INFLUENCE OF THE DISC ON THE ORBITAL DECAY OF SATELLITE GALAXIES

Authors
Citation
M. Wahde et Kj. Donner, INFLUENCE OF THE DISC ON THE ORBITAL DECAY OF SATELLITE GALAXIES, Astronomy and astrophysics, 312(2), 1996, pp. 431-438
Citations number
17
Categorie Soggetti
Astronomy & Astrophysics
Journal title
ISSN journal
00046361
Volume
312
Issue
2
Year of publication
1996
Pages
431 - 438
Database
ISI
SICI code
0004-6361(1996)312:2<431:IOTDOT>2.0.ZU;2-Y
Abstract
Using a formula derived from the Lynden-Bell-Kalnajs theory of angular momentum exchange, we study the angular momentum loss of a satellite galaxy which is moving on a nearly circular, co-planar orbit around a disc galaxy. Using this formula, estimates of the orbital decay time a re computed for several different galaxy models. The results are then compared with the corresponding results from numerical simulations, an d are found to be in agreement for the satellite sizes under study. Th e main difficulty in applying the decay formula is the fact that the d ecay time varies as the square of the satellite softening parameter, w hich is difficult to determine accurately. However, we find that it ca n be chosen in the same way in all cases we have studied. For our mode ls, the dynamical friction of the disc is shown to be significantly la rger than that of the halo.