WIMPS?

On 7/14/13 3:46 AM, Dan Riley wrote:

Still no confidence intervals (the dominant errors are not stochastic,
so minimizing stochastic model RMS isn't appropriate).
Figure 4 of gr-qc/0507052 indicates errors
are not so great as not to consider stochastic model RMS
particularly as time increases
a consideration that is not evident in the snapshot overview
http://arxiv.org/abs/1204.2507v1 Figure 4

A stochastic RMS model minimization
was done for doppler mechanism
and compared to thermal degradation model:
http://arxiv.org/abs/1204.2507v1 Page 4

"Lastly, we mention that both the thermal recoil force
and the Doppler data can be well modeled using
an exponential decay model in the form
aP = aPo * exp(-(t-to)*ln(2)/half_life).
Using t0 = January 1, 1980, the best fit parameters
for the Doppler data are [8]
half_life= (28.8+or-2.0) yr,
a0 = (10.1+or-1.0)×10−10 m/s^2.
In contrast,
the calculated thermal recoil force can be modeled,
with an RMS error of 0.1×10−10 m/s^2,
using the parameters = 36.9+or-6.7 yr,
a0 = (7.4+or-2.5) × 10−10 m/s^2."

The above half_lives (~25 to ~40 years) are too long
in the context of radiation pressure formula

pressure = F*stefan_constant*T^4*(4/(3*c))

with a multiplier factor F as a measure
of material emissivity or absorptivity.

The explaining logic is as follows:
Pioneer recoil deceleration may be calculated as
pressure*pioneer area/pioneer mass or aP
This aP is then proportional to a net system temperature(T)^4.
This system temperature(T) scales
with the RTG radioactive source half_life 87 years.
Deceleration(aP) half_life
then varies with RTG half_life as (1/2)^4 = 1/16.
The pioneer deceleration(aP) half_life
should then be on the order of 87/16 or 5.4 years
(not ~25 to ~40 years as indicated in http://arxiv.org/abs/1204.2507v1)
This relatively short aP half_life (~5 years) is correctly modeled
for both Pioneers
with a combination exponential decay and constant deceleration
with the constant (aPconstant) on the order of 8 x 10^(-10) m/s^2.

The half_lives associated with power consumption (heat, T)
http://arxiv.org/abs/1204.2507v1 Table I
are shorter than 87 years making the above argument more compelling.

It is difficult to escape the conclusion
that the independently developed Pioneer thermal recoil model
(based solely on the decay hypothesis dx/dt = -k*x)
is deficient in modeling the Pioneer anomaly.

Richard D. Saam

Op zaterdag 13 juli 2013 10:38:11 UTC+2 schreef Steve Willner the next:
In article ,
Nicolaas Vroom writes:
For a more general discussion go he
http://users.telenet.be/nicvroom/dark_mat.htm

There are several misconceptions on that page, but I am not sure we
disagree on the overall result: increasing the mass of a galaxy disk
but keeping the same mass distribution cannot produce a flat rotation
curve. Do we agree on that?
IMO any given mass distribution will generate its own rotation curve RC.
Increasing the average density will only increase the values but not
the shape of the curve.
But that is not the issue.
The excel program Circ6.xls calculates the mass distribution as
a function of the RC.
Picture http://users.telenet.be/nicvroom/Cir...0350%20250.jpg
shows a flat RC. The cyan line shows the mass distribution.
Two parameters are important: The size of the bulge (5 units) and the
size of the disc (200 units) The relation 40 to 1 I think is extreme.
Picture http://users.telenet.be/nicvroom/Cir...0350%20250.jpg
shows the relation 20 to 1.
What is also important is the height of the disc.
The height of the disc above the equator is 1 unit.
1 unit = 1000 Lightyear.
The density of the bulge is 1E-10
When you increase the size of the disc to 2 units the density
of the disc decreases with a factor two.
The smallest density in the case of disc height 1 unit is roughly 2E-12
that means 2% of the density of the bulge.
The question is: Is it possible to observe this mass?
(The highest density is 2E-10)

When you consider the 4 nearest stars to us the total mass is 3,17
sun masses the density is 2,15E-11
For the 84 nearest stars (62 star systems) the total mass is 30,2
and the density 3,44E-12
When you remove all the stars above 0.4 mass the total mass left is
9,46 and the density is 1E-12. This are Red Dwarfs and Brown Dwarfs
and can be considered invisble baryonic matter.
What I mean is that a lot of matter in our neighbourhood can be considered
invisible from our point of view compared to the Andromeda Galaxy.
You have to remove that mass in order to calculate the observed
galaxy rotation curve based on visible baryonic matter.

