"SW" == Steve Willner writes:

SW In article , Joseph Lazio
SW writes:

Admittedly, this is not my area, but I'm astounded. Nobody's ever
attempted to measure the stellar velocity dispersion of a spiral
disk?

SW Are we talking about velocity dispersions or rotation curves? I
SW thought the evidence for dark matter was the latter.

I would think so, too. However, a recent set of posts assert that
stellar and gas rotation curves are different. Based on the (few)
references provided, I don't agree. IIRC, the post to which I was
responding even asserted that no stellar velocities were available.
That's what prompted my statement. Although the velocities of
individual stars would be difficult to obtain, it might be possible to
measure the velocity dispersion from the integrated light of the stars
in the disk. I don't know if this has been tried, though.

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