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Precise and Accurate, or Imprecise and Inaccurate
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Eric Flesch
Dec 27, 2012, 6:10:27 AM12/27/12
to
Two new pre-prints with contrasting results are out, kind of like the
scientific equivalent of a food fight. It's a hot topic, the CMB
temperature as a function of redshift -- which, if true, makes any
static model untenable.
On 24 December arxiv:1212.5456 (accepted by A&A): "A precise and
accurate determination of the cosmic microwave background temperature
at z=0.89" by S. Muller et al determines a CMB temp of 5.08K for PKS
1830-211 at z=0.89, although they stated some assumptions,
particularly page 2 column 2 top "of great importance for our study"
that the emission is behind the absorbing gas.
On 27 December arxiv 1212.5625 (accepted by ApJ): "On Measuring the
CMB Temperature at Redshift 0.89" by M. Sato et al, determines a CMB
temp of 1.1 - 2.5K for this same galaxy! They pointedly assert that
high-resolution imaging shows that the absorbing gas covers at best
only part of the emitter.
So the 2nd paper clearly refutes the assumption "of great importance"
of the 1st paper, that the absorbing gas covers the whole emitter.
Reading further, the first paper is based on observations done in
2011-2012, the 2nd paper is based on observations done in 1999 (!).
Not making sense? My loose reading is that the 1999 observers found
that the PKS 1830-211 observations did not confirm the CMB temp /
redshift dependency, but did not publish. Now in 2012 a new group of
"young pups" do find such a dependency, in the process ignoring the
findings of the "old timers" of 1999. These old timers are not happy
because their careful observations are being ignored, so are now
publishing their findings at last.
Appreciate if anyone can shed better light on this.
cheers, Eric
scientific equivalent of a food fight. It's a hot topic, the CMB
temperature as a function of redshift -- which, if true, makes any
static model untenable.
On 24 December arxiv:1212.5456 (accepted by A&A): "A precise and
accurate determination of the cosmic microwave background temperature
at z=0.89" by S. Muller et al determines a CMB temp of 5.08K for PKS
1830-211 at z=0.89, although they stated some assumptions,
particularly page 2 column 2 top "of great importance for our study"
that the emission is behind the absorbing gas.
On 27 December arxiv 1212.5625 (accepted by ApJ): "On Measuring the
CMB Temperature at Redshift 0.89" by M. Sato et al, determines a CMB
temp of 1.1 - 2.5K for this same galaxy! They pointedly assert that
high-resolution imaging shows that the absorbing gas covers at best
only part of the emitter.
So the 2nd paper clearly refutes the assumption "of great importance"
of the 1st paper, that the absorbing gas covers the whole emitter.
Reading further, the first paper is based on observations done in
2011-2012, the 2nd paper is based on observations done in 1999 (!).
Not making sense? My loose reading is that the 1999 observers found
that the PKS 1830-211 observations did not confirm the CMB temp /
redshift dependency, but did not publish. Now in 2012 a new group of
"young pups" do find such a dependency, in the process ignoring the
findings of the "old timers" of 1999. These old timers are not happy
because their careful observations are being ignored, so are now
publishing their findings at last.
Appreciate if anyone can shed better light on this.
cheers, Eric
Phillip Helbig---undress to reply
Dec 30, 2012, 3:01:42 AM12/30/12
to
In article <mt2.0-9104...@hydra.herts.ac.uk>, Eric Flesch
> temperature as a function of redshift -- which, if true, makes any
> static model untenable.
It would certainly make a static model more difficult than it is
already.
> On 24 December arxiv:1212.5456 (accepted by A&A): "A precise and
> accurate determination of the cosmic microwave background temperature
> at z=0.89" by S. Muller et al determines a CMB temp of 5.08K for PKS
> 1830-211 at z=0.89, although they stated some assumptions,
> particularly page 2 column 2 top "of great importance for our study"
> that the emission is behind the absorbing gas.