In the simulation the whole halo above the disc is considered empty.
In reality this space is filled with stars clusters. I do not know
the average density. Also that amount of visible baryonic
matter has to be subtracted to calculate the observed galaxy
rotation curve, which than becomes not flat.

If we do, there are two ways out: modified gravity law ("MOND") or
extra matter that is not distributed the same way as the visible
stars. We call the latter "dark matter" (DM). Whether it's baryonic
or not is a separate question.
But that is the topic of this discussion. Do we need WIMP's
to explain missing matter.

People are working on MOND but so far
without much success. That is to say, one can always "tune" a
gravity law to explain one or a few galaxies, but no single
alternative model explains all the relevant cases.

I fully agree with you. Modifying Newton's Law to match IMO
lack of visibility is not the prefered way to go.

Leaving MOND aside, I think there is a small amount of parameter
space that would let the DM needed to explain galaxy rotation curves
be baryonic. Presumably the DM is mostly made out of hydrogen (else
where is the hydrogen that should go with it?), and that requires
fairly large objects (say Saturn-size or larger). Lensing
observations put upper limits on the number of such objects, and I'm
not sure whether they are yet sensitive enough to rule out such
objects as major contributors to galaxy mass. Larger objects such as
white dwarfs and super-Jupiters are, I think, ruled out.

Red Dwarfs and Brown Dwarfs are not ruled out?

Another limit is the overall baryon budget. We know the average
density of baryons in the Universe (from CMB observations and from
Big Bang nucleosynthesis), and we know where a lot of the baryons
reside. One example is at
http://inspirehep.net/record/1081235/plots
(Look all the way at the bottom.)
I am studying this document. The issue is to which extend this can
be used to explain the missing mass in individual galaxie?

And
even if you can manage the galaxy rotation curves, there is no way to
have enough baryonic matter to explain the galaxy cluster velocity
dispersions.
The same as above.

People interested in playing with galaxy rotation curves may like
http://burro.astr.cwru.edu/JavaLab/RotcurveWeb/
In this document they simulate the galaxy rotation based on visible
baryonic matter and with an halo of darkmatter.
I have done the same in the paragraph's called Question 4 (NFW)
and Question 5 (Hernquist)

Nicolaas Vroom
http://users.pandora.be/nicvroom/

Op zaterdag 13 juli 2013 10:38:11 UTC+2 schreef Steve Willner het volgende:

People interested in playing with galaxy rotation curves may like
http://burro.astr.cwru.edu/JavaLab/RotcurveWeb/

In that document we can read:
" If we assume the galaxy is spherical, we can then say that
V=(GM/r) ? , or solve for mass as M=rV ? /G."
That is correct and true for our solar system. Next:

" The fact that disk galaxies are not spherical means there is a
small correction factor we need to apply, but the basic idea
stays the same."
What you need is a 3D simulation using Newton's Law. To call
the difference between a spherical and spiral galaxy small
is a misconception. Next:
" But when astronomers first tried to do that, they ran into
an astonishing problem: rotation curves of spiral galaxies are flat."
Astronomers knew already that spiral galaxies are flat.
The issue is what exactly is this "small" correction.
If you make this correction too small the calculated and observed
galaxy rotation curve do not match. Next:

"The flatness of spiral galaxy rotation curves is a extremely common;
in fact, no spiral galaxy shows a r -? falling rotation curve.
This result led astronomers to the conclusion that there must be more
mass than meets the eye in spiral galaxies -- in addition to being
filled with stars, galaxies must have other unseen mass associated
with them which provides enough mass to keep the rotation curves
from falling."
The issue is what is this unseen mass. The fact that the rotation
curve does not drop off is no issue because every solution
has the same problem. We also have to be very carefull
here because unseen is a typical human characteristic.
This unseen mass can be easy: small dwarf objects.
When you study http://en.wikipedia.org/wiki/List_of_nearest_stars
you can calculate that the star mass in our neighbourhood is roughly
30 solar mass. 9 solar mass is of stars smaller than 0.4 solar mass.
All that baryonic mass can be considered invisible observed
from large distance.

