Spectroscopic confirmation of dual and offset quasars from the Subaru HSC-SSP program

Abstract

We present a spectroscopic follow-up program targeting closely-separated dual quasar candidates selected from imaging of SDSS quasars with the Subaru Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP). Using two-dimensional image decomposition, our selection identifies PSF-like companions within 0.6-4 arcsec separation (< 30 kpc) around the SDSS quasar. We newly confirm six broad-line dual quasars and eleven offset quasars (quasar-galaxy pairs), spanning 1.5 < z < 3.3 for the duals and predominantly z < 0.6 for the offset systems. No obvious lensed quasars were discovered from this program. We obtained 99 spectra of these candidates from NTT/EFOSC2, Gemini/GMOS-N, Keck/NIRES, and Subaru/FOCAS. From the spectra, we measure the emission-line properties of these dual black holes (BH). At z > 1.5, the confirmed duals exhibit high black hole mass ($M_{\mathrm{BH}}$ $=10^{8.5}$-$10^{10}{M}_{\odot }$) with high bolometric luminosities ($L_{bol}$ $=10^{45.5}$-$10^{47.5}$ erg s${}^{-1}$), yet accrete at moderate Eddington ratios (${\lambda }_{\mathrm{Edd}}=$0.01-0.4). From the spectroscopically-confirmed samples, we estimate the dual fraction of SDSS quasars with separations of 0.6-4 arcsec to be 0.2%-1.2% at z<0.8, 0.08%-0.24% at 0.8<z<1.5, and 0.06% at 1.5<z<3.3. These values are broadly consistent with other recent optical studies, but lower than theoretical expectations of a rising dual fraction at cosmic noon. However, we note that these fractions, especially at high $z$, still need a more accurate assessment of selection and observation effects.

References in corpus (82)

