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Record Details

Record 96 of 2720
The settling of warped disks in oblate dark halos
External Online Source: doi:10.1086/175456
Author and Affiliation:
Dubinski, John(Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, United States)
Kuijken, Konrad(Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, United States)
Abstract: When a galaxy forms, the disk may initially be tilted with respect to a flattened dark halo. The misalignment between the disk and the halo is a common explanation for galactic disk warps, since in this state disks have precessing bending modes which resemble real warps. The gravitational response of the halo has often been ignored, and its strength and effect on possible bending modes is unknown. We therefore calculate the response of an oblate halo to a precessing inclined exponential disk using a variety of techniques. We construct models with a rigid exponential disk precessing in a particle halo, a particle disk precessing inside a static bulge/halo potential, and a self-consistent model with a particle disk, bulge, and halo. When the disk: halo mass ratio is small (approximately 10%) within 5 exponential scale radii, the disk settles to the equatorial plane of the halo within five orbital times. When the disk and halo mass are comparable, the halo rapidly aligns with the disk within a few orbital times, while the disk inclination drops. The rapid response of the halo to an inclined precessing disk suggests that the warps seen in galactic disks are not due to a misalignment between the disk and the inner halo. If a galaxy forms inclined to the principal plane of a dark halo, either the disk will settle to a pricipal plane or the inner halo will twist to align with the disk. The outer halo will remain misaligned for a much longer time and therefore may still exert a torque. Warped bending modes may still exist if the misalignment of the outer halo persists for a Hubble time.
Publication Date: Apr 01, 1995
Document ID:
19950046430
(Acquired Dec 28, 1995)
Accession Number: 95A78029
Subject Category: ASTROPHYSICS
Document Type: Journal Article
Publication Information: Astrophysical Journal; p. p. 492-503; (ISSN 0004-637X); 442; 2, Pa
Publisher Information: United States
Contract/Grant/Task Num: NAS5-26555
Financial Sponsor: NASA; United States
Organization Source: NASA Goddard Space Flight Center; Greenbelt, MD, United States
Description: 12p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: Copyright
NASA Terms: ASTRONOMICAL MODELS; BENDING; GALACTIC BULGE; GALACTIC EVOLUTION; GALACTIC HALOS; GALACTIC STRUCTURE; ROTATING DISKS; SPIRAL GALAXIES; DYNAMIC CHARACTERISTICS; GRAVITATIONAL EFFECTS; MATHEMATICAL MODELS; PRECESSION; TORQUE
Imprint And Other Notes: Astrophysical Journal vol. 442, no. 2, Part 1 p. 492-503 April 1, 1995
Availability Source: Other Sources
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