Outflows from active galactic nuclei (AGNs) seem to be common and are thought to be important from a variety of perspectives: as an agent of chemical enhancement of the interstellar and intergalactic ...media, as an agent of angular momentum removal from the accreting central engine, and as an agent limiting star formation in starbursting systems by blowing out gas and dust from the host galaxy. To understand these processes, we must determine what fraction of AGNs feature outflows and understand what forms they take. We examine recent surveys of quasar absorption lines, reviewing the best means to determine if systems are intrinsic and result from outflowing material, and the limitations of approaches taken to date. The surveys reveal that, while the fraction of specific forms of outflows depends on AGN properties, the overall fraction displaying outflows Is fairly constant, approximately 60%, over many orders of magnitude in luminosity. We emphasize some issues concerning classification of outflows driven by data type rather than necessarily the physical nature of outflows and illustrate how understanding outflows probably requires a more comprehensive approach than has usually been taken in the past.
Abstract
We present quasar bolometric corrections using the ${\rm O}\,\small {III}\,\lambda 5007$ narrow emission line luminosity based on the detailed spectral energy distributions of 53 bright ...quasars at low to moderate redshift (0.0345 < z < 1.0002). We adopted two functional forms to calculate Liso, the bolometric luminosity determined under the assumption of isotropy: ${\rm L_{{\rm iso}}}=A\,{L_{{\rm O}\,\small {III}}}$ for comparison with the literature and ${\rm log(L_{{\rm iso}})}=B+C\,{\rm log}(L_{{\rm O}\,\small {III}})$, which better characterizes the data. We also explored whether ‘Eigenvector 1 (EV1)’, which describes the range of quasar spectral properties and quantifies their diversity, introduces scatter into the $L_{{\rm O}\,\small {III}}$–Liso relationship. We found that the ${{\rm O}\,\small {III}}$ bolometric correction can be significantly improved by adding a term including the equivalent width ratio $R_{{\rm Fe}\,\small {II}}$$\equiv\, {\rm EW}_{{\rm Fe \small {II}}}/{\rm EW}_{{\rm H}\beta }$, which is an EV1 indicator. Inclusion of $R_{{\rm Fe}\,\small {II}}$ in predicting Liso is significant at nearly the 3σ level and reduces the scatter and systematic offset of the luminosity residuals. Typically, ${{\rm O}\,\small {III}}$ bolometric corrections are adopted for Type 2 sources where the quasar continuum is not observed and in these cases, $R_{{\rm Fe}\,\small {II}}$ cannot be measured. We searched for an alternative measure of EV1 that could be measured in the optical spectra of Type 2 sources but were unable to identify one. Thus, the main contribution of this work is to present an improved ${{\rm O}\,\small {III}}$ bolometric correction based on measured bolometric luminosities and highlight the EV1 dependence of the correction in Type 1 sources.
Currently, the ability to produce black hole mass estimates using the C iv λ1549 line that are consistent with Hβ mass estimates is uncertain, due in large part to disagreement between velocity line ...width measurements for the two lines. This discrepancy between Hβ and C iv arises from the fact that both line profiles are treated the same way in single-epoch scaling relationships based on the assumption that the broad-line region is virialized, even though a non-virialized emission component is often significant in the C iv line and absent or weak in the Hβ line. Using quasi-simultaneous optical and ultraviolet spectra for a sample of 85 optically-bright quasars with redshifts in the range z = 0.03-1.4, we present a significant step along the path to rehabilitating the C iv line for black hole mass estimates. We show that the residuals of velocity line width between C iv and Hβ are significantly correlated with the peak flux ratio of Si iv+O iv λ1400 to C iv. Using this relationship, we develop a prescription for estimating black hole masses from the ultraviolet spectrum that agree better with Hβ-based masses than the traditional C iv masses. The scatter between Hβ and C iv masses is initially 0.43 dex in our sample and is reduced to 0.33 dex when using our prescription. The peak flux ratio of Si iv+O iv λ1400 to C iv is an ultraviolet indicator of the suite of spectral properties commonly known as 'Eigenvector 1'; thus, the reduction in scatter between C iv and Hβ black hole masses is essentially due to removing an Eigenvector 1 bias in C iv-based masses.
