Broad absorption line quasars are actively accreting supermassive black holes that have strong outflows characterized by broad absorption lines in their rest-UV spectra. Variability in these absorption lines occurs over months to years depending on the source. WPVS 007, a low-redshift, low-luminosity narrow-line Seyfert 1 (NLS1) shows strong variability over shorter timescales, providing a unique opportunity to study the driving mechanism behind this variability that may mimic longer-scale variability in much more massive quasars. We present the first variability study using the spectral synthesis code
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Abstract SimBAL , which provides velocity-resolved changes in physical conditions of the gas using constraints from multiple absorption lines. Overall, we find WPVS 007 to have a highly ionized outflow with a large mass-loss rate and kinetic luminosity. We determine the primary cause of the absorption-line variability in WPVS 007 to be a change in covering fraction of the continuum by the outflow. This study is the firstSimBAL analysis where multiple epochs of observation were fit simultaneously, demonstrating the ability ofSimBAL to use the time domain as an additional constraint in spectral models. -
Abstract The most reliable single-epoch supermassive black hole mass (
M BH) estimates in quasars are obtained by using the velocity widths of low-ionization emission lines, typically the Hβ λ 4861 line. Unfortunately, this line is redshifted out of the optical band atz ≈ 1, leavingM BHestimates to rely on proxy rest-frame ultraviolet (UV) emission lines, such as Civ λ 1549 or Mgii λ 2800, which contain intrinsic challenges when measuring, resulting in uncertainM BHestimates. In this work, we aim at correctingM BHestimates derived from the Civ and Mgii emission lines based on estimates derived from the Hβ emission line. We find that employing the equivalent width of Civ in derivingM BHestimates based on Mgii and Civ provides values that are closest to those obtained from Hβ . We also provide prescriptions to estimateM BHvalues when only Civ , only Mgii , and both Civ and Mgii are measurable. We find that utilizing both emission lines, where available, reduces the scatter of UV-basedM BHestimates by ∼15% when compared to previous studies. Lastly, we discuss the potential of our prescriptions to provide more accurate and precise estimates ofM BHgiven a much larger sample of quasars at 3.20 ≲z ≲ 3.50, where both Mgii and Hβ can be measured in the same near-infrared spectrum. -
Abstract We present the first systematic study of 50 low-redshift (0.66 <
z < 1.63) iron low-ionization broad absorption-line quasars (FeLoBALQs) usingSimBAL , which represents a more than five-fold increase in the number of FeLoBALQs with detailed absorption line spectral analyses. We found the outflows have a wide range of ionization parameters, and densities, . The objects in our sample showed FeLoBAL gas located at a wide range of distances [pc], although we do not find any evidence for disk winds (withR ≪ 0.01 pc) in our sample. The outflow strength primarily depends on the outflow velocity with faster outflows found in quasars that are luminous or that have flat or redder spectral energy distributions. We found that ∼18% of the FeLoBALQs in the sample have the significantly powerful outflows needed for quasar feedback. Eight objects showedoverlapping troughs in the spectra, and we identified elevenloitering outflow objects, a new class of FeLoBALQs that are characterized by low outflow velocities and high column density winds located [pc] from the central engine. The FeLoBALs in loitering outflows objects do not show properties expected for radiatively driven winds, and these objects may represent a distinct population among FeLoBALQs. We discuss how the potential acceleration mechanisms and the origins of the FeLoBAL winds may differ for outflows at different locations in quasars. -
Abstract We present continued analysis of a sample of low-redshift iron low-ionization broad-absorption-line quasars (FeLoBALQs). Choi et al. presented
SimBAL spectral analysis of broad-absorption-line (BAL) outflows in 50 objects. Leighly et al. analyzed the optical emission lines of 30 of those 50 objects and found that they are characterized by either a high accretion rate (L Bol/L Edd> 0.3) or low accretion rate (0.03 <L Bol/L Edd< 0.3). We report that the outflow velocity is inversely correlated with the BAL location among the high-accretion-rate objects, with the highest velocities observed in parsec-scale outflows. In contrast, the low-Eddington-ratio objects showed the opposite trend. We confirmed the known relationship between the outflow velocity andL Bol/L Eddand found that the scatter plausibly originates in the force multiplier (launch radius) in the low(high)-accretion-rate objects. A log volume filling factor between −6 and −4 was found in most outflows but was as high as −1 for low-velocity compact outflows. We investigated the relationship between the observed [Oiii ] emission and that predicted from the BAL gas. We found that these could be reconciled if the emission-line covering fraction depends on the Seyfert type and BAL location. The difference between the predicted and observed [Oiii ] luminosity is correlated with the outflow velocity, suggesting that [Oiii ] emission in high-Eddington-ratio objects may be broad and hidden under Feii emission. We suggest that the physical differences in the outflow properties as a function of location in the quasar and accretion rate point to different formation, acceleration, and confinement mechanisms for the two FeLoBALQ types. -
Abstract Quasars at
