2008/04/28 by R. G. Detmers, J. S. Kaastra, E. Costantini +2 · 1 citation
Chemistry · Physics and Astronomy · #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Chemistry #Emission spectrum #Flux (metallurgy) #Full width at half maximum #Galaxies: Formation, Evolution, Phenomena #Galaxy #Geometry #Ion #Ionization #Line (geometry) #Optics #Physics #Quasar #Spectral line #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1051/0004-6361:200809862
6 pages, 6 figures, accepted by A&A
arxiv created 2008/04/28 · openalex publication_date 2008/06/16 · arxiv updated 2009/12/01 · openalex created_date 2022/10/05 · openalex updated_date 2026/07/31
We study the variability of the warm absorber and the gas responsible for the emission lines in the Seyfert 1 galaxy NGC 5548 to constrain the location and physical properties of these components. Using X-ray spectra acquired using the Chandra-LETGS in 2002 and 2005, we study the variability of the ionic column densities and line intensities. We measure a lower forbidden emission line flux in 2005, while the Fe Kα line flux remains constant. The warm absorber is less ionized in 2005, which enbles its location to be constrained to within 7 pc of the central source. Using both the observed variability and the limit on the FWHM of the f line, we constrain the location of the narrow line region to a distance of 1 pc from the central source. The apparent lack of variability in the Fe Kα line flux does enable a unique explanation to be derived.