The distribution of dark matter in galaxies. I - Models of spiral galaxies

Abstract

view Abstract Citations (65) References (15) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Distribution of Dark Matter in Galaxies. I. Models of Spiral Galaxies Lake, George ; Feinswog, Laurie Abstract We examine the limits on the distribution of dark matter in galaxies from published rotation curves and photometry. We assume constant mass-to-light ratios for the luminous components and an isothermal model for the halo, and examine a collection of 37 optical rotation curves of Sb and Sc galaxies and 16 H I rotation curves to constrain the halo's core radius r_c_, and the asymptotic velocity v_max_. We find that the central density of the halo (proportional to v^2^_max_ r^-2^_c_) is often well determined. In only three cases, NGC 2403, NGC 2903, and NGC 3198, do we find that the data constrain both r_c_, and υ_max_ rather than just the ratio v_max_/r_c_. These three galaxies are all Sc's and span less than a factor of 2 in luminosity. The constraints are similar in each of the three cases. The limits are typically r_c_ <~ 8 kpc and v_max_ <~ 170 km s^-1^. Experimenting with rotation curves constructed by manipulating that observed for NGC 3198, we find that high-quality data to 6.5-8 disk scalelengths is needed to constrain the parameters. We test whether the observations determine the form of the density distribution by fitting models with r^-3^ and r^-4^ density profiles outside a core radius. We find acceptable fits for such models. Publication: The Astronomical Journal Pub Date: July 1989 DOI: 10.1086/115134 Bibcode: 1989AJ.....98..166L Keywords: Astronomical Models; Dark Matter; Mass To Light Ratios; Spatial Distribution; Spiral Galaxies; Astronomical Photometry; Density Distribution; Galactic Rotation; Astrophysics; GALAXIES: INTERNAL MOTIONS; GALAXIES: STRUCTURE full text sources ADS | data products SIMBAD (9) NED (6) Related Materials (1) Part 2: 1989AJ.....98.1253L