z ≳ 1 most often have redshifts measured from rest-frame ultraviolet emission lines. One of the most common such lines, Civ λ 1549, shows blueshifts up to ≈5000 km s−1and in rare cases even higher. This blueshifting results in highly uncertain redshifts when compared to redshift determinations from rest-frame optical emission lines, e.g., from the narrow [Oiii ]λ 5007 feature. We present spectroscopic measurements for 260 sources at 1.55 ≲z ≲ 3.50 having −28.0 ≲M i ≲ − 30.0 mag from the Gemini Near Infrared Spectrograph–Distant Quasar Survey (GNIRS-DQS) catalog, augmenting the previous iteration, which contained 226 of the 260 sources whose measurements are improved upon in this work. We obtain reliable systemic redshifts based on [Oiii ]λ 5007 for a subset of 121 sources, which we use to calibrate prescriptions for correcting UV-based redshifts. These prescriptions are based on a regression analysis involving Civ full-width-at-half-maximum intensity and equivalent width, along with the UV continuum luminosity at a rest-frame wavelength of 1350 Å. Applying these corrections can improve the accuracy and the precision in the Civ -based redshift by up to ∼850 km s−1and ∼150 km s−1, respectively, which correspond to ∼8.5 and ∼1.5 Mpc in comoving distance atz = 2.5. Our prescriptions also improve the accuracy of the best available multifeature redshift determination algorithm by ∼100 km s−1, indicating that the spectroscopic properties of the Civ emission line can provide robust redshift estimates for high-redshift quasars. We discuss the prospects of our prescriptions for cosmological and quasar studies utilizing upcoming large spectroscopic surveys. -
Abstract We report the results of an analysis of the H
β emission line region of a sample of 30 low-redshift (z < 1) iron low-ionization broad absorption line quasars (FeLoBALQs). Eleven of these objects are newly classified as FeLoBALQs. A matched sample of 132 unabsorbed quasars was analyzed in parallel. The emission lines showed the well-known anticorrelation between the [Oiii ] and Feii emission. Using a summary statistic calledE 1 to quantify this anticorrelation, we found that while the distribution ofE 1 for the unabsorbed quasars has a single peak, the FeLoBALQs have a bimodal shape in this parameter. Previous studies have shown that the line emission properties of BAL and non-BALQs are consistent; therefore, the difference in the Hβ region emission between FeLoBALQs and unabsorbed quasars is a new result. The two populations of FeLoBALQs are characterized by low and high bolometric luminosities and Eddington ratios. Some previous studies have suggested that BALQs are high accretion rate objects and therefore the discovery of the low accretion rate branch of FeLoBAL quasars was unexpected. We also found that the Hβ FWHM is systematically broader among the FeLoBALQs, implying a higher inclination viewing angle or a dearth of low velocity line emitting gas. -
Abstract Weak emission-line quasars (WLQs) are a subset of type 1 quasars that exhibit extremely weak Ly
α + Nv λ 1240 and/or Civ λ 1549 emission lines. We investigate the relationship between emission-line properties and accretion rate for a sample of 230 “ordinary” type 1 quasars and 18 WLQs atz < 0.5 and 1.5 <z < 3.5 that have rest-frame ultraviolet and optical spectral measurements. We apply a correction to the Hβ -based black hole mass (M BH) estimates of these quasars using the strength of the optical Feii emission. We confirm previous findings that WLQs’M BHvalues are overestimated by up to an order of magnitude using the traditional broad-emission-line region size–luminosity relation. With thisM BHcorrection, we find a significant correlation between Hβ -based Eddington luminosity ratios and a combination of the rest-frame Civ equivalent width and Civ blueshift with respect to the systemic redshift. This correlation holds for both ordinary quasars and WLQs, which suggests that the two-dimensional Civ parameter space can serve as an indicator of accretion rate in all type 1 quasars across a wide range of spectral properties. -
Abstract We examine the UV/X-ray properties of 1378 quasars in order to link empirical correlations to theoretical models of the physical mechanisms dominating quasars as a function of mass and accretion rate. The clarity of these correlations is improved when (1) using C
iv broad emission line equivalent width (EQW) and blueshift (relative to systemic) values calculated from high signal-to-noise ratio reconstructions of optical/UV spectra and (2) removing quasars expected to be absorbed based on their UV/X-ray spectral slopes. In addition to using the traditional Civ parameter space measures of Civ EQW and blueshift, we define a “Civ ∥ distance” along a best-fit polynomial curve that incorporates information from both Civ parameters. We find that the Civ ∥ distance is linearly correlated with both the optical-to-X-ray slope,α ox, and broad-line Heii EQW, which are known spectral energy distribution indicators, but does not require X-ray or high spectral resolution UV observations to compute. The Civ ∥ distance may be a better indicator of the mass-weighted accretion rate, parameterized byL /L Edd, than the Civ EQW or blueshift alone, as those relationships are known to break down at the extrema. Conversely, there is only a weak correlation with the X-ray energy index (Γ), an alternateL /L Eddindicator. We find no X-ray or optical trends in the direction perpendicular to the Civ distance that could be used to reveal differences in accretion disk, wind, or corona structure that could be widening the Civ EQW–blueshift distribution. A different parameter (such as metallicity) not traced by these data must come into play.