M51: The Whirlpool Galaxy, analysis and simulation

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1989

OSTI ID:6163779

Howard, S

The grand design spiral galaxy M51 (NGC 5194) was modeled as an interacting system and a three component self-gravitating N-body code was used to simulate the gravitational interaction. The problem reduces to choosing a finite set of orbits (for NGC 5195) that can model the observed features of M51. A simple gas cloud collision algorithm was included that permits features in the gas particles to strengthen. The code is stable and well tested. An analytic method was developed to set limits to some of the orbit parameters. This method is suitable for nearly face-on grand design galaxies with companions. The outer arms of M51 behave like material arms inward to approx. = 140 secs. The transition between the directly excited outer tidal arms and the indirectly excited inner arms explains the symmetrically placed bends in the outer arms of M51. The inner structure is consistent with resonantly excited m = 2 Lindblad dispersion orbits. Three regions of spiral structure in M51 are proposed: (1) the extended tidal arm created by the previous passage of NGC 5195; (2) the strong tidal arms seen in the optical and created by the most recent passage 70 to 84 million years ago; and (3) the inner density wave excited by these tidal arms.

• Research Organization: Georgia Power Co., Atlanta, GA (USA)
• OSTI ID: 6163779
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ALGORITHMS
BASIC INTERACTIONS
COMPUTER CODES
COMPUTERIZED SIMULATION
DATA
GALACTIC EVOLUTION
GALAXIES
GRAVITATIONAL INTERACTIONS
INFORMATION
INTERACTIONS
MANY-BODY PROBLEM
MATHEMATICAL LOGIC
N CODES
NUMERICAL DATA
SIMULATION
STARS
THEORETICAL DATA