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Sparse aperture masking interferometry (SAM) is a high resolution observingtechnique that allows for imaging at and beyond a telescope's diffractionlimit. The technique is ideal for searching for stellar companions at smallseparations from their host star; however, previous analysis of SAMobservations of young stars surrounded by dusty disks have had difficultiesdisentangling planet and extended disk emission. We analyse VLT/SPHERE-IRDISSAM observations of the transition disk LkCa\,15, model the extended diskemission, probe for planets at small separations, and improve contrast limitsfor planets. We fit geometrical models directly to the interferometricobservables and recover previously observed extended disk emission. We usedynamic nested sampling to estimate uncertainties on our model parameters andto calculate evidences to perform model comparison. We compare our extendeddisk emission models against point source models to robustly conclude that thesystem is dominated by extended emission within 50 au. We report detections oftwo previously observed asymmetric rings at $\sim$17 au and $\sim$45 au. Thepeak brightness location of each model ring is consistent with the previousobservations. We also, for the first time with imaging, robustly recover anelliptical Gaussian inner disk, previously inferred via SED fitting. This innerdisk has a FWHM of ~5 au and a similar inclination and orientation as the outerrings. Finally, we recover no clear evidence for candidate planets. Bymodelling the extended disk emission, we are able to place a lower limit on thenear infrared companion contrast of at least 1000.

Two Rings and a Marginally Resolved, 5 AU, Disk Around LkCa 15 Identified Via Near Infrared Sparse Aperture Masking Interferometry