Barred galaxies mass distribution

Oh No wrote:

As far as galaxy evolution models are concerned, we know that CDM models
don't work at all well in creating observed galaxy profiles, and we know
that we have a problem understanding the rate of galaxy formation from
the big bang.

Unless you have a mouse in your pocket, that is
your unsupported opinion; as the Scientific
American article I've now URLed here twice explains,
one of the reasons for the broad acceptance of CDM
is exactly its explanatory power concerning the
development of galaxies.

Please _do_ stop presenting your opinion here as
"fact" in support of your teleconnection theory,
where that opinion is at odds with pretty much all
cosmologists.

xanthian.

[Mod. note: it is of course possible for a model to be good at
explaining how galaxies form and yet have some problems in reproducing
the details. The issue is whether the successes make you want to solve
the problems by tweaking the model, or whether you should tear it up
and start again -- mjh]

Thus spake Kent Paul Dolan
Oh No wrote:

As far as galaxy evolution models are concerned, we know that CDM models
don't work at all well in creating observed galaxy profiles, and we know
that we have a problem understanding the rate of galaxy formation from
the big bang.

Unless you have a mouse in your pocket, that is
your unsupported opinion;

Please do not make unsupported ad hominem attacks on my scientific
integrity. I would not say such a thing as unsupported opinion.

According to evolutionary models dark matter halos should have steep
central density cusps (e.g., Navarro, Frenk, & White 1997) but they
appear not to (e.g., de Blok, Bosma, & McGaugh 2003; Swaters et al.
2003). In a survey of about 3000 galaxies, Biviano & Salucci (2006) find
that X-ray determination of the baryonic component of dark matter haloes
fits evolutionary models, but subhalo components do not. Martel and
Shapiro (2003) have examined the profile of lenses for a number of
evolutionary models. While they find quantitative fits for many
properties, they find that the models do not correctly reproduce the
central region. Park and Ferguson (2003) studied the lensing produced by
Burkert haloes and found, `For the scaling relation that provides the
best fits to spiral-galaxy rotation curve data, Burkert halos will not
produce strong lensing, even if this scaling relation extends up to
masses of galaxy clusters. Tests of a simple model of an exponential
stellar disk superimposed on a Burkert-profile halo demonstrate that
strong lensing is unlikely without an additional concentration of mass
in the galaxy center (e.g. a bulge)'. In a one study for which a
particularly good analysis is possible, Wayth et al. (2005) found that,
for the optical Einstein ring gravitational lens ER 0047-2808, lensing
is consistent with a halo of the same mass distribution as the galaxy
itself. This result is not consistent with either the halo distribution
required to produce galactic rotation curves, or with evolutionary halo
models. It is, of course, trivially consistent with both in a no CDM
model.

Incidentally straight MOND does not resolve these problems, because it
finds it difficult to account for the strength of lensing. MONDian
galaxies are short on mass. The teleconnection survives because it
predicts greater lensing angles from distant galaxies. MOND also has a
problem with galaxy clusters and Lyalpha absorbers. These are modelled
from hydrodynamic principles, not from rotation curves. Again the
teleconnection does not have that problem because it modifies the
interpretation of Doppler shift, not Newtonian dynamics.


Biviano A. & Salucci P., The radial profiles of the different mass
components in galaxy clusters accepted in A&A. astro-ph/0511309. de
Blok, W.J.G., Bosma, A., & McGaugh, S.S. 2003, MNRAS, 340, 657. Martel.
H. and Shapiro P. R., 2003, Printed 4 March 2006, MNRAS, astro-
ph/0305174 Navarro, J. F., Frenk, C. S., & White, S. D. M. 1997, ApJ,
490, 493. Park Y., Ferguson H. C., 2003, Ap.J. 589, L65-L68, astro-
ph/0304317 Power C., Navarro. J. F., Jenkins A., Frenk C. S., White S.
D. M., Swaters, R.A., Madore, B.F., van den Bosch, F.C., & Balcells, M.
2003, ApJ, 583, 732 Wayth R. B., Warren S. J., Lewis G. F., Hewett P.
C., 2005, MNRAS, 360, 1333-1344.




as the Scientific
American article I've now URLed here twice explains,
one of the reasons for the broad acceptance of CDM
is exactly its explanatory power concerning the
development of galaxies.

I have cited some of the literature. There is a lot more if you would
look for it. Now will you accept your own criterion that since
observations on CDM are inconsistent the theory should be scrapped?


