Far-Ultraviolet Spectrum of Fairall 9 with the Hopkins Ultraviolet Telescope

Wei Zheng, Gerard A. Kriss, Arthur F. Davidsen and Jeffrey W. Kruk
Center for Astrophysical Sciences, The Johns Hopkins University
Baltimore, MD 21218-2695

Abstract:

We observed the Seyfert 1 galaxy Fairall 9 with the Hopkins Ultraviolet Telescope (HUT ) for s during the Astro-2 mission. The spectrum covers 820-1840 Å with a resolution of Å. The intrinsic far-UV continuum is unattenuated to wavelengths as short as 920 Å ( Å in the galaxy's rest frame) and can be fitted with a power law with after a correction for E.

The power law fit to the far-UV continuum of Fairall 9 may be extrapolated to connect to the soft X-ray component measured with ROSAT, forming a weak UV bump. Photoionization by such an energy distribution would produce relatively weak high-ionization lines. The intensity ratio of the broad component (FWHM ) of O VI 1034+Ly emission to that of C IV 1549 is . While this is typical for high-redshift quasars, it is one of the lowest among the low-luminosity, low-redshift AGN observed by HUT . A correlation between the strength of O VI emission and the soft X-ray excess is supported by the observations of Fairall 9 and other AGN.

Subject headings: galaxies: active --- galaxies: individual (Fairall 9 ) --- ultraviolet: galaxies





zheng@pha.jhu.edu