• Energy input from quasars regulates the growth and activity of black holes and their host galaxies
• Reverberation Measurements for 17 Quasars and the Size-Mass-Luminosity Relations in Active Galactic Nuclei
• A Unified, Merger-Driven Model for the Origin of Starbursts, Quasars, the Cosmic X-Ray Background, Supermassive Black Holes and Galaxy Spheroids
• A Catalog of Quasar Properties from SDSS DR7
• Laser Interferometer Space Antenna
• Determining Central Black Hole Masses in Distant Active Galaxies and Quasars. II. Improved Optical and UV Scaling Relationships
• The Co-Evolution of Galaxies and Supermassive Black Holes: Insights from Surveys of the Contemporary Universe
• Spectral Energy Distributions and Multiwavelength Selection of Type 1 Quasars
• Using Strong Lines to Estimate Abundances in Extragalactic HII Regions and Starburst Galaxies
• Spectroscopic Target Selection in the Sloan Digital Sky Survey: The Quasar Sample
• Revisiting the Unified Model of Active Galactic Nuclei
• Optimal Techniques in Two-dimensional Spectroscopy: Background Subtraction for the 21st Century
• An Empirical Ultraviolet Template for Iron Emission in Quasars as Derived from I Zw 1
• Alternative diagnostic diagrams and the "forgotten" population of weak line galaxies in the SDSS
• How Do Massive Black Holes Get Their Gas?
• The Hyper Suprime-Cam Software Pipeline
• Obscured Active Galactic Nuclei
• The Sloan Digital Sky Survey Quasar Catalog: Fourteenth Data Release
• Galaxy pairs in the Sloan Digital Sky Survey - IV: Interactions trigger AGN
• Major Galaxy Mergers Only Trigger the Most Luminous AGN
• Third Data Release of the Hyper Suprime-Cam Subaru Strategic Program
• Ionization State of Inter-Stellar Medium in Galaxies: Evolution, SFR-M_star-Z Dependence, and Ionizing Photon Escape
• New fully empirical calibrations of strong-line metallicity indicators in star forming galaxies
• Updating quasar bolometric luminosity corrections
• Binary Quasars in the Sloan Digital Sky Survey: Evidence for Excess Clustering on Small Scales
• Active Galactic Nuclei in the Sloan Digital Sky Survey: I. Sample Selection
• Colors of 2625 Quasars at 0<z<5 Measured in the Sloan Digital Sky Survey Photometric System
• The SINS/zC-SINF survey of z~2 galaxy kinematics: SINFONI adaptive optics-assisted data and kiloparsec-scale emission line properties
• Spectral properties of quasars from Sloan Digital Sky Survey data release 14: The catalog
• Growth and activity of black holes in galaxy mergers with varying mass ratios
• The SDSS-IV extended Baryon Oscillation Spectroscopic Survey: Quasar Target Selection
• The WISSH Quasars Project I. Powerful ionised outflows in hyper-luminous quasars
• Correcting CIV-Based Virial Black Hole Masses
• The mass relations between supermassive black holes and their host galaxies at 1<z<2 with HST-WFC3
• The Sloan Digital Sky Survey Reverberation Mapping Project: Sample Characterization
• The evolution of AGN across cosmic time: what is downsizing?
• The impact of galaxy interactions on AGN activity in zCOSMOS
• Observability of Dual Active Galactic Nuclei in Merging Galaxies
• Morphologies of z~0.7 AGN Host Galaxies in CANDELS: No trend of merger incidence with AGN luminosity
• The NANOGrav 15-year Data Set: Bayesian Limits on Gravitational Waves from Individual Supermassive Black Hole Binaries
• The Sloan Digital Sky Survey Quasar Lens Search. V. Final Catalog from the Seventh Data Release
• Binary Quasars at High Redshift I: 24 New Quasar Pairs at z ~ 3-4
• A High-Velocity Narrow Absorption Line Outflow in the Quasar J212329.46-005052.9
• Origin and properties of dual and offset active galactic nuclei in a cosmological simulation at z=2
• CIV Emission Line Properties and Systematic Trends in Quasar Black Hole Mass Estimates
• A survey of dual active galactic nuclei in simulations of galaxy mergers: frequency and properties
• Characterization and Photometric Performance of the Hyper Suprime-Cam Software Pipeline
• The Sloan Digital Sky Survey Quasar Lens Search. II. Statistical Lens Sample from the Third Data Release
• Constraining Sub-Parsec Binary Supermassive Black Holes in Quasars with Multi-Epoch Spectroscopy. III. Candidates from Continued Radial Velocity Tests
• Major mergers are not the dominant trigger for high-accretion AGNs at z = 2
• Occurrence and Global Properties of Narrow CIV lambda 1549 Absorption Lines in Moderate-Redshift Quasars
• Varstrometry for Off-nucleus and Dual sub-Kpc AGN (VODKA): Methodology and Initial Results with Gaia DR2
• The Intrinsic Eddington Ratio Distribution of Active Galactic Nuclei in Star-forming Galaxies from the Sloan Digital Sky Survey
• Varstrometry for Off-nucleus and Dual sub-Kpc AGN (VODKA): Hubble Space Telescope Discovers Double Quasars
• Very small-scale clustering of quasars from a complete quasar lens survey
• Unveiling the population of dual- and lensed- AGNs at sub-arcsec separations
• Gravitational wave sources in the era of multi-frequency gravitational wave astronomy
• Dual supermassive black holes at close separation revealed by the Hyper Suprime-Cam Subaru Strategic Program
• A hidden population of high-redshift double quasars unveiled by astrometry
• The abundances and properties of Dual AGN and their host galaxies in the EAGLE simulations
• Clustering on very small scales from a large sample of confirmed quasar pairs: Does quasar clustering track from Mpc to kpc scales?
• Properties and Evolution of Dual and Offset AGN in the ASTRID Simulation at $z\sim 2$
• GA-NIFS: High number of dual active galactic nuclei at z~3
• A significant excess in major merger rate for AGNs with the highest Eddington ratios at z<0.2
• New lensed quasars from the MUSCLES survey
• New multiple AGN systems with sub-arcsec separation: confirmation of candidates selected via the novel GMP method
• Near-IR spectroscopy of luminous LoBAL quasars at 1<z<2.5
• Statistics of Galactic-Scale Quasar Pairs at Cosmic Noon
• Prior-Informed AGN-Host Spectral Decomposition Using PyQSOFit
• The X-ray view of optically selected dual AGN
• An FMOS Survey of moderate-luminosity broad-line AGN in COSMOS, SXDS and E-CDF-S
• A study of the ionized gas in Stephan's Quintet from integral field spectroscopy observations
• MUSE adaptive-optics spectroscopy confirms dual active galactic nuclei and strongly lensed systems at sub-arcsec separation
• Unsupervised classification of SDSS galaxy spectra
• AGN luminosity and stellar age -- two missing ingredients for AGN unification as seen with iPTF supernovae
• Mass accretion toward black holes in the final phase of galaxy mergers
• Discovery of merging twin quasars at z = 6.05
• The Relation between Morphological Asymmetry and Nuclear Activity in Low-redshift Galaxies
• The MURALES survey. VI. Properties and origin of the extended line emission structures in radio galaxies
• The circum-galactic medium of quasars: CIV absorption systems
• The Cosmic Owl: Twin Active Collisional Ring Galaxies with Starburst Merging Front at $z=1.14$
• Euclid: A machine-learning search for dual and lensed AGN at sub-arcsec separations