[Mod. note: it is of course possible for a model to be good at
explaining how galaxies form and yet have some problems in reproducing
the details. The issue is whether the successes make you want to solve
the problems by tweaking the model, or whether you should tear it up
and start again -- mjh]

Indeed. Only rarely is theory scrapped wholesale and starts again from
scratch just because of inconsistent observations, especially when
observations are hard to come by, to interpret and to analyse. At a
theoretical level the teleconnection is a very small tweak to general
relativity. It does not modify classical gtr at all, but applies in the
quantum domain. The one change is that light from distant stellar
objects is then treated quantum mechanically. This does mean we have to
reinterpret almost all astronometrical data. The result of doing so is
that no other alterations to known physics appear to be required on
empirical grounds - no CDM, no Lambda, possibly no missing matter, and
certainly no modification to Newtonian Dynamics.


Regards

--
Charles Francis
substitute charles for NotI to email

On Feb 16, 2:19 am, "Kent Paul Dolan" wrote:
"Ken S. Tucker" wrote:

though I think the
Newtonian Roche Limit induction is adequate.

???

Why would there be a Roche Limit involved? If
I understand correctly, that's the point at
which solid bodies orbiting larger bodies are
torn to pieces by tidal forces.

But at the scales involved, galaxies aren't
solid bodies at all, they are swarms of
particles. The galaxy may well be torn apart
by tides, but surely the math is different
than "Roche Limit" math?

For a basic ref...
http://en.wikipedia.org/wiki/Roche_limit
Generally the object undergoing tidal deformation,
such as a galaxy, could be regarded as a
gravitationally bound set of particles of zero pressure,
for purposes of computation.

Interestingly, the tides on Earth deform it into
a prolate spheroid with "high" tide on two sides
of the Earth. It appears to me (subjectively)
barred galaxies often have two main arms, and
when rotation is accounted for suggests a
Roche limit / tidal deformation.
Has a simulation of that been done that anyone
might provide as a ref?
Thanks
Ken

On Feb 17, 4:23 am, "Ken S. Tucker" wrote:
On Feb 16, 2:19 am, "Kent Paul Dolan" wrote

Why would there be a Roche Limit involved? If
I understand correctly, that's the point at
which solid bodies orbiting larger bodies are
torn to pieces by tidal forces.

But at the scales involved, galaxies aren't
solid bodies at all, they are swarms of
particles. The galaxy may well be torn apart
by tides, but surely the math is different
than "Roche Limit" math?

For a basic ref...http://en.wikipedia.org/wiki/Roche_limit

Sorry, then I certainly did NOT understand
correctly, since I had it exactly backwards,
a body solid enough to have tensile strength
is the one that doesn't exactly obey a Roche
limit calculation.

Thanks for the help.

xanthian.

On Feb 16, 3:22 pm, "Kent Paul Dolan" wrote:
Oh No wrote:
As far as galaxy evolution models are concerned, we know that CDM models
don't work at all well in creating observed galaxy profiles, and we know
that we have a problem understanding the rate of galaxy formation from
the big bang.

Unless you have a mouse in your pocket, that is
your unsupported opinion; as the Scientific
American article I've now URLed here twice explains,
one of the reasons for the broad acceptance of CDM
is exactly its explanatory power concerning the
development of galaxies.

And what sort of explanatory power does CDM have
except saying that whatever matter short fall is due
to CDM. Is there a CDM theory that explains both
the large elliptical galaxies and the LSB galaxies?
I am sure with the amount of the broad acceptance
there should be one paper that explains both with
a single theory. Please do point me to such a
paper. Also it should use only one psuedo free
parameter per galaxy (the M/L ratio). It could
have multiple universal parameters. That is what
MOND/TeVeS can achieve. I don't care
that it doesn't work well at Cluster level (maybe
there is some kind of dark matter between
galaxies). But MOND/TeVeS proves that it is
possible to predict galactic rotation curves
without any other free galactic parameter except
M/L ratio. Till any CDM theory can do that, it
is suspect at the Galactic level.


xanthian.

[Mod. note: it is of course possible for a model to be good at
explaining how galaxies form and yet have some problems in reproducing
the details. The issue is whether the successes make you want to solve
the problems by tweaking the model, or whether you should tear it up
and start again -- mjh]

wrote:

Also it should use only one psuedo free parameter
per galaxy (the M/L ratio).

Unfortunately for your contention, and as the Hubble
dark matter map shows, CDM may exist in galaxies,
but it is not limited to galaxies, and so "one
pseudo-free parameter" as a goal is an uncatchable
ephemera.

Instead, CDM will have an inherent local
intergalactic density of its own, which should
influence its density within the embedded galaxies,
adding a second parameter.

Also as shown by the Hubble map, the intergalactic
density of CDM evolves with time, adding yet a third
parameter.

Beyond all that, I'm a math major, not an
astronomer, and if you insist in writing in
acronyms, I will have to insist on not having a
clear understanding of what you try to convey.

Lastly, do your own homework. Google Scholar will
work just as well or ill for you as for me, and you
have the specialist vocabulary to put it to easier use.

