I Observational evidence against expanding universe in MNRAS

[elerner]

Did you perform your radius measurements on single image data, or stacked data?'

(We also note that irrespective of how Lerner etal performed the measurements, the cutoff results are around 50% of the specified FWHM .. instead of being the lower limit of derived FWHM values).

Selfsim, I have said before that the difference between FWHM and radius is just the same as diameter and radius--a factor of 2. That is where your 50% comes from. Every galaxy was measured individually. Jean Tate, the algorithm took annuli cenetered on the center of the galaxy image and calculated the light in each, took the log, plotted and fitted a straight line. The central areas that are affected by PSF were cut out before the fit was done. Look all, we did check our measurements against GALEX catalog at one end and several HUDF measurements at the other. They all come out the same. We just wanted to make sure ours were identical for both HUDF and GALEX. But as my paper points out in comparing our results with Shibuya, they are robust with respect to the exact measurement technique.

 

[elerner]

elerner said: ↑
In the Big Bang model, evolution slows down without limit going forward in time.
I have not seen this in any description of the standard Big Bang model. Where are you getting it from?

Peter, lots of Big Bang papers describe how huge changes in the universe occur in tiny fractions of a second during inflation, slowing down through many magnitudes through decoupling, etc, finally getting to hundreds of millions of years for formation of stars and earliest galaxies and now changes taking many billions of years. Many papers, including some of the earliest ones by Eddington, relate the Big Bang to a general increase in entropy and reduction in energy flows with time, leading to slower and slower change in the future and eventual "heat death" of the universe.

 

[PeterDonis]

lots of Big Bang papers describe how huge changes in the universe occur in tiny fractions of a second during inflation, slowing down through many magnitudes through decoupling, etc, finally getting to hundreds of millions of years for formation of stars and earliest galaxies and now changes taking many billions of years. Many papers, including some of the earliest ones by Eddington, relate the Big Bang to a general increase in entropy and reduction in energy flows with time, leading to slower and slower change in the future and eventual "heat death" of the universe.

Okay, but that's a much weaker claim than the claim you made, which was:

In the Big Bang model, evolution slows down without limit going forward in time. So as you go forward in time, you would eventually get to a time without stars, without galaxies, etc. But evolution in the universe can speed up with time, as we know to be the case here on Earth.

None of the things you mention in the first quote above--rates of inflation, decoupling, star formation, galaxy formation, eventual heat death--are inconsistent with evolution on Earth, or in some other local region, speeding up with time. Nor does the standard Big Bang model claim that all "evolutions" must get slower with time. So whatever "Big Bang model" you think you are refuting, it appears to be a straw man model you made up, not the actual model that cosmologists use.

 

[SelfSim]

Did you perform your radius measurements on single image data, or stacked data?'

Eric;
Could you please answer the only explicit question I asked in post#119?
(Repeated above again, for clarity).

Thanks

 

[timmdeeg]

@elerner How is the observational evidence that CMB temperature dropped down from initially (last scattering) 3000 K to 2.7 K as measured today consistent with the assumption that the universe does not expand?

 

[Jean Tate]

The thread is being reopened in order to allow continued discussion of the specific paper referenced in the OP, and to allow @elerner to respond to specific questions regarding that paper (and the 2014 paper that it is based on). Please limit discussion to that specific topic. This thread is not about the general methodology of science or the overall pros and cons of the current mainstream cosmological model of the universe.

@elerner, in responding to questions, please give specific cites to your papers rather than general claims and opinions. We understand your basic claims; we are looking for the specific evidence and arguments given in your papers that you think support those claims, not repetitions of the claims themselves. Additional fine details of methodology not provided in the papers are fine (since that is a large part of what other posters have asked about).

(my bold)

I fully support this.

It is really interesting to discuss general ideas about, and evidence for, LCDM cosmological models ("the Big Bang Theory"), why general challenges to these might be flawed, and incredibly easy to veer away from the specific scope of the two papers (Lerner 2018, and Lerner+ 2014). So I think it's really important to read what the two papers actually say, and where you can, quote from them.