ABSTRACT
We present the results of photometric and spectroscopic monitoring campaigns of the changing look AGN NGC 3516 carried out in 2018 to 2020 covering the wavelength range from the X-ray to the ...optical. The facilities included the telescopes of the CMO SAI MSU, the 2.3-m WIRO telescope, and the XRT and UVOT of Swift. We found that NGC 3516 brightened to a high state and could be classified as Sy1.5 during the late spring of 2020. We have measured time delays in the responses of the Balmer and He ii λ4686 lines to continuum variations. In the case of the best-characterized broad H β line, the delay to continuum variability is about 17 d in the blue wing and is clearly shorter, 9 d, in the red, which is suggestive of inflow. As the broad lines strengthened, the blue side came to dominate the Balmer lines, resulting in very asymmetric profiles with blueshifted peaks during this high state. During the outburst the X-ray flux reached its maximum on 2020 April 1 and it was the highest value ever observed for NGC 3516 by the Swift observatory. The X-ray hard photon index became softer, ∼1.8 in the maximum on 2020 April 21 compared to the mean ∼0.7 during earlier epochs before 2020. We have found that the UV and optical variations correlated well (with a small time delay of 1–2 d) with the X-ray until the beginning of 2020 April, but later, until the end of 2020 June, these variations were not correlated. We suggest that this fact may be a consequence of partial obscuration by Compton-thick clouds crossing the line of sight.
We study the kinematics and excitation mechanisms of H2 and Fe ii lines in a sample of 67 emission-line galaxies with Infrared Telescope Facility SpeX near-infrared (0.8-2.4 μm) spectroscopy together ...with new photoionization models. H2 emission lines are systematically narrower than narrow-line region lines, suggesting that the two are, very likely, kinematically disconnected. The new models and emission-line ratios show that the thermal excitation plays an important role not only in active galactic nuclei but also in star-forming galaxies. The importance of the thermal excitation in star-forming galaxies may be associated with the presence of supernova remnants close to the region emitting H2 lines. This hypothesis is further supported by the similarity between vibrational and rotational temperatures of H2. We confirm that the diagram involving the line ratios H2 2.121 μm/Brγ and Fe ii 1.257 μm/Paβ is an efficient tool for separating emission-line objects according to their dominant types of activities. We suggest new limits to the line ratios in order to discriminate between the different types of nuclear activities.
With a quasar sample designed for studying orientation effects, we investigate the orientation dependence characteristics of the C iv λ1549 broad emission line in approximately 50 Type 1 quasars with ...z = 0.1-1.4. Understanding the role that orientation plays in determining the observed ultraviolet spectra in quasars is of interest both for the insight it gives into the physical emitting regions and for its ramifications for the estimation of fundamental properties. Orientation is measured for the sample via radio core dominance. In our analysis we include measurements of the continuum luminosity and the optical-to-X-ray spectral slope, spectral properties commonly included in the suite known as 'Eigenvector 1', and the full-width at half-maximum, full-width at one-quarter-maximum, shape, blueshift, and equivalent width of the C iv broad emission line. We also investigate a new prescription that we recently developed for predicting the velocity linewidth of the Hβ broad emission line based on the velocity linewidth of the C iv line and the ratio of continuum-subtracted peak fluxes of Si iv+O iv at 1400 Å to C iv. We find that, while it is known that orientation does not drive Eigenvector 1, it does affect some properties included in Eigenvector 1. Specifically, we find marginal orientation dependencies for the equivalent width of C iv and the equivalent width ratio of the optical Fe ii to Oiii λ5007. Although, in the case of the C iv equivalent width, this may actually be due to an orientation dependence of the ultraviolet continuum luminosity which is found to be marginally significant. The full-width at one-quarter-maximum also shows a marginally significant orientation dependence. Notably, the shape and blueshift of C iv and αox do not depend on orientation. In addition to a correlation analysis of the ultraviolet spectral properties and radio core dominance, we provide composite spectra of edge-on and face-on sources for this sample. In particular, we highlight the orientation dependence of the velocity linewidth predicted for Hβ. We find that this predicted linewidth depends on orientation in a manner similar to the true velocity linewidth of Hβ, where no such dependence is observed for C iv. This is an indication that orientation information concerning the line emitting regions can be extracted from ultraviolet spectra.
In 2007, Australia implemented the National human papillomavirus (HPV) Vaccination Program, which provides quadrivalent HPV vaccine free to all women aged 12-26 years. Following notification of 7 ...presumptive cases of anaphylaxis in the state of New South Wales, Australia, we verified cases and compared the incidence of anaphylaxis following HPV vaccination to other vaccines in comparable settings.