>
> On 27 December arxiv 1212.5625 (accepted by ApJ): "On Measuring the
> CMB Temperature at Redshift 0.89" by M. Sato et al, determines a CMB
> temp of 1.1 - 2.5K for this same galaxy! They pointedly assert that
> high-resolution imaging shows that the absorbing gas covers at best
> only part of the emitter.
There have been determinations of the CMB temperature at high redshift
in the past.
> Appreciate if anyone can shed better light on this.
Not light, but maybe some microwaves. :-)
The general expectation is that the CMB temperature INCREASES with
redshift. How many papers find this, and how many find something else?
Not really relevant here, but IIRC, 1830-211 is a gravitational-lens
system. Any static model needs to QUANTITATIVELY explain the huge
amount of gravitational-lens data.
<er...@flesch.org> writes:
> Two new pre-prints with contrasting results are out, kind of like the
> scientific equivalent of a food fight. It's a hot topic, the CMB
Actually, quite cold, methinks. :-)
> Two new pre-prints with contrasting results are out, kind of like the
> scientific equivalent of a food fight. It's a hot topic, the CMB
> temperature as a function of redshift -- which, if true, makes any
> static model untenable.
already.
> On 24 December arxiv:1212.5456 (accepted by A&A): "A precise and
> accurate determination of the cosmic microwave background temperature
> at z=0.89" by S. Muller et al determines a CMB temp of 5.08K for PKS
> 1830-211 at z=0.89, although they stated some assumptions,
> particularly page 2 column 2 top "of great importance for our study"
> that the emission is behind the absorbing gas.
>
> On 27 December arxiv 1212.5625 (accepted by ApJ): "On Measuring the
> CMB Temperature at Redshift 0.89" by M. Sato et al, determines a CMB
> temp of 1.1 - 2.5K for this same galaxy! They pointedly assert that
> high-resolution imaging shows that the absorbing gas covers at best
> only part of the emitter.
in the past.
> Appreciate if anyone can shed better light on this.
The general expectation is that the CMB temperature INCREASES with
redshift. How many papers find this, and how many find something else?
Not really relevant here, but IIRC, 1830-211 is a gravitational-lens
system. Any static model needs to QUANTITATIVELY explain the huge
amount of gravitational-lens data.
Eric Gisse
Dec 30, 2012, 3:02:52 AM12/30/12
to
On Thursday, December 27, 2012 5:10:27 AM UTC-6, Eric Flesch wrote:
> Two new pre-prints with contrasting results are out, kind of like the
>
> scientific equivalent of a food fight. It's a hot topic, the CMB
>
> temperature as a function of redshift -- which, if true, makes any
>
> static model untenable.
The static universe model hasn't been tenable in the lifetimes of anyone in this newsgroup.
> Two new pre-prints with contrasting results are out, kind of like the
>
> scientific equivalent of a food fight. It's a hot topic, the CMB
>
> temperature as a function of redshift -- which, if true, makes any
>
> static model untenable.
Measurements of the CMB at cosmoglogically relevant scales have been done enough times with different methods that you can plot the temperature as a function of distance and get the expected redshift curve. Eg, Srinand has written about this a *lot* over th years.
[snip]
>
> Not making sense? My loose reading is that the 1999 observers found
>
> that the PKS 1830-211 observations did not confirm the CMB temp /
>
> redshift dependency, but did not publish. Now in 2012 a new group of
>
> "young pups" do find such a dependency, in the process ignoring the
>
> findings of the "old timers" of 1999. These old timers are not happy
>
> because their careful observations are being ignored, so are now
>
> publishing their findings at last.
First off, the later result should be taken with a grain of salt because the result has a value of CMB temperature that is LESS THAN LOCAL.
You can see discussions of the CO lines back in 2001, eg: arXiv:astro-ph/0111563
None of this information was hidden. It was all out there.
Nobody would be stupid enough to sit on something like that for a decade.
craig.m...@gmail.com
Dec 30, 2012, 3:15:07 AM12/30/12
to
On Thursday, December 27, 2012 4:10:27 AM UTC-7, Eric Flesch wrote:
> Appreciate if anyone can shed better light on this.
