Outflow of gas in the Seyfert 1 galaxy Markarian 509.

The nucleus of the luminous Seyfert 1 galaxy Mrk 509 (z = 0.0345) is surrounded by two distinct systems of ionized gas. One is a rotating disk of low ionization and is almost certainly photoionized by hot stars. There is some evidence that this disk's axis of rotation is not aligned with the minor axis of the underlying stellar population. Superposed on this is an outflowing system of high-ionization gas, covering much of the galaxy. We only see gas which is coming toward us relative to the nucleus. A corresponding component on the far side of Mrk 509 may be hidden behind the low-ionization disk. The high-ionization gas appears to be photoionized by the Seyfert nucleus. On a much smaller scale, spectra of the nucleus show what is probably an expanding shell of high-excitation gas.