We contacted all patients with suspected anaphylaxis and obtained detailed histories from telephone interviews and a review of medical records. A multidisciplinary team determined whether each suspected case met the standardized Brighton definition. Some participants also received skin-prick allergy testing for common antigens and components of the HPV vaccine.
Of 12 suspected cases, 8 were classified as anaphylaxis. Of these, 4 participants had negative skin-prick test results for intradermal Gardasil. From the 269 680 HPV vaccine doses administered in schools, 7 cases of anaphylaxis were identified, which represents an incidence rate of 2.6 per 100 000 doses (95% CI 1.0-5.3 per 100 000). In comparison, the rate of identified anaphylaxis was 0.1 per 100 000 doses (95% CI 0.003-0.7) for conjugated meningococcal C vaccination in a 2003 school-based program.
Based on the number of confirmed cases, the estimated rate of anaphylaxis following quadrivalent HPV vaccine was significantly higher than identified in comparable school-based delivery of other vaccines. However, overall rates were very low and managed appropriately with no serious sequelae.
Black hole masses are estimated for radio-loud quasars using several self-consistent scaling relationships based on emission-line widths and continuum luminosities. The emission lines used, Hβ, Mg ii ...λ2798 and C iv λ1549, have different dependencies on orientation as estimated by radio core dominance. We compare differences in the log of black hole masses estimated from different emission lines and show that they depend on radio core dominance in the sense that core-dominated, jet-on objects have systematically smaller Hβ and Mg ii determined masses compared to those from C iv, while lobe-dominated edge-on objects have systematically larger Hβ and Mg ii determined masses compared to those from C iv. The effect is consistent with the Hβ line width, and to a lesser extent that of Mg ii, being dependent upon orientation in the sense of an axisymmetric velocity field plus a projection effect. The size of the effect is nearly an order of magnitude in black hole mass going from one extreme orientation to the other. We find that radio spectral index is a good proxy for radio core dominance and repeating this analysis with radio spectral index yields similar results. Accounting for orientation could in principle significantly reduce the scatter in black hole mass scaling relationships, and we quantify and offer a correction for this effect cast in terms of radio core dominance and radio spectral index.
We have investigated a sample of 5088 quasars from the SDSS DR2 in order to determine how the frequency and properties of BALs depend on black hole mass, bolometric luminosity, Eddington fraction ...(L/L sub(Edd)), and spectral slope. We focus only on high-ionization BALs and find a number of significant results. While quasars accreting near the Eddington limit are more likely to show BALs than lower L/L sub(Edd) systems, BALs are present in quasars accreting at only a few percent Eddington. We find a stronger effect with bolometric luminosity, such that the most luminous quasars are more likely to show BALs. There is an additional effect, previously known, that BAL quasars are redder on average than unabsorbed quasars. The strongest effects involving the quasar physical properties and BAL properties are related to terminal outflow velocity. Maximum observed outflow velocities increase with both the bolometric luminosity and the blueness of the spectral slope, suggesting that the ultraviolet luminosity to a great extent determines the acceleration. These results support the idea of outflow acceleration via ultraviolet line scattering.
We investigate the orientation dependence of the spectral energy distributions in a sample of radio-loud quasars. Selected specifically to study orientation issues, the sample contains 52 sources ...with redshifts in the range 0.16 < z < 1.4 and measurements of radio core dominance, a radio orientation indicator. Measured properties include monochromatic luminosities at a range of wavelengths between the infrared and X-rays, integrated infrared luminosity, spectral slopes and the covering fraction of the obscuring circumnuclear dust. We estimate dust covering fraction assuming that the accretion disc emits anisotropically and discuss the shortcomings and technical difficulties of this calculation. Luminosities are found to depend on orientation, with face-on sources factors of a 2-3 brighter than more edge-on sources, depending on wavelength. The degree of anisotropy varies very little with wavelength such that the overall shape of the spectral energy distribution does not vary significantly with orientation. In the infrared, we do not observe a decrease in anisotropy with increasing wavelength. The spectral slopes and estimates of covering fraction are not significantly orientation dependent. We construct composite spectral energy distributions as a function of radio core dominance and find that these illustrate the results determined from the measured properties.
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