FWIW

xanthian.

On Feb 19, 9:47 pm, "Kent Paul Dolan" wrote:
wrote:
Also it should use only one psuedo free parameter
per galaxy (the M/L ratio).

Unfortunately for your contention, and as the Hubble
dark matter map shows, CDM may exist in galaxies,
but it is not limited to galaxies, and so "one
pseudo-free parameter" as a goal is an uncatchable
ephemera.

I don't understand how the dark matter map makes any difference
because it is generated using standard Relativity. If we assume that
Relativity does not work well at very low acceleration, then the map
will be wrong. So it actually doesn't prove anything. Its actually a
case of circular reasoning.


Instead, CDM will have an inherent local
intergalactic density of its own, which should
influence its density within the embedded galaxies,
adding a second parameter.

Let me first define the only two terms that I used

MOND is MOdified Newtonian Dynamics, it says that the laws of
gravitational force is different than what is predicted by Newtonian
gravity when accelaration due to gravity is too low. It embodies a
single equation which gives the new equation for the force law that
will apply when the accelaration due to gravity is too low. It is not
a proper theory and cannot be used for other things that Relativity
predicts like Gravitational Lensing.

MOND is ad-hoc and was designed to obtain the Tully Fisher
Relationship.

TeVeS is a theory based on MOND's hypothesis. It is proper theory in
that it can be used for Gravitational Lensing. It basically reduces
to Newtonian regime at higher accelaration due to gravity, to
Relativity at higher speed, and to MOND at lower accelaration due to
gravity and low speed.

MOND has been quite successful in fitting rotational speed data for
the galaxies. It has been tested on over 120 galaxies and there have
been no failures. Please see http://www.astro.umd.edu/~ssm/mond/. If
it had no truth behind it there would have been some failures in the
nearly 30 years that it has existed, but there has been none. It does
not work as well in the Clusters of galaxies, so I guess that there
may be some kind of Dark Matter there. But at least according to MOND
there is no evidence of dark matter in the galaxies. It could be that
there is some kind of dark matter that can form stable structures at
much larger scales than galaxies. And these structures are present in
most clusters. It could be that MOND is still an approximation of some
other theory that we don't know. I would like to believe that it is
some kind of Conformal Field Theory, just like the other forces.

BTW MOND can obtain the data from Clusters of Galaxies if 2eV massive
nutrinos could form huge stable structures and was present in most
galaxy clusters.



Also as shown by the Hubble map, the intergalactic
density of CDM evolves with time, adding yet a third
parameter.

Beyond all that, I'm a math major, not an
astronomer, and if you insist in writing in
acronyms, I will have to insist on not having a
clear understanding of what you try to convey.

Well I am Computer Programmer and not a scientist, and also very
interested in the game we call nethack ;-).

Just got interested in the MOND thing a couple of years back and have
been reading everything that I can find on the subject. I find the
results quite intriguing.


Lastly, do your own homework. Google Scholar will
work just as well or ill for you as for me, and you
have the specialist vocabulary to put it to easier use.

Unfortunately I don't know much about maths. And these Relativity
papers are all filled up with so much maths that it makes the head
hurt, and they don't go about explaining the consequences of their
equations. I did find Conformal Theory from Mannheim interesting
because he did bring his equations to lay man perspective.

Hope I am not too full of it.


FWIW

xanthian.

Thus spake
On Feb 19, 9:47 pm, "Kent Paul Dolan" wrote:
wrote:
Also it should use only one psuedo free parameter
per galaxy (the M/L ratio).

Unfortunately for your contention, and as the Hubble
dark matter map shows, CDM may exist in galaxies,
but it is not limited to galaxies, and so "one
pseudo-free parameter" as a goal is an uncatchable
ephemera.

I don't understand how the dark matter map makes any difference
because it is generated using standard Relativity. If we assume that
Relativity does not work well at very low acceleration, then the map
will be wrong. So it actually doesn't prove anything. Its actually a
case of circular reasoning.

Yes. But in this case, I think it is not low accelerations which are the
problem, but the assumption in general relativity about the path of
light in empty space. If the lensing is not as predicted, then too the
dark matter map will be wrong.


TeVeS is a theory based on MOND's hypothesis. It is proper theory in
that it can be used for Gravitational Lensing.

Not with brilliant results, unfortunately. Zhao et al. MNRAS. 368, 171,
astro-ph/0509590 found that =E2=80=9CTeVeS succeeds in providing an alter=
native
to general relativity in some lensing contexts; however, it faces
significant challenges when confronted with particular galaxy lens
systems=E2=80=9D. However, the empirical determination of the mass of the
lensing galaxy is not sufficiently precise to eliminate it for all
choices of parameters. But TeVeS is not the only possibility.

