Weak emission-line quasars (WLQs) are a subset of type 1 quasars that exhibit extremely weak Ly
The most reliable single-epoch supermassive black hole mass (
- PAR ID:
- 10422167
- Publisher / Repository:
- DOI PREFIX: 10.3847
- Date Published:
- Journal Name:
- The Astrophysical Journal
- Volume:
- 950
- Issue:
- 2
- ISSN:
- 0004-637X
- Format(s):
- Medium: X Size: Article No. 96
- Size(s):
- Article No. 96
- Sponsoring Org:
- National Science Foundation
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Abstract 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. -
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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. -
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We present JWST/NIRSpec integral field data of the quasar PJ308-21 at
z = 6.2342. As shown by previous ALMA and HST imaging, the quasar has two companion sources, interacting with the quasar host galaxy. The high-resolution G395H/290LP NIRSpec spectrum covers the 2.87 − 5.27 μm wavelength range and shows the rest-frame optical emission of the quasar with exquisite quality (signal-to-noise ratio ∼100 − 400 per spectral element). Based on the Hβ line from the broad line region, we obtain an estimate of the black hole massM BH, Hβ ∼ 2.7 × 109M ⊙. This value is within a factor ≲1.5 of the Hα -based black hole mass from the same spectrum (M BH, Hα ∼ 1.93 × 109M ⊙) and is consistent with a previous estimate relying on the MgII λ 2799 line (M BH, MgII ∼ 2.65 × 109M ⊙). All theseM BHestimates are within the ∼0.5 dex intrinsic scatter of the adopted mass calibrations. The high Eddington ratio of PJ308-21λ Edd, Hβ ∼ 0.67 (λ Edd, Hα ∼ 0.96) is in line with the overall quasar population atz ≳ 6. The relative strengths of the [OIII ], FeII , and Hβ lines are consistent with the empirical “Eigenvector 1” correlations as observed for low redshift quasars. We find evidence for blueshifted [OIII ]λ 5007 emission with a velocity offset Δv [O III] = −1922 ± 39 km s−1from the systemic velocity and a full width at half maximum (FWHM)FWHM ([OIII ]) = 2776−74+75km s−1. This may be the signature of outflowing gas from the nuclear region, despite the true values of Δv [O III]andFWHM ([OIII ]) likely being more uncertain due to the blending with Hβ and FeII lines. Our study demonstrates the unique capabilities of NIRSpec in capturing quasar spectra at cosmic dawn and studying their properties in unprecedented detail. -
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Aims. We have estimated black hole masses (M BH) for 14 gravitationally lensed quasars using Balmer lines; we also provide estimates based on MgII and CIV emission lines for four and two of them, respectively. We compared these estimates to results obtained for other lensed quasars.Methods. We used spectroscopic data from the Large Binocular Telescope (LBT),Magellan , and the Very Large Telescope (VLT) to measure the full width at half maximum of the broad emission lines. Combined with the bolometric luminosity measured from the spectral energy distribution, we estimatedM BHvalues and provide the uncertainties, including uncertainties from microlensing and variability.Results. We obtainedM BHvalues using the single-epoch method from the Hα and/or Hβ broad emission lines for 14 lensed quasars, including the first-ever estimates for QJ0158−4325, HE0512−3329, and WFI2026−4536. The masses are typical of non-lensed quasars of similar luminosities, as are the implied Eddington ratios. We have thus increased the sample of lenses withM BHestimates by 60%. -
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Abstract We present the final data from the Sloan Digital Sky Survey (SDSS) Reverberation Mapping (RM) project, a precursor to the SDSS-V Black Hole Mapper RM program. This data set includes 11 yr photometric and 7 yr spectroscopic light curves for 849 broad-line quasars over a redshift range of 0.1 <
z < 4.5 and a luminosity range ofL bol= 1044−47.5erg s−1, along with spectral and variability measurements. We report 23, 81, 125, and 110 RM lags (relative to optical continuum variability) for broad Hα , Hβ , Mgii , and Civ using the SDSS-RM sample, spanning much of the luminosity and redshift ranges of the sample. Using 30 low-redshift RM active galactic nuclei with dynamical-modeling black hole masses, we derive a new estimate of the average virial factor ofR –L relations for Hβ and Mgii at high redshift, consistent with the latest measurements based on heterogeneous samples. While we are unable to robustly constrain the slope of theR –L relation for Civ given the limited dynamic range in luminosity, we found substantially larger scatter in Civ lags at fixedL 1350. Using the SDSS-RM lag sample, we derive improved single-epoch (SE) mass recipes for Hβ , Mgii , and Civ , which are consistent with their respective RM masses as well as between the SE recipes from two different lines, over the luminosity range probed by our sample. The new Hβ and Mgii recipes are approximately unbiased estimators at given RM masses, but there are systematic biases in the Civ recipe. The intrinsic scatter of SE masses around RM masses is ∼0.45 dex for Hβ and Mgii , increasing to ∼0.58 dex for Civ .
