Wide Field Multiband Imaging of Low Redshift Quasar Environments

We present photometry of the large scale environments of a sample of twelve broad line AGN with $0.06 < z < 0.37$ from deep images in the SDSS $u$, $g$, $r$, and $i$ filters taken with the 90Prime prime focus camera on the Steward Observatory Bok Telescope. We measure galaxy clustering around these AGN using two standard techniques: correlation amplitude (B$_{gq}$) and the two point correlation function. We find average correlation amplitudes for the 10 radio quiet objects in the sample equal to (9$pm$18, 144$pm$114, -39$pm$56, 295$pm$260) Mpc$^{1.77}$ in ($u$, $g$, $r$, $i$), all consistent with the expectation from galaxy clustering. Using a ratio of the galaxy-quasar cross-correlation function to the galaxy autocorrelation function, we calculate the relative bias of galaxies and AGN, $b_{gq}$. The bias in the $u$ band, $b_{gq}=3.08pm0.51$ is larger compared to that calculated in the other bands, but it does not correlate with AGN luminosity, black hole mass, or AGN activity via the luminosity of the [OIII] emission line. Thus ongoing nuclear accretion activity is not reflected in the large scale environments from $sim$10 h$^{-1}$ kpc to $sim$0.5 h$^{-1}$ Mpc and may indicate a non-merger mode of AGN activity and/or a significant delay between galaxy mergers and nuclear activity in this sample of mostly radio quiet quasars.

Variable Intrinsic Absorption in Mrk 279

We examine the variability in the intrinsic absorption in the Seyfert 1 galaxy Mrk 279 using three epochs of observations from the Far Ultraviolet Spectroscopic Explorer (FUSE) and two epochs of observations with the Space Telescope Imaging Spectrograph on the Hubble Space Telescope. Rather than finding simple photoionization responses of the absorbing gas to changes in the underlying continuum, the observed changes in the absorption profiles can be understood more clearly if the effective covering fraction of the gas in all emission components, continuum and broad and intermediate velocity width emission lines, is accounted for. While we do not uniquely solve for all of these separate covering fractions and the ionic column densities using the spectral data, we examine the parameter space using previously well-constrained solutions for continuum and single emission component covering fractions. Assuming full coverage of the continuum, we find that of the two velocity components of the Mrk 279 absorption most likely associated with its outflow, one likely has zero coverage of the intermediate line region while the other does not. For each component, however, the broad line region is more fully covered than the intermediate line region. Changes in the O VI column densities are unconstrained due to saturation, but we show that small changes in the nonsaturated C IV and N V column densities are consistent with the outflow gas having zero or partial covering of the intermediate line region and an ionization parameter changing from ~0.01 to ~0.1 from 2002 to 2003 as the UV continuum flux increased by a factor of ~8. The absence of a change in the C III absorbing column density is attributed to this species arising outside the Mrk 279 outflow.