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We have obtained quasi-simultaneous ultraviolet-optical spectra for 22 out of 23 quasars in the complete PG-X-ray sample with redshift, z<0.4, and M_B<-23. The spectra cover rest-frame wavelengths from at least Lyman-alpha to H-alpha. Here we provide a detailed description of the data, including careful spectrophotometry and redshift determination. We also present direct measurements of the continua, strong emission lines and features, including Lyman-alpha, SiIV+OIV], CIV, CIII], SiIII], MgII, H-beta, [OIII], He5876+NaI5890,5896, H-alpha, and blended iron emission in the UV and optical. The widths, asymmetries and velocity shifts of profiles of strong emission lines show that CIV and Lyman-alpha are very different from H-beta and H-alpha. This suggests that the motion of the broad line region is related to the ionization structure, but the data appears not agree with the radially stratified ionization structure supported by reverberation mapping studies, and therefore suggest that outflows contribute additional velocity components to the broad emission line profiles., Comment: 42 pages, 10 figures, 13 tables. Accepted by AJ. Supplemental figures not included. Full version available at http://physics.uwyo.edu/~shang/pgxpaper/ShangPaper.pdf

A unique set of UV-optical spectrograms of 22 low redshift QSOs are investigated using principal component analysis. We find three significant principal components over the broad wavelength range from Ly\alpha to H\alpha. They together account for about 78% of the sample intrinsic variance. We present strong arguments that the first principal component represents the Baldwin effect, relating equivalent widths to the luminosity (i.e. accretion rate), but only emission-line cores are involved. The second component represents continuum variations, probably dominated by intrinsic reddening. The third principal component directly relates QSO UV properties to the optical principal component 1 found by Boroson & Green (1992). It is the primary cause of scatter in the Baldwin relationships. It is also directly related to broad emission-line width and soft X-ray spectral index, and therefore probably driven by Eddington accretion ratio. We demonstrate how Baldwin relationships can be derived using our first principal component, virtually eliminating the scatter caused by the third principal component. This rekindles the hope that the Baldwin relationships can be used for cosmological study., Comment: 35 pages, 13 figures, AASTEX, accepted for publication in ApJ

For a sample of 51 blazars with extensive optical polarization data, we used circular statistics to calculate the scatter among the polarization position angles for each object. We found that this scatter is correlated with the radio core dominance. We compared this relationship with the predictions of a simple transverse shock model. The result suggests that blazar jets are likely to cover a wide range of speeds consistent with those derived from observations of superluminal motion., Comment: 4 pages, 2 figures To be published in "Blazar Demographics and Physics", ASP Conf. Series, P. Padovani and C. M. Urry eds

We collected optical and near IR linear polarization data obtained over 20--30 years for a sample of 51 blazars. For each object, we calculated the probability that the distribution of position angles was isotropic. The distribution of these probabilities was sharply peaked, with 27 blazars showing a probability < 15% of an isotropic distribution of position angles. For these 27 objects we defined a preferred position angle. For those 17 out of 27 blazars showing a well-defined radio structure angle (jet position angle) on VLBI scales (1--3mas), we looked at the distribution of angle differences -- the optical polarization relative to the radio position angles. This distribution is sharply peaked, especially for the BL Lac objects, with alignment better than 15 degrees for half the sample. Those blazars with preferred optical position angles were much less likely to have bent jets on 1--20mas scales. These results support a shock-in-jet hypothesis for the jet optical emission regions., Comment: 4 pages, 4 figures. To be published in "Blazar Demographics and Physics", ASP Conf. Series, P. Padovani and C. M. Urry eds

The UV to soft X-rays of luminous AGNs dominate their bolometric luminosity, driven by an accretion-powered dynamo at the center. These photons ionize the surrounding gas, thereby providing clues to fueling and exhaust. Two sets of important relationships - neither of them understood - link the continuum and gas properties. (i) Boroson & Green's `eigenvector 1' relationships: Steeper soft X-ray spectra are clearly related to narrower Hbeta emission and stronger optical Fe II emission from the BLR, and weaker [O III] 5007 from the NLR. We show that these relationships extend to UV spectra: narrower C III] 1909, stronger low ionization lines, larger Si III] 1892/C III] 1909 (a density indicator), weaker C IV 1549 but stronger higher-ionization N V 1240. We speculate that high accretion rates are linked to high columns of dense (1e10 - 1e11 cm-3), nitrogen-enhanced, low-ionization gas from nuclear starbursts. Linewidth, inverse Fe II-[O III] and inverse Fe II-C IV relationships hint at the geometrical arrangement of this gas. (ii) The Baldwin effect (inverse equivalent width - luminosity relationships): Our correlation analyses suggest that these are independent of the above eigenvector 1 relationships. The eigenvector 1 relationships can therefore be used in future work, to reduce scatter in the Baldwin relationships, perhaps fulfilling the dream of using the Baldwin effect for cosmological studies., Comment: Contribution to ``Quasars and Cosmology'', A.S.P. Conference Series (1999), eds. G. J. Ferland and J. A. Baldwin (San Francisco: ASP); 12 pages, 4 figures