You are seeing the scientific process in action. There are debates,
> Appreciate if anyone can shed better light on this.
disagreements, alternate theories, etc., and they haven to get hashed
out somewhere.
CM
[Mod. note: quoted text trimmed -- mjh]
Eric Flesch
Dec 31, 2012, 7:58:37 AM12/31/12
to
On Sun, 30 Dec 12, Phillip Helbig wrote:
>There have been determinations of the CMB temperature at high redshift
>in the past. ...
>There have been determinations of the CMB temperature at high redshift
>The general expectation is that the CMB temperature INCREASES with
>redshift. How many papers find this, and how many find something else?
Sure, Phil, but consider these points from this incident:
>redshift. How many papers find this, and how many find something else?
(1) Team A (1999) found disagreement but did not publish
(2) Team B (2012) found agreement and published.
(3) Team A published in 2012 to balance Team B's finding.
Now consider this, Phil: If it hadn't been for Team A's prior effort,
Team B's affirmative finding would have been published alone. All
would have hailed it as yet another confirmational finding, even
though the paper itself is littered with qualifiers (which you will
see if you read it). But Team A, using VLBI, showed that Team B's
finding is not reliable. (By the way, one member of Team B proof-read
Team A's paper, and another member of Team B was the referee.)
Therefore, how many other such findings have gone unchallenged simply
because there was no other "Team"? Note also from this incident that
papers are more likely to be published when they agree with the
current wisdom -- Team A did not publish for 12 years. So it is
entirely plausible that efforts on this front go 50-50, but the
affirmative ones publish and the negative ones do not.
>Not really relevant here, but IIRC, 1830-211 is a gravitational-lens
>system. Any static model needs to QUANTITATIVELY explain the huge
>amount of gravitational-lens data.
the modelled "dark matter". Good point!
Eric
Phillip Helbig---undress to reply
Dec 31, 2012, 8:54:10 AM12/31/12
to
In article <mt2.0-5823...@hydra.herts.ac.uk>, Eric Flesch
> Therefore, how many other such findings have gone unchallenged simply
> because there was no other "Team"? Note also from this incident that
> papers are more likely to be published when they agree with the
> current wisdom -- Team A did not publish for 12 years.
Again, you are making an assumption without much justification then
extrapolating from it.
> So it is
> entirely plausible that efforts on this front go 50-50, but the
> affirmative ones publish and the negative ones do not.
I agree that publication bias is a serious issue, but it cuts both ways.
A&A has (or at least had at one time; I don't know if it is still true)
a policy of not publishing "boring" results, i.e. those that agreed with
current wisdom and offered nothing new. In some cases, NATURE tends to
be less critical of surprising results and in some of those cases
wouldn't have published them had the result been more in line with
expectations.
> >Not really relevant here, but IIRC, 1830-211 is a gravitational-lens
> >system. Any static model needs to QUANTITATIVELY explain the huge
> >amount of gravitational-lens data.
>
> So you mean, we need to explain the lensing angles in the absence of
> the modelled "dark matter". Good point!
Not just that. The basic idea of gravitational lensing is quite old,
even older than relativistic cosmology, but the theory was put in place
only after relativistic cosmology was established. So, it was developed
with relativistic cosmology in mind, and seems to work quite well. The
analysis of a gravitational-lens survey is a huge undertaking, and the
fact that the cosmological parameters derived from it agree with those
from much simpler (at least conceptually) tests is a huge argument in
favour of the underlying assumptions being correct. Any alternative
model would have to explain why it works if the underlying model is
different. Another example, Arp and others have questioned the
cosmological nature of some high-redshift objects, particularly QSOs.
But there are many examples of lensed QSOs, and in all cases the
redshift of the QSO is higher than that of the lense. If the high
redshifts had another origin, we would expect at least a few examples of
a source with a lower redshift than the lens. (In some cases, Arp has
attempted to explain gravitational-lens systems by claiming that the
multiple images are multiple objects emitted from the lensing galaxy, in
line with his claim that such ejected objects have large
non-cosmological redshifts, but this seems like a HUGE epicycle to save
the appearances of his ideas.)
