Open AccessResonance scattering, absorption and off‐centre abundance peaks in clusters of galaxies
Author(s) -
Sanders J. S.,
Fabian A. C.
Publication year - 2006
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 - 10.1111/j.1365-2966.2006.10497.x
Subject(s) - physics , resonance (particle physics) , astrophysics , scattering , galaxy , spectral line , spectroscopy , absorption (acoustics) , astronomy , atomic physics , optics
A possible explanation for the central abundance dips found from spatially resolved X‐ray spectroscopy of several groups and clusters of galaxies is resonance scattering. A number of the prominent iron emission lines are resonance lines. We construct a unique spectral model which takes account of resonance scattering for several thousand resonance lines, projection effects, photoelectric absorption, and allows direct spectral fitting. We apply our model to Chandra observations of two clusters with pronounced central abundance dips, Centaurus and Abell 2199. The results show that the effect of resonance scattering on emission from the centre of the cluster can be as much as 30 per cent for the Fe‐K resonance lines, and 10 per cent for several Fe‐L lines, if turbulence is low. The change to the metallicities obtained by fitting low‐resolution CCD spectra is at most 10 per cent. Accounting for resonance scattering does not remove the central dip. Allowing for internal absorption within Centaurus significantly improves the quality of the fits, indicating the presence of absorbing material within the inner 40 kpc of NGC 4696.