Astronomy and Astrophysics – Astrophysics – Cosmology and Extragalactic Astrophysics
Scientific paper
2010-11-03
Astronomy and Astrophysics
Astrophysics
Cosmology and Extragalactic Astrophysics
52 pages, 36 figures; Accepted for publication in AJ; minor corrections
Scientific paper
We present mass models for the dark matter component of seven dwarf galaxies taken from "The HI Nearby Galaxy Survey" (THINGS) and compare these with those from numerical Lambda Cold Dark Matter (LCDM) simulations. The THINGS high-resolution data significantly reduce observational uncertainties and thus allow us to derive accurate dark matter distributions in these systems. We here use the bulk velocity fields when deriving the rotation curves of the galaxies. Compared to other types of velocity fields, the bulk velocity field minimizes the effect of small-scale random motions more effectively and traces the underlying kinematics of a galaxy more properly. The "Spitzer Infrared Nearby Galaxies Survey" (SINGS) 3.6 micron and ancillary optical data are used for separating the baryons from their total matter content in the galaxies. The sample dwarf galaxies are found to be dark matter dominated over most radii. We find discrepancies between the derived dark matter distributions of the galaxies and those of LCDM simulations, even after corrections for non-circular motions have been applied. The observed solid body-like rotation curves of the galaxies rise too slowly to reflect the cusp-like dark matter distribution in CDM halos. Instead, they are better described by core-like models such as pseudo-isothermal halo models dominated by a central constant-density core. The mean value of the logarithmic inner slopes of the mass density profiles is alpha = -0.29 +- 0.07. They are significantly different from the steep slope of ~ -1.0 inferred from previous dark-matter-only simulations, and are more consistent with shallower slopes found in recent LCDM simulations of dwarf galaxies in which the effects of baryonic feedback processes are included.
Brinks Elias
de Blok J. G. W.
Kennicutt Robert C. Jr.
Oh Se-Heon
Walter Fabian
No associations
LandOfFree
Dark and luminous matter in THINGS dwarf galaxies does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Dark and luminous matter in THINGS dwarf galaxies, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Dark and luminous matter in THINGS dwarf galaxies will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-603585