Dark Matter in Dwarf Galaxies: Latest Density Profile Results
نویسندگان
چکیده
We present high-resolution two-dimensional velocity fields in Hα and CO of the nearby dwarf galaxy NGC 2976. Our observations were made at both higher spatial resolution (∼ 75 pc) and higher velocity resolution (13 km s in Hα and 2 km s in CO) than most previous studies. We show that NGC 2976 has a very shallow dark matter density profile, with ρ(r) lying between ρ ∝ r and ρ ∝ r. We carefully test the effects of systematic uncertainties on our results, and demonstrate that well-resolved, two-dimensional velocity data can eliminate many of the systematic problems that beset longslit observations. We also present a preliminary analysis of the velocity field of NGC 5963, which appears to have a nearly NFW density profile.
منابع مشابه
Mass loss from dwarf spheroidal galaxies: the origins of shallow dark matter cores and exponential surface brightness profiles
Dwarf spheroidal galaxies have shallow central dark matter density profiles, low angular momentum and approximately exponential surface brightness distributions. Through N-body simulations and analytic calculations we investigate the extent to which these properties can be generated from “typical” ΛCDM galaxies, which differ in all of these properties, by the dynamical consequences of feedback....
متن کاملDark Matter in Dwarf Galaxies: High Resolution Observations
We present observations and analysis of rotation curves and dark matter halo density profiles in the central regions of four nearby dwarf galaxies. This observing program has been designed to overcome some of the limitations of other rotation curve studies that rely mostly on longslit spectra. We find that these objects exhibit the full range of central density profiles between ρ ∝ r (constant ...
متن کاملDwarf Galaxy Rotation Curves and the Core Problem of Dark Matter Halos
The standard cold dark matter (CDM) model has recently been challenged by the claim that dwarf galaxies have dark matter halos with constant density cores, whereas CDM predicts halos with steeply cusped density distributions. Consequently, numerous alternative dark matter candidates have recently been proposed. In this paper, we scrutinize the observational evidence for the incongruity between ...
متن کاملDark Matter Scaling Relations
We investigate the structure of dark matter halos by means of the kinematics of a very large sample of spiral galaxies of all luminosities. The observed rotation curves show an universal profile which is the sum of an exponential thin disk term and a spherical halo term with a flat density core. We find that the Burkert profile proposed to describe the dark matter halo density distribution of d...
متن کاملThe shapes of dark matter dominated dwarf spheroidal stellar density profiles
A Bayesian likelihood analysis of the stellar density profile shapes of several dark matter dominated Galactic dwarf spheroidal galaxies (dSphs) has been completed. This analysis indicates that the inner power law, ρ ∝ r , of each of these profiles satisfies γ < 1.21 at greater than 99% confidence with a slight preference for γ ∼ 0.7. Speculating that this bound on the stellar profiles may be r...
متن کامل