Maximal Disks and the Tully-Fisher Relation

Details Maximal Disks and the Tully-Fisher Relation Maximal Disks and the Tully-Fisher Relation

Dec 1997

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1997aas...191.7702c&link_type=abstract

American Astronomical Society, 191st AAS Meeting, #77.02; Bulletin of the American Astronomical Society, Vol. 29, p.1332

Statistics

1

Scientific paper

We use Tully-Fisher (TF) residuals for more than 600 luminous, high-surface brightness (HSB) spirals from the catalogs of Courteau (1992) and Mathewson et al. (1992) to show that a maximal disk fit is ruled out by the statistics of the rotation speed, V{_2.2}, at 2.2 exponential scale lengths. For maximal disks, a large fraction of the total rotational support should arise from their stellar mass. Therefore the size, or surface-brightness, of the disk should be a significant additional parameter in the TF relation. At a given absolute luminosity, M_r, (i.e. fixed mass), more compact disks (as measured by Rexp) should have higher rotation speeds, V{_2.2}. Using our well-defined sample of exponential disks, we find that the fractional deviations, Delta log V{_2.2} and Delta log Rexp, from the mean relations, V{_2.2}(M_r) and Rexp(M_r), are not significantly correlated. The case of {partial log {V{_2.2}} / partial log {Rexp}}=-0.5, expected for pure exponential disks, is clearly ruled out. Broad-band colors and spectral synthesis models allow us to show that the color dependence on disk scale length at a fixed luminosity is small, thus reinforcing our dynamical interpretation. We use simple models of adiabatic infall of the luminous matter to explore what values of {partial log {V{_2.2}} / partial log {Rexp}} are expected in the presence of modest bulges and a variety of dark matter halos. We find that the TF relation requires that Vdisk ~ 0.5 Vtot (Vdisk/Vtot=0.66 at 95% confidence), fairly insensitive to the details of the dark matter halo and the presence of a bulge. Traditionally, a disk is considered maximal if Vdisk = (0.85 +/- 0.10) Vtot; our result thus excludes the notion of maximal disks for luminous spirals. Sub-maximal disks are also consistent with constraints from stellar velocity dispersions in HSB spirals (Bottema 1997), and establish a natural continuity between HSB and LSB galaxies which appear to be completely dark matter dominated even in their inner regions.

Affiliated with

Also associated with

No associations

Rating

Maximal Disks and the Tully-Fisher Relation 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 Maximal Disks and the Tully-Fisher Relation, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Maximal Disks and the Tully-Fisher Relation will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1175446