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Simultaneous X-ray and Far-Ultraviolet Spectra of AGN with ASCA and HUTWe obtained ASCA spectra of the Seyfert 1 galaxy NGC 3516 in March 1995. Simultaneous far-UV observations were obtained with the Hopkins Ultraviolet Telescope on the Astro-2 shuttle mission. The ASCA spectrum shows a lightly absorbed power law of energy index 0.78. The low energy absorbing column is significantly less than previously seen. Prominent 0 VII and 0 VIII absorption edges are visible, but, consistent with the much lower total absorbing column, no Fe K absorption edge is detectable. A weak, narrow Fe K(alpha) emission line from cold material is present as well as a broad Fe K(alpha) line. These features are similar to those reported in other Seyfert 1 galaxies. A single warm absorber model provides only an imperfect description of the low energy absorption. In addition to a highly ionized absorber with ionization parameter U = 1.66 and a total column density of 1.4 x 10(exp 22)/sq cm, adding a lower ionization absorber with U = 0.32 and a total column of 6.9 x 10(exp 21)/sq cm significantly improves the fit. The contribution of resonant line scattering to our warm absorber models limits the Doppler parameter to less than 160 km/s at 90% confidence. Turbulence at the sound speed of the photoionized gas provides the best fit. None of the warm absorber models fit to the X-ray spectrum can match the observed equivalent widths of all the UV absorption lines. Accounting for the X-ray and UV absorption simultaneously requires an absorbing region with a broad range of ionization parameters and column densities.
Document ID
19980004055
Acquisition Source
Goddard Space Flight Center
Document Type
Contractor Report (CR)
Authors
Kriss, Gerard A. (Johns Hopkins Univ. Baltimore, MD United States)
Date Acquired
September 6, 2013
Publication Date
December 8, 1997
Subject Category
Astronomy
Report/Patent Number
NASA/CR-97-112949
NAS 1.26:112949
Funding Number(s)
CONTRACT_GRANT: NAG5-2935
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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