TY - JOUR

T1 - Global structure and formation of polar-ring galaxies

AU - Reshetnikov, V. P.

AU - Sotnikova, N

PY - 1997/9

Y1 - 1997/9

N2 - We present an analysis of structural features of all known galaxies with optical polar rings. We find a clear dichotomy for objects of this peculiar class. Bulge-dominated S0 galaxies possess only short narrow rings, while disk-dominated objects always have wide extended polar rings. We try by gas dynamical simulations to explain such a segregation by dependence of the ring-forming process on different galaxy potentials. It is found that the total mass captured into the ring during an encounter of a host-ring system with a gas-rich spiral galaxy of comparable mass exceeds 10(9)M(circle dot) (or about 10% of all gas in the donor galaxy), which is of the order of that found by observation. The process of gas to gather into a steady-state ring takes approximately (7-9) x 10(8) years. This time is somewhat shorter for rings forming around bulge-dominated galaxies. We also present observational arguments for S0 galaxies with extended rings to be similar to late-type spirals by their photometric properties, while numerical modelling of the extended ring formation suggests that these galaxies must possess massive dark halos as well. In this case, the sizes of the modelled rings turn out large enough (up to 30 kpc in diameter), and the time scale for ring formation is prolonged up to several Gyrs.

AB - We present an analysis of structural features of all known galaxies with optical polar rings. We find a clear dichotomy for objects of this peculiar class. Bulge-dominated S0 galaxies possess only short narrow rings, while disk-dominated objects always have wide extended polar rings. We try by gas dynamical simulations to explain such a segregation by dependence of the ring-forming process on different galaxy potentials. It is found that the total mass captured into the ring during an encounter of a host-ring system with a gas-rich spiral galaxy of comparable mass exceeds 10(9)M(circle dot) (or about 10% of all gas in the donor galaxy), which is of the order of that found by observation. The process of gas to gather into a steady-state ring takes approximately (7-9) x 10(8) years. This time is somewhat shorter for rings forming around bulge-dominated galaxies. We also present observational arguments for S0 galaxies with extended rings to be similar to late-type spirals by their photometric properties, while numerical modelling of the extended ring formation suggests that these galaxies must possess massive dark halos as well. In this case, the sizes of the modelled rings turn out large enough (up to 30 kpc in diameter), and the time scale for ring formation is prolonged up to several Gyrs.

KW - galaxies, interactions

KW - kinematics and dynamics

KW - peculiar

KW - structure

KW - dark matter

KW - NEUTRAL HYDROGEN SURVEY

KW - DARK HALO

KW - ELLIPTIC GALAXIES

KW - NGC 4650A

KW - GAS

KW - ACCRETION

KW - UGC-7576

KW - CLOUDS

KW - STARS

M3 - статья

VL - 325

SP - 933

EP - 942

JO - ASTRONOMY & ASTROPHYSICS

JF - ASTRONOMY & ASTROPHYSICS

SN - 0004-6361

IS - 3

ER -