To solve the problem the most obvious solution is to assume that
there is more mass in the disc than what is directly visible.
To solve the solution in a halo outside the disc IMO
is first of all a theoretical (mathematical) solution. In that
direction there are two solutions: NFW and Hernquist profile
which each has its own free paramaters.
Each allows you to simulate flat rotation curves. However
the same can be done assuming that all mass is in the disc.
For example program 14 tries to do that.
See: http://users.telenet.be/nicvroom/progrm14.htm

It should be mentioned that the simulations in the document
describe a ratio bulge to disc as 1 to 2. The simulations
I do are at least 1 to 10 or much more.

Nicolaas Vroom

[Mod. note: non-ASCII characters replaced with ? -- readers familiar
with Newton's laws may be able to figure out what these should have
been. Please, please, please, do not cut and paste non-ASCII
characters from papers or the web and assume that they will work here
-- mjh]

In article , Nicolaas Vroom
writes:

" The fact that disk galaxies are not spherical means there is a
small correction factor we need to apply, but the basic idea
stays the same."
What you need is a 3D simulation using Newton's Law. To call
the difference between a spherical and spiral galaxy small
is a misconception.

It depends on what one means. If the difference leads to small effects,
then it is, by this definition, a small difference. The appearance
doesn't matter here, since we are concerned with the distribution of
mass, not light.

" But when astronomers first tried to do that, they ran into
an astonishing problem: rotation curves of spiral galaxies are flat."
Astronomers knew already that spiral galaxies are flat.
The issue is what exactly is this "small" correction.
If you make this correction too small the calculated and observed
galaxy rotation curve do not match.

You seem to be implying that this issue is due to a simple mistake.
That's not the case.

This unseen mass can be easy: small dwarf objects.
When you study http://en.wikipedia.org/wiki/List_of_nearest_stars
you can calculate that the star mass in our neighbourhood is roughly
30 solar mass. 9 solar mass is of stars smaller than 0.4 solar mass.
All that baryonic mass can be considered invisible observed
from large distance.

Microlensing observations show that the dark matter in our galaxy cannot
be in compact objects over quite a range of masses. I'll have to check
if all dark matter inferred from galaxy rotation curves could be
baryonic, but I suspect this is a tight squeeze, given the constraints
from big-bang nucleosynthesis. However, we know from other observations
that most of the mass in the universe is not baryonic, so whether all
galaxy dark matter could be baryonic is not really an interesting
question; one would have to somehow separate the other dark matter from
baryonic matter in galaxies etc.

Op maandag 22 juli 2013 22:42:23 UTC+2 Phillip Helbig writes:
In article , Nicolaas Vroom
writes:

What you need is a 3D simulation using Newton's Law. To call
the difference between a spherical and spiral galaxy small
is a misconception.

It depends on what one means. If the difference leads to small effects,
then it is, by this definition, a small difference.
That is true. The problem is that the difference between an spherical
and spiral galaxy is large.

" But when astronomers first tried to do that, they ran into
an astonishing problem: rotation curves of spiral galaxies are flat."
Astronomers knew already that spiral galaxies are flat.
The issue is what exactly is this "small" correction.
If you make this correction too small the calculated and observed
galaxy rotation curve do not match.

You seem to be implying that this issue is due to a simple mistake.
That's not the case.
Two mistakes a
1. You should "not use" the mathematics which describe eliptical galaxies
to describe eliptical galaxies because eliptical galaxies are more
complex. The reverse is true.
2. You should not assume, when at a certain distance you cannot
measure the galaxy rotation curve, that the disc stops.
This is identical that assuming that outside Pluto the solar system
stops. (We know now that this is not true and we call that region
the Kuiper Belt). Something equivalent exists for the disc of a Galaxy.

Microlensing observations show that the dark matter in our galaxy cannot
be in compact objects over quite a range of masses.
In this sentence do you mean non-baryonic matter?

I'll have to check
if all dark matter inferred from galaxy rotation curves could be
baryonic, but I suspect this is a tight squeeze, given the constraints
from big-bang nucleosynthesis.
In this discussion the following documents are interesting:
http://astrobites.org/2013/04/04/do-...-matter-halos/
http://arxiv.org/abs/1303.6896
The articles indicate that elliptical galaxies contain no darkmatter in
the halo. The second article claims: (Search with baryonic):
" This suggests that the total mass distribution in early-type galaxies
closely follows the light distribution and sheds doubts on the existence of
extended galactic halos made of exotic, non-baryonic particles"

However, we know from other observations
that most of the mass in the universe is not baryonic, so whether all
galaxy dark matter could be baryonic is not really an interesting
question
It is an interesting question because many articles claim that (almost)
all inivisble matter (darkmatter) to explain the actual (flat) galaxy
rotation curves is non-baryonic (exotic ?) which is the topic
of this post.
I'am not claiming that all this matter has to be baryonic.

