Mg II lambda2798 emission in QSOs, Seyfert 1 galaxies, and broad-line radio galaxies

Journal Article · Sat Sep 15 04:00:00 EDT 1979 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/157324· OSTI ID:5730558

Grandi, S A; Phillips, M M

Spectrophotometric observations of Mg II lambda2798 and H..beta.. emission in 14 QSOs, four Seyfert 1 galaxies, and two broad-line radio galaxies are presented. Both broad and narrow components of Mg II lambda2798 are found to occur. In most cases the profiles of the broad components of Mg II and H..beta.. are observed to be virtually identical, suggesting that these lines arise from the same optically thick emission clouds, and that these clouds have the same average Mg II/H..beta.. ratio. In five objects, however, the Mg II lambda2798 line is significantly broader than H..beta... The Mg II/H..beta.. ratio in the broad components is generally observed to range from roughly 0.5 to 2.5, thus apparently ruling out emission-line clouds with huge transition zone. Either internal dust or radiatively accelerated clouds might explain the truncated transition regions. Narrow Mg II lambda2798 emission is found to be surprisingly weak in comparison with other narrow lines such as (O II) lambda3727. It is suggested that the weakness of the narrow Mg II emission may be related to the observed rareness of Mg II lambda2798 absorption in QSOs near the emission-line redshift.

• Research Organization: Lick Observatory, Board of Studies in Astronomy and Astrophysics, University of California, Santa Cruz
• OSTI ID: 5730558
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 232:3; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640103 -- Astrophysics & Cosmology-- Quasi-Stellar
Radio
& X-Ray Sources-- (-1987)
640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ATOMIC IONS
BALMER LINES
CHARGED PARTICLES
COSMIC RADIO SOURCES
EMISSION SPECTRA
GALAXIES
IONS
MAGNESIUM IONS
NEBULAE
QUASARS
RADIO GALAXIES
SEYFERT GALAXIES
SPECTRA
SPECTROPHOTOMETRY