<er...@flesch.org> writes:
> >The general expectation is that the CMB temperature INCREASES with
> >redshift. How many papers find this, and how many find something else?
>
> Sure, Phil, but consider these points from this incident:
> (1) Team A (1999) found disagreement but did not publish
> (2) Team B (2012) found agreement and published.
> (3) Team A published in 2012 to balance Team B's finding.
Of course, you are speculating on the motivation in (3).
> >The general expectation is that the CMB temperature INCREASES with
> >redshift. How many papers find this, and how many find something else?
>
> Sure, Phil, but consider these points from this incident:
> (1) Team A (1999) found disagreement but did not publish
> (2) Team B (2012) found agreement and published.
> (3) Team A published in 2012 to balance Team B's finding.
> Therefore, how many other such findings have gone unchallenged simply
> because there was no other "Team"? Note also from this incident that
> papers are more likely to be published when they agree with the
> current wisdom -- Team A did not publish for 12 years.
extrapolating from it.
> So it is
> entirely plausible that efforts on this front go 50-50, but the
> affirmative ones publish and the negative ones do not.
A&A has (or at least had at one time; I don't know if it is still true)
a policy of not publishing "boring" results, i.e. those that agreed with
current wisdom and offered nothing new. In some cases, NATURE tends to
be less critical of surprising results and in some of those cases
wouldn't have published them had the result been more in line with
expectations.
> >Not really relevant here, but IIRC, 1830-211 is a gravitational-lens
> >system. Any static model needs to QUANTITATIVELY explain the huge
> >amount of gravitational-lens data.
>
> So you mean, we need to explain the lensing angles in the absence of
> the modelled "dark matter". Good point!
even older than relativistic cosmology, but the theory was put in place
only after relativistic cosmology was established. So, it was developed
with relativistic cosmology in mind, and seems to work quite well. The
analysis of a gravitational-lens survey is a huge undertaking, and the
fact that the cosmological parameters derived from it agree with those
from much simpler (at least conceptually) tests is a huge argument in
favour of the underlying assumptions being correct. Any alternative
model would have to explain why it works if the underlying model is
different. Another example, Arp and others have questioned the
cosmological nature of some high-redshift objects, particularly QSOs.
But there are many examples of lensed QSOs, and in all cases the
redshift of the QSO is higher than that of the lense. If the high
redshifts had another origin, we would expect at least a few examples of
a source with a lower redshift than the lens. (In some cases, Arp has
attempted to explain gravitational-lens systems by claiming that the
multiple images are multiple objects emitted from the lensing galaxy, in
line with his claim that such ejected objects have large
non-cosmological redshifts, but this seems like a HUGE epicycle to save
the appearances of his ideas.)
Eric Flesch
Jan 1, 2013, 5:45:52 AM1/1/13
to
On Mon, 31 Dec 12, Phillip Helbig wrote:
>analysis of a gravitational-lens survey is a huge undertaking, and the
>fact that the cosmological parameters derived from it agree with those
>from much simpler (at least conceptually) tests is a huge argument in
>favour of the underlying assumptions being correct.
Agreed, although that "missing matter" is a required part of the
>analysis of a gravitational-lens survey is a huge undertaking, and the
>fact that the cosmological parameters derived from it agree with those
>from much simpler (at least conceptually) tests is a huge argument in
>favour of the underlying assumptions being correct.
picture should put the spanner in, at least a little.
> Another example, Arp and others have questioned the
>cosmological nature of some high-redshift objects, particularly QSOs.
motivate my earliest cataloguing efforts back in the late 90's,
because I thought the additional data would show whether Arp's ideas
of QSO patterns around large (NGC-type) galaxies would hold. I
corresponded with Arp on the topic, and we collaborated on my first
paper (http://adsabs.harvard.edu/abs/1999astro.ph..7219F). But the
final outcome was that his model was not supported by the additional
data because the large data would be expected to randomly produce the
numbers of patterns that were found. And as attractive as the concept
of "intrinsic redshift" is, today I believe all quasars are at their
cosmological-redshift distance.
