Top-left: velocity map of the same model (inclination 60°, orientation 0°). Then for the simulated rotation a rigid body is assumed, and a velocity around 90% of the critical velocity of the star. Top-right: simulated intensity map in the continuum assuming von Zeipel gravity and limb-darkening effects where the poles are brighter than at the equator. Center-left: corresponding 2D map of the visibility modulus, where the four interferometric baselines cited above are represented by circles: ([ 75 m,45° ] in red circle, [ 150 m,45° ] in green circle, [ 75 m,90° ] in blue circle and [ 150 m,90° ] in magenta circle). Center-right: same as for the 2D map of the visibility phase. ([ 75 m,45° ] in red circle, [ 150 m,45° ] in green circle, [ 75 m,90° ] in blue circle and [ 150 m,90° ] in magenta circle). Bottom-left: monochromatic intensity map for a given Doppler shift across the Brackett spectral line. Bottom-right: top: photo-center along the Z axis. (Z axis represents the declination and Y axis the right ascension.) Middle: photo-center along Y (the photo-centers are in radians). Bottom: normalized spectrum with the Brackett γ rotationally broadened line.