 

[elerner]

selfsim, I did answer your question:

Every galaxy was measured individually.

I also agree that, while the general topic deserves its own thread, this thread should focus on these two papers. So I will not respond further here to general questions on cosmology models.

 

[PeterDonis]

It is really interesting to discuss general ideas about, and evidence for, LCDM cosmological models

That is off topic for this thread, as @elerner has correctly pointed out.

 

[SelfSim]

Did you perform your radius measurements on single image data, or stacked data?'

Every galaxy was measured individually.

Apologies for my persistence here, but your answer is somewhat ambiguous.
The question pertains to the data you used .. not the measurements you performed on that data.

 

[elerner]

Selfsim, you should take the time to read the papers. I am re-summarizing stuff described clearly there. Here is the quote from Lerner et al 2014:

To measure total flux and half light radius, we extracted the average surface brightness profile for each galaxy from the HUDF or GALEX images.

My answer had no ambiguity at all. GALEX images and HUDF images of individual galaxies were measured. That is the data used. The images are not stacked. Stacking is the process where many images from different galaxies are added together. We measured each galaxy separately. The galaxy measurements were then combined into samples as described in detail in the papers and a median radius for each sample determined. I am not going to answer further questions that are explicitly answered in the papers. I am assuming people read these two papers before asking. Otherwise everyone's time will be wasted--not the purpose of this forum.

 

[SelfSim]

Selfsim, you should take the time to read the papers. I am re-summarizing stuff described clearly there. Here is the quote from Lerner et al 2014:

To measure total flux and half light radius, we extracted the average surface brightness profile for each galaxy from the HUDF or GALEX images.

My answer had no ambiguity at all. GALEX images and HUDF images of individual galaxies were measured. That is the data used. The images are not stacked. Stacking is the process where many images from different galaxies are added together. We measured each galaxy separately. The galaxy measurements were then combined into samples as described in detail in the papers and a median radius for each sample determined.

Ok thanks for your response.

So, my next question is:

'Did you then subtract the sky background data corresponding to the individual image files?

(.. because this would then impact the cut off values).

I am not going to answer further questions that are explicitly answered in the papers.

Umm .. I think you need to, if you expect others to follow your atypical methodology and thence consider, at least as a possibility, accepting your results(?)

I am assuming people read these two papers before asking. Otherwise everyone's time will be wasted--not the purpose of this forum.

We are attempting to bridge gaps here between your paper, which contains a non-standard approach, and others with which we are more familiar.
Your generosity in assisting in this process is appreciated.

 

[Dale]

As I pointed out in a previous post, fits to a data set can’t be tested against that data set. They can be tested only against new, different data sets that don’t exist at the time that the fits are made.

Given the size of these data sets k fold cross validation or other similar approaches would be entirely appropriate. Such approaches are specifically designed to address the statistical issue you raise here. So you could, in fact, both fit and test using these techniques. The time when the data set is made is not relevant.

 

[Copernicuson]

Elearner,

I want to believe your model, but I don't understand why you don't copy and paste the appropriate sections of your paper to answer the questions.

 

[SelfSim]

Eric;

'Would you also please provide a reference source (a link preferably) for the specific HUDF datasets you used?'

Thanks.

 

[Jean Tate]

I need to quote an earlier post, to provide adequate background:

While this thread was locked, there was an exchange in a thread in International Skeptics Forum that I think is highly pertinent:

Eric;
For the sake of brevity, could you please provide maybe a link to the specific Galex dataset(s) you used?
Thanks

http://galex.stsci.edu/casjobs/
<snip>

<snip>

From L14:

We have determined the minimum measurable angular radius of galaxies, m, for each of the telescopes by plotting the abundance of galaxies (with stellarity index<0.4) [...]

Checking the GALEX Schema Browser, per the link you provided, @elerner, I could find no "stellarity index" ("No Column Names or Descriptions Contain: 'stellarity'" and "No Table Names or Function Names Contain: 'stellarity'").

What is this index? How did you determine the stellarity index for each of the GALEX objects (galaxies?) you used at this stage of your sample selection?

