New Polar Ring Galaxies
Galaxies with polar rings (PRGs) are a unique class of extragalactic objects,
consisting of a ring or disk of gas, stars and dust orbiting in a plane
nearly perpendicular to the disk of a central galaxy. Is is believed that
the formation of PRGs is in most cases caused by galaxy mergers with the
corresponding direction of angular momentum, the accretion by the host
galaxy of the companion's matter, or gas filaments from the intergalactic
medium. The progress that has been made in the study of PRGs has been
constrained by the small number of known objects of this type. Any definite
conclusions about their origin, evolution, characteristics of their dark
halos are of limited importance due to absence of enough statistics and
of good homogeneous data sets. At present, there are only about two dozen
kinematically confirmed galaxies in this PRG class, mostly from the Whitmore
et al. (1990) catalogue, based on photographic images.
Fig.1. Examples of object from our catalogue SPRC (=SDSS-based Polar Ring Catalogue). A colour combination of images in g, r, i is provided by the SDSS server.
Fig.2. The contours of SDSS images of the galaxy SPRC-14 (right). The positions of the spectrograph slit are indicated. Left: the distribution of the line-of-sight velocities of gas and stars in the corresponding sections. The dotted line marks the centre of the galaxy and the value of systemic velocity. The thick coloured lines schematically mark the kinematic components, rotating in different planes: blue lines for the central galaxy and yellow lines for the polar ring.