We have surveyed the optical linear polarimetric properties of 65 soft X-ray selected ROSAT Active Galactic Nuclei (AGN). Most of these sources show low polarization (<1%) and no optical reddening. This is in agreement with the X-ray results suggesting a direct view on the center. However, two of our AGN show polarization as high as 7--8% and high reddening. This optical reddening suggests a high column of dusty gas, but why does this gas not absorb the soft X-rays? We suggest that the dusty gas is actually ionized. There is evidence for these 'warm' absorbers from X-ray absorption features seen in ROSAT and ASCA spectra., Comment: 3 pages, including 3 pages, to appear in the proc. of "Highlights in X-ray Astronomy" (Garching, June 1998), B Aschenbach et al. (eds); MPE preprint 448, also available at: http://www.xray.mpe.mpg.de/~dgrupe/research/unrefereed.html

A unique, essentially complete sample of 22 QSOs, with high quality soft X-ray spectra from ROSAT, as well as HST and optical spectrophotometry from below Ly-alpha to above H-alpha, is being used to investigate the relationships among the ionizing continuum and the optical and UV continuum, emission and absorption lines. Here we present a first analysis showing that optical `Eigenvector 1' linking steeper soft X-ray spectra with increasing optical Fe II strength, decreasing [O III] 5007 emission, and narrower BLR H-beta emission, extends to the UV emission lines, and is manifested by weaker C IV 1549 emission, stronger Si III] 1892/C III] 1909 ratio, and narrower C III] 1909 emission. Steeper soft X-ray spectra have been linked to higher L/L_Edd ratios, thus apparently linking BLR densities, high and low ionization gas, and kinematics, to the accretion process., Comment: 7 pages with 2 figures. Needs paspconf.sty. To appear in Proc. of the Conference `Structure and Kinematics of Quasar Broad Line Regions' held 1998, March 23-26 in Lincoln, Nebraska (eds. C.M. Gaskell et al.)

We have surveyed the optical linear polarization of a completely identified sample of 43 bright soft-X-ray-selected ROSAT AGN. Most (40) of these AGN show low polarization (<1%), and no clear optical reddening. This supports the suggestion from rapid X-ray variability, disk-like spectral energy distributions, and lack of cold X-ray absorption, that we are viewinga bare AGN disk. IRAS F12397+3333 and IRAS 13349+2438 show high polarization increasing to the UV -- clear evidence for scattering. As well as steep, soft-X-ray spectra, they show optical reddening and rapid X-ray variability, but almost no cold X-ray absorption -- a combination that suggests dusty ionized gas along the line-of-sight. Brandt et al. suggested and found these `warm absorbers' for IRAS 13349+2438. IRAS F12397+3333 is a new candidate. Combining our data with the optical and X-ray spectra of the high polarization narrow-line Seyfert 1 nuclei (NLSy1s) investigated by Goodrich reveals strong correlations among optical reddening indicators (such as the optical continuum slope and Balmer decrement), [OIII]/H-beta, and cold intrinsic X-ray absorption. Optical reddening underpredicts the cold X-ray absorption, suggesting dusty warm absorbers in all the highly polarized AGN. The existence of these scattering-polarized and reddened NLSy1s suggests an orientation Unified Scheme within the class of NLSy1s, analogous to that linking Seyfert 1 and Seyfert 2 nuclei. For some highly polarized and optically selected AGN we present new analysis of archival X-ray data, and for the highly polarized AGN new optical spectroscopy is presented in an appendix., Comment: 16 pages, including 5 figures and 4 tables, to appear in A&A Subj.-class: Extra-Galactic Astronomy

We report the detection of ionized absorption in the ASCA spectrum of the narrow-line Seyfert 1 galaxy IRAS 17020+4544. Subsequent optical spectropolarimetry revealed high polarization increasing from 3% in the red to 5% in the blue, indicating electron or dust scattering as a likely origin. The broad emission line H$\alpha$ is somewhat less polarized than the continuum, supporting a location of the polarizing material within the AGN. The Balmer line decrement and reddened optical spectrum support the presence of a dusty warm absorber in this object. We compared the broad band optical polarization and ionized X-ray absorption of a collection of Seyfert 1 and 1.5 galaxies, excluding classes of objects that are likely to have significant neutral X-ray absorption. Warm absorber objects are generally more likely to have high optical polarization than objects with no detected ionized absorption. This result lends additional support to the idea that the warm absorber is associated with dust and implies either that dust transmission is responsible for at least part of the polarization or that the polarization is revealed because of the dimming of the optical spectrum. Spectropolarimetry of Seyfert 1s generally locates the scattering material inside the narrow-line region and often close to or within the broad line region, consistent with estimates of the location of the dusty warm absorber., Comment: 11 pages using (AASTeX) aaspp4.sty and 3 Postscript figures. Accepted for publication in Astrophysical Journal Letters