Eric
Phillip Helbig---undress to reply
Jan 1, 2013, 7:43:17 AM1/1/13
to
In article <mt2.0-2558...@hydra.herts.ac.uk>, Eric Flesch
otherwise the assumption is that all matter is visible. Dark matter is
seen by some pundits as an epicycle put in to save the appearances.
However, there is no reason to expect all matter to be visible by
default. Indeed, there is baryonic matter which is not in stars, which
was also considered "missing matter". Then it was detected (e.g. via
X-ray emission of hot gas in clusters). OK, due to constraints from
primordial nucleosynthesis, we now know that most of the dark matter is
non-baryonic but, again, it seems rather anthropocentric to believe that
all matter must be baryonic. We live on a planet, but we don't expect
all matter to be in planets. The difference is that we knew that stars
existed before starting to think about missing mass. If non-baryonic
matter had been detected before modern cosmology came into being, no-one
would consider non-baryonic matter to be strange.
<er...@flesch.org> writes:
> On Mon, 31 Dec 12, Phillip Helbig wrote:
> >analysis of a gravitational-lens survey is a huge undertaking, and the
> >fact that the cosmological parameters derived from it agree with those
> >from much simpler (at least conceptually) tests is a huge argument in
> >favour of the underlying assumptions being correct.
>
> Agreed, although that "missing matter" is a required part of the
> picture should put the spanner in, at least a little.
Very little. Actually, this seems to me the simplest explanation, since
> On Mon, 31 Dec 12, Phillip Helbig wrote:
> >analysis of a gravitational-lens survey is a huge undertaking, and the
> >fact that the cosmological parameters derived from it agree with those
> >from much simpler (at least conceptually) tests is a huge argument in
> >favour of the underlying assumptions being correct.
>
> Agreed, although that "missing matter" is a required part of the
> picture should put the spanner in, at least a little.
otherwise the assumption is that all matter is visible. Dark matter is
seen by some pundits as an epicycle put in to save the appearances.
However, there is no reason to expect all matter to be visible by
default. Indeed, there is baryonic matter which is not in stars, which
was also considered "missing matter". Then it was detected (e.g. via
X-ray emission of hot gas in clusters). OK, due to constraints from
primordial nucleosynthesis, we now know that most of the dark matter is
non-baryonic but, again, it seems rather anthropocentric to believe that
all matter must be baryonic. We live on a planet, but we don't expect
all matter to be in planets. The difference is that we knew that stars
existed before starting to think about missing mass. If non-baryonic
matter had been detected before modern cosmology came into being, no-one
would consider non-baryonic matter to be strange.
Richard D. Saam
Jan 1, 2013, 12:39:31 PM1/1/13
to
On 1/1/13 6:43 AM, Phillip Helbig---undress to reply wrote:
> OK, due to constraints from
> primordial nucleosynthesis, we now know that most of the dark matter is
> non-baryonic
I would like to hear the logic underlying this statement.
> OK, due to constraints from
> primordial nucleosynthesis, we now know that most of the dark matter is
> non-baryonic
Isn't our knowledge of primordial nucleosynthesis
based on nuclear species ratios ie H/He or H/Li
and not absolute mass of each species
and these ratios are termed abundances?
Observation of these abundances in the present era
substantiates a primordial nucleosynthetic origin.
But this does not negate the possibility
of primordial nucleosynthetic species ie H/He or H/Li
in a different physical density phase
that remains invisible in the present era.
It would be like the calcium and carbonate species in the ocean
at very small concentrations (milli-equivalents/liter)
but in equilibrium with large calcium carbonate 'chalk' geological
formation (tons and tons) such as the white cliffs of Dover
and having the same calcium/carbonate 'abundance' ratio
but invisible to an oceanic observer.
