital time is twice the Hubble time.
Where it is noticed that the Hubble time is around 14 billion years.

[mikehelland]

https://arxiv.org/abs/2410.14671

Rapid Dust Formation in the Early Universe

Interstellar dust links the formation of the first stars to the rocky planet we inhabit by playing a pivotal role in the cooling and fragmentation of molecular clouds, and catalyzing the formation of water and organic molecules. Despite its central role, the origin of dust and its formation timescale remain unknown. Some models favor rapid production in supernova ejecta as the primary origin of dust, while others invoke slower production by evolved asymptotic giant branch stars or grain growth in the interstellar medium (ISM). The dust content of young early-universe galaxies is highly sensitive to the dust formation timescales. Here, we evaluate the dust content of 631 galaxies at 3<zspec<14 based on rest-UV to optical spectroscopy obtained with JWST NIRSpec. We find that dust appears rapidly. Attenuation immediately follows star formation on timescales shorter than ∼30 Myr, favoring dust production by supernovae. The degree of attenuation is ∼30 times lower than expected if the entire supernova dust yield were preserved in the ISM, and had Milky Way-like grain properties. This can be reconciled if the early-universe dust is composed mostly of silicate or grains much larger than those in the Milky Way, and if significant dust destruction or ejection by outflows takes place.

[LifeIsStrange]

related about anomalous dust transparency
https://arxiv.org/abs/2410.19042

[LifeIsStrange]

unrelated to high Z but still the historic first imaging of extragalactic brown dwarf cluster
https://iopscience.iop.org/article/10.3847/1538-4357/ad779e
(cf figure 1)

[LifeIsStrange]

https://news.ycombinator.com/item?id=41958593

[LifeIsStrange]

https://phys.org/news/2024-10-webb-dozens-supernovae-remnants-triangulum.html