X-ray heating and ionization of broad-line emission regions in QSOs and active galaxies

Journal Article · Wed Apr 15 04:00:00 EST 1981 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/158819· OSTI ID:6184630

Weisheit, J C; Shields, G A; Tarter, C B

Absorption of X-rays deep within the broad-line emitting clouds in QSOs and the nuclei of active galaxies creates extensive zones of warm (Tapprox.10/sup 4/ K), partially ionized (N/sub e//Napprox.0.1) gas. Because L..cap alpha.. photons are trapped in these regions, the X-ray energy is efficiently channeled into Balmer lines collisionally excited from the n = 2 level. These H I regions plus the H II regions created by ultraviolet photons illuminating the surfaces of the clouds give rise to integrated L..cap alpha../H..cap alpha.. line emission ratios between 1 and 2. Enhanced Mg II line emission from the H I regions gives rise to integrated Mg II/H..cap alpha.. ratios near 0.5. The O I line lambda8446 is efficiently pumped ty trapped H..cap alpha.. photons, and, in the X-ray heated zone, we calculate an intensity ratio I(lambda8446)/I(H..cap alpha..)< or approx. =0.1. All of these computed ratios are now in agreement with observations.

• Research Organization: Plasma Physics Laboratory, Princeton University
• OSTI ID: 6184630
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 245:2; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics &amp; Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BALMER LINES
COMPUTERIZED SIMULATION
COSMIC RADIO SOURCES
COSMIC RAY SOURCES
COSMIC X-RAY SOURCES
ELECTROMAGNETIC RADIATION
EMISSION SPECTRA
GALAXY NUCLEI
H1 REGIONS
H2 REGIONS
HEATING
IONIZATION
IONIZING RADIATIONS
LYMAN LINES
QUASARS
RADIATION HEATING
RADIATIONS
SIMULATION
SPECTRA
X RADIATION