Observational constraints on disk galaxy formation

Astronomy and Astrophysics – Astrophysics

Scientific paper

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

7 pages, latex, with figures, submitted to MNRAS, also at http://www.mpa-garching.mpg.de/~syer/papers

Scientific paper

We use data from the literature to constrain theoretical models of galaxy formation. We show how to calculate the dimensionless spin parameter $\lambda$ of the halos of disk galaxies and we compare the distribution of $\lambda$ with that observed in cosmological $N$-body simulations. The agreement is excellent, which provides strong support for the hierarchical picture of galaxy formation. Assuming only that the radial surface density distribution of disks is exponential, we estimate crudely the maximum-disk mass-to-light ratio in the $I$-band and obtain $ \la 3.56h$, for a Hubble constant of $100h~\kms \mpc^{-1}$. We discuss this result and its limitations in relation to other independent determinations of $M/L$. We also define a dimensionless form of the Tully-Fisher relation, and use it to derive a value of the baryon fraction in disk galaxies. For galaxies with circular velocity $\vmax>100\kms$, the median value is $md = 0.086 (M/L/3.56h)$. Assuming that the gas fraction in galactic halos is at most as large as that in clusters, we also conclude that $ \la 2.48h^{-1/2}$.

No associations

LandOfFree

Say what you really think

Search LandOfFree.com for scientists and scientific papers. Rate them and share your experience with other people.

Rating

Observational constraints on disk galaxy formation does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Observational constraints on disk galaxy formation, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Observational constraints on disk galaxy formation will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFWR-SCP-O-607328

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.