- Is there a small, radial gradient of stellar redshifts in individual galaxies, with bluer light coming from the center, and redder light from stars in the galaxy periphery?
The summary says it all. Such small gradients, if they exist, would be visible in the Milky Way and local galaxies in our cluster. I'm not familiar enough with the raw data--and haven't tried to search the astronomical literature--to know whether any such small effect has been reported. (If such effects were large, I'm sure I'd have already heard about them, as they'd be discussed actively. Tiny effects, however, might be ascribed to gravitational red/blueshifts, star temperature differences, or other unknown causes, and not widely known.)