Interacting binary galaxies. II - Matching models to observations

Abstract

view Abstract Citations (26) References (25) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Interacting Binary Galaxies. II. Matching Models to Observations Borne, Kirk D. Abstract This paper presents an efficient numerical simulation algorithm for the study of interacting elliptical galaxies. Each model galaxy, represented by a collection of gravitating particles, can be (1) endowed with arbitrary degrees of flattening and rotation, (2) oriented in any spatial direction, (3) evolved along any chosen orbital trajectory for an arbitrary length of time, and (4) projected onto the "sky" of a randomly oriented observer. How "observations" of simulated tidal interactions between model galaxies are best matched to the measured properties of real binaries is discussed in detail. Rotation curves, radial variations in velocity dispersion, and surface density maps are all matched to the data in an effort to determine the physical state of an observed pair. Strong support is given to the acquisition of velocity measurements and to their application in any model-matching efforts. That the combined spectroscopic and photometric data for specific binaries can be reproduced by appropriate projections of select numerical simulations of the pairs is demonstrated in the companion papers (Papers III and IV). Each matching simulation constrains the masses of the galaxies, their internal dynamics, the properties of their relative orbit, and the three-dimensional orientation of the pair in space. The uniqueness of such dynamical solutions is discussed in detail in the context of a particular representation of the binary orbits: the specification of their speed and separation at pericenter. It is shown that tidal impulse and duration of pericenter passage are the relevant physical parameters affecting the observed tidal distortions in colliding galaxies. Provided that the images of such systems are supplemented with detailed kinematic data, the study of tidally distorted binary galaxies thus represents a fertile avenue to the direct measurement of galaxy masses. Publication: The Astrophysical Journal Pub Date: July 1988 DOI: 10.1086/166453 Bibcode: 1988ApJ...330...38B Keywords: Astronomical Models; Computerized Simulation; Elliptical Galaxies; Galactic Clusters; Galactic Mass; Galactic Structure; Interacting Galaxies; Algorithms; Dark Matter; Dynamical Systems; Velocity Distribution; Astrophysics; GALAXIES: CLUSTERING; GALAXIES: INTERNAL MOTIONS; GALAXIES: STRUCTURE full text sources ADS | Related Materials (6) Part 1: 1984ApJ...287..503B Part 3: 1988ApJ...330...51B Part 4: 1988ApJ...330...61B Part 5: 1988ApJ...333..567B Part 6: 1989ApJ...336..655B Part 7: 1994ApJ...435...79B