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tokens: magenta boxes in Figure 3 ). In particular, S3 has a best-fit temperature similar to that of the gas within the interface and is in pressure equilibrium with the external gas. We note that the temperature gradient to the east is much smoother than that in the west (Figure 7 ). This difference may be due to more evident KHI to the east, which may have disrupted a previously existing cold front. KHI accelerates the turbulent mixing of gas of different phases, as we expect from theory and simulations (ZuHone et al. 2011 ; Roediger et al. 2015a , 2015b ). Large KHI rolls (above certain wavelengths, l max ) are expected to be suppressed by gravity (Chandrasekhar 1961 ). We do not expect to observe KHI rolls larger thanwhere U is the shear velocity at the front and g is the gravitational acceleration (Roediger et al. 2012b ). We assume ρ c = 1.5 ρ h and U ( r ) = 0.3 c s ( r ); c s and g ( r ) were calculated from the best-fit deprojected temperature profile and the X-ray hydrostatic mass profile (Paper 1 ). We present the maximum KHI length scale as a function of radius at the cluster center in Figure 10 . The size of these features stays below this upper limit. A potential ghost bubble of ≳5 kpc diameter resides at r = 13 kpc ( r = 10 kpc in projection) to the northwest (Figure 2 , see Paper 1 for details). Interestingly, Walker et al. ( 2017 ) propose that such giant X-ray surface brightness decrement may be due to KHI instead of AGN bubbles. The position and size of this ghost bubble candidate are also in the allowed parameter space for a giant KHI roll. Figure 10. Maximum wavelength for KHI rolls as a function of radius in NGC 1399 (black solid line). Gravity suppresses KHI above this length scale. Blue, green, magenta, and red circles mark the sizes and radii of S1, S2, S3, and a ghost bubble candidate, respectively. Alternatively, S1, S2, and S3 may be thermally unstable X-ray filaments resulting from gas cooling (David et al. 2014 , 2017 ). The growth time of KHI can be estimated from (Roediger et al. 2012a ) We calculate τ KH for the maximum KHI length scale, the maximum growth time, at each radius as shown in Figure 8 . The maximum growth time of KHI is shorter than the cooling time by two orders of magnitude. KHI is thus somewhat favored as their origin. The timescale of KHI is also significantly shorter than the dynamical timescale (free-fall time or buoyant rising time), implying that KHI, coupled with gas sloshing, may have played an important role in regulating the thermal state of the hot plasma at cluster centers. 5. Conclusions The Fornax Cluster is a nearby low-mass cool-core cluster. It displays prominent sloshing structure wrapping around the cluster center. We analyzed a mosaic XMM-Newton observation and a total of 250 ks Chandra observations centered on its BCG NGC 1399. We present the properties of the hot gas over a radial range of 1–250 kpc. We found the following. 1. Four sloshing fronts are visible at radii of 200 kpc,