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1. Gemini Near Infrared Spectrograph–Distant Quasar Survey: Prescriptions for Calibrating UV-based Estimates of Supermassive Black Hole Masses in High-redshift Quasars

   https://doi.org/10.3847/1538-4357/acd04b  

   Dix, Cooper; Matthews, Brandon; Shemmer, Ohad; Brotherton, Michael S; Myers, Adam D; Andruchow, I; Brandt, W N; Ferrero, Gabriel A; Green, Richard; Lira, Paulina; et al (June 2023, The Astrophysical Journal)

   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 Hβλ4861 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 Civλ1549 or Mgiiλ2800, which contain intrinsic challenges when measuring, resulting in uncertainM_BHestimates. In this work, we aim at correctingM_BHestimates derived from the Civand Mgiiemission lines based on estimates derived from the Hβemission line. We find that employing the equivalent width of Civin derivingM_BHestimates based on Mgiiand Civprovides values that are closest to those obtained from Hβ. We also provide prescriptions to estimateM_BHvalues when only Civ, only Mgii, and both Civand Mgiiare 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 Mgiiand Hβcan be measured in the same near-infrared spectrum. 

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2. Gemini Near Infrared Spectrograph–Distant Quasar Survey: Augmented Spectroscopic Catalog and a Prescription for Correcting UV-based Quasar Redshifts

   https://doi.org/10.3847/1538-4357/acd04c  

   Matthews, Brandon M; Dix, Cooper; Shemmer, Ohad; Brotherton, Michael S; Myers, Adam D; Andruchow, I; Brandt, W N; Gallagher, S C; Green, Richard; Lira, Paulina; et al (June 2023, The Astrophysical Journal)

   Abstract Quasars atz≳ 1 most often have redshifts measured from rest-frame ultraviolet emission lines. One of the most common such lines, Civλ1549, 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]λ5007 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]λ5007 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 Civfull-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 Civemission 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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3. A quasar-galaxy merger at z ∼ 6.2: Black hole mass and quasar properties from the NIRSpec spectrum

   https://doi.org/10.1051/0004-6361/202348535  

   Loiacono, Federica; Decarli, Roberto; Mignoli, Marco; Farina, Emanuele Paolo; Bañados, Eduardo; Bosman, Sarah; Eilers, Anna-Christina; Schindler, Jan-Torge; Strauss, Michael A; Vestergaard, Marianne; et al (May 2024, Astronomy & Astrophysics)

   We present JWST/NIRSpec integral field data of the quasar PJ308-21 atz = 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 Hβline from the broad line region, we obtain an estimate of the black hole massM_BH, Hβ ∼ 2.7 × 10⁹ M_⊙. This value is within a factor ≲1.5 of the Hα-based black hole mass from the same spectrum (M_BH, Hα ∼ 1.93 × 10⁹ M_⊙) and is consistent with a previous estimate relying on the Mg IIλ2799 line (M_BH, MgII ∼ 2.65 × 10⁹ M_⊙). 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 [O III], Fe II, and Hβlines are consistent with the empirical “Eigenvector 1” correlations as observed for low redshift quasars. We find evidence for blueshifted [O III]λ5007 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([O III]) = 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([O III]) likely being more uncertain due to the blending with Hβand Fe IIlines. 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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4. Balmer Absorption in Iron Low-ionization Broad Absorption Line Quasars

   https://doi.org/10.3847/1538-4357/ae04df  

   Leighly, Karen M; Gallagher, Sarah C; Choi_최, Hyunseop 현섭; Terndrup, Donald M; Voelker, Julianna R; Richards, Gordon T; Morabito, Leah K (October 2025, The Astrophysical Journal)

   Abstract While Civis the most common absorption line in broad absorption line quasar spectra, Balmer absorption lines (BALs) are among the rarest. We present analysis of Balmer absorption in a sample of 14 iron low-ionization BAL quasars (FeLoBALQs); eight are new identifications. We measured velocity offset, width, and apparent optical depth. The partial covering that is ubiquitous in BAL quasar spectra alters the measured Balmer optical depth ratios; accounting for this, we estimated the true H(n= 2) column density. We found the anticipated correlation between Eddington ratio and outflow speed, but it is weak in this sample because nearly all of the objects have the low outflow speeds characterizing loitering outflow FeLoBAL quasars, objects that are also found to have low accretion rates. Measurements ofdN/dv, the differential column density with respect to the outflow speed, are anticorrelated with the luminosity and Eddington ratio: the strongest absorption is observed at the lowest speeds in the lowest-luminosity objects. The absorption line width is correlated withα_oi, theF_λpoint-to-point slope between 5100 Å and 3μm. This parameter is strongly correlated with the Eddington ratio among low-redshift quasars. BALs have been recently found in the spectra of little red dots (LRDs), a class of high-redshift objects discovered by JWST. We note suggestive similarities between LRDs and FeLoBAL quasars in the emission-line shape, the presence of steep reddening and a scattered blue continuum, the lack of hot dust emission, and X-ray weakness. 

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5. A SPectroscopic Survey of Biased Halos in the Reionization Era (ASPIRE): A First Look at the Rest-frame Optical Spectra of z > 6.5 Quasars Using JWST

   https://doi.org/10.3847/2041-8213/acc9c8  

   Yang, Jinyi; Wang, Feige; Fan, Xiaohui; Hennawi, Joseph F.; Barth, Aaron J.; Bañados, Eduardo; Sun, Fengwu; Liu, Weizhe; Cai, Zheng; Jiang, Linhua; et al (June 2023, The Astrophysical Journal Letters)

   Abstract Studies of rest-frame optical emission in quasars at z > 6 have historically been limited by the wavelengths accessible by ground-based telescopes. The James Webb Space Telescope (JWST) now offers the opportunity to probe this emission deep into the reionization epoch. We report the observations of eight quasars at z > 6.5 using the JWST/NIRCam Wide Field Slitless Spectroscopy as a part of the “A SPectroscopic survey of biased halos In the Reionization Era (ASPIRE)” program. Our JWST spectra cover the quasars’ emission between rest frame ∼4100 and 5100 Å. The profiles of these quasars’ broad H β emission lines span a full width at half maximum from 3000 to 6000 km s −1 . The H β -based virial black hole (BH) masses, ranging from 0.6 to 2.1 billion solar masses, are generally consistent with their Mg ii -based BH masses. The new measurements based on the more reliable H β tracer thus confirm the existence of a billion solar-mass BHs in the reionization epoch. In the observed [O iii ] λ λ 4960,5008 doublets of these luminous quasars, broad components are more common than narrow core components (≤ 1200 km s −1 ), and only one quasar shows stronger narrow components than broad. Two quasars exhibit significantly broad and blueshifted [O iii ] emission, thought to trace galactic-scale outflows, with median velocities of −610 and −1430 km s −1 relative to the [C ii ] 158 μ m line. All eight quasars show strong optical Fe ii emission and follow the eigenvector 1 relations defined by low-redshift quasars. The entire ASPIRE program will eventually cover 25 quasars and provide a statistical sample for the studies of the BHs and quasar spectral properties. 

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