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D.M. Crenshaw (GSU), S.B. Kraemer (CUA), J.R. Gabel (UC), NGC 4151 Team
We present a detailed analysis of the blueshifted UV absorption seen in high-resolution spectra of the Seyfert 1 galaxy NGC 4151. We include observations from our program to obtain near-simultaneous HST/STIS, FUSE, and CXO spectra of NGC 4151 in 2002 May, as well as previous STIS and FUSE spectra from the MAST archives to study the absorption variability. The velocity resolution of the spectra is in the range 7 to 15 km/sec. Some of the observations were obtained when the continuum and broad-line fluxes were extremely low, allowing us to deconvolve the remaining emission-line profiles into narrow (FWHM = 250 km/sec) and intermediate (FWHM = 1150 km/sec) components. The high-column C IV absorption at -500 km/sec absorbs the blue wing of the intermediate component, indicating that it coincident with or outside of the emission-line region responsible for this component. The equivalent widths of the low-ionization lines from this absorber are anti-correlated with the UV continuum flux, which suggests they are responding to variations in the ionizing continuum. However, in our 2002 observation at a moderate continuum level, most of the low-ionization lines had nearly disappeared, indicating a large column of gas moved out of the line of sight to the BLR at a transverse velocity greater than 2000 km/sec.
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Bulletin of the American Astronomical Society, 37 #4
© 2005. The American Astronomical Soceity.