Broadband X‐Ray Observations of the Narrow‐Line X‐Ray Galaxy NGC 5506

We present a detailed analysis of broad band X-ray data of the Seyfert 2galaxy NGC5506. 2-10 keV band are detected during a 1-day ASCA observation,while no significant change in the 2-10 keV continuum shape is found. The ASCAspectrum consists of an absorbed power-law, a 'soft excess' below 2 keV, and anFe K$\alpha$ emission line at 6.4 keV. The 'soft excess' can be well describedby either thermal emission from very low abundance material at a temperaturekT$\simeq$0.8 keV, or scattered/leaking flux from the primary power-law plus asmall amount of thermal emission. Analysis of ROSAT HRI data reveals that thesoft X-ray emission is extended on kpc scales in this object, and the extendedcomponent may account for most of the soft X-ray excess observed by the ASCA.The result suggests that in this type 2 AGN, the 'soft excess' at least partlycomes from an extended region, imposing serious problem for the model in whichthe source is partially covered. Fe K$\alpha$ profile is complex and can not besatisfactorily modeled by a single gaussian. Models of either double gaussians,or a narrow gaussian plus a line from a relativistic accretion disk viewed atan inclination of about 40$\pm10^\circ$ provide good fits to the data. However,the inclination of the disk can be substantially larger if there is a smallamount of excessive Fe K edge absorption. The intermediate inclinations forNLXGs are consistent with the ideas that the inner accretion disk is alignedwith the outer obscuring torus.Comment: 8 pages, 5 postscript figures. to appear in Astrophy. J., 1999, April 2