I also checked the SDSS DR5 Schema Browser, with the same result, "The expression has not been found in the column and flag names, their units and descriptions, or in the SDSSConstants table.".

 

[Jean Tate]

Thanks, @elerner.

<snip>
Jean Tate, the algorithm took annuli cenetered on the center of the galaxy image and calculated the light in each, took the log, plotted and fitted a straight line. The central areas that are affected by PSF were cut out before the fit was done. Look all, we did check our measurements against GALEX catalog at one end and several HUDF measurements at the other. They all come out the same. We just wanted to make sure ours were identical for both HUDF and GALEX. But as my paper points out in comparing our results with Shibuya, they are robust with respect to the exact measurement technique.

I have several follow-on questions, but they are of lower priority and importance than some others I've been waiting to ask. Like the one on "stellarity index" I just posted.

 

[Jean Tate]

This post has no explicit question to @elerner (though your response would be welcome); rather, it's my attempt to make the first para of L14 somewhat less confusing (I will be editing this later, to try get the symbols and formatting right). Of course, others' inputs and comments are most welcome.

As Tolman1,2 demonstrated, the dependence of the bolometric surface brightness (SB) of identical objects as a function of redshift z is independent of the specific parameter of the adopted cosmology, e.g., Hubble constant, dark matter Ω_M and dark energy Ω_Λ content of the Universe. For this reason the comparison of the surface brightness of similar objects at different distance was seen as a powerful tool to test for the expansion of the Universe. In fact, in any expanding cosmology, the SB is expected to decrease very rapidly, being proportional to (1+z)^-4, where z is the redshift and where SB is measured in the bolometric units (VEGA-magnitudes/arcsec⁻² or erg sec⁻¹cm⁻²arcsec⁻²). One factor of (1+z) is due to time-dilation (decrease in photons per unit time), one factor is from the decrease in energy carried by photons, and the other two factors are due to the obΩject being closer to us by a factor of (1+z) at the time the light was emitted and thus having a larger apparent angular size. (If AB magnitudes or flux densities are used, the dimming is by a factor of (1+z)³, while for space telescope magnitudes or flux per wavelength units, the dimming is by a factor of (z+1)⁵). By contrast, in a static (non expanding) Universe, where the redshift is due to some physical process other than expansion (e.g., light-aging), the SB is expected to dim only by a factor (1+z), or be strictly constant when AB magnitudes are used.

For me, confusion set in early: "the bolometric surface brightness (SB)" is ambiguous ... does "SB" refer to "surface brightness" of any kind? Or is it strictly limited to "bolometric surface brightness"? It would seem the former ... but is it used consistently throughout the rest of the paper? Stay tuned.

Then there are the magnitudes, and fluxes: "bolometric units (VEGA-magnitudes/arcsec⁻² or erg sec⁻¹cm⁻²arcsec⁻²)", "If AB magnitudes or flux densities are used,", and "While for space telescope magnitudes or flux per wavelength units,".

One aid to disentangling these terms: the Wikipedia article on Luminosity. Another, Wikipedia on AB magnitudes. Fundamentally, this is all about energy, or power (energy per unit time). Sadly, the terms "flux" and "flux density" are not always used consistently, though I think them both being used inter-changeably in the one paper is rare these days; between papers? well you have to keep a sharp eye out. In either case, "flux" ~= perpendicular through a unit surface. Not relevant for L14, but definitely for radio astronomy, is whether there's also a "per steradian" aspect, or is isotropy assumed (and so an implicit 4π).

Then there's the system of units and zero points. As the above extract makes clear, L14 uses the cgs system (MKS is far more common); however, while both VEGA and AB are used - their zero-points are fixed - that of "space telescope magnitudes" is not.

Finally, there's the bandwidth and filter: filters do not have infinitely sharp boundaries, nor is the wavelength (or frequency) response perfectly uniform; conversions between observations made using one system on one facility (telescope, filter, camera) and another are a bane of astronomers. And converting to bolometric ("absolute") magnitudes even more full of a shopping list of assumptions (to quote from an earlier post).

 

[elerner]

Hi all, I will be replying but somewhat delayed as we are busy at the lab making fusion.

