Related papers: Counterrotation in Galaxies
Counter-rotating galaxies host two components rotating in opposite directions with respect to each other. The kinematic and morphological properties of lenticulars and spirals hosting counter-rotating components are reviewed. Statistics of…
We present an alternate origin scenario to explain the observed phenomena of (1) counter-rotation between different galaxy components and (2) the formation of ring galaxies. We suggest that these are direct consequences of the galaxy being…
Modern galaxy formation theory suggests that the misalignment between stellar and gaseous components usually results from an external gas accretion and/or interaction with other galaxies. The extreme case of the kinematic misalignment is…
A gaseous counter-rotating galaxy is a galaxy containing a gas component with opposite angular momentum to the main stellar disk. The counter-rotating gas provides direct evidence for the accretion of external material, a key aspect in…
Counterrotating stars in disk galaxies are a puzzling dynamical feature whose origin has been ascribed to either satellite accretion events or to disk instabilities triggered by deviations from axisymmetry. We use a cosmological simulation…
Stars in galaxies form from the cold rotationally supported gaseous disks that settle at the center of dark matter halos. In the simplest models, such angular momentum is acquired early on at the time of collapse of the halo and preserved…
The observation of counter rotation in galaxies (i.e. gas that rotates in the opposite direction to the stellar component or two co-spatial stellar populations with opposite rotation) is becoming more commonplace with modern integral field…
The process of galactic disc growing is still not fully understood. In the majority of disk galaxies the gas and stars are located in the same plane and rotate in the same direction. However, there are kinematically peculiar galaxies…
We have identified two new galaxies with gas counter-rotation (NGC1596 and NGC3203) and have confirmed similar behaviour in another one (NGC128), this using results from separate studies of the ionized-gas and stellar kinematics of a…
Ionized gas and stellar kinematics have been measured along the major axes of seventeen nearby spiral galaxies of intermediate to late morphological type. We discuss the properties of each sample galaxy distinguishing between those…
We investigate, by means of numerical simulations, the possibility of forming counter-rotating old stellar components by major mergers between an elliptical and a spiral galaxy. We show that counter-rotation can appear both in dissipative…
We use an N-body simulation, constructed using GADGET-2, to investigate an accretion flow onto an astrophysical disk that is in the opposite sense to the disk's rotation. In order to separate dynamics intrinsic to the counter-rotating flow…
(Reduced)Using the NewHorizon simulation, we have studied ten gas-versus-star counter-rotating galaxies in field environments with a stellar mass of M*~[1-5]x10^10 Msun. For all of them, the retrograde accretion of gas either from gas…
In this paper we present a statistical study of the environments of 49 galaxies in which there is gas- or stellar- counterrotation. The number of possible companions in the field (to apparent magnitude 22), their size and concentration were…
Kinematic misalignment between gas and stellar components observed in a certain fraction of galaxies. It believed to be caused by acquisition of gas from the external reservoir by major or minor mergers, accretion from cosmological…
We search for bulk counterrotation of the gas and stars in 67 galaxies of all types and a wide range of luminosities. Bulk counterrotation characterizes \~25-30% of E/S0's with extended gas, but at most a few percent of Sa-Sbc spirals. For…
Frequent accretion of external cold gas is thought to play an important role in galaxy assembly. However, almost all known kinematically misaligned galaxies identify only one gas disk that is misaligned with the stellar disk, implying a…
Counter-rotating discs can arise from the accretion of a counter-rotating gas cloud onto the surface of an existing co-rotating disc or from the counter-rotating gas moving radially inward to the outer edge of an existing disc. At the…
The Sa(r) galaxy NGC 4138 has been recently found to contain an extensive counterrotating disk which appears to be still forming. Up to a third of the stars in the disk system may be on retrograde orbits. A counterrotating ring of H II…
Galaxies grow through both internal and external processes. In about 10% of nearby red galaxies with little star formation, gas and stars are counter-rotating, demonstrating the importance of external gas acquisition in these galaxies.…