  Stellar photospheric inhomogeneities are a significant source of noise which
currently precludes the discovery of Earth-mass planets orbiting Sun-like stars
with the radial-velocity (RV) method. To complement several previous studies
which have used ground- and spaced-based facilities to characterize the RV of
the Sun, we here characterize the center-to-limb variability (CLV) of solar RVs
arising from various solar-surface inhomogeneities observed by SDO/HMI and
SDO/AIA. By using various SDO observables to classify pixels and calculate
line-of-sight velocities as a function of pixel classification and limb angle,
we show that each identified feature type, including the umbrae and penumbrae
of sunspots, quiet-Sun magnetoconvective cells, magnetic network, and plage,
exhibit distinct and complex CLV signatures, including a notable limb-angle
dependence in the observed suppression of convective blueshift for magnetically
active regions. We discuss the observed distributions of velocities by
identified region type and limb angle, offer interpretations of the physical
phenomena that shape these distributions, and emphasize the need to understand
the RV signatures of these regions as astrophysical signals, rather than simple
(un)correlated noise processes.
