2016A&A...588A..48C


Query : 2016A&A...588A..48C

2016A&A...588A..48C - Astronomy and Astrophysics, volume 588A, 48-48 (2016/4-1)

Asymmetric mass models of disk galaxies.

CHEMIN L., HURE J.-M., SOUBIRAN C., ZIBETTI S., CHARLOT S. and KAWATA D.

Abstract (from CDS):

Mass models of galactic disks traditionally rely on axisymmetric density and rotation curves, paradoxically acting as if their most remarkable asymmetric features, such as lopsidedness or spiral arms, were not important. In this article, we relax the axisymmetry approximation and introduce a methodology that derives 3D gravitational potentials of disk-like objects and robustly estimates the impacts of asymmetries on circular velocities in the disk midplane. Mass distribution models can then be directly fitted to asymmetric line-of-sight velocity fields. Applied to the grand-design spiral M 99, the new strategy shows that circular velocities are highly nonuniform, particularly in the inner disk of the galaxy, as a natural response to the perturbed gravitational potential of luminous matter. A cuspy inner density profile of dark matter is found in M 99, in the usual case where luminous and dark matter share the same center. The impact of the velocity nonuniformity is to make the inner profile less steep, although the density remains cuspy. On another hand, a model where the halo is core dominated and shifted by 2.2-2.5kpc from the luminous mass center is more appropriate to explain most of the kinematical lopsidedness evidenced in the velocity field of M 99. However, the gravitational potential of luminous baryons is not asymmetric enough to explain the kinematical lopsidedness of the innermost regions, irrespective of the density shape of dark matter. This discrepancy points out the necessity of an additional dynamical process in these regions: possibly a lopsided distribution of dark matter.

Abstract Copyright: © ESO, 2016

Journal keyword(s): galaxies: kinematics and dynamics - galaxies: fundamental parameters - galaxies: structure - galaxies: spiral - galaxies: individual: Messier 99 (NGC 4254) - dark matter

Simbad objects: 8

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Number of rows : 8
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
#notes
1 M 74 G 01 36 41.7451236624 +15 47 01.107512304 10.52 10.00 9.46 9.16   ~ 1583 1
2 NGC 2366 H2G 07 28 51.85 +69 12 31.1 12.25 11.86 11.39 11.33   ~ 734 0
3 UGC 3974 G 07 41 56.3059298112 +16 48 07.451632188   15.4       ~ 215 0
4 NGC 2976 GiP 09 47 15.458 +67 54 58.97 11.77 11.03 10.16 9.51   ~ 632 1
5 IC 2574 G 10 28 23.6148831408 +68 24 43.440012756 11.70 11.07 10.87 10.74   ~ 639 1
6 NGC 3319 SyG 10 39 09.533 +41 41 12.74   11.48 11.07     ~ 297 1
7 M 99 H2G 12 18 49.625 +14 24 59.36 10.45 10.44 9.87     ~ 852 2
8 NAME Virgo Cluster ClG 12 26 32.1 +12 43 24           ~ 6320 0

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2022.10.02-02:01:57

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