A dynamical model for the twisted gas disk in centaurus A

被引:43
作者
Sparke, LS
机构
[1] Washburn Observatory, University of Wisconsin-Madison, Madison, WI
关键词
galaxies; individual; (NGC; 5128); kinematics and dynamics; structure;
D O I
10.1086/178193
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
The prominent minor-axis dust lane across the radio galaxy Cen A has been extensively mapped in the emission lines of H alpha, H I, and CO, revealing an ordered velocity held which has been interpreted as that of a warped and twisted disk of gas seen nearly edge-on. Here it is shown that the geometry of this disk can be explained as that of a near-polar structure precessing about the symmetry axis of an approximately oblate galaxy potential which, like the stellar body, is nearly round at the center, becoming flattened farther out. Both freely precessing models and those taking account of the self-gravity of the gas are presented. The broken elliptical. ring of H I gas recently found to be associated with the faint outer shells of Cen A can be explained naturally as a continuation of the same precessing disk. This precessing model for the gas disk assumes that the gravitational potential of Cen A is close to axisymmetric; precession should be qualitatively similar if the figure is triaxial and tumbling about its short axis in the same sense as the rotation of the stars.
引用
收藏
页码:810 / 821
页数:12
相关论文
共 46 条
[1]   SELF-GRAVITATING POLAR RINGS IN AXISYMMETRICAL AND TRIAXIAL GALAXY POTENTIALS [J].
ARNABOLDI, M ;
SPARKE, LS .
ASTRONOMICAL JOURNAL, 1994, 107 (03) :958-970
[2]   Gas accretion in NGC 3656 (Arp 155) [J].
Balcells, M ;
Sancisi, R .
ASTRONOMICAL JOURNAL, 1996, 111 (03) :1053-1056
[4]   THE STRUCTURE AND KINEMATICS OF THE IONIZED-GAS WITHIN NGC-5128 (CEN-A) .1. TAURUS OBSERVATIONS [J].
BLAND, J ;
TAYLOR, K ;
ATHERTON, PD .
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 1987, 228 (03) :595-621
[5]  
BLAND J, 1985, THESIS U SUSSEX
[6]  
Chandrasekhar S., 1969, Ellipsoidal figures of equilibrium
[7]  
COOPER BFC, 1965, AUST J PHYS, V18, P589
[8]  
DEZEEUW PT, 1988, MNRAS, V262, P1087
[9]   POTENTIAL-DENSITY PAIRS FOR GALAXIES [J].
DEZEEUW, T ;
PFENNIGER, D .
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 1988, 235 (04) :949-995
[10]   PICTURE PROCESSING ANALYSIS OF THE OPTICAL STRUCTURE OF NGC 5128 (CENTAURUS-A) [J].
DUFOUR, RJ ;
VANDENBERGH, S ;
HARVEL, CA ;
MARTINS, DH ;
SCHIFFER, FH ;
TALBOT, RJ ;
TALENT, DL ;
WELLS, DC .
ASTRONOMICAL JOURNAL, 1979, 84 (03) :284-301