RDS
Phillip Helbig---undress to reply
Jan 2, 2013, 3:59:29 AM1/2/13
to
In article <mt2.0-19586...@hydra.herts.ac.uk>, "Richard D. Saam"
so we know the total number of baryons. (Almost all photons are in the
CMB, by the way.)
<rds...@att.net> writes:
> > OK, due to constraints from
> > primordial nucleosynthesis, we now know that most of the dark matter is
> > non-baryonic
> I would like to hear the logic underlying this statement.
> Isn't our knowledge of primordial nucleosynthesis
> based on nuclear species ratios ie H/He or H/Li
> and not absolute mass of each species
> and these ratios are termed abundances?
> Observation of these abundances in the present era
> substantiates a primordial nucleosynthetic origin.
> But this does not negate the possibility
> of primordial nucleosynthetic species ie H/He or H/Li
> in a different physical density phase
> that remains invisible in the present era.
One parameter is the photon-to-baryon ratio. We can count the photons,
> > OK, due to constraints from
> > primordial nucleosynthesis, we now know that most of the dark matter is
> > non-baryonic
> I would like to hear the logic underlying this statement.
> Isn't our knowledge of primordial nucleosynthesis
> based on nuclear species ratios ie H/He or H/Li
> and not absolute mass of each species
> and these ratios are termed abundances?
> Observation of these abundances in the present era
> substantiates a primordial nucleosynthetic origin.
> But this does not negate the possibility
> of primordial nucleosynthetic species ie H/He or H/Li
> in a different physical density phase
> that remains invisible in the present era.
so we know the total number of baryons. (Almost all photons are in the
CMB, by the way.)
Richard D. Saam
Jan 3, 2013, 2:36:45 AM1/3/13
to
On 1/2/13 2:59 AM, Phillip Helbig---undress to reply wrote:
> In article <mt2.0-19586...@hydra.herts.ac.uk>, "Richard D. Saam"
> <rds...@att.net> writes:
>
>> > OK, due to constraints from
>>> primordial nucleosynthesis, we now know that most of the dark matter is
>>> non-baryonic
>> I would like to hear the logic underlying this statement.
>
> In article <mt2.0-19586...@hydra.herts.ac.uk>, "Richard D. Saam"
> <rds...@att.net> writes:
>
>> > OK, due to constraints from
>>> primordial nucleosynthesis, we now know that most of the dark matter is
>>> non-baryonic
>> I would like to hear the logic underlying this statement.
>
> One parameter is the photon-to-baryon ratio. We can count the photons,
> so we know the total number of baryons. (Almost all photons are in the
> CMB, by the way.)
>
The photon density rho_p = 413/cm^3
> so we know the total number of baryons. (Almost all photons are in the
> CMB, by the way.)
>
reflects the Black Body calculation at 2.73 K
and actual photon counting (WMAP)
The critical density rho_c is separately calculated
at (3/8pi)*H^2/G = 9.56E-30 g/cc
It is understood that
rho_c*(1+z)^3/rho_p*(1+z)^3
is constant
and expressed in terms of hydrogen atoms
rho_c*(1+z)^3/(Avogadro*rho_p*(1+z)^3)
is constant
and that .0464 (WMAP) of critical density is baryonic
as measured by Baryonic Acoustic Oscillation at z=1100.
It would appear that knowing the photon density rho_p
does not dictate the number of baryons.
RDS
Phillip Helbig---undress to reply
Jan 3, 2013, 2:20:27 PM1/3/13
to
In article <mt2.0-4612...@hydra.herts.ac.uk>, "Richard D. Saam"
constant.
> and that .0464 (WMAP) of critical density is baryonic
> as measured by Baryonic Acoustic Oscillation at z=1100.
We know the critical density, we know the fraction of baryons and thus
we know the number of baryons.
> It would appear that knowing the photon density rho_p
> does not dictate the number of baryons.
What I meant was that the predictions of big-bang nucleosynthesis depend
on this ratio, thus knowing the ratio ties down the predictions so that
there is no leeway.
