As part of a collaborative research programme between the gravitational lensing groups at the UC, United States Naval Academy (USNA) and other institutions, we have measured the central black hole mass of the doubly-imaged quasar SDSS J1339+1310 using GTC and VLT spectroscopic data. We infer Log(M/solar mass) = 8.6+0.4−0.4 from the widths of the Civ, Mgii, and Hbeta emission lines, and the continuum luminosities at 1350, 3000, and 5100 Å (see figure below). In addition, the 2009-2019 LT light curves in the r band showed significant microlensing variations that allowed us to constrain the half-light radius of the 1930 Å continuum-emitting region. Hot gas responsible for this continuum emission is likely orbiting a black hole of four hundred million solar masses at a half-light radius of only a few tens of Schwarzschild radii.
Paper: Resolving the inner accretion flow towards the central supermassive black hole in SDSS J1339+1310 by V. N. Shalyapin, L. J. Goicoechea, C. W. Morgan, M. A. Cornachione, A. V. Sergeyev [A&A 646, A165 (2021)]
Updated optical-NIR light curves of the gravitationally lensed quasars Q0957+561 and SBS0909+532 also display prominent microlensing features. Using a Bayesian Monte Carlo technique developed at the USNA, these features were analysed to constrain the quasar continuum emission region sizes in the g, r, and H passbands. We report sizes as half-light radii scaled to a 60° inclination angle. For Q0957+561 we measure Log(R1/2 /cm) = 16.54+0.33−0.33 , 16.66+0.37−0.62 , and 17.37+0.49−0.40 in the g, r, and H bands, respectively. For SBS0909+532 we measure Log(R1/2 / cm) = 15.83+0.33−0.33 , 16.21+0.37−0.62 , and 17.90+0.61−0.63 in the g, r, and H band respectively. With size measurements in three bands spanning the quasar rest frame UV to optical, we can place constraints on the scaling of accretion disc size with wavelength, Rλ ∝ λa . In a joint analysis of both systems we find a slope shallower than that predicted by thin-disc standard theory, a = 2.86+0.84−0.90 (astd = 1.33).
Paper: Near-infrared and Optical Continuum Emission Region Size Measurements in the Gravitationally lensed Quasars Q0957+561 and SBS0909+532 by M. A. Cornachione, C. W. Morgan, H. R. Burger, V. N. Shalyapin, L. J. Goicoechea, F. J. Vrba, S. E. Dahm, T. M. Tilleman [ApJ 905, A7 (2020)]