An Empirical Ultraviolet Iron Spectrum Template Applicable to Active Galaxies

Iron emission is often a severe contaminant in optical-ultraviolet spectra of active galaxies. Its presence complicates emission line studies. A viable solution, already successfully applied at optical wavelengths, is to use an empirical iron emission template. We have generated FeII and FeIII templates for ultraviolet active galaxy spectra based on HST archival 1100 - 3100 A spectra of IZw1. Their application allows fitting and subtraction of the iron emission in active galaxy spectra. This work has shown that in particular CIII] lambda 1909 can be heavily contaminated by other line emission, including iron transitions. Details of the data processing, generation, and use of the templates, are given by Vestergaard & Wilkes (2001).Comment: 4 pages, including 1 figure, to appear in "Spectroscopic Challenges of Photoionized Plasmas", ASP Conf. Series, Eds. Gary Ferland and Daniel Wolf Savi

Determining Central Black Hole Masses in Distant Active Galaxies and Quasars. II. Improved Optical and UV Scaling Relationships

We present four improved empirical relationships useful for estimating the central black hole mass in nearby AGNs and distant luminous quasars alike using either optical or UV single-epoch spectroscopy. These mass-scaling relationships between line widths and luminosity are based on recently improved empirical relationships between the broad-line region size and luminosities in various energy bands and are calibrated to the improved mass measurements of nearby AGNs based on emission-line reverberation mapping. The mass-scaling relationship based on the Hbeta line luminosity allows mass estimates for low-redshift sources with strong contamination of the optical continuum luminosity by stellar or non-thermal emission, while that based on the C IV lambda 1549 line dispersion allows mass estimates in cases where only the line dispersion (as opposed to the FWHM) can be reliably determined. We estimate that the absolute uncertainties in masses given by these mass-scaling relationships are typically around a factor of 4. We include in an Appendix mass estimates for all the Bright Quasar Survey (PG) quasars for which direct reverberation-based mass measurements are not available.Comment: 48 pages including 12 figures and 7 tables. Accepted by Ap

The Cambridge-Cambridge ROSAT Serendipity Survey - I. X-ray-luminous galaxies

We report on the first results obtained from a new optical identification programme of 123 faint X-ray sources with $S$(0.5--2$\,{\rm keV)}>2\times 10^{-14}\,$erg$\,$s$^{-1}\,$cm$^{-2}\,$ serendipitously detected in {\it ROSAT} PSPC pointed observations. We have spectroscopically identified the optical counterparts to more than 100 sources in this survey. Although the majority of the sample (68 objects) are QSOs, we have also identified 12 narrow emission line galaxies which have extreme X-ray luminosities ($10^{42} < L_{\rm X} < 10^{43.5}\,$erg$\,$s$^{-1}$). Subsequent spectroscopy reveals them to be a mixture of starburst galaxies and Seyfert 2 galaxies in approximately equal numbers. Combined with potentially similar objects identified in the {\it Einstein} Extended Medium Sensitivity Survey, these X-ray-luminous galaxies exhibit a rate of cosmological evolution, $L_{\rm X} \propto (1+z)^{2.5\pm1.0}$, consistent with that derived for X-ray QSOs. This evolution, coupled with the steep slope determined for the faint end of the X-ray luminosity function ($\Phi(L_{\rm X}) \propto L_{\rm X}^{-1.9}$), implies that such objects could comprise 15--35 per cent of the soft (1--2$\,$keV)Comment: Accepted for publication in MNRAS. 7 pages including 5 figures; uuencoded compressed postscript; RGO-21

The Velocity Field of Quasar Broad Emission Line Gas

In this Letter, the broad emission line (BEL) profiles of superluminal quasars with apparent jet velocities, $\beta_{a}>10$, (ultraluminal QSOs, or ULQSOs hereafter) are studied as a diagnostic of the velocity field of the BEL emitting gas in quasars. The ULQSOs are useful because they satisfy a very strict kinematical constraint, their parsec scale jets must be propagating within $12^{\circ}$ of the line of sight. We know the orientation of these objects with great certainty. The large BEL FWHM, $\sim 3,000 \mathrm{km/s} - 6,000 \mathrm{km/s}$, in ULQSOs tend to indicate that the BEL gas has a larger component of axial velocity (either random or in a wind) along the jet direction than previously thought.Comment: To appear in ApJ Letter

ISO Key Project: Exploring the full range of QUASAR/AGN properties

The PIA (PHOT Interactive Analysis) software was upgraded as new releases were made available by VILSPA. We have continued to analyze our data but, given the large number of still outstanding problems with the calibration and analysis (listed below), we remain unable to move forward on our scientific program. We have concentrated on observations with long (256 sec) exposure times to avoid the most extreme detector responsivity drift problems which occur with a change in observed flux level, ie. as one begins to observe a new target. There remain a significant number of problems with analyzing these data including: (1) the default calibration source (FCS) observations early in the mission were too short and affected by strong detector responsivity drifts; (2) the calibration of the FCS sources is not yet well-understood, particularly for chopped observations (which includes most of ours); (3) the detector responsivity drift is not well-understood and models are only now becoming available for fitting chopped data; (4) charged particle hits on the detector cause transient responsivity drifts which need to be corrected; (5) the "flat-field" calibration of the long-wavelength (array) detectors: C1OO, C200 leaves significant residual structure and so needs to be improved;(6) the vignetting correction, which affects detected flux levels in the array detectors, is not yet available; (7) the intra-filter calibrations are not yet available; and (8) the background above 60 microns has a significant gradient which results in spurious positive and negative "detections" in chopped observations. ISO Observation planning, conferences and talks, ground based observing and other grant related activities are also briefly discussed

Exploring the Full Range of Properties of Quasar Spectral Distributions

The aim of this work is to support our ISO, far-infrared (IR) observing program of quasars and active galaxies. We have obtained, as far as possible, complete spectral energy distributions (radio-X-ray) of the ISO sample in order to fully delineate the continuum shapes and to allow detailed modelling of that continuum. This includes: ground-based optical, near-IR and mm data, the spectral ranges closest to the ISO data, within 1-2 years of the ISO observations themselves. ISO was launched in Nov 1995 and is currently observing routinely. It has an estimated lifetime is 2 years. All near-IR and optical imaging and spectroscopy are now in hand and in the process of being reduced, mm data collection and proposal writing continues

Clues to Quasar Broad Line Region Geometry and Kinematics

We present evidence that the high-velocity CIV lambda 1549 emission line gas of radio-loud quasars may originate in a disk-like configuration, in close proximity to the accretion disk often assumed to emit the low-ionization lines. For a sample of 36 radio-loud z~2 quasars we find the 20--30% peak width to show significant inverse correlations with the fractional radio core-flux density, R, the radio axis inclination indicator. Highly inclined systems have broader line wings, consistent with a high-velocity field perpendicular to the radio axis. By contrast, the narrow line-core shows no such relation with R, so the lowest velocity CIV-emitting gas has an inclination independent velocity field. We propose that this low-velocity gas is located at higher disk-altitudes than the high-velocity gas. A planar origin of the high-velocity CIV-emission is consistent with the current results and with an accretion disk-wind emitting the broad lines. A spherical distribution of randomly orbiting broad-line clouds and a polar high-ionization outflow are ruled out.Comment: 5 Latex pages, 1 figure, accepted for publication in ApJ Letter