A Super-Eddington, Lensing-magnified Quasar at z = 5.07 Observed with JWST

Abstract We present JWST/NIRCam F070W and F480M imaging for a quasar at z = 5.07, J0025–0145, which is magnified by a foreground lensing galaxy. Existing Hubble Space Telescope (HST) imaging does not have sufficient spatial resolution to determine whether the background quasar is multiply imaged. Exploiting the sharp point-spread function (PSF) of the F070W band, we confirm that the background quasar can be well described by a single PSF, essentially ruling out the existence of multiple lensed images. We do not detect the quasar host galaxy in either the F070W or the F480M band. Using the HST and JWST photometry, we fit the spectral energy distribution of the foreground galaxy. The estimated mass ( log ( M * / M ⊙ ) = 11.15 ± 0.16 ) and redshift ( z phot = 3.6 2 − 0.04 + 0.06 ) of the foreground galaxy are consistent with a single-image lensing model. We estimate the maximum possible magnification of the quasar to be μ max = 3.2, which implies that the intrinsic Eddington ratio of the quasar is at least λ Edd intrinsic > 4.9 . Therefore, J0025–0145 has one of the highest Eddington ratios among z > 5 supermassive black holes known so far, suggesting the viability of super-Eddington growth for supermassive black holes in the early Universe.