Figure 22. The possible evolution of the spiral arm pattern of UGC 6093. A: 470◦ of bar rotation angle (time) past; B: 270◦ of galactic bar rotation angle past; C: Current; D: 150◦ of galactic bar rotation angle (time) future

From

Spirals and Rings in Barred Galaxies by the ROTASE Model

Hongjun Pan

International Journal of Physics. 2021, 9(6), 286-307 doi:10.12691/ijp-9-6-5