The circumnuclear environment of nearby non-interacting Seyfert galaxies

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1988

OSTI ID:5247007

Pogge, R W

An investigation into the physical conditions prevailing in the regions immediately surrounding the active nuclei in 20 nearby, non-interacting Seyfert galaxies is reported. CCD interference-band images isolating the bright emission lines of H{alpha} + (N II) {lambda}{lambda}6548, 6583 and (O III) {lambda}5007 have been obtained to search for spatially extended circumnuclear emission regions. Long-slit, low resolution spectrophotometry of interesting cases was used to probe the ionization state of the extended emission regions. For comparison, a CCD H{alpha} + (N II) interference-band imaging survey of a statistically significant sample of 91 bright non-Seyfert spiral galaxies meeting the same non-interaction criteria has been carried out. Only three out of nine Seyfert 1s have spatially extended ionized gas regions compared with eight out of eleven Seyfert 2s. Enhanced circumnuclear star formation is uncommon to both Seyfert 1s and 2s. Extended emission in Seyfert 1s has essentially the same morphology in both H{alpha} + (N II) and (O III) emission. In the Seyfert 2s, the H{alpha} + (N II) and (O III) images show different extended emission morphologies. The (O III) emission regions appear as either one- or two-sided structures, four of which are resolved into two distinct cones of high-ionization gas emanating from the active nucleus. The morphology and ionization of these regions suggest collimation of the nuclear ionizing radiation field. The 91 non-interacting non-Seyfert spiral galaxies exhibit a rich variety of nuclear and circumnuclear emission-line structures ranging from no emission detected to bright stellar nuclei with complicated circumnuclear emission regions extending for many kiloparsecs.

• Research Organization: California Univ., Santa Cruz, CA (USA)
• OSTI ID: 5247007
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CHARGE-COUPLED DEVICES
CONFIGURATION
COSMIC GASES
FLUIDS
GALAXIES
GALAXY NUCLEI
GASES
IONIZATION
IONIZED GASES
IONIZING RADIATIONS
MORPHOLOGY
RADIATIONS
SEMICONDUCTOR DEVICES
SEYFERT GALAXIES
SPECTROPHOTOMETRY
SPIRAL CONFIGURATION
STAR EVOLUTION