<rds...@att.net> writes:
> >> > OK, due to constraints from
> >>> primordial nucleosynthesis, we now know that most of the dark matter is
> >>> non-baryonic
> >> I would like to hear the logic underlying this statement.
> >
> >> > OK, due to constraints from
> >>> primordial nucleosynthesis, we now know that most of the dark matter is
> >>> non-baryonic
> >> I would like to hear the logic underlying this statement.
> >
> > One parameter is the photon-to-baryon ratio. We can count the photons,
> > so we know the total number of baryons. (Almost all photons are in the
> > CMB, by the way.)
> >
> > so we know the total number of baryons. (Almost all photons are in the
> > CMB, by the way.)
> >
> The photon density rho_p = 413/cm^3
> reflects the Black Body calculation at 2.73 K
> and actual photon counting (WMAP)
> The critical density rho_c is separately calculated
> at (3/8pi)*H^2/G = 9.56E-30 g/cc
>
> It is understood that
> rho_c*(1+z)^3/rho_p*(1+z)^3
> is constant
> and expressed in terms of hydrogen atoms
> rho_c*(1+z)^3/(Avogadro*rho_p*(1+z)^3)
> is constant
We can elimate (1+z)^3 from the above and just say that the ratio is
> reflects the Black Body calculation at 2.73 K
> and actual photon counting (WMAP)
> The critical density rho_c is separately calculated
> at (3/8pi)*H^2/G = 9.56E-30 g/cc
>
> It is understood that
> rho_c*(1+z)^3/rho_p*(1+z)^3
> is constant
> and expressed in terms of hydrogen atoms
> rho_c*(1+z)^3/(Avogadro*rho_p*(1+z)^3)
> is constant
constant.
> and that .0464 (WMAP) of critical density is baryonic
> as measured by Baryonic Acoustic Oscillation at z=1100.
we know the number of baryons.
> It would appear that knowing the photon density rho_p
> does not dictate the number of baryons.
on this ratio, thus knowing the ratio ties down the predictions so that
there is no leeway.
Richard D. Saam
Jan 5, 2013, 3:10:21 AM1/5/13
to
On 1/3/13 1:20 PM, Phillip Helbig---undress to reply wrote:
>
> What I meant was that the predictions of big-bang nucleosynthesis depend
> on this ratio, thus knowing the ratio ties down the predictions so that
> there is no leeway.
>
Does big-bang nucleosynthetic baryonic production
>
> What I meant was that the predictions of big-bang nucleosynthesis depend
> on this ratio, thus knowing the ratio ties down the predictions so that
> there is no leeway.
>
based on the photon-to-baryon ratio
assume Fermi-Dirac statistics
and not any Bose-Einstein statistical contribution?
RDS
Dan Riley
Mar 1, 2013, 5:01:02 AM3/1/13
to
Eric Flesch <er...@flesch.org> writes:
> Two new pre-prints with contrasting results are out, kind of like the
> scientific equivalent of a food fight. It's a hot topic, the CMB
> temperature as a function of redshift -- which, if true, makes any
> static model untenable.
[apologies for the much delayed response...]
> Two new pre-prints with contrasting results are out, kind of like the
> scientific equivalent of a food fight. It's a hot topic, the CMB
> temperature as a function of redshift -- which, if true, makes any
> static model untenable.
Add a couple more exhibits:
[1] K. M. Menten, C. L. Carilli, and M. J. Reid (1998),
"Interferometric Observations of Redshifted Molecular Absorption
toward Gravitational Lenses"
"Given that Trot=Tcrnb, the accurate optical depth determinations
afforded by our interferometer measurements allow for a meaningful
estimate of the cosmic microwave background temperature at z = 0.89,
for which big bang theory predicts a value of (1+z)2.73 K = 5.14 K. In
particular, from the HC3N J = 3-2 and 5-4 spectra shown in Fig. 3 we
derive Trot = 4.5+1.5-0.6 K. We note that the errors quoted for the
HC3N rotation temperature are formal uncertainties and do not take
into consideration systematic effects such as variations in the source
covering factor between 14.5 and 24.1 GHz, the frequencies of the
redshifted 3-2 and 5-4 lines."