It could be that MOND is still an approximation of some
other theory that we don't know. I would like to believe that it is
some kind of Conformal Field Theory, just like the other forces.

BTW MOND can obtain the data from Clusters of Galaxies if 2eV massive
nutrinos could form huge stable structures and was present in most
galaxy clusters.

Straight MOND also has a problem with Galaxy Clusters. So too does CDM.
At the moment neither seems capable of consistent predictions. According
to the teleconnection the problem lies not with Newtonian gravity, but
with the interpretation of Doppler shifts. The prediction is that
cosmological expansion affects Doppler shifts in just such a way as to
produce the illusion of a flat rotation curve.




Regards

--=20
Charles Francis
substitute charles for NotI to email

On Feb 20, 4:19 am, wrote:

http://www.astro.umd.edu/~ssm/mond/

I went through the FAQ at that site.

MOND seems to be self-falsifying.

It wants us to believe that there is a very low
acceleration law of gravity, and a normal
acceleration law of gravity, and that the atoms in a
star, which of necessity are in the "high
acceleration" regime _because_ they are in a star,
are *at the very same time* in a "low acceleration"
regime due to gravity of distant stars accumulated
as a "center of galaxy" force.

That's just too much handwaving to swallow.

MOND may well _fit_ mass/light for galaxies, but
making equations to fit is presumably "easy" for
those comfortable with that level of math. What MOND
does not do is _explain_ the rotation of galaxies,
and its attempts to do so are just silly, as far as
I can tell.

In comparision, CDM attempts to _explain_ galaxy
rotations, and evidence that CDM (and Cold Dark
Energy) exist seems to accumulate regularly, the
Hubble survey being merely one prominent example.

FWIW

xanthian.

Notice also that checking whether accelerations at
the MOND level exist is perfectly straightforward
(if tedious) to do in an earth based lab. If you can
factor away the gravity inside a star as MOND
proponents pretend is possible, you can surely
factor away the lesser gravity of earth to detect
with interferometry whether two appropriately sized
and spaced masses attract each other "differently in
essence" above and below the a0 parameter
gravitational behavior regime breakpoint of MOND.

If thirty years after MOND was proposed that still
hasn't been attempted and the results documented,
why is MOND still being taken seriously?

An appropriate place to attempt that Real Soon Now.
would be the "under improvement" earth based
gravity wave detection facilities where effects of
outside vibration will be carefully controlled and
culled from the data, and detection of such minor
motions are a design goal.

http://news.bbc.co.uk/1/hi/sci/tech/2774163.stm

Thus spake Kent Paul Dolan
On Feb 20, 4:19 am, wrote:

http://www.astro.umd.edu/~ssm/mond/

I went through the FAQ at that site.

MOND seems to be self-falsifying.

An empirical law found purely from observation cannot be self
falsifying.

It wants us to believe that there is a very low
acceleration law of gravity, and a normal
acceleration law of gravity, and that the atoms in a
star, which of necessity are in the "high
acceleration" regime _because_ they are in a star,
are *at the very same time* in a "low acceleration"
regime due to gravity of distant stars accumulated
as a "center of galaxy" force.

That's just too much handwaving to swallow.

It doesn't come with an explanation. But the observation of the fits
cannot be denied. Nor can it be explained with CDM.

MOND may well _fit_ mass/light for galaxies, but
making equations to fit is presumably "easy" for
those comfortable with that level of math.

The level of maths is not that high. Laws close to MOND might also work.

What MOND
does not do is _explain_ the rotation of galaxies,
and its attempts to do so are just silly, as far as
I can tell.

Actually attempts like Bekenstein's TeVes and Moffat's scalar tensor
theory are quite sophisticated.

In comparision, CDM attempts to _explain_ galaxy
rotations, and evidence that CDM (and Cold Dark
Energy) exist seems to accumulate regularly, the
Hubble survey being merely one prominent example.

Not really. Lensing profiles and evolutionary models appear to falsify
it quite well, as does the baryon catastrophy. The Hubble survey is not
evidence if it assumes an incorrect lensing law.

Notice also that checking whether accelerations at
the MOND level exist is perfectly straightforward
(if tedious) to do in an earth based lab.

It's well established that MOND does not apply in the inner solar
system. Nor does the Pioneer blueshift.


If thirty years after MOND was proposed that still
hasn't been attempted and the results documented,
why is MOND still being taken seriously?

Because many cosmologists don't find CDM a credible explanation, and the
fits to the MOND law are definite empirical evidence which is also
mounting. It also applies to globular clusters, in which CDM is a non-
starter as an explanation - it would mean inconsistent amounts of CDM in
the cluster as is supposed to exist within the Milky Way.

The teleconnection does explain these observations, by modifying
redshifts and lensing, and without modifying either particle physics or
dynamics.


Regards

--
Charles Francis
substitute charles for NotI to email