Almost polar elements in a ring

Polar Ring Galaxies and Warps

Polar ring galaxies, where matter is in equilibrium in perpendicular orbits around spiral galaxies, are ideal objects to probe the 3D shapes of dark matter halos. The conditions to constrain the halos are that the perpendicular system does not strongly perturb the host galaxy, or that it is possible to derive back its initial shape, knowing the formation scenario of the polar ring. The formatio...

Formation of polar ring galaxies

Polar ring galaxies are peculiar systems in which a gas rich, nearly polar ring surrounds an early-type or elliptical host galaxy. Two formation scenarios for these objects have been proposed: they are thought to form either in major galaxy mergers or by tidal accretion of the polar material from a gas rich donor galaxy. Both scenarios are studied through N-body simulations including gas dynami...

Almost commuting elements in compact Lie groups

Radio-Continuum Emission in Polar-Ring Galaxies

We have used the Very Large Array aperture synthesis telescope to conduct a radio continuum survey of polar-ring galaxies, at 20 cm and 6 cm. Forty objects were observed at 20 cm with ≃ 5 resolution. Twenty (50%) of the program sources were detected at 20 cm, down to our 5-σ limit of 0.5 mJy beam−1. This detection rate is similar to those in surveys with comparable sensitivity for early-type ga...

Formation of a polar-ring galaxy in a galaxy merger

We numerically investigate stellar and gas dynamics in star-forming and dissipative galaxy mergers between two disk galaxies with specific orbital configurations. We find that violent relaxation combined with gaseous dissipation in galaxy merging transforms two disk galaxies into one S0 galaxy with polar-rings: Both the central S0-like host and the polar-ring component in a polar-ring galaxy ar...