I thought you guys might be interested to know that our M51 paper (Jokimake, Orr & Russell) has finally been cited in another paper.  Just do an ADS search for the paper.

Dave

About time...

:)

Yeah.   I've taken the last almost 2 years off from doing any research.  I'm gearing up to do a little more.  The last couple of days I've been looking over my K-band Tully-Fisher data/papers/files and thinking about what to do with some findings I never included in my K-TFR Hubble Constant paper.  Good thing I pulled it out too because some of it was starting to get a little rusty in my head.

http://adsabs.harvard.edu/abs/2008Ap%26SS.315..249J

Here is the ADS paper.

Welcome back Dave :>))

From the Abstract
"(4) It was found that only 18% of the M51 type companions have redshift measurements in the literature. There is a significant need for spectroscopic study of the companions in order to improve the value of the catalog as a sample for studying the effects of M51 type interaction on galaxy dynamics"

This obviously important, as they/mainstream are making determinations based on such a small data set!

But, here is a quick question for mainly Dave, but everyone can answer.

How can the stars rotational speed/velocity in the disc/equitorial plane even be determined considering that M51 is a "Face On" Galaxy from our line of site?

I mean by this that the stars in the disc are neither coming toward us nor going away from us (Accept for the possibility that they are going up or down in the thickness of the ecliptic) so how can a "Blue Shift/Red Shift" even be determined?

M51 is my "Wall Paper" on my Puter, so I have spent a great deal of time studying it and many other galaxies correlations from Birth/evolution. IF M51's "Jets" were "On" one would be pointed directly at us and the other Jet (From the other side of the galactic center: the 'supposed' other 'pole')  would be pointed directly away from us!

Hi Russ,

The global redshift is measured as any other redshift via displacement of spectral lines.  The orientation of the galaxy is not important for that measurement.  The measured rotational velocity for a galaxy is affected by the inclination.    The observed rotational velocity is corrected by dividing by sin(i).  So for a 90 degree inclination the observed Vrot is equal to the actual Vrot.  

Dave

Good for you Ari!  I'm currently beginning the process of writing up a paper based upon some of the galaxies in my sample that deviate rather strongly from the Hubble relation.