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).

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Also archived in: arXiv: astro-ph/9711137 v1 12 Nov 1997 E.J.M.C. thanks Kim Weaver, Michael Dahlem and Martin Elvis for providing information and for helpful discussions and Michael Corcoran for helping with the NASA/HEASARC data archive. E.J.M.C. acknowledges support from the Director’s Office of the Space Telescope Science Institute, NASA grant NAG5-3016, and the National Research Council. S.V. acknowledges the financial support of NASA through grant LTSA 035-97. This research has made extensive use of the NASA/IPAC Extragalactic Database (NED), which is operated by the Jet Propulsion Laboratory, Caltech, under contract with NASA. The Digitized Sky Surveys were produced at STScI under U.S. Government grant NAGW-2166. This paper represents a portion of E.J.M.C.’s Ph.D. thesis, submitted in partial fulfillment of the requirements of the Graduate School of the University of Maryland.ISSN:1538-4365 Note: imported from RIT’s Digital Media Library running on DSpace to RIT Scholar Works in February 2014.

Document Type


Department, Program, or Center

School of Physics and Astronomy (COS)


RIT – Main Campus