This paper is about the possibility of looking for direct signs of dark matter from the spheroidal dwarf galaxy in Draco. There is already some evidence for this observation already having been made at a barely above the noise level.

The idea is that if dark matter is made largely of neutralinos, these will have a small cross section for self annihilation, which will give off gamma rays in the hundreds of GeV to low TeV range. Other efforts have looked for this signal from the center of the Milky Way, and MIGHT have seen something, but it is such an astrophysically rich area that it is difficult to identify what is the source of such gammas.

The Dwarf Spheroidal galaxy in Draco has a high mass to brightness ratio, is located about 80 kpc away from here, and has few other bright potential TeV sources nearby.

Like many papers, this one is making the case for the authors to be able to get significant funding and/or observing time for tools to look for these gammas. One is a ground based operation in Spain with good angular resolution. another is the GLAST probe. Note that a null result is also interesting.

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Dark matter is not needed to explain the spiral galaxies' flat rotation curves.

Dark matter is a help hypothesis that was needed to explain the flat velocity curve that was based on Doppler-shifted measurings of rotating spiral galaxies’ arms. This hitherto unintelligible anomaly was observed via calculations by Fritz Zwicky and later reconstructed by Vera Rubin from her newer confusing analyses.

They found that all the stars in the galaxies they choused to measure had the same Doppler velocity.
But their measurings were misinterpreted so, as if the spiral galaxies rotated as stiff plates with the same angular velocity over the whole galaxy’s arms.

The astronomers’ conclusion was that the centrifugal forces from the angular acceleration of the mass should increase with the square of the velocity and proportional to the distance away from its center
(F = (m*v^2) / r).
Parallel with that the galaxy's gravity should decrease proportionally with the square of the distance which should throw the outer stars out into the space
(F =G*(m*m) / r^2).

Hithereto the astronomers have mistaken orbital velocity as angular velocity.
So, the right explanation is that the orbital velocity is the same for all the stars in those spiral galaxies’ arms, which implies that when an outer star in the galaxy rotates one revolution then another star in the same galaxy’s arm at half of that distance rotates two revolutions.
-- Hence, both have the same (orbital) velocity distribution.
And as the stars' mass and velocity are the same and balancing each other in the both directions, the force in each galaxy-arm is:
Gravitation-force (F=(m*G^-2) / r) and
Centrifugal-force (F=(m* v^ 2) / r).

The mass is the same in both arms, and the velocity is the same all over the arms, which implies that the stars in the spiral galaxies’ two arms in opposite directions are in equilibrium with each other, and that the arms' angular acceleration decreases proportionally with the distance and with the arms decreasing gravitation.

Consequently – DARK MATTER IS NOT NEEDED to explain the galaxies’ rotation and gravitation – if you use the right interpretation.

See more interesting discoveries and analyses at my site:
http://www.theuniphysics.info

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People who wish to see the measurements of galactic rotation curves for themselves might want to look at this article for a start:

http://adsbit.harvard.edu/cgi-bin/np...pJ...238..471R

There are many others, of course, but this shows the diversity in rotation curves, as well as the fact that many spirals do have relatively flat rotation curves.

I can't understand what s-i-a is trying to say in the previous message.

He is completely missing the point of the paper I linked to. It looks like he's simply parroting an old thing he'd written years ago. Clearly there is more evidence for Dark Matter than simply the rotation curves of galaxies. Lensing by galaxies and clusters of galaxies is a much better measure these days.

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Forming opinions as we speak