C.D.S. - SIMBAD4 rel 1.7 - 2020.12.02CET12:12:26

2007A&A...469..511K - Astronomy and Astrophysics, volume 469, 511-527 (2007/7-2)

Dark matter in the Milky Way. II. The HI gas distribution as a tracer of the gravitational potential.


Abstract (from CDS):

Gas within a galaxy is forced to establish pressure balance against gravitational forces. The shape of an unperturbed gaseous disk can be used to constrain dark matter models. We derive the 3D HI volume density distribution for the Milky Way out to a galactocentric radius of 40kpc and a height of 20kpc to constrain the Galactic mass distribution. We used the Leiden/Argentine/Bonn all sky 21-cm line survey. The transformation from brightness temperatures to densities depends on the rotation curve. We explored several models, reflecting different dark matter distributions. Each of these models was set up to solve the combined Poisson-Boltzmann equation in a self-consistent way and optimized to reproduce the observed flaring. Besides a massive extended halo of M∼1.8x1012M, we find a self-gravitating dark matter disk with M=2 to 3x1011M, including a dark matter ring at 13<R<18.5kpc with M=2.2 to 2.8x1010M. The existence of the ring was previously postulated from EGRET data and coincides with a giant stellar structure that surrounds the Galaxy. The resulting Milky Way rotation curve is flat up to R∼27kpc and slowly decreases outwards. The HI gas layer is strongly flaring. The HWHM scale height is 60pc at R=4kpc and increases to ∼2700pc at R=40kpc. Spiral arms cause a noticeable imprint on the gravitational field, at least out to R=30kpc. Our mass model supports previous proposals that the giant stellar ring structure is due to a merging dwarf galaxy. The fact that the majority of the dark matter in the Milky Way for R≲40kpc can be successfully modeled by a self-gravitating isothermal disk raises the question of whether this massive disk may have been caused by similar merger events in the past. The substructure in the Galactic dark matter disk suggests a dissipative nature for the dark matter disk.

Abstract Copyright:

Journal keyword(s): Galaxy: disk - Galaxy: structure - Galaxy: kinematics and dynamics - galaxies: interactions - ISM: structure - Galaxy: halo

CDS comments: Complex R not in SIMBAD.

Simbad objects: 7

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Number of rows : 7

N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
1 NAME Magellanic Stream HVC 00 32 -30.0           ~ 831 1
2 NGC 891 H2G 02 22 32.907 +42 20 53.95 11.08 10.81 9.93 7.86   ~ 1542 2
3 NGC 2403 AGN 07 36 51.396 +65 36 09.17 9.31 8.84 8.38 8.19   ~ 1630 1
4 NGC 4244 GiG 12 17 29.659 +37 48 25.60   10.71   9.99   ~ 518 1
5 M 51 GiP 13 29 52.698 +47 11 42.93   9.26 8.36 8.40   ~ 3851 4
6 NGC 5775 GiP 14 53 57.653 +03 32 40.10   13.0 11.34     ~ 397 2
7 NAME Gal Center reg 17 45 40.04 -29 00 28.1           ~ 11840 0

    Equat.    Gal    SGal    Ecl

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