相关论文: Resolving the Disc-Halo Degeneracy II: NGC 6946

Little is known about the content and distribution of dark matter in spiral galaxies. To break the degeneracy in galaxy rotation curve decompositions, which allows a wide range of dark matter halo density profiles, an independent measure of…

We propose that the lower bound of the stellar radial velocity dispersion c_r of an equilibrium stellar disk is determined by the gravitational stability condition. We compared the estimates of stellar velocity dispersion at radii r>(1.5 -…

Several recent studies reinforce the existence of a thick molecular disc in galaxies along with the dynamically cold thin disc. Assuming a two-component molecular disc, we model the disc of NGC 6946 as a four-component system consisting of…

We determine the mass distribution of a spiral galaxy, 2237+0305 using both gravitational lensing and dynamical constraints. We find that lensing can break the disc-halo degeneracy. 2237+0305 has a sub-maximal disc, contributing 57+/-3 per…

We present a pilot study on the nearby massive barred galaxy NGC 1291, in which we use dynamical modelling to constrain the disc mass-to-light ratio (M/L), thus breaking the degeneracy between the baryonic and dark matter in its central…

We use deep r-band photometry and Halpha rotation curves for a sample of 290 late-type spirals to model their mass distribution within the optical radius. We examine luminosity profile decompositions into bulge and disk carefully and…

We present a simple technique to estimate mass-to-light (M/L) ratios of stellar populations based on two broadband photometry measurements, i.e. a color-M/L relation. We apply the color-M/L relation to galaxy rotation curves, using a large…

We present a detailed and unique mass budget for the high-surface-brightness galaxy UGC 463, showing it is dominated by dark matter (DM) at radii beyond one scale length (h_R) and has a baryonic-to-DM mass ratio of approximately 1:3 within…

The observed stellar velocity dispersions of galactic discs show that the maximum rotation of a disc is on average 63% of the observed maximum rotation. This criterion can, however, not be applied to small or low surface brightness (LSB)…

We perform a structural decomposition of galaxies identified in three cosmological hydrodynamical simulations by applying Gaussian Mixture Models (GMMs) to the kinematics of their stellar particles. We study the resulting disc, bulge, and…

The mass discrepancy in disk galaxies is shown to be well correlated with acceleration, increasing systematically with decreasing acceleration below a critical scale a0 = 3700 km^2/s^2/kpc = 1.2E-10 m/s/s. For each galaxy, there is an…

High-accuracy rotation curves of spiral galaxies show a steep rise in the central few hundred pc region, indicating high concentration of mass toward the center. Using the rotation curves, we idrectly calculate radial distributions of the…

We analyse the global structure of the old stellar discs in 34 edge-on spiral galaxies. The radial and vertical exponential scale parameters of the discs are obtained by applying an improved two-dimensional decomposition technique to our…

For a compiled sample of disk galaxies with available photometry (B and K bands), velocity line-widths and HI integral fluxes, several parameters which trace the luminous, baryonic and dark matter contents were inferred. We investigated how…

We construct a model for the Milky Way Galaxy composed of a stellar disc and bulge embedded in a dark-matter halo. All components are modelled as $N$-body systems with up to 8 billion equal-mass particles and integrated up to an age of…

This article summarizes recent work on the luminosity and mass distribution of the Galactic bulge and disk, and on the mass of the Milky Way's dark halo. A new luminosity model consistent with the COBE NIR data and the apparent magnitude…

The baryonic mass-to-light ratio used to perform the photometry-to-mass conversion has a tremendous influence on the measurement of the baryonic content and distribution, as well as on the determination of the dark halo parameters. Since…

The best-fitting 2-dimensional plane within the 3-dimensional space of spiral galaxy disk observables (rotational velocity v_{rot}, central disk surface brightness \mu_0 = -2.5log I_0, and disk scale-length h) has been constructed. Applying…

We are studying the mass distribution in a sample of 50 early type spiral galaxies, with morphological type betweens S0 and Sab and absolute magnitudes M_B between -18 and -22; they form the massive and high-surface brightness extreme of…

The analysis of the vertical velocity dispersion of disc stars is the most direct astronomical means of estimating the local dark matter density, $\rho_{DM}$. Current estimates based on the mid-plane dynamic density use a local baryonic…