High-excitation extranuclear gas in Seyfert galaxies

Journal Article · Fri Feb 01 04:00:00 EST 1991 · Astrophysical Journal; (USA)

DOI:https://doi.org/10.1086/169679· OSTI ID:5912746

Haniff, C A; Ward, M J; Wilson, A S ^[1]

---

1. Palomar Observatory, Pasadena, CA (USA) Royal Greenwich Observatory, Cambridge (England) Maryland Univ., College Park (USA)

High-resolution images have been obtained in the emission lines forbidden O III 4959 A, 5007 A and H-alpha + forbidden N II 6548 A, 6584 A for three Seyfert galaxies - Mrk 573, NGC 2110, and NGC 5252. In at least Mrk 573 and NGC 2110, the emission line and radio continuum axes are closely related. Maps reveal localized regions of high-excitation gas away from the nucleus of each galaxy. In all cases the off-nucleus excitation is comparable to or higher than that at the nucleus itself, which may reflect increases in the ionization parameter, the presence of optically thin clouds or extra heating sources for the gas. In Mrk 573 and NGC 5252, the distribution of the ionized gas resembles a pair of conical structures, each with its apex at the nucleus, implying preferential escape of ionizing photons in two oppositely directed cones. The possible significance that high-excitation gas around Seyfert nuclei is observed preferentially in host galaxies of type S0 is discussed. 36 refs.

• OSTI ID: 5912746
• Journal Information: Astrophysical Journal; (USA), Journal Name: Astrophysical Journal; (USA) Vol. 368; ISSN ASJOA; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COSMIC GASES
DISTRIBUTION
ELECTROMAGNETIC RADIATION
EMISSION SPECTRA
ENERGY-LEVEL TRANSITIONS
EXCITATION
FLUIDS
GALAXIES
GALAXY NUCLEI
GASES
INTERSTELLAR SPACE
IONIZATION
IONIZED GASES
MARKARIAN GALAXIES
PHOTOIONIZATION
RADIATIONS
RADIOWAVE RADIATION
SEYFERT GALAXIES
SPACE
SPATIAL DISTRIBUTION
SPECTRA