 

[elerner]

Jean Tate--the stellarity index has the name "NUV_class_star" and "FUV_class_star"
Selfsim--the HUDF data was from Coe D., Bentez N. Sanchez S. F., Jee M., Bouwens R., Ford H. 2006, AJ 132, 926
Jean Tate--they key thing is that bolometric units are just energy. AB units are energy per unit frequency, so since the light is redshifted, that means different exponents for the surface brightness. No physical difference, just how you measure it.

 

[Jean Tate]

Jean Tate--the stellarity index has the name "NUV_class_star" and "FUV_class_star"

Thanks.

<snip>
Jean Tate--they key thing is that bolometric units are just energy. AB units are energy per unit frequency, so since the light is redshifted, that means different exponents for the surface brightness. No physical difference, just how you measure it.

Well, you and I are going to have to disagree, I think, on both this and (more importantly) on how consistent L14 is, in its words and how they have been applied to both the data and analyses. The words L14 seems to use rather loosely and/or inconsistently include "intrinsic luminosity", "distance d", "apparent magnitudes", "absolute magnitudes", "flux-luminosity relation", "bolometric luminosity", and "flux" ... and that's just in Section 2. However, I'll leave my concerns on this topic for a later time.

Instead, I have just one question about something in Section 3. Again, concerning only GALEX. Here's the full context:

Moreover, to avoid biasing the comparison of data obtained with telescopes having different resolutions, we also require that the minimum measurable physical size of galaxies r_m is the same, in each pair of samples, for GALEX (low z) and HUDF (high z). We have determined the minimum measurable angular radius of galaxies, θ_m, for each of the telescopes by plotting the abundance of galaxies (with stellarity index <0.4) vs. angular radius for all GALEX MIS3-SDSSDR5 galaxies and for all HUDF galaxies and determining the lower-cutoff angular radius for each.

For each and every GALEX MIS3-SDSSDR5 galaxy, how did you determine the "angular radius"?

OK, two questions: did you cut on NUV_class_star and FUV_class_star first (selecting those with values <0.4 only), and then determine the angular radii?

 

[elerner]

For each and every GALEX MIS3-SDSSDR5 galaxy, how did you determine the "angular radius"?

The GALEX catalog provides a 50% flux radius--half light radius--for both FUV and NUV. We used those for this calculation. So, yes first we eliminated the >0.4 stellarity entries and then we plotted the numbers. there was a sharp fall-off at the minimum measurable radius.

 

[Jean Tate]

Thanks.

The GALEX catalog provides a 50% flux radius--half light radius--for both FUV and NUV. We used those for this calculation. So, yes first we eliminated the >0.4 stellarity entries and then we plotted the numbers. there was a sharp fall-off at the minimum measurable radius.

Searching the GALEX Schema Browser, I found the following Column names, Units, and Descriptions which seem to match your description (the Tables in which they appear in curly brackets):

NUV_FLUX_RADIUS_2, {blank}, Fraction-of-light radius ( 0.5000) {PhotoObjAll, VisitPhotoObjAll}
FUV_FLUX_RADIUS_2, {blank}, Fraction-of-light radius ( 0.5000) {PhotoObjAll, VisitPhotoObjAll}
fuv_ncat_flux_radius_2, {blank}, FUV FLUX_RADIUS #2 (-fd-ncat)(px)[0.50] {PhotoObjAll, VisitPhotoObjAll}

Can you please confirm that what you used was NUV_FLUX_RADIUS_2 and FUV_FLUX_RADIUS_2?

L14 has HUDF and SDSS references, but apparently no GALEX ones. Only if you can fit it in (otherwise feel free to skip this question), may I ask why you did not include a GALEX reference?

The sentence immediately after the one I quoted in my last post is ("this cutoff" refers to "the lower-cutoff angular radius"):

We took this cutoff to be the point at which the abundance per unit angular radius falls to 1/5 of the modal value.

I guess "abundance" means something like number, or relative frequency. For GALEX - NUV and FUV - what were the units of angular radius that you used? Why did you choose "1/5 of the modal value"?

This seems - to me - to be strange and arbitrary.