[2] C. Henkel, K. M. Menten, M. T. Murphy, N. Jethava, V. V. Flambaum,
J. A. Braatz, S. Muller, J. Ott, and R. Q. Mao, A&A 500, 725 (2009)
"The density, the cosmic microwave background, and the
proton-to-electron mass ratio in a cloud at redshift 0.9"
"[...] toward the south-western source, excitation temperatures of
molecular species with optically thin lines and higher rotational
constants are, on average, consistent with the expected temperature of
the cosmic microwave background, TCMB = 5.14 K. However, individually,
there is a surprisingly large scatter which far surpasses expected
uncertainties. A comparison of CS J = 1-0 and 4-3 optical depths
toward the weaker north-western absorption component results in Tex =
11 K and a 1-sigma error of 3 K."
> On 24 December arxiv:1212.5456 (accepted by A&A): "A precise and
> accurate determination of the cosmic microwave background temperature
> at z=0.89" by S. Muller et al determines a CMB temp of 5.08K for PKS
> 1830-211 at z=0.89, although they stated some assumptions,
> particularly page 2 column 2 top "of great importance for our study"
> that the emission is behind the absorbing gas.
> On 27 December arxiv 1212.5625 (accepted by ApJ): "On Measuring the
> CMB Temperature at Redshift 0.89" by M. Sato et al, determines a CMB
> temp of 1.1 - 2.5K for this same galaxy! They pointedly assert that
> high-resolution imaging shows that the absorbing gas covers at best
> only part of the emitter.
are the authors of [1], and Menten is also a co-author of [2] (with
Muller).
> So the 2nd paper clearly refutes the assumption "of great importance"
> of the 1st paper, that the absorbing gas covers the whole emitter.
> Reading further, the first paper is based on observations done in
> 2011-2012, the 2nd paper is based on observations done in 1999 (!).
>
> Not making sense? My loose reading is that the 1999 observers found
> that the PKS 1830-211 observations did not confirm the CMB temp /
> redshift dependency, but did not publish. Now in 2012 a new group of
> "young pups" do find such a dependency, in the process ignoring the
> findings of the "old timers" of 1999. These old timers are not happy
> because their careful observations are being ignored, so are now
> publishing their findings at last.
to go with the observations, it would go something like this:
(1) Menten et al. make high res observations of PKS 1830-211 and
publish a CMB temp consistent with standard theory, using nominal
assumptions about the systematics
(2) Henkel et al. (including Menten and Muller) observe larger than
expected variability in observations, challenging the assumptions
about systematic effects made in (1)
(3) Muller et al. publish arxiv:1212.5456, essentially claiming that
the systematics found in (2) are well enough understood or small
enough for a precision analysis
(4) Sato et al. publish arxiv:1212.5625, challenging the Muller et
al. claim that the systematics are well understood. I don't really
see this paper as challenging the CMB temp per se, but rather
primarily challenging the systematic uncertainty estimates in Muller
et al.
If you want to really delve into reading the tea leaves, it would seem
that Sato--a relative newcomer to the group--played some significant
role in reanalyzing the 1998 data to test the covering factor
homegeneity.
-dan
Eric Flesch
Mar 6, 2013, 5:39:07 AM3/6/13
to
On Fri, 01 Mar 13, Dan Riley <d...@mail.lns.cornell.edu> wrote:
>If you want to really delve into reading the tea leaves, it would seem
>that Sato--a relative newcomer to the group--played some significant
>role in reanalyzing the 1998 data to test the covering factor
>homegeneity.
Yes, she is evidently a VLT multi-wave specialist at Max-Planck.
>If you want to really delve into reading the tea leaves, it would seem
>that Sato--a relative newcomer to the group--played some significant
>role in reanalyzing the 1998 data to test the covering factor
>homegeneity.
Possibly she will review other papers for similar problems.
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