Query : 2006A&A...446..905T

2006A&A...446..905T - Astronomy and Astrophysics, volume 446, 905-918 (2006/2-2)

On stability and spiral patterns in polar disks.


Abstract (from CDS):

To investigate the stability properties of polar disks we performed two-dimensional hydrodynamical simulations for flat polytropic gaseous self-gravitating disks which were perturbed by a central S0-like component. Our disk was constructed to resemble that of the proto-typical galaxy NGC 4650A. This central perturbation induces initially a stationary two-armed tightly-wound leading spiral in the polar disk. For a hot disk (Toomre parameter Q>1.7), the structure does not change over the simulation time of 4.5Gyr. In case of colder disks, the self-gravity of the spiral becomes dominant, it decouples from the central perturbation and grows, until reaching a saturation stage in which an open trailing spiral is formed, rather similar to that observed in NGC 4650A. The timescale for developing non-linear structures is 1-2Gyr; saturation is reached within 2-3Gyr. The main parameter controlling the structure formation is the Toomre parameter. The results are surprisingly insensitive to the properties of the central component. If the polar disk is much less massive than that in NGC 4650A, it forms a weaker tightly-wound spiral, similar to that seen in dust absorption in the dust disk of NGC 2787. Our results are derived for a polytropic equation of state, but appear to be generic as the adiabatic exponent is varied between γ=1 (isothermal) and γ=2 (very stiff).

Abstract Copyright:

Journal keyword(s): galaxies: evolution - galaxies: kinematics and dynamics - galaxies: individual: NGC 4650A

Simbad objects: 2

goto Full paper

goto View the references in ADS

Number of rows : 2
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
1 NGC 2787 LIN 09 19 18.6046606656 +69 12 11.630716128   12.92 11.79     ~ 347 0
2 ESO 322-69 GiG 12 44 49.0352044176 -40 42 51.691570488   14.12 13.58 13.29 13.9 ~ 195 0

To bookmark this query, right click on this link: simbad:objects in 2006A&A...446..905T and select 'bookmark this link' or equivalent in the popup menu


© Université de Strasbourg/CNRS

    • Contact