| Type |
Journal Article |
| Names |
Matthew A. Bershady, Marc A. W. Verheijen, Kyle B. Westfall, David R. Andersen, Rob A. Swaters, Thomas Martinsson |
| Publication |
The Astrophysical Journal |
| Volume |
716 |
| Issue |
1 |
| Pages |
234-268 |
| Date |
June 1, 2010 |
| URL |
http://adsabs.harvard.edu/abs/2010ApJ...716..234B |
| Library Catalog |
NASA ADS |
| Abstract |
We present a performance analysis of the DiskMass Survey. The survey
uses collisionless tracers in the form of disk stars to measure the
surface density of spiral disks, to provide an absolute calibration of
the stellar mass-to-light ratio (\Upsilon_{*}), and to yield robust
estimates of the dark-matter halo density profile in the inner regions
of galaxies. We find that a disk inclination range of 25°-35° is
optimal for our measurements, consistent with our survey design to
select nearly face-on galaxies. Uncertainties in disk scale heights are
significant, but can be estimated from radial scale lengths to 25% now,
and more precisely in the future. We detail the spectroscopic analysis
used to derive line-of-sight velocity dispersions, precise at low
surface-brightness, and accurate in the presence of composite stellar
populations. Our methods take full advantage of large-grasp
integral-field spectroscopy and an extensive library of observed stars.
We show that the baryon-to-total mass fraction (\mathcal {F}_bar) is not
a well-defined observational quantity because it is coupled to the halo
mass model. This remains true even when the disk mass is known and
spatially extended rotation curves are available. In contrast, the
fraction of the rotation speed supplied by the disk at 2.2 scale lengths
(disk maximality) is a robust observational indicator of the baryonic
disk contribution to the potential. We construct the error budget for
the key quantities: dynamical disk mass surface density
(Σdyn), disk stellar mass-to-light ratio
(\Upsilon^disk_{*}), and disk maximality (\mathcal
{F}_{\ast,max}^disk\equiv V^disk_{\ast,\rm max}/ V_c). Random and
systematic errors in these quantities for individual galaxies will be
~25%, while survey precision for sample quartiles are reduced to 10%,
largely devoid of systematic errors outside of distance uncertainties. |
| Tags |
GALAXIES: EVOLUTION, GALAXIES: FUNDAMENTAL PARAMETERS, GALAXIES: STELLAR CONTENT, GALAXIES: STRUCTURE, Galaxies: Halos, Techniques: Spectroscopic, dark matter, galaxies: formation, galaxies: kinematics and dynamics, galaxies: spiral, methods: data an |