For refcode 2005ApJ...633..844P: Retrieve 81 NED objects in this reference. Please click here for ADS abstract
NED Abstract
Copyright by American Astronomical Society.
Reproduced by permission
2005ApJ...633..844P
Dark Matter and Stellar Mass in the Luminous Regions of Disk Galaxies
James Pizagno, Francisco Prada, David H. Weinberg, HansWalter Rix, Daniel
Harbeck, Eva K. Grebel, Eric F. Bell, Jon Brinkmann, Jon Holtzman, and
Andrew West
Abstract. We investigate the correlations among stellar mass (M_*_),
disk scale length (R_d_), and rotation velocity at 2.2 disk scale
lengths (V_2.2_) for a sample of 81 diskdominated galaxies (disk/total
>= 0.9) selected from the SDSS. We measure V_2.2_ from longslit
H{alpha} rotation curves and infer M_*_ from galaxy iband luminosities
(L_i_) and gr colors. We find logarithmic slopes of 2.60+/0.13 and
3.05+/0.12 for the (forward fit) L_i_V_2.2_ and M_*_V_2.2_ relations,
somewhat shallower than most previous studies, with intrinsic scatter of
0.13 and 0.16 dex, respectively. Our direct estimates of the
totaltostellar mass ratio within 2.2R_d_, assuming a Kroupa IMF, yield
a median ratio of 2.4 for M_*_>10^10^ M_sun_ and 4.4 for M_*_=10^9^ 
10^10^ M_sun_, with large scatter at a given M_*_ and R_d_. The typical
ratio of the rotation speed predicted for the stellar disk alone to the
observed rotation speed at 2.2R_d_ is ~0.65. The distribution of scale
lengths at fixed M_*_ is broad, but we find no correlation between disk
size and the residual from the M_*_V_2.2_ relation, implying that the
M_*_V_2.2_ relation is an approximately edgeon view of the disk galaxy
fundamental plane. Independent of the assumed IMF, this result implies
that stellar disks do not, on average, dominate the mass within 2.2R_d_.
We discuss our results in the context of infall models where disks form
in adiabatically contracted cold dark matter halos. A model with a
disktohalo mass ratio m_d_=0.05 provides a reasonable match to the
R_d_M_*_ distribution for spin parameters {lambda} ranging from ~0.04
to 0.08, and it yields a reasonable match to the mean M_*_V_2.2_
relation. A model with m_d_=0.1 predicts overly strong correlations
between disk size and M_*_V_2.2_ residual. Explaining the wide range of
halotodisk mass ratios within 2.2R_d_ requires significant scatter in
m_d_ values, with systematically lower m_d_ for galaxies with lower M_*_
or lower stellar surface density {SIGMA}_*_.
Key words: Cosmology: Dark Matter, Galaxies: Kinematics and Dynamics,
Galaxies: Photometry
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