Is optical Fe II emission related to the soft X-ray properties of quasars

Journal Article · Thu Oct 01 04:00:00 EDT 1987 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/184999· OSTI ID:5554343

Wilkes, B J; Elvis, M; Mchardy, I

Radio-quiet quasars generally show broad, blended multiplets of Fe II emission in their optical and UV spectra. Radio-loud quasars also show UV Fe II emission, but their optical Fe II emission is generally weaker. No satisfactory theory connecting the generation of Fe II and radio emission has been found to explain this effect. A second, well-established distinction between the two clases of quasar is in their X-ray properties: radio-loud quasars are more X-ray luminous, and recent results have shown that they also have systematically flatter soft X-ray slopes. Here it is proposed that the second effect causes the first; i.e., that the primary factor controlling the optical Fe II emission is the soft X-ray spectrum. This proposition is supported by X-ray and optical data for nine quasars, which shows a correlation between the soft X-ray slope and the strength of the optical Fe II emission. One of these quasars (1803+676) is radio-quiet, and yet its optical spectrum shows no evidence for Fe II emission. This quasar is also unusual in that it has a flat X-ray spectrum. This further supports the proposal that the X-ray spectrum is important in determining the relative strengths of UV and optical Fe II emission. 33 references.

• Research Organization: Harvard-Smithsonian Center for Astrophysics, Cambridge, MA; Leicester Univ., England
• OSTI ID: 5554343
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 321; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COSMIC RADIO SOURCES
ELECTROMAGNETIC RADIATION
ELEMENTS
EMISSION SPECTRA
IONIZING RADIATIONS
IRON
MATHEMATICAL MODELS
METALS
QUASARS
RADIATIONS
RADIOWAVE RADIATION
SOFT X RADIATION
SPECTRA
TRANSITION ELEMENTS
ULTRAVIOLET SPECTRA
VISIBLE SPECTRA
X RADIATION
X-RAY SPECTRA