Revisiting the Lensed Fraction of High-Redshift Quasars

Abstract

The observed lensed fraction of high-redshift quasars $(\sim 0.2\%)$ is significantly lower than previous theoretical predictions $(\gtrsim 4\%)$. We revisit the lensed fraction of high-redshift quasars predicted by theoretical models, where we adopt recent measurements of galaxy velocity dispersion functions (VDFs) and explore a wide range of quasar luminosity function (QLF) parameters. We use both analytical methods and mock catalogs which give consistent results. For ordinary QLF parameters and the depth of current high-redshift quasar surveys $(m_z\lesssim 22)$, our model suggests a multiply-imaged fraction of $F_{\text{multi}}\sim 0.4\%-0.8\%$. The predicted lensed fraction is $\sim 1\%-6\%$ for the brightest $z_s\sim 6$ quasars $(m_z\lesssim 19)$, depending on the QLF. The systematic uncertainties of the predicted lensed fraction in previous models can be as large as $2-4$ times and are dominated by the VDF. Applying VDFs from recent measurements decreases the predicted lensed fraction and relieves the tension between observations and theoretical models. Given the depth of current imaging surveys, there are $\sim 15$ lensed quasars at $z_s>5.5$ detectable over the sky. Upcoming sky surveys like the LSST survey and the {\em Euclid} survey will find several tens of lensed quasars at this redshift range.

10 pages, 6 figures. Accepted by ApJ

References in corpus (8)

• A Luminous Quasar at Redshift 7.642
• Pōniuā'ena: A Luminous $z=7.5$ Quasar Hosting a 1.5 Billion Solar Mass Black Hole
• The Final SDSS High-Redshift Quasar Sample of 52 Quasars at z>5.7
• The UKIRT Hemisphere Survey: Definition and J-band Data Release
• Strong lensing optical depths in a LCDM universe II: the influence of the stellar mass in galaxies
• Correcting the z~8 Galaxy Luminosity Function for Gravitational Lensing Magnification Bias
• The Impact of Strong Gravitational Lensing on Observed Lyman-Break Galaxy Numbers at 4<z<8 in the GOODS and the XDF Blank Fields
• The velocity dispersion function of early-type galaxies and its redshift evolution: the newest results from lens redshift test

Cited by in corpus (18)

• EIGER III. JWST/NIRCam observations of the ultra-luminous high-redshift quasar J0100+2802
• The Pan-STARRS1 $\mathbf{z}>5.6$ Quasar Survey: III. The $\mathbf{z}\approx 6$ Quasar Luminosity Function
• Gravitational Lensing by Black Holes with Multiple Photon Spheres
• Stellar prospects for FRB gravitational lensing
• A Survey for High-redshift Gravitationally Lensed Quasars and Close Quasars Pairs. I. the Discoveries of an Intermediately-lensed Quasar and a Kpc-scale Quasar Pair at $z\sim 5$
• A Mock Catalog of Gravitationally Lensed Quasars for the LSST Survey
• The accretion of a solar mass per day by a 17-billion solar mass black hole
• Streamlined Lensed Quasar Identification in Multiband Images via Ensemble Networks
• Discovering strongly lensed quasar candidates with catalogue-based methods from DESI Legacy Surveys
• Observable Signatures of RN Black Holes with Dark Matter Halos via Strong Gravitational Lensing and Constraints from EHT Observations
• When Spectral Modeling Meets Convolutional Networks: A Method for Discovering Reionization-era Lensed Quasars in Multi-band Imaging Data
• Combining strongly lensed and unlensed fast radio bursts: To be a more precise late-universe probe
• Forecast of strongly lensed supernovae rates in the China Space Station Telescope surveys
• Detecting and Characterizing Young Quasars. III. The Impact of Gravitational Lensing Magnification
• The Effect of Gravitational Lensing on Fast Transient Event Rates
• Strong gravitational lensing with upcoming wide-field radio surveys
• Lensing in the Darkness: A Bayesian Analysis of 22 Chandra Sources at $z\gtrsim 6$ Shows No Evidence of Lensing
• A Super-Eddington, Lensing-Magnified Quasar at $z=5.07$ observed with JWST