NGC 4622

Astronomical objections centered on the fact that dust reddening and cloud silhouettes were used to determine that the outer arms lead.

In response, new research determined[3] NGC 4622's spiral arm sense with a method independent of the previous work.

The Fourier component method reveals two new weak arms in the inner disk winding opposite the outer strong clockwise pair.

On 25 May 2001, an image taken by the Hubble Space Telescope captured a supernova in NGC 4622, designated SN 2001jx (type unknown, mag.

[4] It was discovered by R. Buta and GG Byrd of the University of Alabama as well as T. Freeman of Bevill State Community College.

Based only on their shape, one would expect from observations of other spiral galaxies that the outermost spiral arms (blue and blue-green ) move by rotating counterclockwise around the center of the galaxy. This is not the case; the outermost spiral arms rotate clockwise, just like the inner spiral arm and the rest of the galaxy's disk. Additionally, the "trailing" inner spiral arm (green) and the "leading" outer spiral arms (blue and blue-green) curl around the galaxy in opposite directions (although both move clockwise around the galaxy's center).
A simulation of the NGC 4622 arm pairs, exhibiting the Fourier transform m = 2