2000/02/08 by G. Risaliti, R. Maiolino, Risaliti, G. +3
Physics and Astronomy · #Advanced X-ray Imaging Techniques #Astrophysical Phenomena and Observations #Astrophysics (astro-ph) #FOS: Physical sciences #X-ray Spectroscopy and Fluorescence Analysis #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/0002169
8 LaTeX pages including 4 postscript figures. Accepted by A&A
arxiv created 2000/02/08 · openalex publication_date 2000/02/08 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We present BeppoSAX observations of the Seyfert 1.8 galaxy NGC1365 in the 0.1--100 keV range. The source was 6 times brighter than during an ASCA observation 3 years earlier. The 4--10 keV flux is highly variable during the BeppoSAX observation, while the soft (0.1-4 keV) emission is constant within the errors. Both a cold and a warm reflector and a cold absorber are required to explain the observed spectrum. The comparison between ASCA and BeppoSAX spectra strongly suggests that the circumnuclear material has a more complex structure than a simple homogeneous torus, with quite different absorbing gas columns along different lines of sight. A broad iron Kalpha line is also present in the spectrum, with the peak energy significantly redshifted. This can be explained by means of a relativistic disk line model. Alternatively, a warm absorption Fe line system with NH ~ 1023 cm^(-2) could account for the observed line profile.