29 research outputs found
The Mass Distribution and Rotation Curve in the Galaxy
The mass distribution in the Galaxy is determined by dynamical and
photometric methods. Rotation curves are the major tool for determining the
dynamical mass distribution in the Milky Way and spiral galaxies. The
photometric (statistical) method utilizes luminosity profiles from optical and
infrared observations, and assumes empirical values of the mass-to-luminosity
(M/L) ratio to convert the luminosity to mass. In this chapter the dynamical
method is described in detail, and rotation curves and mass distribution in the
Milky Way and nearby spiral galaxies are presented. The dynamical method is
categorized into two methods: the decomposition method and direct method. The
former fits the rotation curve by calculated curve assuming several mass
components such as a bulge, disk and halo, and adjust the dynamical parameters
of each component. Explanations are given of the mass profiles as the de
Vaucouleurs law, exponential disk, and dark halo profiles inferred from
numerical simulations. Another method is the direct method, with which the mass
distribution can be directly calculated from the data of rotation velocities
without employing any mass models. Some results from both methods are
presented, and the Galactic structure is discussed in terms of the mass.
Rotation curves and mass distributions in external galaxies are also discussed,
and the fundamental mass structures are shown to be universal.Comment: 54 pages, 25 figures, in 'Planets, Stars and Stellar Systems',
Springer, Vol. 5, ed. G. Gilmore, Chap. 19. Note: Preprint with full figures
is available from http://www.ioa.s.u-tokyo.ac.jp/~sofue/htdocs/2013psss
Reciprocal Regulation of Lymphoid Tissue Development in the Large Intestine by IL-25 and IL-23:Regulation of colonic ILF by IL-25/IL-23
Clinical features of subclinical left ventricular systolic dysfunction in patients with diabetes mellitus
Application of decellularized allograft for primary repair of congenital heart disease in Japan
Egg Maturation and Events Leading to Embryonic Development in the Sawfly, Athalia rosae (Hymenoptera)
Coexistence of high performance resistance and capacitance memory based on multilayered metal-oxide structures
Sample composition alters associations between age and brain structure
The influence of sample composition on human neuroimaging results is unknown. Here, the authors weight a large, community-based sample to better reflect the US population and describe how applying these sample weights changes conclusions about age-related variation in brain structure