We present ROSAT PSPC and HRI images of eight galaxies selected from a distance-limited sample of 22 edge-on Seyfert galaxies. Kiloparsec-scale soft X-ray nebulae extend along the galaxy minor axes in three galaxies (NGC 2992, NGC 4388, and NGC 5506). The extended X-ray emission has 0.2-2.4 keV X-ray luminosities of 0.4-3.5 x 10^40 ergs s^-1. The X-ray nebulae are roughly cospatial with the largescale radio emission, suggesting that both are produced by large-scale galactic outflows. Assuming pressure balance between the radio and X-ray plasmas, the X-ray filling factor is >~10^4 times larger than the radio plasma filling factor, suggesting that large-scale outflows in Seyfert galaxies are predominantly winds of thermal X-ray-emitting gas. We favor an interpretation in which large-scale outflows originate as active galactic nucleus-driven jets that entrain and heat gas on kiloparsec scales as they make their way out of the galaxy. Active galactic nucleus- and starburst-driven winds are also possible explanations in cases where the winds are oriented along the rotation axis of the galaxy disk (Refer to PDF file for exact formulas).
Department, Program, or Center
School of Physics and Astronomy (COS)
Astrophysical Journal 496 (1998) 786-796
RIT – Main Campus