Nicolaas Vroom

In article , Nicolaas Vroom
writes:

Microlensing observations show that the dark matter in our galaxy cannot
be in compact objects over quite a range of masses.
In this sentence do you mean non-baryonic matter?

Microlensing doesn't care if the matter is baryonic or not. All mass
affects light, so gravitational lensing can detect mass, be it dark or
shining, be it baryonic or not.

Op woensdag 24 juli 2013 07:39:36 UTC+2 schreef Phillip Helbig:
In article , Nicolaas Vroom

writes:

Microlensing observations show that the dark matter in our galaxy cannot
be in compact objects over quite a range of masses.
In this sentence do you mean non-baryonic matter?

Microlensing doesn't care if the matter is baryonic or not. All mass
affects light, so gravitational lensing can detect mass, be it dark or
shining, be it baryonic or not.

This makes the discussion simpler. However I do not fully understand
the sentence. Do you mean something like:
" Microlensing observations show that the size of (invisible) baryonic
objects in our Galaxy have certain limitations."
IMO the size of the objects in our Galaxy can be in an almost
continuous range of values. From 100 Solar Masses to dust, excluding
the Black Hole in the center.

The only thing that I can imagine is that using Microlensing there
is a lower limit on the size of an object that can be detected.
For more detail read this:
https://en.wikipedia.org/wiki/Gravit...l_microlensing
The message that emerges is that it is obvious that to explain the
missing mass problem in Galaxy Rotation curves solely based on
exotic particles is shortsighted.

Nicolaas Vroom

In article , Nicolaas Vroom
writes:

Microlensing doesn't care if the matter is baryonic or not. All mass
affects light, so gravitational lensing can detect mass, be it dark or
shining, be it baryonic or not.

This makes the discussion simpler. However I do not fully understand
the sentence. Do you mean something like:
" Microlensing observations show that the size of (invisible) baryonic
objects in our Galaxy have certain limitations."

Yes.

IMO the size of the objects in our Galaxy can be in an almost
continuous range of values. From 100 Solar Masses to dust, excluding
the Black Hole in the center.

No; certain mass ranges are quite strictly ruled out.

The only thing that I can imagine is that using Microlensing there
is a lower limit on the size of an object that can be detected.

Of course there is a lower limit. However, things of planet mass, or
larger, would be detected if they make up a substantial fraction of dark
matter in the galaxy.

On 7/16/13 1:35 AM, Richard D. Saam wrote:

The explaining logic is as follows:

Some corrections and additions from previous post
Ref: 1. http://arxiv.org/abs/1107.2886v1
2. http://arxiv.org/abs/1204.2507v1
3. The Pioneer Anomaly:Known and Unknown Unknowns
by Donald Rumsfeld, Viktor T. Toth
Pioneer Anomaly seminar
Perimeter Institute for Theoretical Physics, May 26, 2011
http://streamer.perimeterinstitute.c...77/viewer.html
Distance and geometric velocity Pioneer 10
(about 3/4 through)

Pioneer recoil deceleration may be calculated as
pressure*pioneer area/pioneer mass or aP
This aP is then proportional to a net system temperature(T)^4.

pressure = F*stefan_constant*T^4*(4/(3*c))

with a multiplier factor F as a measure
of material emissivity or absorptivity.

Pioneer recoil deceleration(aP) may be calculated as
aP = pressure*pioneer area/pioneer mass
or
aP = F*stefan_constant*T^4*(4/(3*c))*pioneer area/pioneer mass

in refs 1&2, a theoretically consistent model was used:

aP = n*Q/(pioneer mass *c)

where Q is directed radiation power (watt)
and n represents empirically determined F and pioneer projecting areas.

This system temperature(T) scales
with the RTG radioactive source half_life 87 years.
Deceleration(aP) half_life
then varies with RTG half_life as (1/2)^4 = 1/16.

Deceleration (aP) as well as radiation power half_life
vary as 1/4 of RTG half_life.

The pioneer deceleration(aP) half_life
should then be on the order of 87/16 or 5.4 years

Deceleration (aP) as well as radiation power half_life
should then be on the order of 87.7/4 or 21.9 years

These half_lives should be considered very accurate
and this accuracy is far greater than earth monitors
can observe through thermal telemetry
and on-board radiation pressure
should follow the well established decay law dx/dt = -kx

model one

daP/dt = -k*aP = -(ln(2)/21.9)*aP

The stochastic data half life more accurately follows
a modified version (not addressed in ref 1 and 2).

model two

aP/dt = -k*aP = -k*(aP - aPinfinity)

indicating aP approaches a constant value (aPinfinity)
5.00E-10 m/sec^2 with time.

