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Title: Formation of warped disks by galactic flyby encounters. I. Stellar disks

Warped disks are almost ubiquitous among spiral galaxies. Here we revisit and test the 'flyby scenario' of warp formation, in which impulsive encounters between galaxies are responsible for warped disks. Based on N-body simulations, we investigate the morphological and kinematical evolution of the stellar component of disks when galaxies undergo flyby interactions with adjacent dark matter halos. We find that the so-called 'S'-shaped warps can be excited by flybys and sustained for even up to a few billion years, and that this scenario provides a cohesive explanation for several key observations. We show that disk warp properties are governed primarily by the following three parameters: (1) the impact parameter, i.e., the minimum distance between two halos; (2) the mass ratio between two halos; and (3) the incident angle of the flyby perturber. The warp angle is tied up with all three parameters, yet the warp lifetime is particularly sensitive to the incident angle of the perturber. Interestingly, the modeled S-shaped warps are often non-symmetric depending on the incident angle. We speculate that the puzzling U- and L-shaped warps are geometrically superimposed S-types produced by successive flybys with different incident angles, including multiple interactions with a satellite on a highly elongatedmore » orbit.« less
Authors:
; ;  [1] ;  [2] ;  [3] ;  [4]
  1. Department of Astronomy and Center for Galaxy Evolution Research, Yonsei University, Seoul 120-749 (Korea, Republic of)
  2. Institut d'Astrophysique de Paris, (UMR 7095: CNRS and UPMC), 98 bis Bd Arago, 75014 Paris (France)
  3. Department of Astronomy and Space Science, Kyung Hee University, Yongin-shi, Kyungki 446-701 (Korea, Republic of)
  4. Division of Science Education, Pusan National University, Jangjeon-Dong Gumjeong-Gu, Busan 609-735 (Korea, Republic of)
Publication Date:
OSTI Identifier:
22356463
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 789; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; GALAXIES; IMPACT PARAMETER; INTERACTIONS; LIFETIME; MASS; NONLUMINOUS MATTER; ORBITS; SATELLITES; SIMULATION; SYMMETRY