A Microlensing Accretion Disk Size Measurement in the Lensed Quasar WFI 2026-4536 [HEAP]

http://arxiv.org/abs/1911.06218


We use thirteen seasons of R-band photometry from the 1.2m Leonard Euler Swiss Telescope at La Silla to examine microlensing variability in the quadruply-imaged lensed quasar WFI 2026-4536. The lightcurves exhibit ${\sim}\,0.2\,\text{mag}$ of uncorrelated variability across all epochs and a prominent single feature of ${\sim}\,0.1\,\text{mag}$ within a single season. We analyze this variability to constrain the size of the quasar’s accretion disk. Adopting a nominal inclination of 60$^\text{o}$, we find an accretion disk scale radius of $\log(r_s/\text{cm}) = 15.74^{+0.34}{-0.29}$ at a rest-frame wavelength of $2043\,\unicode{xC5}$, and we estimate a black hole mass of $\log(M{\text{BH}}/M_{\odot}) = 9.18^{+0.39}_{-0.34}$, based on the CIV line in VLT spectra. This size measurement is fully consistent with the Quasar Accretion Disk Size – Black Hole Mass relation, providing another system in which the accretion disk is larger than predicted by thin disk theory.

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M. Cornachione, C. Morgan, M. Millon, et. al.
Fri, 15 Nov 19
31/73

Comments: 26 pages, 8 figures, Appendix with data table, pg 12-25