The thermal data ref 2 table 1
conforms to model one as follows:

speed of light c = 3.00E8 m/sec
pioneer mass = 241 kg

nRTG = 0.0104
nelectric = 0.406
asymmetric radiated power(P) = nRTG*QRTG + nelectrical*Qelectrical
ref 2

aP = P/(pioneer mass * c)

AU is converted to time by ref 3.

Table 1.
AU time(yrs)) P(watt) aP(m/s^2) model one
0.00 7.98E-10
3 1.80 141.6 7.54E-10
10 5.19 121.8 6.77E-10
25 10.32 103.1 5.76E-10
40 15.75 90.8 4.85E-10
70 27.14 65.5 3.38E-10

Stochastic data for Pioneer 10 Table 2 conforms to model two
with aP approaching aPinifinity (5E-10 m/sec^2) with time.
(aP is result of averaging out residuals dfrequency/dt
over a time interval)

Table 2. (digitized for ref 1 and 2)
time(yr) aP(m/sec^2)
0 12.58E-10
8.79 9.82E-10
10.78 9.33E-10
12.80 8.78E-10
14.82 8.21E-10
16.81 8.21E-10
18.80 7.39E-10
20.81 7.34E-10
22.82 7.23E-10
24.85 7.72E-10

Logic indicates the difference in table 1 and 2 aP values with time
is an indication of the omnipresent aP(infinity).

More limited Pioneer 11 data yields the same results as above.

The presence of an aP(infinity) may be an indication
of a universal object Stokes' law drag force response
to the space vacuum viscosity
as suggested in: arXiv:0806.3165v3 [hep-th] 14 Nov 2008
Hydrodynamics of spacetime and vacuum viscosity

This overall logic could be confirmed or denied
by parallel analysis of pioneer spin deceleration
as discussed in ref 3.

It would be helpful if pioneer raw data were available
to the general scientific community for analysis.

On 7/31/13 11:08 AM, Richard D. Saam wrote:
Further clarification:


Ref: 1. http://arxiv.org/abs/1107.2886v1
2. http://arxiv.org/abs/1204.2507v1
In summary the references
model the Pioneer aP as the theoretically correct

aP = n*Q/(pioneer mass * c)

with two components

aP = (nRTG*QRTG + nelectrical*Qelectrical)/(pioneer mass * c)

The data for component:
aP = (nelectrical*Qelectrical)/(pioneer mass * c)
follows the relationship linked to 1/4 of RTG half life (87.7 years)

daP/dt = -(ln(2)/(87.7/4))*aP

Ref 2 suggests that RTG component:
aP = (nRTG*QRTG)/(pioneer mass * c)
is directly linked to RTG 87.7 year half life.

daP/dt = -(ln(2)/87.7)*aP

But this is theoretically not possible since
radiation pressure and related aP
aP = radiation pressure*pioneer area/pioneer mass
is related to RTG temperature(T)^4
aP = F*stefan_constant*T^4*(4/(3*c))*pioneer area/pioneer mass
(F = empirical emissivity absorptivity factor)

Further, the RTG geometric design symmetry does not in principle
allow for asymmetric radiation pressure contributing to aP.

Further, the theoretical aP identities
aP = F*stefan_constant*T^4*(4/(3*c))*pioneer area/pioneer mass
and
aP = n*Q/(pioneer mass *c)
indicates n represents
empirically determined F and pioneer projecting areas
Any anticipated extremely small RTG manufacturing area asymmetries
would contribute in a congruent extremely small manner.

Further, the RTG component decay is only about 20 percent over 25 years.

It is suggested the RTG component is incorrectly identified in refs
as contributing to aP.
The actual contribution to model stochastic data is from
aP = (nelectrical*Qelectrical)/(pioneer mass * c)
plus an anomalous constant factor (aPinfinity)
such that

aP/dt =-k*(aP - aPinfinity)

and aPinfinity is testing the space vacuum:
arXiv:0806.3165v3 [hep-th] 14 Nov 2008
Hydrodynamics of spacetime and vacuum viscosity

Such a conclusion has at least the standing
as the 1/1,000,000 particle statistical analysis
conducted for Higgs at LHC.

Richard D. Saam