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Title: Pitch angle of galactic spiral arms

One of the key parameters that characterizes spiral arms in disk galaxies is a pitch angle that measures the inclination of a spiral arm to the direction of galactic rotation. The pitch angle differs from galaxy to galaxy, which suggests that the rotation law of galactic disks determines it. In order to investigate the relation between the pitch angle of spiral arms and the shear rate of galactic differential rotation, we perform local N-body simulations of pure stellar disks. We find that the pitch angle increases with the epicycle frequency and decreases with the shear rate and obtain the fitting formula. This dependence is explained by the swing amplification mechanism.
Authors:
 [1] ;  [2]
  1. Department of Environmental Systems Science, Doshisha University, Tatara Miyakodani 1-3, Kyotanabe City, Kyoto 610-0394 (Japan)
  2. Division of Theoretical Astronomy, National Astronomical Observatory of Japan, Osawa, Mitaka, Tokyo 181-8588 (Japan)
Publication Date:
OSTI Identifier:
22356742
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 787; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; AMPLIFICATION; COMPUTERIZED SIMULATION; GALAXIES; INCLINATION; MANY-BODY PROBLEM; ROTATION; SPIRAL CONFIGURATION; STARS