Open AccessX‐ray spectroscopy of the broad‐line radio galaxy 3C 111
Author(s) -
Reynolds C. S.,
Iwasawa K.,
Crawford C. S.,
Fabian A. C.
Publication year - 1998
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.1998.01791.x
Subject(s) - physics , astrophysics , line (geometry) , galaxy , torus , active galactic nucleus , accretion (finance) , spectroscopy , emission spectrum , molecular cloud , absorption spectroscopy , radio galaxy , accretion disc , absorption (acoustics) , astronomy , spectral line , optics , stars , geometry , mathematics
We present an ASCA observation of the broad‐line radio galaxy 3C 111. The X‐ray spectrum is well described by a model consisting of a photoelectrically absorbed power‐law form. The inferred absorbing column density is significantly greater than expected on the basis of 21‐cm measurements of Galactic H I . Whilst this may be the result of intrinsic absorption from a circumnuclear torus or highly warped accretion disc, inhomogeneities and molecular gas within the foreground giant molecular cloud may also be responsible for some of this excess absorption. We also claim a marginal detection of a broad iron Kα line which is well explained as being a fluorescent line originating from the central regions of a radiatively efficient accretion disc. This line appears weak in comparison to those found in (radio‐quiet) Seyfert nuclei. We briefly discuss the implications of this fact.